Fatal crash Arizona [Archive]

Renny[_2_]

May 6th 14, 02:38 PM

In doing some research last night I sadly came upon another fatal glider accident that also happened at Aguila, AZ. This occurred 8 years ago to the day in 2006. The NTSB report is at this URL:

http://www.ntsb.gov/aviationquery/brief.aspx?ev_id=20060510X00545&key=1

In a strange twist of fate this accident also occurred on May 3 and it also happened during the early portion of the launch when the glider reached approx 150 feet on tow.

Let's all hope that important lessons are learned and that everyone can be more aware and better prepared in case of a problem early in a launch.

Thx - Renny

On Monday, May 5, 2014 11:07:50 PM UTC-6, wrote:
> On Monday, May 5, 2014 8:17:31 PM UTC-7, kirk.stant wrote:
>
> > On Monday, May 5, 2014 1:38:32 PM UTC-7, Mike the Strike wrote:
>
> >
>
> > > I have flown into and out of Sampley's a few times. The terrain at Sampley's rises to the east and falls to the west. Heading west, you are over slightly falling terrain with open fields for landing. On an easterly departure, you may be at an indicated 200 feet above take-off but may only be 100' over terrain. Straight-ahead landing options are not very enticing to the east once you've passed the end of the strip, so a turn back from an indicated 200' may seem like the best option.
>
> >
>
> >
>
>
>
>
>
> >
>
> > Minor correction: Sampley runs North-South, with takeoffs invariably uphill to the South. South gets slowly higher until some hills (all raw desert), North gently slopes down to the center of the valley (mostly agricultural fields - all landable).
>
> >
>
> >
>
> >
>
> > Not too many good options if PTT is really low taking off to the South; you pretty much have to either get back to the runway or accept a desert landing.
>
> >
>
> >
>
> >
>
> > Sad.
>
> >
>
> >
>
> >
>
> > Kirk
>
> >
>
> > 66
>
>
>
> I took off about 15 minutes ahead of Bob (was 1st in line and he was 3rd).. There were the usual bumpy spots (up and down gusts) in the first 50 or so feet AGL and then the usual booming lift at the end of the runway. As we got to the end of the runway we were lower than I had experienced previously there, and I have probably 10 years of flying from there. The tow plane was running fine, it just seemed like we towed through some bumpy sinking air til the big boomer at the runway end.
>
>
>
> One of the pilots made the comment Saturday evening that the release on a Zuni could "self release / back release" without pilot input.... it was not a Tost, and required the big ring. If that is correct, the bumpy air down low could have caused yo-yo effect and an inadverdant release. That would have probably put Bob in the sinking air around the big lift at the end of the runway about the time of release To me, the only options would have been straight ahead, either hopefully on what was left of the runway or into the bushes past the end. Other than "south of Cliff's hanger" I don't know how far down the runway he was when he crashed / how much, if any runway was left in front of him. Wind on the ground at the north end of the runway, where we were staged was 5-15 mph SSW.
>
>
>
> Whenever I take off I constantly calculate where I would have to go if the rope were to break, and, as I was lower than usual that day, I was looking at that. A damaged or totaled glider is still better than taking a chance on a stall-spin. My count to 200 ft. AGL) lasted until we had been in the boomer past the runway end for a few seconds. If Bob had been in exactly the same air, any release before the runway end, he would have been under 100'AGL.
>
>
>
> I enjoyed my conversations with Bob before we gridded, and thinking of him now gives me an erie feeling. Such a nice guy, happy with gliding, and willing and eager to learn more about desert flying. But, in the end, what can be said other than it was just his time to go. Yes, gliding is dangerous. I've been into soaring since 1996 and he was the 7th I've known to be called to the other side.
>
>
>
> We try to learn from others' mistakes, but in this case, as there were no glider pilots who observed the event, little can be learned.
>
>
>
> My heart goes out to his family and friends.
>
>
>
> Bob T

[email protected]

May 6th 14, 05:04 PM

On Tuesday, May 6, 2014 6:38:20 AM UTC-7, Renny wrote:
> In doing some research last night I sadly came upon another fatal glider accident that also happened at Aguila, AZ. This occurred 8 years ago to the day in 2006. The NTSB report is at this URL:
>
>
>
> http://www.ntsb.gov/aviationquery/brief.aspx?ev_id=20060510X00545&key=1
>
>
>
> In a strange twist of fate this accident also occurred on May 3 and it also happened during the early portion of the launch when the glider reached approx 150 feet on tow.
>
>
>
> Let's all hope that important lessons are learned and that everyone can be more aware and better prepared in case of a problem early in a launch.
>
>
>
> Thx - Renny
>
>
>
>
>
>
>
> On Monday, May 5, 2014 11:07:50 PM UTC-6, wrote:
>
> > On Monday, May 5, 2014 8:17:31 PM UTC-7, kirk.stant wrote:
>
> >
>
> > > On Monday, May 5, 2014 1:38:32 PM UTC-7, Mike the Strike wrote:
>
> >
>
> > >
>
> >
>
> > > > I have flown into and out of Sampley's a few times. The terrain at Sampley's rises to the east and falls to the west. Heading west, you are over slightly falling terrain with open fields for landing. On an easterly departure, you may be at an indicated 200 feet above take-off but may only be 100' over terrain. Straight-ahead landing options are not very enticing to the east once you've passed the end of the strip, so a turn back from an indicated 200' may seem like the best option.
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> >
>
> >
>
> >
>
> >
>
> > >
>
> >
>
> > > Minor correction: Sampley runs North-South, with takeoffs invariably uphill to the South. South gets slowly higher until some hills (all raw desert), North gently slopes down to the center of the valley (mostly agricultural fields - all landable).
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > > Not too many good options if PTT is really low taking off to the South; you pretty much have to either get back to the runway or accept a desert landing.
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > > Sad.
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > > Kirk
>
> >
>
> > >
>
> >
>
> > > 66
>
> >
>
> >
>
> >
>
> > I took off about 15 minutes ahead of Bob (was 1st in line and he was 3rd). There were the usual bumpy spots (up and down gusts) in the first 50 or so feet AGL and then the usual booming lift at the end of the runway. As we got to the end of the runway we were lower than I had experienced previously there, and I have probably 10 years of flying from there. The tow plane was running fine, it just seemed like we towed through some bumpy sinking air til the big boomer at the runway end.
>
> >
>
> >
>
> >
>
> > One of the pilots made the comment Saturday evening that the release on a Zuni could "self release / back release" without pilot input.... it was not a Tost, and required the big ring. If that is correct, the bumpy air down low could have caused yo-yo effect and an inadverdant release. That would have probably put Bob in the sinking air around the big lift at the end of the runway about the time of release To me, the only options would have been straight ahead, either hopefully on what was left of the runway or into the bushes past the end. Other than "south of Cliff's hanger" I don't know how far down the runway he was when he crashed / how much, if any runway was left in front of him. Wind on the ground at the north end of the runway, where we were staged was 5-15 mph SSW.
>
> >
>
> >
>
> >
>
> > Whenever I take off I constantly calculate where I would have to go if the rope were to break, and, as I was lower than usual that day, I was looking at that. A damaged or totaled glider is still better than taking a chance on a stall-spin. My count to 200 ft. AGL) lasted until we had been in the boomer past the runway end for a few seconds. If Bob had been in exactly the same air, any release before the runway end, he would have been under 100'AGL.
>
> >
>
> >
>
> >
>
> > I enjoyed my conversations with Bob before we gridded, and thinking of him now gives me an erie feeling. Such a nice guy, happy with gliding, and willing and eager to learn more about desert flying. But, in the end, what can be said other than it was just his time to go. Yes, gliding is dangerous. I've been into soaring since 1996 and he was the 7th I've known to be called to the other side.
>
> >
>
> >
>
> >
>
> > We try to learn from others' mistakes, but in this case, as there were no glider pilots who observed the event, little can be learned.
>
> >
>
> >
>
> >
>
> > My heart goes out to his family and friends.
>
> >
>
> >
>
> >
>
> > Bob T

Interesting coincidence... same date, same place. But, the similarities stop there. Russ's 2006 crash was due to medical event reasons. While in line to fly he did not feel good and considered backing out. As the line got shorter he changed his mind. There are a number of medical issues and pharmaceutical issues that I won't get into, but he just shouldn't have even tried to fly that day.

In talking with Tom Knauff (no relation to Bob Knauff that I know of) a few months ago, he commented that he was shocked at the number of fatal accidents that involved medical and / or pharmaceutical issues.

And, perhaps for superstitious reasons it might not be a good thing for glider ops on May 3, 2015 at Samply airport?

[email protected]

May 6th 14, 05:06 PM

On Tuesday, May 6, 2014 6:38:20 AM UTC-7, Renny wrote:
> In doing some research last night I sadly came upon another fatal glider accident that also happened at Aguila, AZ. This occurred 8 years ago to the day in 2006. The NTSB report is at this URL:
>
>
>
> http://www.ntsb.gov/aviationquery/brief.aspx?ev_id=20060510X00545&key=1
>
>
>
> In a strange twist of fate this accident also occurred on May 3 and it also happened during the early portion of the launch when the glider reached approx 150 feet on tow.
>
>
>
> Let's all hope that important lessons are learned and that everyone can be more aware and better prepared in case of a problem early in a launch.
>
>
>
> Thx - Renny
>
>
>
>
>
>
>
> On Monday, May 5, 2014 11:07:50 PM UTC-6, wrote:
>
> > On Monday, May 5, 2014 8:17:31 PM UTC-7, kirk.stant wrote:
>
> >
>
> > > On Monday, May 5, 2014 1:38:32 PM UTC-7, Mike the Strike wrote:
>
> >
>
> > >
>
> >
>
> > > > I have flown into and out of Sampley's a few times. The terrain at Sampley's rises to the east and falls to the west. Heading west, you are over slightly falling terrain with open fields for landing. On an easterly departure, you may be at an indicated 200 feet above take-off but may only be 100' over terrain. Straight-ahead landing options are not very enticing to the east once you've passed the end of the strip, so a turn back from an indicated 200' may seem like the best option.
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> >
>
> >
>
> >
>
> >
>
> > >
>
> >
>
> > > Minor correction: Sampley runs North-South, with takeoffs invariably uphill to the South. South gets slowly higher until some hills (all raw desert), North gently slopes down to the center of the valley (mostly agricultural fields - all landable).
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > > Not too many good options if PTT is really low taking off to the South; you pretty much have to either get back to the runway or accept a desert landing.
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > > Sad.
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > > Kirk
>
> >
>
> > >
>
> >
>
> > > 66
>
> >
>
> >
>
> >
>
> > I took off about 15 minutes ahead of Bob (was 1st in line and he was 3rd). There were the usual bumpy spots (up and down gusts) in the first 50 or so feet AGL and then the usual booming lift at the end of the runway. As we got to the end of the runway we were lower than I had experienced previously there, and I have probably 10 years of flying from there. The tow plane was running fine, it just seemed like we towed through some bumpy sinking air til the big boomer at the runway end.
>
> >
>
> >
>
> >
>
> > One of the pilots made the comment Saturday evening that the release on a Zuni could "self release / back release" without pilot input.... it was not a Tost, and required the big ring. If that is correct, the bumpy air down low could have caused yo-yo effect and an inadverdant release. That would have probably put Bob in the sinking air around the big lift at the end of the runway about the time of release To me, the only options would have been straight ahead, either hopefully on what was left of the runway or into the bushes past the end. Other than "south of Cliff's hanger" I don't know how far down the runway he was when he crashed / how much, if any runway was left in front of him. Wind on the ground at the north end of the runway, where we were staged was 5-15 mph SSW.
>
> >
>
> >
>
> >
>
> > Whenever I take off I constantly calculate where I would have to go if the rope were to break, and, as I was lower than usual that day, I was looking at that. A damaged or totaled glider is still better than taking a chance on a stall-spin. My count to 200 ft. AGL) lasted until we had been in the boomer past the runway end for a few seconds. If Bob had been in exactly the same air, any release before the runway end, he would have been under 100'AGL.
>
> >
>
> >
>
> >
>
> > I enjoyed my conversations with Bob before we gridded, and thinking of him now gives me an erie feeling. Such a nice guy, happy with gliding, and willing and eager to learn more about desert flying. But, in the end, what can be said other than it was just his time to go. Yes, gliding is dangerous. I've been into soaring since 1996 and he was the 7th I've known to be called to the other side.
>
> >
>
> >
>
> >
>
> > We try to learn from others' mistakes, but in this case, as there were no glider pilots who observed the event, little can be learned.
>
> >
>
> >
>
> >
>
> > My heart goes out to his family and friends.
>
> >
>
> >
>
> >
>
> > Bob T
Interesting coincidence... same date, same place. But, the similarities stop there. Russ's 2006 crash was due to medical event reasons. While in line to fly he did not feel good and considered backing out. As the line got shorter he changed his mind. There are a number of medical issues and pharmaceutical issues that I won't get into, but he just shouldn't have even tried to fly that day.

In talking with Tom Knauff (no relation to Bob Knauff that I know of) a few months ago, he commented that he was shocked at the number of fatal accidents that involved medical and / or pharmaceutical issues.

And, perhaps for superstitious reasons it might not be a good thing for glider ops on May 3, 2015 at Samply airport?

Bob T.

May 6th 14, 07:10 PM

> Glider was a Zuni. Crash not observed by any glider pilots. Tow pilot felt the sudden lack of pull behind him, circled back and observed the wreckage a bit east of the runway among homes and bushes. Bummer day.

My condolences to the family and friends of Mr. Knauff.
Is it known whether the tow rope failed or did it come out of the release? Just curious.
Uli

WAVEGURU

May 6th 14, 07:42 PM

The rope was intact. We don't know what caused the release. I'm not even sure we know if he turned back or rotated 180 during the spin. No pilot saw what happened.

Boggs

MNLou

May 6th 14, 08:57 PM

On Tuesday, May 6, 2014 1:42:53 PM UTC-5, Waveguru wrote:
> The rope was intact. We don't know what caused the release. I'm not even sure we know if he turned back or rotated 180 during the spin. No pilot saw what happened.
>
>
>
> Boggs

I heard Tom Knauff speak at the Senior Soaring Championships in March about in flight medical issues. (A great presentation by the way.)

One possibility is that Bob Knauff was experiencing a medical emergency and, in a last act of heroism, released to save the tow pilot.

We may never know but if this is the case, hats off to General Knauff.

Lou

Bob Whelan[_3_]

May 6th 14, 09:22 PM

Given no one actually saw the final moments of the ship's flight, all any of
us can do is draw our own conclusions. Cutting and inserting from others'
comments...

>> Not too many good options if PTT is really low taking off to the South;
>> you pretty much have to either get back to the runway or accept a desert
>> landing.

From descriptions of the launch field, "...or accept a desert landing" is a
key point below safe-turn-around altitude (whatever that might be for the
location/conditions of the day). It's critical ANYwhere. History - and slight
use of one's imagination - both suggest it's far, far better to hit the ground
horizontally than vertically. Screw the airframe, it can be rebuilt and it's
likely going to get broken regardless of the mode of ground contact at a lot
of western-U.S. strips.

> One of the pilots made the comment Saturday evening that the release on a
> Zuni could "self release / back release" without pilot input.... it was
> not a Tost, and required the big ring.

I've had two uncommanded-by-me back releases on aerotows, both due to LARGE
bows in the rope induced by strongly shearing western thermals, which on both
days resulted in significant airspeed variations of tug & glider (hence the
bows). So far as I was concerned, both back releases showed the releases had
operated as the designer intended, though neither bow put the glider at risk
of rope entanglement because both times I was above the rope, "admiring the
bow." The ships were an HP-14 and a Zuni (which has a functional copy of
Schreder's dirt-simple release mechanism; between both ships I've 760+ tows;
you can do the arithmetic). Under similar circumstances, I expect a Tost
belly-hook should've similarly self-released.

The HP incident was at Taos, and I've never been so terrified of a rope break
in my life, as the first big bow appeared below turn-around height, above the
tallest sagebrush I've ever seen (taller than I). The actual release occurred
at 1500' agl (whew!). I mentally wrote the ship off until WELL above return to
the airstrip height on that one...

I never again towed from Taos, given the lack of options below turn-around
height; for me the potential return wasn't worth the risk.

The Zuni incident was at Buena Vista (CO), again sufficiently high agl to
climb away and go soaring.

> If [uncommanded back release] is correct, the bumpy air
> down low could have caused yo-yo effect and an inadvertent release.

See above...for the record, the mechanical engineer in me happens to like the
Schreder release design for a number of reasons, though as with everything
aeronautical, it does contain compromises...

> That
> would have probably put Bob in the sinking air around the big lift at the
> end of the runway about the time of release To me, the only options would
> have been straight ahead, either hopefully on what was left of the runway
> or into the bushes past the end...

I'm a Big Fan of "accepting the bushes..."

>
> Whenever I take off I constantly calculate where I would have to go if the
> rope were to break...

....as should every glider pilot on every launch...

>... and, as I was lower than usual that day, I was looking
> at that. A damaged or totaled glider is still better than taking a chance
> on a stall-spin.

The concept in the preceding sentence can't POSSIBLY be overemphasized!!!

> My count to 200 ft. AGL) lasted until we had been in the
> boomer past the runway end for a few seconds. If Bob had been in exactly
> the same air, any release before the runway end, he would have been under
> 100'AGL.
>
> I enjoyed my conversations with Bob before we gridded, and thinking of him
> now gives me an eerie feeling. Such a nice guy, happy with gliding, and
> willing and eager to learn more about desert flying. But, in the end,
> what can be said other than it was just his time to go. Yes, gliding is
> dangerous. I've been into soaring since 1996 and he was the 7th I've known
> to be called to the other side.
>
> We try to learn from others' mistakes, but in this case, as there were no
> glider pilots who observed the event, little can be learned.

Not intending to quibble, but unless he was so unlucky as to center punch or
slide into something very hard with the fuselage after non-vertical impact
with the earth, the "little [to] be learned" is some variation of "Fly it into
the crash!" It's critical whenever flying anything with wings into ground contact.

> My heart goes out to his family and friends.

As does mine...

Bob W.

Don Johnstone[_4_]

May 6th 14, 09:41 PM

While in no way do I wish to speculate on the cause of this accident or
indeed suggest that my comments in any way address the cause of this
accident.
I feel that comment is needed on some of the things said here. We have a
rule here in the UK, launch failure on aerotow below 300ft a landing should
be made ahead, or slightly to one side. No attempt should be made to turn
back below this height.
The reason is simple, a controlled crash into difficult terrain is likely
to result in a better outcome than an uncontrolled arrival on the airfield.
The important bit to keep intact is the bit you are sitting in, the rest of
the glider does not really matter too much. The best chance of achieving
that is flying to the ground with the wings level. It has only happened to
me once, there was a field ahead but it was full of the Tiger Moth tug that
had landed in the middle. I discovered that there was just enough space for
a Skylark 2 as well. I have no doubt that a turn back would have resulted
in an accident. I was at 250ft agl max.
If there really is nowhere to land ahead you should really ask the
question, "should I be taking a launch".
Frankly I would be horrified to be required to conduct a turn back at
200ft, I would suggest that this is one of those occasions where the danger
of practice is to great to justify.

CindyB[_2_]

May 6th 14, 09:43 PM

On Saturday, May 3, 2014 9:27:10 PM UTC-7, Waveguru wrote:
> Premature termination of the tow at 100ft. Did not complete the turn back to the runway.

It is so disheartening to me..... that the industry hasn't picked up
my technique of teaching about requiring students to be speaking aloud during the
departure climb --

"I can land here (xxxxxx) ,
I can land there (xxxxxx ) ,
I can turn for a downwind landing (meaning sufficient altitude and within-limits tailwind component),
I can make an abbreviated pattern into wind,
I can make a full pattern."

Meaning -
they can land straight ahead somewhere on the remaining airport.
they can land somewhere ahead or aside/outside the premises in the 'best available' place,
they know they have enough to land downwind ( if appropriate - sometimes you would never choose DW),
they can make a teensy, tight short pattern onto the upwind end of the airfield.
they can make a pretty leisurely, semi-normal landing into wind on the airfield.

The simplistic rote teaching of requiring students to say aloud --

200 feet --

That doesn't get them 'ahead of the glider' and actively looking, thinking,
assessing where they can go during each moment of the departure climb.
IF pilots were taught to think that way,
I believe,
we would eliminate these PTTT turn/stall accidents almost entirely.

Folks might land in less than wonderful places, but it would
be a landing, not an example of gravity in control. Arriving in a
comparatively level and comparatively slow descent rate is
hugely more survivable than what we see in these types of
accidents.

If any CFIGs would like to discuss their airfield, their trainings ships and tugs, and their departure options, I would be happy to assist them in understanding and incorporating this training protocol.

With great regret for the loss of another pilot,

Cindy Brickner

Caracole Soaring
(760) 373-1019 cell phone

Mike the Strike

May 6th 14, 11:08 PM

On Tuesday, May 6, 2014 1:41:23 PM UTC-7, Don Johnstone wrote:
> While in no way do I wish to speculate on the cause of this accident or
>
> indeed suggest that my comments in any way address the cause of this
>
> accident.
>
> I feel that comment is needed on some of the things said here. We have a
>
> rule here in the UK, launch failure on aerotow below 300ft a landing should
>
> be made ahead, or slightly to one side. No attempt should be made to turn
>
> back below this height.
>
> The reason is simple, a controlled crash into difficult terrain is likely
>
> to result in a better outcome than an uncontrolled arrival on the airfield.
>
> The important bit to keep intact is the bit you are sitting in, the rest of
>
> the glider does not really matter too much. The best chance of achieving
>
> that is flying to the ground with the wings level. It has only happened to
>
> me once, there was a field ahead but it was full of the Tiger Moth tug that
>
> had landed in the middle. I discovered that there was just enough space for
>
> a Skylark 2 as well. I have no doubt that a turn back would have resulted
>
> in an accident. I was at 250ft agl max.
>
> If there really is nowhere to land ahead you should really ask the
>
> question, "should I be taking a launch".
>
> Frankly I would be horrified to be required to conduct a turn back at
>
> 200ft, I would suggest that this is one of those occasions where the danger
>
> of practice is to great to justify.

I have also voiced my concern at this tow termination training. Most times, it is a planned event and the towplane flies a modified pattern to give the trainee the best opportunity of returning to the launch runway. I have done several of these and they are not problematic. They also don't much resemble what happens in the real world when a rope break or disconnect is unplanned.

I have had only one of these in nearly 50 years of gliding. In one of my biannual tests, the instructor reassured me that no low altitude rope breaks would be simulated and then pulled the plug on me at a hair under 200 feet. Being unplanned. my reaction time was much longer - you have to work through the "holy ****, the tow rope's gone" thought process before taking any action. I landed successfully, but not on the departure runway - a story for another day. it did teach me that I didn't want a rope break under 200 feet and preferably not under 500 feet!

I have had several ropes break on the initial acceleration but none in the air. I have had three tugs lose power - two on the take-off run and one during climb-out. From my experience, I am skeptical that rope breaks between take-off and 200 feet are common enough to warrant the attention and training they get here in the USA..

I can also comment on the weather the day of the accident. It was perhaps one of the strongest (and highest) blue days I have seen in Arizona. The atmosphere was stable and dry under a dominant high-pressure system. Thermals were created by heating the air so much it had to rise, but these conditions resulted in very narrow, very strong, often multi-core, thermals surrounded by vicious sink and turbulence. These can be challenging if encountered on tow and can rapidly erode any height margin you have. You can expect to bash your head a few times (and perhaps your shins) on a day like this.. Good when you're high, but nasty below pattern altitude.

Mike

Bill D

May 6th 14, 11:22 PM

On Tuesday, May 6, 2014 2:41:23 PM UTC-6, Don Johnstone wrote:

> Frankly I would be horrified to be required to conduct a turn back at
>
> 200ft, I would suggest that this is one of those occasions where the danger
>
> of practice is to great to justify.

If you should check out in the USA, you'll be required to demonstrate competence in this maneuver. Every pre-solo student is required to do so and more than a half century of safety records do not suggest a problem. In fact, even with low performance gliders, there's quite a large safety margin. The most likely outcome is a pilot will find the glider uncomfortably high for a downwind landing requiring full spoilers and a slip.

The logic is simple - it's better to have pilots trained for the option. No one says a pilot is required to turn back or that 200' is always adequate to do so. What is illogical is to suggest a pilot be required to crash in unlandable terrain when a safe option exists to land on the departure runway.

Don Johnstone[_4_]

May 7th 14, 12:56 AM

At 22:22 06 May 2014, Bill D wrote:
>On Tuesday, May 6, 2014 2:41:23 PM UTC-6, Don Johnstone wrote:
>
>> Frankly I would be horrified to be required to conduct a turn back at
>>=20
>> 200ft, I would suggest that this is one of those occasions where the
>dang=
>er
>>=20
>> of practice is to great to justify.
>
>If you should check out in the USA, you'll be required to demonstrate
>compe=
>tence in this maneuver. Every pre-solo student is required to do so and
>mo=
>re than a half century of safety records do not suggest a problem. In
>fact=
>, even with low performance gliders, there's quite a large safety margin.
>T=
>he most likely outcome is a pilot will find the glider uncomfortably high
>f=
>or a downwind landing requiring full spoilers and a slip.
>
>The logic is simple - it's better to have pilots trained for the option.
>N=
>o one says a pilot is required to turn back or that 200' is always
>adequate=
> to do so. What is illogical is to suggest a pilot be required to crash
>in=
> unlandable terrain when a safe option exists to land on the departure
>runw=
>ay.
>
What are you trying to save? The pilot or the aircraft? The priority should
be survival of the soft bit, that is you and me.
As an instructor with nearly 50 years experience I know that when I
initiate an emergency procedure I do so allowing a margin to ensure my
survival if it does not work out, I have been bold but never certifiable.
Most living instructors have the same survival instinct. That is why I have
lived long enough to do 10,000 launches, and of course landings. It has
already been hinted that the practice you describe involves modifying what
you normally do, in my view that probably makes it pretty useless and not
real preparation for the event. If you did carry out the training in
exactly the same way as the possible real event you might find that the
results were very different, not to mention painful. I will stick with my
300ft thank you, I know it works. Low turns, below that height may have
been acceptable in old wooden gliders, the minimum height in T31 and T21
gliders was 150ft, but for modern glass gliders it is just far too low, you
only have to look at the accident statistics to see that low final turns
figure to a large degree in accidents so why plan for it?
I repeat a controlled descent with wings level is far more likely to have a
better result than hitting the ground in a turn or even worse spinning in
trying to avoid it.

PS Despite all that there have been times when I have initiated a practice
emergency and very quickly wished I had not, no plan survives first
contact.

Mike the Strike

May 7th 14, 01:30 AM

On Tuesday, May 6, 2014 4:56:44 PM UTC-7, Don Johnstone wrote:
> At 22:22 06 May 2014, Bill D wrote:
>
> >On Tuesday, May 6, 2014 2:41:23 PM UTC-6, Don Johnstone wrote:
>
> >
>
> >> Frankly I would be horrified to be required to conduct a turn back at
>
> >>=20
>
> >> 200ft, I would suggest that this is one of those occasions where the
>
> >dang=
>
> >er
>
> >>=20
>
> >> of practice is to great to justify.
>
> >
>
> >If you should check out in the USA, you'll be required to demonstrate
>
> >compe=
>
> >tence in this maneuver. Every pre-solo student is required to do so and
>
> >mo=
>
> >re than a half century of safety records do not suggest a problem. In
>
> >fact=
>
> >, even with low performance gliders, there's quite a large safety margin..
>
> >T=
>
> >he most likely outcome is a pilot will find the glider uncomfortably high
>
> >f=
>
> >or a downwind landing requiring full spoilers and a slip.
>
> >
>
> >The logic is simple - it's better to have pilots trained for the option.
>
> >N=
>
> >o one says a pilot is required to turn back or that 200' is always
>
> >adequate=
>
> > to do so. What is illogical is to suggest a pilot be required to crash
>
> >in=
>
> > unlandable terrain when a safe option exists to land on the departure
>
> >runw=
>
> >ay.
>
> >
>
> What are you trying to save? The pilot or the aircraft? The priority should
>
> be survival of the soft bit, that is you and me.
>
> As an instructor with nearly 50 years experience I know that when I
>
> initiate an emergency procedure I do so allowing a margin to ensure my
>
> survival if it does not work out, I have been bold but never certifiable.
>
> Most living instructors have the same survival instinct. That is why I have
>
> lived long enough to do 10,000 launches, and of course landings. It has
>
> already been hinted that the practice you describe involves modifying what
>
> you normally do, in my view that probably makes it pretty useless and not
>
> real preparation for the event. If you did carry out the training in
>
> exactly the same way as the possible real event you might find that the
>
> results were very different, not to mention painful. I will stick with my
>
> 300ft thank you, I know it works. Low turns, below that height may have
>
> been acceptable in old wooden gliders, the minimum height in T31 and T21
>
> gliders was 150ft, but for modern glass gliders it is just far too low, you
>
> only have to look at the accident statistics to see that low final turns
>
> figure to a large degree in accidents so why plan for it?
>
> I repeat a controlled descent with wings level is far more likely to have a
>
> better result than hitting the ground in a turn or even worse spinning in
>
> trying to avoid it.
>
>
>
> PS Despite all that there have been times when I have initiated a practice
>
> emergency and very quickly wished I had not, no plan survives first
>
> contact.

I should also add that over the years, I have retrieved various sailplanes that made controlled landings into terrain in Arizona, including mesquite bushes, palo verde trees and ironwood trees. Only one of these aircraft was seriously damaged and all the others have been repaired. No pilot was seriously injured. Level flight into quite evil terrain does appear a much better option than a sharp turn at low altitude, with a significant possibility of stall/spin or uncontrolled ground impact.

Mike

Bill D

May 7th 14, 02:07 AM

On Tuesday, May 6, 2014 4:08:26 PM UTC-6, Mike the Strike wrote:
> On Tuesday, May 6, 2014 1:41:23 PM UTC-7, Don Johnstone wrote:
>
> > While in no way do I wish to speculate on the cause of this accident or
>
> >
>
> > indeed suggest that my comments in any way address the cause of this
>
> >
>
> > accident.
>
> >
>
> > I feel that comment is needed on some of the things said here. We have a
>
> >
>
> > rule here in the UK, launch failure on aerotow below 300ft a landing should
>
> >
>
> > be made ahead, or slightly to one side. No attempt should be made to turn
>
> >
>
> > back below this height.
>
> >
>
> > The reason is simple, a controlled crash into difficult terrain is likely
>
> >
>
> > to result in a better outcome than an uncontrolled arrival on the airfield.
>
> >
>
> > The important bit to keep intact is the bit you are sitting in, the rest of
>
> >
>
> > the glider does not really matter too much. The best chance of achieving
>
> >
>
> > that is flying to the ground with the wings level. It has only happened to
>
> >
>
> > me once, there was a field ahead but it was full of the Tiger Moth tug that
>
> >
>
> > had landed in the middle. I discovered that there was just enough space for
>
> >
>
> > a Skylark 2 as well. I have no doubt that a turn back would have resulted
>
> >
>
> > in an accident. I was at 250ft agl max.
>
> >
>
> > If there really is nowhere to land ahead you should really ask the
>
> >
>
> > question, "should I be taking a launch".
>
> >
>
> > Frankly I would be horrified to be required to conduct a turn back at
>
> >
>
> > 200ft, I would suggest that this is one of those occasions where the danger
>
> >
>
> > of practice is to great to justify.
>
>
>
> I have also voiced my concern at this tow termination training. Most times, it is a planned event and the towplane flies a modified pattern to give the trainee the best opportunity of returning to the launch runway. I have done several of these and they are not problematic. They also don't much resemble what happens in the real world when a rope break or disconnect is unplanned.
>
>
>
> I have had only one of these in nearly 50 years of gliding. In one of my biannual tests, the instructor reassured me that no low altitude rope breaks would be simulated and then pulled the plug on me at a hair under 200 feet. Being unplanned. my reaction time was much longer - you have to work through the "holy ****, the tow rope's gone" thought process before taking any action. I landed successfully, but not on the departure runway - a story for another day. it did teach me that I didn't want a rope break under 200 feet and preferably not under 500 feet!
>
>
>
> I have had several ropes break on the initial acceleration but none in the air. I have had three tugs lose power - two on the take-off run and one during climb-out. From my experience, I am skeptical that rope breaks between take-off and 200 feet are common enough to warrant the attention and training they get here in the USA..
>
>
>
> I can also comment on the weather the day of the accident. It was perhaps one of the strongest (and highest) blue days I have seen in Arizona. The atmosphere was stable and dry under a dominant high-pressure system. Thermals were created by heating the air so much it had to rise, but these conditions resulted in very narrow, very strong, often multi-core, thermals surrounded by vicious sink and turbulence. These can be challenging if encountered on tow and can rapidly erode any height margin you have. You can expect to bash your head a few times (and perhaps your shins) on a day like this. Good when you're high, but nasty below pattern altitude.
>
>
>
> Mike

Mike,

Turns do not cause stall/spin accidents. In fact, the steeper the turn, the greater the stall margin. That's because elevator authority is progressively used up making the glider turn as the bank gets steeper until the angle of attack can't be raised above stall. Try it. You'll find many gliders will run out of up elevator before they can be stalled at bank angles over 45 degrees.

Low turns don't cause stall spins either - they just insure there will be a permanent record should one occur. Pilots spin gliders unintentionally at higher altitudes too but they don't tell anybody.

Spins happen because the pilot stalled the glider, not because the pilot was turning.

The root cause of stall/spin accidents is pilot incompetence although it may not be their fault. Pilot training in gliders skips over an important area that is well covered in airplane training - its called ground reference maneuvers. If a student is drilled in low turns, it's less likely they will spin in on turns to final.

Bill D

May 7th 14, 02:20 AM

On Tuesday, May 6, 2014 5:56:44 PM UTC-6, Don Johnstone wrote:
> At 22:22 06 May 2014, Bill D wrote:
>
> >On Tuesday, May 6, 2014 2:41:23 PM UTC-6, Don Johnstone wrote:
>
> >
>
> >> Frankly I would be horrified to be required to conduct a turn back at
>
> >>=20
>
> >> 200ft, I would suggest that this is one of those occasions where the
>
> >dang=
>
> >er
>
> >>=20
>
> >> of practice is to great to justify.
>
> >
>
> >If you should check out in the USA, you'll be required to demonstrate
>
> >compe=
>
> >tence in this maneuver. Every pre-solo student is required to do so and
>
> >mo=
>
> >re than a half century of safety records do not suggest a problem. In
>
> >fact=
>
> >, even with low performance gliders, there's quite a large safety margin.
>
> >T=
>
> >he most likely outcome is a pilot will find the glider uncomfortably high
>
> >f=
>
> >or a downwind landing requiring full spoilers and a slip.
>
> >
>
> >The logic is simple - it's better to have pilots trained for the option.
>
> >N=
>
> >o one says a pilot is required to turn back or that 200' is always
>
> >adequate=
>
> > to do so. What is illogical is to suggest a pilot be required to crash
>
> >in=
>
> > unlandable terrain when a safe option exists to land on the departure
>
> >runw=
>
> >ay.
>
> >
>
> What are you trying to save? The pilot or the aircraft? The priority should
>
> be survival of the soft bit, that is you and me.
>
> As an instructor with nearly 50 years experience I know that when I
>
> initiate an emergency procedure I do so allowing a margin to ensure my
>
> survival if it does not work out, I have been bold but never certifiable.
>
> Most living instructors have the same survival instinct. That is why I have
>
> lived long enough to do 10,000 launches, and of course landings. It has
>
> already been hinted that the practice you describe involves modifying what
>
> you normally do, in my view that probably makes it pretty useless and not
>
> real preparation for the event. If you did carry out the training in
>
> exactly the same way as the possible real event you might find that the
>
> results were very different, not to mention painful. I will stick with my
>
> 300ft thank you, I know it works. Low turns, below that height may have
>
> been acceptable in old wooden gliders, the minimum height in T31 and T21
>
> gliders was 150ft, but for modern glass gliders it is just far too low, you
>
> only have to look at the accident statistics to see that low final turns
>
> figure to a large degree in accidents so why plan for it?
>
> I repeat a controlled descent with wings level is far more likely to have a
>
> better result than hitting the ground in a turn or even worse spinning in
>
> trying to avoid it.
>
>
>
> PS Despite all that there have been times when I have initiated a practice
>
> emergency and very quickly wished I had not, no plan survives first
>
> contact.

So, you're saying the pilot will be safer if they don't learn to perform the return to runway maneuver when it's safe to do so?

I can assure you that the higher a glider's performance, the safer it is. It's the old, low L/D gliders that can run out of altitude before getting lined up with the runway.

son_of_flubber

May 7th 14, 03:28 AM

I just practiced 10 simulated PTOTs at my home field using Condor. It gave me a better perspective on my options. I will practice again with different wind directions and speed.

Bob Whelan[_3_]

May 7th 14, 04:35 AM

On 5/6/2014 5:56 PM, Don Johnstone wrote:
<Major Snip...>

> I will stick with my
> 300ft thank you, I know it works. Low turns, below that height may have
> been acceptable in old wooden gliders, the minimum height in T31 and T21
> gliders was 150ft, but for modern glass gliders it is just far too low...
<Snip...>

Volunteers for testing whether a lower-speed/higher-rate glider (T21/T31
certainly qualify) requires less height to execute a course reversal compared
to a higher speed/lower-sink rate modern plastic one? While testing, please do
contact the ground in controlled flight...

>...you
> only have to look at the accident statistics to see that low final turns
> figure to a large degree in accidents so why plan for it?

Because: a) it happens (statistics); and b) (IMO) we reasonably safely can?
(That's certainly NOT the case when practicing the inadvertent departure from
controlled flight in the pattern.) And the skill might be good to have in
one's skill set? I'm not trying to be snarky, but it's the *uncontrolled*
ground contact that jumps out from the death statistics I've seen.

> I repeat a controlled descent with wings level is far more likely to have a
> better result than hitting the ground in a turn or even worse spinning in
> trying to avoid it.

Roger both thoughts...especially that last one!

It's not "merely" the broken rope Joe Glider Pilot needs to be prepared for
as "the" source of an in-pattern prematurely terminated tow. Except for
training flights, I've never had an in-pattern premature tow termination...but
I know of lots of others who "for real" have, with causes including (off the
top of my head) unlatched canopies, passenger idiocy, improperly connected tow
rings and almost certainly more I'm forgetting.

Stuff happens. Prepare - mentally, training, muscle memory - accordionly.

Bob W.

Robert M

May 7th 14, 05:41 AM

Why is anyone aero towing with a tow hook that will back release? To me it is a basic safety issue. It is not just this latest tragic accident, I have seen more wild gyrations and damages brought on by aero towing with a C.G.. hook than with a nose hook that does not back release. There are, I think, very few glider models that cannot be retro fitted with a forward hook that does not back release. To those who admire the so called "Zuni hook", well I have one on my desk right now, it is a poor piece of engineering.

In Germany regulations have been enacted setting currency standards that one must meet before using a C.G. hook for aero tow.

It would be interesting to analyze damage claims on aero launches, sorted by nose, E-85 or similar, tow hooks against back releasing C.G. hooks.

But then maybe I should not make a big issue of it as I am in the glider repair business.

Robert Mudd
Moriarty, NM

Bruce Hoult

May 7th 14, 07:55 AM

On Wednesday, May 7, 2014 1:20:44 PM UTC+12, Bill D wrote:
> So, you're saying the pilot will be safer if they don't learn to perform the return to runway maneuver when it's safe to do so?
>
> I can assure you that the higher a glider's performance, the safer it is. It's the old, low L/D gliders that can run out of altitude before getting lined up with the runway.

I agree with you. I'm shaking my head every time I read this thread.

In a modern glass glider (such as the DG1000's I instruct in) with a 40 knot stall speed and being towed at 70 knots you should be able to execute a safe 180º turn with *zero* loss of height.

Just slowing down from 70 knots towing speed to 55 knots gains you 80 ft on top of whatever you already had.[1]

How much height do you lose in a 45º banked turn at 55 knots? Most modern gliders lose no more than 120 fpm at 45 knots in straight and level flight.. A 45º banked turn gives 1.41 Gs (1/cos(45)), which needs sqrt(1.41) = 1.19 times more speed for the same angle of attack and L/D. 45 knots times 1.19 is 53.6 knots. So 55 knots in a 45º turn has a little more margin above stall than 45 knots in straight and level. The sink rate will be 120 * 1.41 = 170 fpm.

Converting to SI and using a=v^2/r, a 45º banked turn at 55 knots (28.3 m/s) has 115.3m radius, or 725m circumference for a full turn. A 180º turn (362m) will take 12.8 seconds. In 12.8 seconds at 170 fpm you'll lose 36 feet.

So the height loss in the turn is only about half the height gained from slowing down from towing speed to circling speed!

It would actually be better to start turning immediately, but these calculations assume you delay (deliberately or not) and climb straight ahead (no pull-up required) for several seconds before starting the turn.

With 18m wingspan in a 45º bank your wingtip is 18m/2*sin(45) = 6.4m or 21 ft below you.

So you theoretically could do this from absolutely zero height, with nearly 20 ft to spare.

I wouldn't want to try it! But from 100ft? No problem at all. IF you start from normal towing speed and reasonably benign weather conditions.

Even if you're releasing from a sick tug that's slowed to 55 knots, you'll be fine from 200 ft.

Another post mentioned that glider pilots make mistakes when flying close to the ground because they are not trained to do so and don't do "ground reference" manoeuvres like power plane pilots do.

Obviously that person lives in very flat ground, because I can assure them that here we're flying close to ridges and peaks a LOT, from almost the first flight, doing 180º turns at the end of ridge lift runs, or circling low over a peak or head of a gully looking for a thermal. We'd very often be only 100-200 ft or so above the terrain while doing so.

[1] handy formula: X knots of kinetic energy is worth (X/5)^2 feet of gravitational potential energy. e.g. 70 knots = (70/5)^2 = 14^2 = 196 ft. 50 knots = (50/5)^2 = 10^2 = 100 ft. Less drag loses of course. You'll never turn speed into quite that much height, and you'll need more height than that to get speed. But the differences are large in a high performance glider at moderate speeds.

James Metcalfe

May 7th 14, 12:49 PM

At 06:55 07 May 2014, Bruce Hoult wrote:
>[1] handy formula: X knots of kinetic energy is worth (X/5)^2 feet of
gravitational potential energy. e.g. 70 knots = (70/5)^2 = 14^2 = 196 ft.
50 knots = (50/5)^2 = 10^2 = 100 ft. Less drag loses of course.
You'll never turn speed into quite that much height, and you'll need more
height than that to get speed. But the differences are large in a high
performance glider at moderate speeds.

...or you could use my rule of thumb: a change of speed of 10 knots IAS
gives
you (or costs you) the number of feet in height of the speed you arrive at.

For example:
70 knots to 60 knots : plus 60 feet
60 knots to 70 knots: minus 60 feet
70 knots to 50 knots (i.e. 70 to 60, then 60 to 50) : (60+50) = plus 110
feet

(N.B. Done without undue delay, and at sea level - more height change at
greater altitudes. Height in feet, IAS in knots, works for a change of
speed of 10 knots. Results
are realistic but approximate.)

James Metcalfe

May 7th 14, 01:19 PM

At 11:49 07 May 2014, James Metcalfe wrote:
>60 knots to 70 knots: minus 60 feet
sorry - s.b. minus 70 feet

Vaughn

May 7th 14, 02:20 PM

On 5/7/2014 2:55 AM, Bruce Hoult wrote:
> On Wednesday, May 7, 2014 1:20:44 PM UTC+12, Bill D wrote:
>> >I can assure you that the higher a glider's performance, the safer
it is. It's the old, low L/D gliders that can run out of altitude
before getting lined up with the runway.
> I agree with you. I'm shaking my head every time I read this thread.
>
> In a modern glass glider (such as the DG1000's I instruct in) with a
>40 knot stall speed and being towed at 70 knots you should be able to
>execute a safe 180º turn with*zero* loss of height.

The comparison isn't quite as simple as just looking at L/D. Turn
radius also has a lot to do with your chances of making it back to the
field, and turn radius is proportional to the SQUARE of airspeed.

Compare your example (40 knot stall) with a (horrors) 2-33. The highest
stall listed for a 2-33 is around 30 knots. If you do the math, you
will find that your DG1000 has nearly double the turn radius of the
slower glider.

Vaughn

Mike the Strike

May 7th 14, 02:28 PM

....now redo your calculations while flying through 8 knots of sink.

Mike

Mike the Strike

May 7th 14, 02:35 PM

On Wednesday, May 7, 2014 6:28:41 AM UTC-7, Mike the Strike wrote:
> ...now redo your calculations while flying through 8 knots of sink.
>
>
>
> Mike

...and calculate the height loss while making a 180-degree turn. Taking the 12.8 seconds just mentioned at 800 feet per minute gives you a height loss of 170 feet from the airmass movement alone, plus whatever you add for the glider itself. Safety margins in severe sink disappear frighteningly quickly.

Mike

[email protected]

May 7th 14, 04:16 PM

On Wednesday, May 7, 2014 9:35:46 AM UTC-4, Mike the Strike wrote:
> On Wednesday, May 7, 2014 6:28:41 AM UTC-7, Mike the Strike wrote:
>
> > ...now redo your calculations while flying through 8 knots of sink.
>
> >
>
> >
>
> >
>
> > Mike
>
>
>
> ..and calculate the height loss while making a 180-degree turn. Taking the 12.8 seconds just mentioned at 800 feet per minute gives you a height loss of 170 feet from the airmass movement alone, plus whatever you add for the glider itself. Safety margins in severe sink disappear frighteningly quickly.
>
>
>
> Mike

Now throw in wind shear and tailwind component when failure to anticipate leads to turning in the wrong direction.
Double AARRGGHH!!
UH

WAVEGURU

May 7th 14, 04:18 PM

Can you really get 8kts of sink at 200ft? Where is the air going, into the ground?

Boggs

Bill D

May 7th 14, 04:34 PM

On Wednesday, May 7, 2014 7:20:33 AM UTC-6, Vaughn wrote:
> On 5/7/2014 2:55 AM, Bruce Hoult wrote:
>
> > On Wednesday, May 7, 2014 1:20:44 PM UTC+12, Bill D wrote:
>
> >> >I can assure you that the higher a glider's performance, the safer
>
> it is. It's the old, low L/D gliders that can run out of altitude
>
> before getting lined up with the runway.
>
> > I agree with you. I'm shaking my head every time I read this thread.
>
> >
>
> > In a modern glass glider (such as the DG1000's I instruct in) with a
>
> >40 knot stall speed and being towed at 70 knots you should be able to
>
> >execute a safe 180ï¿½ turn with*zero* loss of height.
>
>
>
> The comparison isn't quite as simple as just looking at L/D. Turn
>
> radius also has a lot to do with your chances of making it back to the
>
> field, and turn radius is proportional to the SQUARE of airspeed.
>
>
>
> Compare your example (40 knot stall) with a (horrors) 2-33. The highest
>
> stall listed for a 2-33 is around 30 knots. If you do the math, you
>
> will find that your DG1000 has nearly double the turn radius of the
>
> slower glider.
>
>
>
> Vaughn

You're exaggerating the stall speed differences. Regardless of what the 2-33 "manual" says, no 2-33 ever got as slow as 30 knots. 35 knots is a practical minimum speed. The flight test stall speed for a DG 1000 is 37 knots..

However, no one should consider a turn back at stall speed. Virtually all gliders will be at 50 - 55 knots so the turn radius will be essentially the same.

8 knots sink? That's a straw man argument. While extreme air movement is always possible, most PT3 incidents are in relatively benign conditions. In extreme conditions a turn back is probably moot anyway.

The point is when conditions allow, a pilot should know how to turn back safely.

BobW

May 7th 14, 06:01 PM

On 5/6/2014 10:41 PM, Robert M wrote:
> Why is anyone aero towing with a tow hook that will back release?

Excellent question. In the U.S., looking back in time (e.g. the Schweizer
fleet), historical inertia? In any event, I've never owned a glider that did
NOT have a back-releasable, non-CG hook on it, and except for my club's
G-103s, never piloted one either.

Bob W.

kirk.stant

May 7th 14, 06:01 PM

On Wednesday, May 7, 2014 10:34:48 AM UTC-5, Bill D wrote:

> The point is when conditions allow, a pilot should know how to turn back safely.

Precisely. It's called airmanship - knowing how to handle your plane in any conceivable situation.

If you aren't practicing something new and unusual (or at least thinking about it) on every flight, you are limiting your growth as a pilot.

My one real PTT happened at Turf Soaring (Pleasant Valley Airport) many years ago, giving a ride in old 66W - a beat up old 2-32. Tow rope was hooked up incorrectly (muddy) and released just past the end of the runway (taking off to the East) at what i guess was around 150 - 200 ft, no more. No good options other than turning back or landing in the desert; so I turned back...and had enough energy to roll back up to the surprised line boy who had just launched me. Turned the glider around, hooked up again, and the customer got his full ride the second time.

BUT--conditions were calm with light winds and no lift; and the tow was fast - and it was pretty easy to whip that big old beast around in a steep turn and bring it back to land, as I had a lot of time in 2-32s at the time. Never felt that I was too low during the turn, but didn't even try getting real slow (if you have time in 2-32s you will appreciate why!).

Yes, it can be done. But you have to know your plane WELL, and have the right conditions, and fully understand the consequences of pooching it!

Get out there and practice!

Kirk
66

BobW

May 7th 14, 06:10 PM

> Can you really get 8kts of sink at 200ft? Where is the air going, into the
> ground?
>

Having experienced two in-pattern microbursts, I'd say, "Yes, indeed!" to Q1.

As to Q2, as soon as I finish interviewing the bugs on my leading edges and
car windshield, I'll post the interview on YouTube. :-)

Bob W.

P.S. Putting my More Seriously Hat, elsewhere in this thread someone else
pointed out the relative uselessness of L/D in patterns when "real sink" was
an issue. Thoughtful pilots will agree. Maybe this is more of a "routine
issue" in (say) the western U.S. than elsewhere in the country, but I have my
doubts when it comes to (e.g.) wavish pattern conditions (e.g. Cumberland, MD;
Petersburg, WV).

Don Johnstone[_4_]

May 7th 14, 07:40 PM

At 17:01 07 May 2014, kirk.stant wrote:
>On Wednesday, May 7, 2014 10:34:48 AM UTC-5, Bill D wrote:
>=20
>> The point is when conditions allow, a pilot should know how to turn
back
>=
>safely.
>
>Precisely. It's called airmanship - knowing how to handle your plane in
>an=
>y conceivable situation.
>
>If you aren't practicing something new and unusual (or at least thinking
>ab=
>out it) on every flight, you are limiting your growth as a pilot.
>
>My one real PTT happened at Turf Soaring (Pleasant Valley Airport) many
>yea=
>rs ago, giving a ride in old 66W - a beat up old 2-32. Tow rope was
>hooked=
> up incorrectly (muddy) and released just past the end of the runway
>(takin=
>g off to the East) at what i guess was around 150 - 200 ft, no more. No
>go=
>od options other than turning back or landing in the desert; so I turned
>ba=
>ck...and had enough energy to roll back up to the surprised line boy who
>ha=
>d just launched me. Turned the glider around, hooked up again, and the
>cus=
>tomer got his full ride the second time.
>
>BUT--conditions were calm with light winds and no lift; and the tow was
>fas=
>t - and it was pretty easy to whip that big old beast around in a steep
>tur=
>n and bring it back to land, as I had a lot of time in 2-32s at the time.
>N=
>ever felt that I was too low during the turn, but didn't even try getting
>r=
>eal slow (if you have time in 2-32s you will appreciate why!).
>
>Yes, it can be done. But you have to know your plane WELL, and have the
>ri=
>ght conditions, and fully understand the consequences of pooching it!
>
>Get out there and practice!
>
>Kirk
>66

and that dear reader illustrates the problem nicely. Emergency procedures
do not have to be formulated for experienced thinking pilots. I would like
to think that I could get away with doing what Kirk has done. Emergency
procedures have to be formulated for the lowest common denominator, would a
low launches pilot be able to achieve success? Would a relatively
experience pilot who is flying minimum launches per year cope with it? That
is what formulating procedures is all about, having something that everyone
can achieve, not just the top 10%.

Bill D

May 7th 14, 10:45 PM

On Wednesday, May 7, 2014 12:40:09 PM UTC-6, Don Johnstone wrote:
> At 17:01 07 May 2014, kirk.stant wrote:
>
> >On Wednesday, May 7, 2014 10:34:48 AM UTC-5, Bill D wrote:
>
> >=20
>
> >> The point is when conditions allow, a pilot should know how to turn
>
> back
>
> >=
>
> >safely.
>
> >
>
> >Precisely. It's called airmanship - knowing how to handle your plane in
>
> >an=
>
> >y conceivable situation.
>
> >
>
> >If you aren't practicing something new and unusual (or at least thinking
>
> >ab=
>
> >out it) on every flight, you are limiting your growth as a pilot.
>
> >
>
> >My one real PTT happened at Turf Soaring (Pleasant Valley Airport) many
>
> >yea=
>
> >rs ago, giving a ride in old 66W - a beat up old 2-32. Tow rope was
>
> >hooked=
>
> > up incorrectly (muddy) and released just past the end of the runway
>
> >(takin=
>
> >g off to the East) at what i guess was around 150 - 200 ft, no more. No
>
> >go=
>
> >od options other than turning back or landing in the desert; so I turned
>
> >ba=
>
> >ck...and had enough energy to roll back up to the surprised line boy who
>
> >ha=
>
> >d just launched me. Turned the glider around, hooked up again, and the
>
> >cus=
>
> >tomer got his full ride the second time.
>
> >
>
> >BUT--conditions were calm with light winds and no lift; and the tow was
>
> >fas=
>
> >t - and it was pretty easy to whip that big old beast around in a steep
>
> >tur=
>
> >n and bring it back to land, as I had a lot of time in 2-32s at the time..
>
> >N=
>
> >ever felt that I was too low during the turn, but didn't even try getting
>
> >r=
>
> >eal slow (if you have time in 2-32s you will appreciate why!).
>
> >
>
> >Yes, it can be done. But you have to know your plane WELL, and have the
>
> >ri=
>
> >ght conditions, and fully understand the consequences of pooching it!
>
> >
>
> >Get out there and practice!
>
> >
>
> >Kirk
>
> >66
>
>
>
> and that dear reader illustrates the problem nicely. Emergency procedures
>
> do not have to be formulated for experienced thinking pilots. I would like
>
> to think that I could get away with doing what Kirk has done. Emergency
>
> procedures have to be formulated for the lowest common denominator, would a
>
> low launches pilot be able to achieve success? Would a relatively
>
> experience pilot who is flying minimum launches per year cope with it? That
>
> is what formulating procedures is all about, having something that everyone
>
> can achieve, not just the top 10%.

So, if the dumbest, least competent guy on the airfield might not be able to pull it off the UK solution is to eliminate the requirement for everybody? Talk about dumbing down.

I'm absolutely sure I can pull off at turn back and I'm certain my students can as well. I'll probably have to when I take a check ride in a couple of weeks in a 2-32. If so, the examiner will give me no warning whatsoever when he pulls the release at 200' AGL on departure. No sweat - even though there's no off field options.

I've had it happen for real many times including a couple of "What's this gizmo do?" on ride flights. I've watched post solo students pull it off when a rope broke. If we had not trained for this skill, we wouldn't be here. It's a lifesaver.

Tony V

May 8th 14, 12:18 AM

On 5/7/2014 11:18 AM, Waveguru wrote:
> Can you really get 8kts of sink at 200ft? Where is the air going, into the ground?

Dunno, but one time I was checking out a new club member in a Blanik. We
were on short final, rwy 16 at 3B3, when I said something like "this is
perfect, the right position at the right speed". About 5 seconds later I
couldn't see the rwy 'cause the tree tops were in the way. The thing
that saved us was the extra speed in anticipation of the wind gradient.

Tony "6N"

waremark

May 8th 14, 12:23 AM

We have a
rule here in the UK, launch failure on aerotow below 300ft a landing should
be made ahead, or slightly to one side. No attempt should be made to turn
back below this height.

As a UK FI(S) and FIC, previously a Full Cat instructor, this is news to me. Where is it expressed?

I thought the rule was to exercise judgement. I always address 'where would you go now' issues with students and on check flights. In most conditions and situations I would turn back from lower than 300 foot.

Bruce Hoult

May 8th 14, 12:50 AM

On Wednesday, May 7, 2014 11:49:46 PM UTC+12, James Metcalfe wrote:
> At 06:55 07 May 2014, Bruce Hoult wrote:
> >[1] handy formula: X knots of kinetic energy is worth (X/5)^2 feet of
> gravitational potential energy. e.g. 70 knots = (70/5)^2 = 14^2 = 196 ft.
> 50 knots = (50/5)^2 = 10^2 = 100 ft. Less drag loses of course.
> You'll never turn speed into quite that much height, and you'll need more
> height than that to get speed. But the differences are large in a high
> performance glider at moderate speeds.
>
> ..or you could use my rule of thumb: a change of speed of 10 knots IAS
> gives
> you (or costs you) the number of feet in height of the speed you arrive at.
>
> For example:
>
> 70 knots to 60 knots : plus 60 feet
> 60 knots to 70 knots: minus 60 feet
> 70 knots to 50 knots (i.e. 70 to 60, then 60 to 50) : (60+50) = plus 110
> feet

It's nearly the same formula. If you made it "every 12.5 knots IAS" instead of 10 then it'd be nearly exact.

The derivative of my formula (X/5)^2 i.e. X^2/25 is X/12.5. So gaining or losing X feet at X knots takes roughly 12.5 knots of speed change.

Doing it using the speed you're changing *to* is clever, as it makes some allowance for drag losses. However your height estimates are systematically biased 20% too large.

If you said 70 to 50 is (60+50)-20% = 110-22 = a gain of 88 ft then that would be good.
And 50 to 70 is (60+70)-20% = 130-26 = a loss of 104 ft, which is pretty good too.

If you're doing something like "how high can I zoom to after a 140 knot low pass and still have 60 knots for the circuit?" then I'm not convinced that adding up eight numbers is easier than calculating two squares and subtracting them :-)

By me: 28^2 - 12^2 = ~800 - ~150 = 650 ft (784-144 = 640 if you do it exact)
By you: 130+120+110+100+90+80+70+60 = 760 ft
By you with my -20% correction: 760 - 152 = 608

(remember folks, that's 140 knots at the END of the low pass, not the start!)

150flivver

May 8th 14, 01:00 AM

Someone wrote:
"Turns do not cause stall/spin accidents. In fact, the steeper the turn, the greater the stall margin. That's because elevator authority is progressively used up making the glider turn as the bank gets steeper until the angle of attack can't be raised above stall. Try it. You'll find many gliders will run out of up elevator before they can be stalled at bank angles over 45 degrees."

Any comments on the above statement. Steep turns offer a greater stall margin--really?

Bruce Hoult

May 8th 14, 01:05 AM

On Thursday, May 8, 2014 1:20:33 AM UTC+12, Vaughn wrote:
> The comparison isn't quite as simple as just looking at L/D. Turn
> radius also has a lot to do with your chances of making it back to the
> field, and turn radius is proportional to the SQUARE of airspeed.
>
> Compare your example (40 knot stall) with a (horrors) 2-33. The highest
> stall listed for a 2-33 is around 30 knots. If you do the math, you
> will find that your DG1000 has nearly double the turn radius of the
> slower glider.

I've done the math :-) With a 30 knot stall instead of 40, you'll want 41 knots for that 45º banked turn instead of 55 knots. And, yes, the radius will be about 56% as large, or about 65m instead of 115.

Whether that 100m difference laterally after the turn makes a difference is highly airfield dependent. On a wide field you can land straight in in either case. Somewhere else, it might put you on the wrong side of a row of trees.

In a typical place, I'd much rather be twice as far off the center line with twice the L/D :-)

Bob Whelan[_3_]

May 8th 14, 02:14 AM

On 5/7/2014 6:00 PM, 150flivver wrote:
> Someone wrote: "Turns do not cause stall/spin accidents. In fact, the
> steeper the turn, the greater the stall margin. That's because elevator
> authority is progressively used up making the glider turn as the bank gets
> steeper until the angle of attack can't be raised above stall. Try it.
> You'll find many gliders will run out of up elevator before they can be
> stalled at bank angles over 45 degrees."
>
> Any comments on the above statement. Steep turns offer a greater stall
> margin--really?
>

We're really drifting away from this thread's initial topic, but if some folks
learn a useful thing or two from so doing, then maybe thread drift ain't
always so bad!

I think I can relate to the (presumed on my part) bemusement underlying the
question...it took some cogitation on my part when first exposed to the
concept, too.

My short form answer to the question is: Yes.

Assuming a still atmosphere, consider what constitutes a wing stall, what
control is used to drive the wing to stalling angle of attack, and what that
control has to be doing to get/sustain the glider into a constant speed bank,
and the light bulb may begin to glimmer.

And if you're a glider pilot with access to a glider capable of stalling the
wing in steady, 1G flight, go try it out at a safe height (e.g. steep
thermalling)...and ponder some more. Remember, it's not the speed, it's the
angle (of attack)...glider pilots are just used to using speed in the pattern
as a proxy for AoA.

Bob W.

P.S. I am not a lawyer nor have I ever played one on TV, but do keep in mind
two things: 1) all free instruction is worth exactly what you paid for it; 2)
the reader assumes all risks involved in testing any advice they may presume I
may be offering... :-)

Bruce Hoult

May 8th 14, 02:24 AM

On Thursday, May 8, 2014 3:34:48 AM UTC+12, Bill D wrote:
> You're exaggerating the stall speed differences. Regardless of what the 2-33 "manual" says, no 2-33 ever got as slow as 30 knots. 35 knots is a practical minimum speed. The flight test stall speed for a DG 1000 is 37 knots.

I knew 40 knots was conservative with the DG1000 stall speed, but that difference is less than I'd have expected. I've never flown a 2-33, but I've had Blaniks under 35 knots :-)

> However, no one should consider a turn back at stall speed. Virtually all gliders will be at 50 - 55 knots so the turn radius will be essentially the same.

I've put together a spreadsheet for the calculations and In fact it turns out that for minimum loss of height in a 180º turn -- and also much smaller turn radius -- you should fly a bit faster and bank a bit steeper.

https://docs.google.com/spreadsheets/d/1tXeOBMg4EsBMW8YgNbRdRyzHkWZUyFXBnfP8tauGK1k

No matter what your stall speed or L/D, it turns out the optimum to minimise loss of height in a turn is to bank at 54.7 degrees.

This is the bank angle at which the total G loading is 1.732 (sqrt(3)) and the G available to turn you is 1.414 (sqrt(2)).

In that glass ship with 120 fpm min sink at 45 knots you're looking at 67m turn radius at 59 knots, with 24 feet loss of height in a 180º turn.

In a Blanik with 160 fpm at 42 knots you'll get a 58m turn radius at 55 knots, with 30 feet loss of height.

In a 2-33 with 168 fpm at 35 knots you'll get a 40.5m turn radius at 46 knots, with 26 feet loss of height.

Feel free to play.

Bruce Hoult

May 8th 14, 02:46 AM

On Thursday, May 8, 2014 12:00:45 PM UTC+12, 150flivver wrote:
> Someone wrote:
>
> "Turns do not cause stall/spin accidents. In fact, the steeper the turn, the greater the stall margin. That's because elevator authority is progressively used up making the glider turn as the bank gets steeper until the angle of attack can't be raised above stall. Try it. You'll find many gliders will run out of up elevator before they can be stalled at bank angles over 45 degrees."
>
>
>
> Any comments on the above statement. Steep turns offer a greater stall margin--really?

Sure.

If you have a glider that stalls at 35 knots then in a 60º banked turn (2 Gs) at 49.5 knots your turn radius is about 38m.

If your glider has 6m (20ft) between the wing and the tailplane then they are 9 degrees around the circle from each other and will see 9º different angle of attack to each other compared to straight and level flight. That 9º comes off your available back elevator movement.

In a corresponding 5G turn the numbers are 78.46º of bank, 78.3 knots, 33..8m radius and over 10 degrees of difference between wing and tailplane airflow. Plus you're going to need a lot more back elevator to pull those Gs.

Can you stall your glider in straight and level flight if you don't use the last 9 or 10 degrees of elevator deflection?

Another factor is that in a high G steep turn the two wingtips are seeing more more nearly the same airspeed and same angle of attack. So even if you do manage to stall, the spin tendency is much less and the merest easing of back pressure will stop it instantly.

son_of_flubber

May 8th 14, 02:51 AM

On Wednesday, May 7, 2014 2:40:09 PM UTC-4, Don Johnstone wrote:
> Emergency procedures do not have to be formulated for experienced thinking pilots.

Why do so many experienced thinking pilots enter spins from low altitude turns?

I want to know because I'm becoming more experienced and thoughtful with every flight.

[email protected]

May 8th 14, 04:37 AM

>
> Why do so many experienced thinking pilots enter spins from low altitude turns?
>
> I want to know because I'm becoming more experienced and thoughtful with every flight.

My sincere sympathies to the friends and family of this pilot. John did a great job explaining the the answer to this question: Why do experienced pilots spin in low. Here is a link to his thoughts:

https://groups.google.com/forum/?fromgroups#!searchin/rec.aviation.soaring/john$20cochrane|sort:date/rec.aviation.soaring/ibhUAkQ6Z1s/8WoOYyZIlqEJ

Stay safe,
Bruno - B4

[email protected]

May 8th 14, 05:02 AM

"Why is anyone aero towing with a tow hook that will back release?"

Some of us don't have much of a choice. For example the two ASW-19's and two ASW-15's at my field all have both a C of G hook AND a forward mounted aerotow hook. The forward hooks have a back release function as well. Short of engineering, building, installing and getting an STC from Transport Canada for a completely redesigned forward hook mechanism there's not much we can do about this.

Bruce Hoult

May 8th 14, 06:00 AM

On Thursday, May 8, 2014 3:37:26 PM UTC+12, wrote:
> > Why do so many experienced thinking pilots enter spins from low altitude turns?
>
> > I want to know because I'm becoming more experienced and thoughtful with every flight.
>
> My sincere sympathies to the friends and family of this pilot. John did a great job explaining the the answer to this question: Why do experienced pilots spin in low. Here is a link to his thoughts:
>
> https://groups.google.com/forum/?fromgroups#!searchin/rec.aviation.soaring/john$20cochrane|sort:date/rec.aviation.soaring/ibhUAkQ6Z1s/8WoOYyZIlqEJ

Hi Bruno, and thanks for all the great videos.

I agree with what John says there. The primary one is that around steep hills adverse horizontal gusts are a much bigger danger than many people realise, and a bigger danger than sink.

I vary my speed a lot. When I'm pointing at the rocks, or low over them, I want to see 65-70 knots on the clock on a normal day. A sudden 20 knot gust up the tail isn't going to stall me. If it's windy then I'll use 80.

As soon as I'm pointing away from the ridge and suddenly have hundreds of feet under the nose I'm happy to drop it back to 50 or 55, and accelerate again as I turn back towards the hill.

You can see an example here, in a video a passenger shot back in 2009 on their iPhone 3GS (the new ones are MUCH better).

https://www.youtube.com/watch?v=IU8IDDBgwg0

Remember: it's not actually the gust from behind and loss of airspeed that makes you stall and spin -- it's only if/when YOU pull the stick back to try to stop the nose from dropping (or to tighten the turn). If you keep the stick in the same place it was before the gust then YOU CAN NOT STALL/SPIN. The nose will drop. You'll eventually speed up again. Nothing worse than that will happen provided there is nothing solid in front of you, even if the ASI is reading well below your 1 G stall speed.

The bigger mystery is why competent people stall and spin over flat land, on the notorious turn from base to final.

If it's windy then the gradient can explain it. The lower wingtip gets less windspeed, less lift. The upper wingtip gets more speed, more lift. You could get rolled a lot, rather than a spin as such. Still not healthy. Turning higher can keep you out of the gradient. Flying faster will keep everything flying and give you more control authority.

That's on turns into wind (for landing). With turns away from the wind (turning back after a PTT), the gradient helps you into the turn at the start, but helps right you as you complete it.

Not that I want to be landing downwind on a day with enough wind to have that kind of gradient!! Fortunately, on those days you should have plenty of height over the fence to do a proper circuit.

son_of_flubber

May 8th 14, 01:50 PM

On Wednesday, May 7, 2014 9:51:43 PM UTC-4, son_of_flubber wrote:

> Why do so many experienced thinking pilots enter spins from low altitude turns?

The explanations offered for ridge flyers make sense. I wonder if risk taken in normal ridge flying (and the low-altitude experience gained) reduce pattern spin risk?

On Thursday, May 8, 2014 1:00:20 AM UTC-4, Bruce Hoult wrote:

> The bigger mystery is why competent people stall and spin over flat land, on the notorious turn from base to final.

Just after posting my question, I found something in Dr. Dan's latest Soaring RX column "How to Spin Unintentionally":

Dr. Dan wrote in Soaring Magazine May 2014:
>>>"We may get into trouble because we spend too much of our time soaring and not enough doing pattern tows. Our brains then build patterns that don't include the sensations of low-level flight. A reason to go to the airfield and do pattern work on poor soaring days is to rebuild those low-level gestalts, so that our brains easily shift from the high-altitude to the low-altitude vection sensations as both being normal and expected."

This is a compelling idea. As the average duration of my flights gets longer, I get relatively more experience flying at high-altitude than at low-altitude. I spent a much higher percentage of my time doing pattern tows as a student pilot. As a student, I was much more current at low-altitude flight. Dr. Dan recommends pattern tows to keep my low-altitude proficiency current and in balance with my ever stronger high-altitude proficiency.

Dr. Dan also notes (as have others) that soaring pilots can refresh their proficiency in low-altitude flight by practicing ground reference maneuvers in a power plane (with a CFI that is current in low-level flight).

So the next time that the lift does not materialize at the airport, I will 'waste money' on some pattern tows. I also plan to 'waste money' flying ground-reference maneuvers in a power plane with a current CFI.

JJ Sinclair[_2_]

May 8th 14, 02:00 PM

Well, we have plenty of opinions about what to do after the rope suddenly releases, lets take a quick check on how to keep the rope firmly attached until we decide to release it. When you hooked up the rope, did the 'pull' feel normal? If it didn't take much of a pull, one of the springs in the over-center mechanism may have failed. Did the cable return all the way back into its tube? If not, broken cable strands may be flaring out and preventing the tow hook from returning all the way back to its fully closes and locked position. I have seen low altitude releases caused by both of these malfunctions.
Condolences to the family,
JJ

Don Johnstone[_4_]

May 8th 14, 02:54 PM

At 04:02 08 May 2014, wrote:
>"Why is anyone aero towing with a tow hook that will back release?"
>
>Some of us don't have much of a choice. For example the two ASW-19's and
>tw=
>o ASW-15's at my field all have both a C of G hook AND a forward mounted
>ae=
>rotow hook. The forward hooks have a back release function as well. Short
>o=
>f engineering, building, installing and getting an STC from Transport
>Canad=
>a for a completely redesigned forward hook mechanism there's not much we
>ca=
>n do about this.=20
>
I had for a time an ASW17 which has the same release arrangement as the
ASW15,19,and 20. There was a wooden block attached to the rear of the
aerotow release aperture which prevented operation of the back release. It
never crossed my mind that this was not how it was built. It was
effective.
In the days of yore it was common practice to use bodge tape to prevent the
operation of the back release when aerotowing.

James Metcalfe

May 8th 14, 05:44 PM

At 23:50 07 May 2014, Bruce Hoult wrote:
> However your height estimates are systematically biased 20% too large.
Well, about 8% for a pull-up, and 17% for a dive - at the high-speed end of
the scale.
(Better and worse, respectively, at the low-speed end.) Whereas your rule
is about 10%
low throughout.

> By me: 28^2 - 12^2 = ~800 - ~150 = 650 ft (784-144 = 640 if you do it
exact)
> By you: 130+120+110+100+90+80+70+60 = 760 ft
> By you with my -20% correction: 760 - 152 = 608
And the truth (from v^2 = u^2 + 2gh ... whence we both started, I'm sure)
is 708.66 ft. (I
knew you'd like the ".66" ;o) )

Spreadsheet here: http://tinyurl.com/mzokpyk for those amused by such
things.

But of course these are both rules of thumb, intended more to give better
understanding
than for exact calculation. I have more often referred to mine in
discussing recovery of
lost speed low on finals (or after a low winch-launch failure) than for the
120kt beat-up
case!

Robert M

May 8th 14, 09:05 PM

On Thursday, May 8, 2014 7:00:00 AM UTC-6, JJ Sinclair wrote:
> Well, we have plenty of opinions about what to do after the rope suddenly releases, lets take a quick check on how to keep the rope firmly attached until we decide to release it.

It is interesting how this discussion has become a data geek's exchange about the physics of a turn back. If the rope had stayed attached he would likely not have tried to turn back, if indeed that is what he tried to do. Apparently no one saw it.

I was always told a Superior pilot uses his superior judgment to keep himself out of situations where his superior piloting skill are needed. The superior judgment in this case would be to not use a back releasing tow hook for aero tow.

When you hooked up the rope, did the 'pull' feel normal? If it didn't take much of a pull, one of the springs in the over-center mechanism may have failed.

JJ, the "Zuni towhook" does not use an over center system. This one of the problems with it. Unlike the Tost hook the force to actuate it is proportional to the tow rope tension.

I am very interested in knowing if there is an obvious malfunction of any part of the tow release system, that was not caused by the actual crash.

Robert Mudd

Bruce Hoult

May 9th 14, 01:16 AM

On Friday, May 9, 2014 4:44:38 AM UTC+12, James Metcalfe wrote:
> At 23:50 07 May 2014, Bruce Hoult wrote:
> (Better and worse, respectively, at the low-speed end.) Whereas your rule
> is about 10% low throughout.

Yes, it's deliberately biased a little to the low side from the true (as you note) /4.7516 to make it more of a "guaranteed to pull up that far". Also useful for "I'd like to be down on that ridge line, but I don't want to overspeed". Of course in that case the height difference is going to be pure guess anyway.

I've contemplated using /4 for dives where you want to make sure you have some minimum speed, but I think that overdoes it. /4.5 would be better but not easy to calculate in your head.

May 9th 14, 01:39 AM

On Tuesday, May 6, 2014 6:20:44 PM UTC-7, Bill D wrote:
> On Tuesday, May 6, 2014 5:56:44 PM UTC-6, Don Johnstone wrote:
>
> > At 22:22 06 May 2014, Bill D wrote:
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> >
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> > >On Tuesday, May 6, 2014 2:41:23 PM UTC-6, Don Johnstone wrote:
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> >
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> > >
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> >
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> > >> Frankly I would be horrified to be required to conduct a turn back at
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> >
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> > >>=20
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> >
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> > >> 200ft, I would suggest that this is one of those occasions where the
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> >
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> > >dang=
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> >
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> > >er
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> >
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> > >>=20
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> >
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> > >> of practice is to great to justify.
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> >
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> > >
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> >
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> > >If you should check out in the USA, you'll be required to demonstrate
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> >
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> > >compe=
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> >
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> > >tence in this maneuver. Every pre-solo student is required to do so and
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> >
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> > >mo=
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> >
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> > >re than a half century of safety records do not suggest a problem. In
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> >
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> > >fact=
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> >
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> > >, even with low performance gliders, there's quite a large safety margin.
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> >
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> > >T=
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> >
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> > >he most likely outcome is a pilot will find the glider uncomfortably high
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> >
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> > >f=
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> >
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> > >or a downwind landing requiring full spoilers and a slip.
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> >
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> > >
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> >
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> > >The logic is simple - it's better to have pilots trained for the option.
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> >
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> > >N=
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> >
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> > >o one says a pilot is required to turn back or that 200' is always
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> >
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> > >adequate=
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> >
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> > > to do so. What is illogical is to suggest a pilot be required to crash
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> >
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> > >in=
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> >
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> > > unlandable terrain when a safe option exists to land on the departure
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> >
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> > >runw=
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> >
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> > >ay.
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> >
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> > >
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> >
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> > What are you trying to save? The pilot or the aircraft? The priority should
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> >
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> > be survival of the soft bit, that is you and me.
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> >
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> > As an instructor with nearly 50 years experience I know that when I
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> >
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> > initiate an emergency procedure I do so allowing a margin to ensure my
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> >
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> > survival if it does not work out, I have been bold but never certifiable.
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> >
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> > Most living instructors have the same survival instinct. That is why I have
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> >
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> > lived long enough to do 10,000 launches, and of course landings. It has
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> >
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> > already been hinted that the practice you describe involves modifying what
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> >
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> > you normally do, in my view that probably makes it pretty useless and not
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> >
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> > real preparation for the event. If you did carry out the training in
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> >
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> > exactly the same way as the possible real event you might find that the
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> >
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> > results were very different, not to mention painful. I will stick with my
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> >
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> > 300ft thank you, I know it works. Low turns, below that height may have
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> >
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> > been acceptable in old wooden gliders, the minimum height in T31 and T21
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> >
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> > gliders was 150ft, but for modern glass gliders it is just far too low, you
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> >
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> > only have to look at the accident statistics to see that low final turns
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> >
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> > figure to a large degree in accidents so why plan for it?
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> >
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> > I repeat a controlled descent with wings level is far more likely to have a
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> >
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> > better result than hitting the ground in a turn or even worse spinning in
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> >
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> > trying to avoid it.
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> >
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> >
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> >
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> > PS Despite all that there have been times when I have initiated a practice
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> >
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> > emergency and very quickly wished I had not, no plan survives first
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> >
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> > contact.
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>
>
> So, you're saying the pilot will be safer if they don't learn to perform the return to runway maneuver when it's safe to do so?
>
>
>
> I can assure you that the higher a glider's performance, the safer it is. It's the old, low L/D gliders that can run out of altitude before getting lined up with the runway.

The discussion seems to focus exclusively on the decision height for a turn around. I think that is only one factor in making this decision. As reported by Bob T there was heavy sinking air on the departure end of the runway. Returning to the airport would have required transiting thru this air a 2nd time, which strikes me as inadvisable without much more altitude than Knauff had.

The other issue is that a tow rope break requires immediate lowering of the nose. This is done routinely at altitude, but at low altitude this means pointing the glider's nose uncomfortably down at the ground while executing a steep banked turn. If the ground is rising, as it is at Sampley, the picture seen by the pilot is even more disturbing. All that it takes is a momentary hesitation in this reflex and the outcome can be fatal.

As an aside, I once did a wind mill start in my DG400 below 1000' (over a runway). This maneuver requires achieving in excess of 90 kt airspeed. Because the engine & prop act like dive brakes, you feel like you are standing on your rudder pedals when you do this close to the ground. I got to this airspeed and the prop still didn't rotate. This meant that I had to steepen the descent even more. All of my instincts said no, but my brain said yes, which is what I did. The engine started, but I decided that this maneuver really needs to be started at a higher altitude.

Bill D

May 9th 14, 01:55 AM

On Thursday, May 8, 2014 6:39:06 PM UTC-6, 2G wrote:

> The other issue is that a tow rope break requires immediate lowering of the nose.

Why would anyone lower the nose? The glider is presumably at aero tow speed - 65 - 70 knots which is way above the pattern speed. A better plan is to use the excess airspeed to maintain height while turning until airspeed drops to pattern speed.

This is done routinely at altitude, but at low altitude this means pointing the glider's nose uncomfortably down at the ground while executing a steep banked turn. If the ground is rising, as it is at Sampley, the picture seen by the pilot is even more disturbing. All that it takes is a momentary hesitation in this reflex and the outcome can be fatal.

The nose is not "uncomfortably down". The turn back is a normal turn.
>
>
>
> As an aside, I once did a wind mill start in my DG400 below 1000' (over a runway). This maneuver requires achieving in excess of 90 kt airspeed. Because the engine & prop act like dive brakes, you feel like you are standing on your rudder pedals when you do this close to the ground. I got to this airspeed and the prop still didn't rotate. This meant that I had to steepen the descent even more. All of my instincts said no, but my brain said yes, which is what I did. The engine started, but I decided that this maneuver really needs to be started at a higher altitude.

Aha! You're really a motor glider pilot, not an aero tow pilot which explains your misconceptions.

son_of_flubber

May 9th 14, 02:43 AM

On Thursday, May 8, 2014 8:55:27 PM UTC-4, Bill D wrote:

> Why would anyone lower the nose? The glider is presumably at aero tow speed - 65 - 70 knots which is way above the pattern speed.

Perhaps I have a fundamental misunderstanding...
but I thought that the AofA at 65 knots on aerotow is steeper than the AofA at 65 knots in free flight. So if you don't reduce the AofA (aka drop the nose) after the rope breaks, the glider will slow down. If you start the turn before reducing the AofA, you may find yourself going too slow for the turn.

It is true that you can use the speed coming off aerotow or PTOT to gain a bit of altitude, but that just means lowering the nose gradually as you bleed off the speed. In both cases the AofA needs to be adjusted to match the desired free flight speed.

I thought that we practiced this 'gain altitude and slowly drop the nose' every time we release from aerotow?

Bruce Hoult

May 9th 14, 03:06 AM

On Wednesday, May 7, 2014 1:20:44 PM UTC+12, Bill D wrote:
> I can assure you that the higher a glider's performance, the safer it is. It's the old, low L/D gliders that can run out of altitude before getting lined up with the runway.

It's a mystery to me why some people think you can "get away with" so much more in old gliders than in those great big heavy clumsy glass ones.

Somewhere in this thread I saw a statement that you could safely turn back from 150 ft in an old glider (which I agree with), but you're a dead man if you try it below 300 ft in glass.

The differences that govern such a thing just aren't that big!

Let's look at some numbers for weight and wing area of typical training gliders (from Wikipedia):

ASK13: 290 kg, 17.5 m^2
Blanik L13: 292 kg, 19.15 m^2

PW6: 360 kg, 15.3 m^2
ASK21: 360 kg, 17.95 m^2
Puchacz: 368 kg, 18.16 m^2
Janus: 365 kg, 17.3 m^2

G103: 390 kg, 17.9 m^2
Duo Discus: 410 kg, 16.4 m^2
DG1000: 415 kg, 17.5 m^2

There's not a lot of difference in the wing areas, with individual variations bigger than the generational differences.

Yes, the glass ones weigh a bit more. How much more?

Someone flying solo in an ASK21 is at about the same all up weight as someone in a ASK13 with a smaller than average instructor in the back seat.

Someone flying solo in a DG1000 is at about the same all up weight as someone in a ASK13 with a largish instructor in the back seat.

We expect students to be able to cope with the flying characteristic differences between having an instructor and not having one -- and to cope with that difference on their first time flying alone!

Bill D

May 9th 14, 03:41 AM

On Thursday, May 8, 2014 7:43:42 PM UTC-6, son_of_flubber wrote:
> On Thursday, May 8, 2014 8:55:27 PM UTC-4, Bill D wrote:
>
>
>
> > Why would anyone lower the nose? The glider is presumably at aero tow speed - 65 - 70 knots which is way above the pattern speed.
>
>
>
> Perhaps I have a fundamental misunderstanding...
>
> but I thought that the AofA at 65 knots on aerotow is steeper than the AofA at 65 knots in free flight.
---------------
I think you are confusing pitch attitude with angle of attack. In unaccelerated flight, for a given weight and airspeed, the AOA will always be the same whether you are being towed or not.
------------
So if you don't reduce the AofA (aka drop the nose) after the rope breaks, the glider will slow down.
------------
Yes it will slow down if the pitch attitude isn't reduced. However, lowering the nose to establish a normal glide at pattern speed will actually see an increase in AOA due to the lower speed - you're just changing the flight path from a climb to a glide at a slower speed.
--------------
If you start the turn before reducing the AofA, you may find yourself going too slow for the turn.
--------------
What you are saying is if the pilot attempts a turn while continuing the nose-up climb after a rope break, the glider will slow down. Of course it will but in most cases this is desirable since the tow speed was well above pattern speed. Just don't continue the slowdown below pattern speed. The AOA is more closely related to airspeed than pitch attitude.
>
>
>
> It is true that you can use the speed coming off aerotow or PTOT to gain a bit of altitude, but that just means lowering the nose gradually as you bleed off the speed. In both cases the AofA needs to be adjusted to match the desired free flight speed. I thought that we practiced this 'gain altitude and slowly drop the nose' every time we release from aerotow?

Yes, this technique is correct but the glider is just transitioning from being towed to a normal glide. The AOA will actually increase as the glider slows down.

Discussions like this highlights why gliders should have an AOA indicator in addition to and ASI.

[email protected]

May 9th 14, 02:42 PM

On Thursday, May 8, 2014 9:43:42 PM UTC-4, son_of_flubber wrote:
> On Thursday, May 8, 2014 8:55:27 PM UTC-4, Bill D wrote:
>
>
>
> > Why would anyone lower the nose? The glider is presumably at aero tow speed - 65 - 70 knots which is way above the pattern speed.
>
>
>
> Perhaps I have a fundamental misunderstanding...
>
> but I thought that the AofA at 65 knots on aerotow is steeper than the AofA at 65 knots in free flight. So if you don't reduce the AofA (aka drop the nose) after the rope breaks, the glider will slow down. If you start the turn before reducing the AofA, you may find yourself going too slow for the turn.
>
>
>
> It is true that you can use the speed coming off aerotow or PTOT to gain a bit of altitude, but that just means lowering the nose gradually as you bleed off the speed. In both cases the AofA needs to be adjusted to match the desired free flight speed.
>
>
>
> I thought that we practiced this 'gain altitude and slowly drop the nose' every time we release from aerotow?

You have a few things wrong.
First- angle of attack is related to the geometry of the glider and airflow over it. On tow the attitude of the glider is slightly nose up relative to the ground compared to the attitude it would have at the same angle of attack in a gliding configuration.
Second- "Every time" implies that we handle all releases the same. In normal flight we will transition from tow attitude and speed to gliding attitude and the associated speed. If in lift, that likely means slowing to thermalling speed. If not in lift we would be going to the appropriate speed to fly.
Third- There is no reason to try to gain altitude in PTT as the amount of gain accomplished by going from tow speed to pattern/approach speed is likely to be quite small. The correct action is to lower the nose slightly to establish a gliding attitude and speed appropriate for the conditions. In many cases, tow speed is about right for the return to the runway.
Also note that "every time" we turn right on release because that is standard. There is a 50% chance that, due to wind velocity and direction(including shear that may be present), terrain considerations, and position, that the correct action is to turn left.
These considerations are why we MUST have an emergency response plan in mind on every launch. There is no time to figure it out- you must execute the plan you have in your head already.
And forget all the mumbo jumbo calculations espoused in this thread.
UH

Tom[_12_]

May 9th 14, 03:42 PM

This discussion clearly indicates one of the fundamental reasons gliding safety is far worse than it should be. Issues such as rope breaks (PT3) have been discussed over and over again, for many years, and this thread demonstrates the wide variation of knowledge of procedures of this and other common launching emergencies.

Also, one must wonder how many pilots flying gliders with the Tost tow hook have ever returned them to the factory for the required periodic overhaul.

Considering who the glider community is - intelligent, well educated, well to do individuals, you must wonder why most simply go out of their way to avoid the simple educational process which will allow safe flight.

Tom Knauff

Chris Rollings[_2_]

May 9th 14, 05:33 PM

At 14:42 09 May 2014, Tom wrote:
>This discussion clearly indicates one of the fundamental reasons gliding
>sa=
>fety is far worse than it should be. Issues such as rope breaks (PT3)
have
>=
>been discussed over and over again, for many years, and this thread
>demonst=
>rates the wide variation of knowledge of procedures of this and other
>commo=
>n launching emergencies.
>
>Also, one must wonder how many pilots flying gliders with the Tost tow
>hook=
> have ever returned them to the factory for the required periodic
overhaul.
>
>Considering who the glider community is - intelligent, well educated,
well
>=
>to do individuals, you must wonder why most simply go out of their way to
>a=
>void the simple educational process which will allow safe flight.
>
>Tom Knauff
>
>
Not for the first time, I find myself in complete agreement with you Tom.

Chris Rollings

Don Johnstone[_4_]

May 10th 14, 12:59 AM

At 16:33 09 May 2014, Chris Rollings wrote:
>At 14:42 09 May 2014, Tom wrote:
>>This discussion clearly indicates one of the fundamental reasons gliding
>>sa=
>>fety is far worse than it should be. Issues such as rope breaks (PT3)
>have
>>=
>>been discussed over and over again, for many years, and this thread
>>demonst=
>>rates the wide variation of knowledge of procedures of this and other
>>commo=
>>n launching emergencies.
>>
>>Also, one must wonder how many pilots flying gliders with the Tost tow
>>hook=
>> have ever returned them to the factory for the required periodic
>overhaul.
>>
>>Considering who the glider community is - intelligent, well educated,
>well
>>=
>>to do individuals, you must wonder why most simply go out of their way
to
>>a=
>>void the simple educational process which will allow safe flight.
>>
>>Tom Knauff
>>
>>
>Not for the first time, I find myself in complete agreement with you Tom.
>
>Chris Rollings
>
Me too

Don Johnstone[_4_]

May 10th 14, 01:13 AM

At 02:06 09 May 2014, Bruce Hoult wrote:
>On Wednesday, May 7, 2014 1:20:44 PM UTC+12, Bill D wrote:
>> I can assure you that the higher a glider's performance, the safer it
is.
>It's the old, low L/D gliders that can run out of altitude before getting
>lined up with the runway.
>
>It's a mystery to me why some people think you can "get away with" so
much
>more in old gliders than in those great big heavy clumsy glass ones.
>
>Somewhere in this thread I saw a statement that you could safely turn
back
>from 150 ft in an old glider (which I agree with), but you're a dead man
if
>you try it below 300 ft in glass.
>
>The differences that govern such a thing just aren't that big!
>
>Let's look at some numbers for weight and wing area of typical training
>gliders (from Wikipedia):
>
>ASK13: 290 kg, 17.5 m^2
>Blanik L13: 292 kg, 19.15 m^2
>
>PW6: 360 kg, 15.3 m^2
>ASK21: 360 kg, 17.95 m^2
>Puchacz: 368 kg, 18.16 m^2
>Janus: 365 kg, 17.3 m^2
>
>G103: 390 kg, 17.9 m^2
>Duo Discus: 410 kg, 16.4 m^2
>DG1000: 415 kg, 17.5 m^2
>
>There's not a lot of difference in the wing areas, with individual
>variations bigger than the generational differences.
>
>Yes, the glass ones weigh a bit more. How much more?
>
>Someone flying solo in an ASK21 is at about the same all up weight as
>someone in a ASK13 with a smaller than average instructor in the back
seat.
>
>Someone flying solo in a DG1000 is at about the same all up weight as
>someone in a ASK13 with a largish instructor in the back seat.
>
>We expect students to be able to cope with the flying characteristic
>differences between having an instructor and not having one -- and to
cope
>with that difference on their first time flying alone!

I think you are missing the point. The difference between the perceived
attitude of a Discus flying at 45kts (too slow) or 55kts (much better) in a
turn is very small, easy to get wrong.
The perceived attitude difference in a T21 Sedburgh between 35kts (slow)
and 45kts(better) is quite large, easy to spot if you got it wrong. Bearing
in mind that a T21 would not stall until you got it back to 22-25kts made
low turns much more unexciting. The T21 and T31 are the gliders I was
referring to.
When it all turns to ratsh1t in a glass glider it happens that much more
quickly than it ever did in wood.

CindyB[_2_]

May 10th 14, 01:57 AM

On Friday, May 9, 2014 4:59:59 PM UTC-7, Don Johnstone wrote:
> At 16:33 09 May 2014, Chris Rollings wrote:
>
> >At 14:42 09 May 2014, Tom wrote:
> must wonder why most simply go out of their way to
> avoid the simple educational process which will allow safe flight.
>
> >>Tom Knauff
>

> >Not for the first time, I find myself in complete agreement with you Tom.
>
> >Chris Rollings
>
> >
>
> Me too

Me three. That makes it unanimous. Both sides of the pond, and both coasts.
If we count Dean Carswell, that's both sides of the here and after.

Cindy B

Chris Rollings[_2_]

May 10th 14, 08:20 AM

At 00:13 10 May 2014, Don Johnstone wrote:
>At 02:06 09 May 2014, Bruce Hoult wrote:
>>On Wednesday, May 7, 2014 1:20:44 PM UTC+12, Bill D wrote:
>>> I can assure you that the higher a glider's performance, the safer it
>is.
>>It's the old, low L/D gliders that can run out of altitude before
getting
>>lined up with the runway.
>>
>>It's a mystery to me why some people think you can "get away with" so
>much
>>more in old gliders than in those great big heavy clumsy glass ones.
>>
>>Somewhere in this thread I saw a statement that you could safely turn
>back
>>from 150 ft in an old glider (which I agree with), but you're a dead man
>if
>>you try it below 300 ft in glass.
>>
>>The differences that govern such a thing just aren't that big!
>>
>>Let's look at some numbers for weight and wing area of typical training
>>gliders (from Wikipedia):
>>
>>ASK13: 290 kg, 17.5 m^2
>>Blanik L13: 292 kg, 19.15 m^2
>>
>>PW6: 360 kg, 15.3 m^2
>>ASK21: 360 kg, 17.95 m^2
>>Puchacz: 368 kg, 18.16 m^2
>>Janus: 365 kg, 17.3 m^2
>>
>>G103: 390 kg, 17.9 m^2
>>Duo Discus: 410 kg, 16.4 m^2
>>DG1000: 415 kg, 17.5 m^2
>>
>>There's not a lot of difference in the wing areas, with individual
>>variations bigger than the generational differences.
>>
>>Yes, the glass ones weigh a bit more. How much more?
>>
>>Someone flying solo in an ASK21 is at about the same all up weight as
>>someone in a ASK13 with a smaller than average instructor in the back
>seat.
>>
>>Someone flying solo in a DG1000 is at about the same all up weight as
>>someone in a ASK13 with a largish instructor in the back seat.
>>
>>We expect students to be able to cope with the flying characteristic
>>differences between having an instructor and not having one -- and to
>cope
>>with that difference on their first time flying alone!
>
>I think you are missing the point. The difference between the perceived
>attitude of a Discus flying at 45kts (too slow) or 55kts (much better) in
a
>turn is very small, easy to get wrong.
>The perceived attitude difference in a T21 Sedburgh between 35kts (slow)
>and 45kts(better) is quite large, easy to spot if you got it wrong.
Bearing
>in mind that a T21 would not stall until you got it back to 22-25kts made
>low turns much more unexciting. The T21 and T31 are the gliders I was
>referring to.
>When it all turns to ratsh1t in a glass glider it happens that much more
>quickly than it ever did in wood.
>
>

All completely correct but there is one even bigger problem, most pilots
when making a low level turn off a launch failure or to modify a
circuit/pattern that has got too low, tend to be looking for/at the place
they intend to land with little or no attention to spare for the ASI,
attitude or slip/skid indicator, that's why these events are so productive
of stall/spin accidents. Training needs to emphasise, GLANCE AT THE ASI
EVERY 2 - 3 SECONDS IN THESE CIRCUMSTANCES. Attitude is un unreliable
indicator very near the ground, even the smallest undulations in the
terrain can give a false impression and just being low can make the
attitude look more nose down than it is.

[email protected]

May 10th 14, 11:49 AM

On Wednesday, May 7, 2014 6:24:23 PM UTC-7, Bruce Hoult wrote:

> No matter what your stall speed or L/D, it turns out the optimum to minimise loss of height in a turn is to bank at 54.7 degrees.
>
> Feel free to play.

Thanks Bruce - I did play with this a bit. Always helpful to do the math.

Several observations pop out from the numbers:

1) The 25-30' height loss for a 180 is small compared to the 200' I always use as the minimum safe altitude to make this maneuver. Not that I'm recommending a smaller margin - there are considerations of sink and wind and clearance for the bottom wingtip in the bank.

2) Speaking of the bottom wingtip in the bank, if you subtract that height difference for each different bank angle you get a height loss for a 180 measured at the bottom wingtip that is actually minimal at a lower bank angle than 54.7 degrees. Obviously this would be most likely to apply at the end of the maneuver, not the beginning, unless there is unusual terrain.

3) Whether you include the wingtip clearance in the calculation or not, the total height loss doesn't vary all that much between 30 and 60 degrees of bank - about 6 feet of difference for the center of the aircraft and only a foot or two of difference at the lower wingtip.

The conclusion this draws me to is that the most important consideration in PTT is to make a smooth, coordinated, deliberate turn that you can manage easily - and to make sure not to dig the bottom wing into the ground. Within a pretty broad range, there isn't much percentage in optimizing the bank angle.

9B

Jim White[_3_]

May 10th 14, 12:24 PM

At 07:20 10 May 2014, Chris Rollings wrote:
>All completely correct but there is one even bigger problem, most pilots
>when making a low level turn off a launch failure or to modify a
>circuit/pattern that has got too low, tend to be looking for/at the place
>they intend to land with little or no attention to spare for the ASI,
>attitude or slip/skid indicator, that's why these events are so
productive
>of stall/spin accidents. Training needs to emphasise, GLANCE AT THE ASI
>EVERY 2 - 3 SECONDS IN THESE CIRCUMSTANCES. Attitude is un unreliable
>indicator very near the ground, even the smallest undulations in the
>terrain can give a false impression and just being low can make the
>attitude look more nose down than it is.
>
>
Surely best practice is simply to keep the speed on until you have got it
all sorted. Certainly in modern slippery gliders. Too much speed is much
safer than too little and costs very little in height through a turn.

Isn't this what you taught us Chris?

[email protected]

May 10th 14, 12:28 PM

On Saturday, May 10, 2014 6:49:57 AM UTC-4, wrote:
> On Wednesday, May 7, 2014 6:24:23 PM UTC-7, Bruce Hoult wrote:
>
>
>
> > No matter what your stall speed or L/D, it turns out the optimum to minimise loss of height in a turn is to bank at 54.7 degrees.
>
> >
>
> > Feel free to play.
>
>
>
> Thanks Bruce - I did play with this a bit. Always helpful to do the math.
>
>
>
> Several observations pop out from the numbers:
>
>
>
> 1) The 25-30' height loss for a 180 is small compared to the 200' I always use as the minimum safe altitude to make this maneuver. Not that I'm recommending a smaller margin - there are considerations of sink and wind and clearance for the bottom wingtip in the bank.
>
>
>
> 2) Speaking of the bottom wingtip in the bank, if you subtract that height difference for each different bank angle you get a height loss for a 180 measured at the bottom wingtip that is actually minimal at a lower bank angle than 54.7 degrees. Obviously this would be most likely to apply at the end of the maneuver, not the beginning, unless there is unusual terrain.
>
>
>
> 3) Whether you include the wingtip clearance in the calculation or not, the total height loss doesn't vary all that much between 30 and 60 degrees of bank - about 6 feet of difference for the center of the aircraft and only a foot or two of difference at the lower wingtip.
>
>
>
> The conclusion this draws me to is that the most important consideration in PTT is to make a smooth, coordinated, deliberate turn that you can manage easily - and to make sure not to dig the bottom wing into the ground. Within a pretty broad range, there isn't much percentage in optimizing the bank angle.
>
>
>
> 9B

I agree with B. Further,advocating very steep turns near the ground, even if technically optimum, is likely to result in a less safe result for a number of reasons.
First- few pilots can execute such a turn accurately. Speed control goes to crap as bank gets steeper.
Second- The effect of wind shear is much greater at very steep banks.
Third- Timing of the turn is much harder at high turn rate usually leading to overshoot.
A moderate bank of 30-45 degrees, Tom commonly points out correctly that most pilots, when asked for 45 degrees will come out about 30, is close enough to optimum and much more likely to be executed correctly.
I submit that having a plan that includes turning promptly in the correct direction for the conditions is an order of magnitude more important than the bank angle used.
UH

Bruce Hoult

May 10th 14, 01:33 PM

On Saturday, May 10, 2014 10:49:57 PM UTC+12, wrote:
> On Wednesday, May 7, 2014 6:24:23 PM UTC-7, Bruce Hoult wrote:
> > No matter what your stall speed or L/D, it turns out the optimum to minimise loss of height in a turn is to bank at 54.7 degrees.
>
> 2) Speaking of the bottom wingtip in the bank, if you subtract that height difference for each different bank angle you get a height loss for a 180 measured at the bottom wingtip that is actually minimal at a lower bank angle than 54.7 degrees. Obviously this would be most likely to apply at the end of the maneuver, not the beginning, unless there is unusual terrain.

You also can't change bank angle instantaneously.

I think it makes sense to peak at around 60 degrees of bank as you're about halfway through the turn, and decrease it by the time you're only 45º or so from having reversed direction.

> 3) Whether you include the wingtip clearance in the calculation or not, the total height loss doesn't vary all that much between 30 and 60 degrees of bank - about 6 feet of difference for the center of the aircraft and only a foot or two of difference at the lower wingtip.

The biggest difference between 30º and 60º isn't the couple of meters of difference in height lost, but the 100m difference in lateral displacement at the end of the turn. That means you have to turn further and take more time and height to get back in line with the runway (assuming you don't just have a very wide airfield), and increases the chances of finding yourself on the wrong side of some obstacle.

I think it's completely reasonable to expect students to be able to do a crisp 180º reversal turn using between 45º and 60º of bank more or less instinctively before they get to solo. You use such turns all the time when ridge soaring, either when you discover you've gone too far and got into sink, or just to end up no too far out in front of the ridge.

Bruce Hoult

May 10th 14, 01:51 PM

On Saturday, May 10, 2014 10:49:57 PM UTC+12, wrote:
> 3) Whether you include the wingtip clearance in the calculation or not, the total height loss doesn't vary all that much between 30 and 60 degrees of bank - about 6 feet of difference for the center of the aircraft and only a foot or two of difference at the lower wingtip.

I've added the wingtip calculation.

The bank angle that keeps the wingtip the highest varies with the wingspan .... it's about 39 degrees with 18m wingspan, and 41 degrees with 15m.

The difference in wingtip clearance between this 39º or 41º bank angle and 55º is 1.8 ft for 15m and 2.7 ft for 18m.

If you're low enough for this to make a difference then you probably shouldn't be turning back :-)

I still think the horizontal displacement from the centerline is the biggest factor.

Vaughn

May 10th 14, 02:43 PM

On 5/10/2014 7:24 AM, Jim White wrote:
> Certainly in modern slippery gliders. Too much speed is much
> safer than too little and costs very little in height through a turn.

From the standpoint of preventing stalls, I can only agree. But if
your goal is to actually make it back to the runway, that advice should
be tempered with a bit more information!

Remember that turn radius increases with the SQUARE of airspeed. That
means that a small increase in airspeed will result in a significant
increase in turn radius. As the pilot, your goal in that situation
should be to shoot for the proper airspeed for the situation. Not too
much, but certainly always keeping a margin above stall speed.

By all means don't risk a stall! But remember that too much airspeed
could add to your troubles.

[email protected]

May 10th 14, 04:01 PM

Don't do 60 degree banked turns close to the ground! I don't want to tell someone that's he's wrong, but I think that some people may think that the conclusions are right just because there are some numbers behind them, and start practicing rope breaks with 60 deg banks.
I went through the spread sheet and I found everything correct except for the calculation of the "enhanced sink rate". The sink rate is not just the unbanked rate multiplied by the load factor!
Some manufactures include a circling polar. Using the circling polar of an asw-24 with a total weight of 750 lbs, the speed and sink are:

at 30 deg: 45 kt, 150 ft/min
at 45 deg: 50 kt, 205 ft/min
at 60 deg: 59 kt, 345 ft/min

Now, the time and height lost to complete a full turn (divide by two for a 180 deg turn):

at 30 deg: 26 secs, 64 ft
at 45 deg: 16 secs, 56 ft
at 60 deg: 11 secs, 65 ft

The differences are not much, anyway, but it is easier to bank and unbank at 45 deg.

I gotta go and can't expand, but I'll try to get the numbers based on the real formulas at a later time. In the mean time, you can check Fred Thomas book, Fundamentals of Sailplane Design, pgs 64 and 65. The minimum sink rate in a turn will be higher than the minimum sink rate in level flight by a factor of 1/(cosangle)^1.5

Bill D

May 10th 14, 04:16 PM

On Saturday, May 10, 2014 5:28:51 AM UTC-6, wrote:
> On Saturday, May 10, 2014 6:49:57 AM UTC-4, wrote:
>
> > On Wednesday, May 7, 2014 6:24:23 PM UTC-7, Bruce Hoult wrote:
>
> >
>
> >
>
> >
>
> > > No matter what your stall speed or L/D, it turns out the optimum to minimise loss of height in a turn is to bank at 54.7 degrees.
>
> >
>
> > >
>
> >
>
> > > Feel free to play.
>
> >
>
> >
>
> >
>
> > Thanks Bruce - I did play with this a bit. Always helpful to do the math.
>
> >
>
> >
>
> >
>
> > Several observations pop out from the numbers:
>
> >
>
> >
>
> >
>
> > 1) The 25-30' height loss for a 180 is small compared to the 200' I always use as the minimum safe altitude to make this maneuver. Not that I'm recommending a smaller margin - there are considerations of sink and wind and clearance for the bottom wingtip in the bank.
>
> >
>
> >
>
> >
>
> > 2) Speaking of the bottom wingtip in the bank, if you subtract that height difference for each different bank angle you get a height loss for a 180 measured at the bottom wingtip that is actually minimal at a lower bank angle than 54.7 degrees. Obviously this would be most likely to apply at the end of the maneuver, not the beginning, unless there is unusual terrain.
>
> >
>
> >
>
> >
>
> > 3) Whether you include the wingtip clearance in the calculation or not, the total height loss doesn't vary all that much between 30 and 60 degrees of bank - about 6 feet of difference for the center of the aircraft and only a foot or two of difference at the lower wingtip.
>
> >
>
> >
>
> >
>
> > The conclusion this draws me to is that the most important consideration in PTT is to make a smooth, coordinated, deliberate turn that you can manage easily - and to make sure not to dig the bottom wing into the ground. Within a pretty broad range, there isn't much percentage in optimizing the bank angle.
>
> >
>
> >
>
> >
>
> > 9B
>
>
>
> I agree with B. Further,advocating very steep turns near the ground, even if technically optimum, is likely to result in a less safe result for a number of reasons.
>
> First- few pilots can execute such a turn accurately. Speed control goes to crap as bank gets steeper.
>
> Second- The effect of wind shear is much greater at very steep banks.
>
> Third- Timing of the turn is much harder at high turn rate usually leading to overshoot.
>
UH

Ground reference maneuver training teaches pilots how to very accurately fly turns at low altitudes.

Bob Whelan[_3_]

May 10th 14, 05:00 PM

On 5/10/2014 5:28 AM, wrote:

<Cogent numerical analyses/discussions snipped...>

>> The conclusion this draws me to is that the most important consideration
>> in PTT is to make a smooth, coordinated, deliberate turn that you can
>> manage easily - and to make sure not to dig the bottom wing into the
>> ground. Within a pretty broad range, there isn't much percentage in
>> optimizing the bank angle.

<Snip...>

> I agree with B. Further,advocating very steep turns near the ground, even
> if technically optimum, is likely to result in a less safe result for a
> number of reasons. First- few pilots can execute such a turn accurately.
> Speed control goes to crap as bank gets steeper. Second- The effect of wind
> shear is much greater at very steep banks. Third- Timing of the turn is
> much harder at high turn rate usually leading to overshoot. A moderate bank
> of 30-45 degrees, [Tom Knauff...] points out correctly that most pilots, when
> asked for 45 degrees will come out about 30, is close enough to optimum and
> much more likely to be executed correctly. I submit that having a plan that
> includes turning promptly in the correct direction for the conditions is an
> order of magnitude more important than the bank angle used. UH

How cool (it is to me!) that experienced (instructors, number-crunching
engineers, thoughtful and concerned sailplane pilots) are contributing their
insights on this topic in the wake of what may or may not have been (yet
another) avoidable tragedy involving a low-altitude premature release from
aerotow. I'm sure I'm not alone in thanking them for their heartfelt offerings
toward improving soaring's future accident record.

Writing as a non-instructor, erstwhile practicing engineer and longtime pilot
with a lifelong interest in preservation (of self, soaring, general aviation,
nifty hand-crafted machines, etc.) here's my summation-to-this-point of
takeaway points for similarly interested future readers of this thread:
1) Mental preparation matters - be prepared with an executable plan!
2) Begin executing it as rapidly as informedly and safely practicable.
3) Retain control always!
4) Hit whatever you're going to hit, while still under control and flying.

Everything else is of lesser particular (though not necessarily ignorable :-))
criticality: mental flexibility (really, an extension of 1) above); bank angle
(see preceding-post excerpts above...with which I agree); even arguably speed.
Get the fundamentals right, and the details are much more likely to then be
correct...

Based on both numerous/uncounted field/B.S. conversations about soaring safety
aspects - as well as others' previous contributions to this thread - I'm
convinced "many of us (soaring practitioners)" can benefit from seriously
seeking to comprehend, absorb and internalize "fundamental takeaways" from
these sorts of RAS threads, skeptics notwithstanding...

Thanks everyone!!! Keep contributing!

Bob W.

P.S. Please take my above little attempt at summation as nothing more than one
individual's expressing some things he simply deems important...

Dan Marotta

May 10th 14, 06:22 PM

Let's not forget the time it takes to complete the turn or the distance
covered over the ground.

Without getting into the math, I can comfortably say that, using a 30 deg
bank will take longer to complete the turn and leave you further from the
runway. Likewise, at higher elevation airports your sink speed will be
higher (think true airspeed) so height loss will be greater than at sea
level.

> wrote in message
...
On Wednesday, May 7, 2014 6:24:23 PM UTC-7, Bruce Hoult wrote:

> No matter what your stall speed or L/D, it turns out the optimum to
> minimise loss of height in a turn is to bank at 54.7 degrees.
>
> Feel free to play.

Thanks Bruce - I did play with this a bit. Always helpful to do the math.

Several observations pop out from the numbers:

1) The 25-30' height loss for a 180 is small compared to the 200' I always
use as the minimum safe altitude to make this maneuver. Not that I'm
recommending a smaller margin - there are considerations of sink and wind
and clearance for the bottom wingtip in the bank.

2) Speaking of the bottom wingtip in the bank, if you subtract that height
difference for each different bank angle you get a height loss for a 180
measured at the bottom wingtip that is actually minimal at a lower bank
angle than 54.7 degrees. Obviously this would be most likely to apply at the
end of the maneuver, not the beginning, unless there is unusual terrain.

3) Whether you include the wingtip clearance in the calculation or not, the
total height loss doesn't vary all that much between 30 and 60 degrees of
bank - about 6 feet of difference for the center of the aircraft and only a
foot or two of difference at the lower wingtip.

The conclusion this draws me to is that the most important consideration in
PTT is to make a smooth, coordinated, deliberate turn that you can manage
easily - and to make sure not to dig the bottom wing into the ground. Within
a pretty broad range, there isn't much percentage in optimizing the bank
angle.

9B

[email protected]

May 10th 14, 07:26 PM

On Saturday, May 10, 2014 10:22:28 AM UTC-7, Dan Marotta wrote:
> Let's not forget the time it takes to complete the turn or the distance
> covered over the ground.
>
> Without getting into the math, I can comfortably say that, using a 30 deg
> bank will take longer to complete the turn and leave you further from the
> runway. Likewise, at higher elevation airports your sink speed will be
> higher (think true airspeed) so height loss will be greater than at sea
> level.

Bruce raised the lateral displacement issue as well. Here is a link to a graphical depiction of the main parameters we've been discussing versus bank angle:

https://drive.google.com/file/d/0Bw1ChKkWEYLNZHlVT2pjNjNudFk/edit?usp=sharing

As to the lateral displacement versus bank angle tradeoff, I have some thoughts:

For the range of bank angles being discussed you are going to end up 400-600 feet (two turn radii) laterally displaced from the centerline (less wind drift - assuming a turn into any crosswind component). Where that puts you will depend A LOT on the airport configuration. If your plan is to land back on a 50-100 foot wide paved runway you will have to turn more than 180 degrees initially then do a reversal to get lined up and the displacement is less of a factor. If you are taking off from the centerline of a 800 foot wide turf runway bordered by 150 foot trees the difference between 400 feet of displacement and 600 feet of displacement matters quite a lot. Have situational awareness and control the airplane - words to live by.

Assuming in most cases the pilot will be trying to get back to a more narrow runway we have the challenge of turning 210-220 degrees on the initial turn and then making a reverse turn to get lined up. The reversal will be when the glider is the lowest so it's probably safe to presume that this turn will be at a lower bank angle (say, 20-30 degrees, perhaps in ground effect). This allows you to avoid performing a cartwheel in front of all your friends. I did this at a high bank angle when I was 11 years old (a story in itself) and can attest that it is not fun.

I'd say the best advice (summarizing the summary) is the following:

- Know ahead of time what your specific plan is for the specific takeoff, not just a general idea - including accounting for crosswinds, obstacles and where you are going to go straight ahead if needed. I have walked fields off the ends of the runways of several problematic airports and it helps a lot - if a field is not an airport it is likely full of surprises.
- Call out the decision height for straight ahead versus 180 while towing out.
- When committing to a 180 make a decisive, controlled and coordinated turn - initially up to 45-55 degrees of bank OR whatever maximum bank angle over 30 degrees you still have rock-solid speed control and coordination. Not being honest with yourself on this point can prove fatal.
- Gradually reduce the bank angle as you approach 180 degrees and continue turning until you can make a smooth turn reversal to the runway centerline.
- Fly the airplane - watch airspeed, coordination, wingtip clearance and obstacles (mine was a fence).
- Try to be aware when a controlled crash is better than the chance you are taking - it can happen quickly.

9B

Bruce Hoult

May 11th 14, 04:25 AM

On Sunday, May 11, 2014 3:01:30 AM UTC+12, wrote:
> I went through the spread sheet and I found everything correct except for the calculation of the "enhanced sink rate". The sink rate is not just the unbanked rate multiplied by the load factor!

Ahh . yes .. you are correct. That's right for the descent angle, but then you need to adjust that by the ratio of the airspeeds to get the descent rate.

> Some manufactures include a circling polar. Using the circling polar of an asw-24 with a total weight of 750 lbs, the speed and sink are:
>
> at 30 deg: 45 kt, 150 ft/min
> at 45 deg: 50 kt, 205 ft/min
> at 60 deg: 59 kt, 345 ft/min

With the correction of multiplying the sink rate by "speed needed"/"min sink speed" my spreadsheet gets the above numbers (and same turn times and height loss) for a glider with a min sink of 122 fpm at 42 knots.

[email protected]

May 11th 14, 06:51 AM

On Saturday, May 10, 2014 8:25:35 PM UTC-7, Bruce Hoult wrote:

>With the correction of multiplying the sink rate by "speed needed"/"min sink speed" my spreadsheet gets the above numbers (and same turn times and height loss) for a glider with a min sink of 122 fpm at 42 knots.

New summary chart with correction: https://drive.google.com/file/d/0Bw1ChKkWEYLNLXZnNUtYbHJEZGs/edit?usp=sharing

The new minimum altitude loss bank angle is...drum roll...45 degrees.

If for some reason you are worried about dragging the wingtip the bank angle that keeps the wingtip the highest is 36 degrees, though obviously this only matters as you sink lower and/or encounter obstacles.

The discussion about offset from the runway is unchanged going from 45 to 60 degrees of bank will reduce the runway offset by 80 feet or so - I don't think it's worth the risk to crank it over that far in most situations. The simple observation is that between 30 and 55 degrees the amount of altitude lost doesn't vary much, so do whatever allows you to control the airplane and get to a laudable spot in go shape to land.

9B

[email protected]

May 11th 14, 10:07 AM

On Saturday, May 10, 2014 10:51:36 PM UTC-7, wrote:
> On Saturday, May 10, 2014 8:25:35 PM UTC-7, Bruce Hoult wrote:
>
>
>
> >With the correction of multiplying the sink rate by "speed needed"/"min sink speed" my spreadsheet gets the above numbers (and same turn times and height loss) for a glider with a min sink of 122 fpm at 42 knots.
>
>
>
> New summary chart with correction: https://drive.google.com/file/d/0Bw1ChKkWEYLNLXZnNUtYbHJEZGs/edit?usp=sharing
>
>
>
> The new minimum altitude loss bank angle is...drum roll...45 degrees.
>
>
>
> If for some reason you are worried about dragging the wingtip the bank angle that keeps the wingtip the highest is 36 degrees, though obviously this only matters as you sink lower and/or encounter obstacles.
>
>
>
> The discussion about offset from the runway is unchanged going from 45 to 60 degrees of bank will reduce the runway offset by 80 feet or so - I don't think it's worth the risk to crank it over that far in most situations. The simple observation is that between 30 and 55 degrees the amount of altitude lost doesn't vary much, so do whatever allows you to control the airplane and get to a laudable spot in go shape to land.
>
>
>
> 9B

....get to a landable spot in good shape to land.

Chris Rollings[_2_]

May 11th 14, 12:01 PM

At 11:24 10 May 2014, Jim White wrote:
>At 07:20 10 May 2014, Chris Rollings wrote:
>>All completely correct but there is one even bigger problem, most pilots
>>when making a low level turn off a launch failure or to modify a
>>circuit/pattern that has got too low, tend to be looking for/at the
place
>>they intend to land with little or no attention to spare for the ASI,
>>attitude or slip/skid indicator, that's why these events are so
>productive
>>of stall/spin accidents. Training needs to emphasise, GLANCE AT THE ASI
>>EVERY 2 - 3 SECONDS IN THESE CIRCUMSTANCES. Attitude is un unreliable
>>indicator very near the ground, even the smallest undulations in the
>>terrain can give a false impression and just being low can make the
>>attitude look more nose down than it is.
>>
>>
>Surely best practice is simply to keep the speed on until you have got it
>all sorted. Certainly in modern slippery gliders. Too much speed is much
>safer than too little and costs very little in height through a turn.
>
>Isn't this what you taught us Chris?
>
>
Certainly a bit faster than optimum costs very little but you still need to
GLANCE AT THE ASI
>>EVERY 2 - 3 SECONDS IN THESE CIRCUMSTANCES to check what speed you are
doing.

John Firth[_4_]

May 11th 14, 01:38 PM

Lots of playing with numbers but I think Chris'
airspeed checking is the most important; a well sealed modern sailplane
gives no clue to the airspeed from the
air noise. Furthermore you may be in turbulence/ wind
shear situation.
Apologies if this was said before.
John F.

At 11:01 11 May 2014, Chris Rollings wrote:
>At 11:24 10 May 2014, Jim White wrote:
>>At 07:20 10 May 2014, Chris Rollings wrote:
>>>All completely correct but there is one even bigger problem, most
pilots
>>>when making a low level turn off a launch failure or to modify a
>>>circuit/pattern that has got too low, tend to be looking for/at th
>place
>>>they intend to land with little or no attention to spare for the ASI,
>>>attitude or slip/skid indicator, that's why these events are so
>>productive
>>>of stall/spin accidents. Training needs to emphasise, GLANCE AT THE
ASI
>>>EVERY 2 - 3 SECONDS IN THESE CIRCUMSTANCES. Attitude is un unreliable
>>>indicator very near the ground, even the smallest undulations in the
>>>terrain can give a false impression and just being low can make the
>>>attitude look more nose down than it is.
>>>
>>>
>>Surely best practice is simply to keep the speed on until you have got
it
>>all sorted. Certainly in modern slippery gliders. Too much speed is much
>>safer than too little and costs very little in height through a turn.
>>
>>Isn't this what you taught us Chris?
>>
>>
>Certainly a bit faster than optimum costs very little but you still need
t
>GLANCE AT THE ASI
>>>EVERY 2 - 3 SECONDS IN THESE CIRCUMSTANCES to check what speed you ar
>doing.
>
>

Bill D

May 11th 14, 04:46 PM

On Sunday, May 11, 2014 5:01:08 AM UTC-6, Chris Rollings wrote:
> At 11:24 10 May 2014, Jim White wrote:
>
> >At 07:20 10 May 2014, Chris Rollings wrote:
>
> >>All completely correct but there is one even bigger problem, most pilots
>
> >>when making a low level turn off a launch failure or to modify a
>
> >>circuit/pattern that has got too low, tend to be looking for/at the
>
> place
>
> >>they intend to land with little or no attention to spare for the ASI,
>
> >>attitude or slip/skid indicator, that's why these events are so
>
> >productive
>
> >>of stall/spin accidents. Training needs to emphasise, GLANCE AT THE ASI
>
> >>EVERY 2 - 3 SECONDS IN THESE CIRCUMSTANCES. Attitude is un unreliable
>
> >>indicator very near the ground, even the smallest undulations in the
>
> >>terrain can give a false impression and just being low can make the
>
> >>attitude look more nose down than it is.
>
> >>
>
> >>
>
> >Surely best practice is simply to keep the speed on until you have got it
>
> >all sorted. Certainly in modern slippery gliders. Too much speed is much
>
> >safer than too little and costs very little in height through a turn.
>
> >
>
> >Isn't this what you taught us Chris?
>
> >
>
> >
>
> Certainly a bit faster than optimum costs very little but you still need to
>
> GLANCE AT THE ASI
>
> >>EVERY 2 - 3 SECONDS IN THESE CIRCUMSTANCES to check what speed you are
>
> doing.

Being constantly aware of one's airspeed is nothing more than basic airmanship. Why and where would this not be the case?

Don Johnstone[_4_]

May 12th 14, 12:40 AM

At 15:46 11 May 2014, Bill D wrote:
>On Sunday, May 11, 2014 5:01:08 AM UTC-6, Chris Rollings wrote:
>> At 11:24 10 May 2014, Jim White wrote:
>>
>> >At 07:20 10 May 2014, Chris Rollings wrote:
>>
>> >>All completely correct but there is one even bigger problem, most
>pilots
>>
>> >>when making a low level turn off a launch failure or to modify a
>>
>> >>circuit/pattern that has got too low, tend to be looking for/at the
>>
>> place
>>
>> >>they intend to land with little or no attention to spare for the ASI,
>>
>> >>attitude or slip/skid indicator, that's why these events are so
>>
>> >productive
>>
>> >>of stall/spin accidents. Training needs to emphasise, GLANCE AT THE
>ASI
>>
>> >>EVERY 2 - 3 SECONDS IN THESE CIRCUMSTANCES. Attitude is un
unreliable
>>
>> >>indicator very near the ground, even the smallest undulations in the
>>
>> >>terrain can give a false impression and just being low can make the
>>
>> >>attitude look more nose down than it is.
>>
>> >>
>>
>> >>
>>
>> >Surely best practice is simply to keep the speed on until you have got
>it
>>
>> >all sorted. Certainly in modern slippery gliders. Too much speed is
much
>>
>> >safer than too little and costs very little in height through a turn.
>>
>> >
>>
>> >Isn't this what you taught us Chris?
>>
>> >
>>
>> >
>>
>> Certainly a bit faster than optimum costs very little but you still
need
>to
>>
>> GLANCE AT THE ASI
>>
>> >>EVERY 2 - 3 SECONDS IN THESE CIRCUMSTANCES to check what speed you
are
>>
>> doing.
>
>Being constantly aware of one's airspeed is nothing more than basic
>airmanship. Why and where would this not be the case?

Maybe when you are distracted having been surprised by a launch failure.
It happens, it happened on a check ride I did 2 weeks ago with a pilot who
had not flown for a while. That is why a procedure needs to be formulated
for a moderate level of skill and currency. An experience pilot, current
and on top of his game probably does not need a procedure, he is capable of
formulating and executing his own, he knows his own limitations and the
limitations of his aircraft.
Solly made it up as he went along, procedure dictated that he found a
runway.
The key is knowing what you are going to do before the worst happens.

Bill D

May 12th 14, 01:09 AM

On Sunday, May 11, 2014 5:40:53 PM UTC-6, Don Johnstone wrote:
> At 15:46 11 May 2014, Bill D wrote:
>
> >On Sunday, May 11, 2014 5:01:08 AM UTC-6, Chris Rollings wrote:
>
> >> At 11:24 10 May 2014, Jim White wrote:
>
> >>
>
> >> >At 07:20 10 May 2014, Chris Rollings wrote:
>
> >>
>
> >> >>All completely correct but there is one even bigger problem, most
>
> >pilots
>
> >>
>
> >> >>when making a low level turn off a launch failure or to modify a
>
> >>
>
> >> >>circuit/pattern that has got too low, tend to be looking for/at the
>
> >>
>
> >> place
>
> >>
>
> >> >>they intend to land with little or no attention to spare for the ASI,
>
> >>
>
> >> >>attitude or slip/skid indicator, that's why these events are so
>
> >>
>
> >> >productive
>
> >>
>
> >> >>of stall/spin accidents. Training needs to emphasise, GLANCE AT THE
>
> >ASI
>
> >>
>
> >> >>EVERY 2 - 3 SECONDS IN THESE CIRCUMSTANCES. Attitude is un
>
> unreliable
>
> >>
>
> >> >>indicator very near the ground, even the smallest undulations in the
>
> >>
>
> >> >>terrain can give a false impression and just being low can make the
>
> >>
>
> >> >>attitude look more nose down than it is.
>
> >>
>
> >> >>
>
> >>
>
> >> >>
>
> >>
>
> >> >Surely best practice is simply to keep the speed on until you have got
>
> >it
>
> >>
>
> >> >all sorted. Certainly in modern slippery gliders. Too much speed is
>
> much
>
> >>
>
> >> >safer than too little and costs very little in height through a turn.
>
> >>
>
> >> >
>
> >>
>
> >> >Isn't this what you taught us Chris?
>
> >>
>
> >> >
>
> >>
>
> >> >
>
> >>
>
> >> Certainly a bit faster than optimum costs very little but you still
>
> need
>
> >to
>
> >>
>
> >> GLANCE AT THE ASI
>
> >>
>
> >> >>EVERY 2 - 3 SECONDS IN THESE CIRCUMSTANCES to check what speed you
>
> are
>
> >>
>
> >> doing.
>
> >
>
> >Being constantly aware of one's airspeed is nothing more than basic
>
> >airmanship. Why and where would this not be the case?
>
>
>
> Maybe when you are distracted having been surprised by a launch failure.
>
A basic standard of airmanship requires a pilot to expect every launch to fail. One is allowed surprise only when a launch DOES NOT fail. Inattention to airspeed is never acceptable even with a pre-solo student.

Andrew[_13_]

May 12th 14, 04:44 AM

I totally agree that pilots should glance at the ASI very frequently on
every approach. When students have trouble keeping a constant
airspeed on approach, I find it helpful to do a demonstration
approach, calling out the airspeed every time I glance at the ASI. Its
about every 2 seconds, as other people have said.

About doing 180 degree turns after a low tow failure: I also totally
agree with writers who say the immediate question is 'can I land
straight ahead' and to do that if its possible. Training students to
automatically do a 180 degree turn at 200ft is teaching the wrong
thing. Some damage to the glider should be taught to be acceptable,
since its an emergency situation. Maybe training this at all is a bad
thing, since statistically some solo pilots are going to get it
disastrously wrong attempting it. One could argue that going more-
or-less straight ahead is safer, while attempting a 180 degree turn at
200ft is risking one's life to save the glider from minor damage, or
the club the inconvenience of a retrieve. One could say that a site
where a straight-ahead landing from 200ft will certainly result in
more than minor damage, is a site that should not be used.

I wonder how other countries teach this, and how accident rates
compare. I was taught to glide in the UK, in the 60s, on a winch.
When I could eventually afford aerotows, I was never trained or
practiced a 180 degree turn from 200ft. As I recall, the BGA training
at that time was simply a verbal briefing for a low rope break was to
land more-or-less straight ahead (or at my club, to fly out over the
valley). It was accepted that the glider might be damaged.
Personally, I suspect this verbal briefing to go straight ahead may
produce better severe-accident statistics than the US emphasis on
training low 180 degree turns.

WAVEGURU

May 12th 14, 05:00 AM

I think it's sad that we seem to think its fine for pilots to be so under proficient that they can't even do a safe 180 from 200ft... It's plenty of altitude under all but the most extreme conditions. IMHO if you can't, maybe you shouldn't be flying at all? This is a clue as to why there are so many accidents.

Bruce Hoult

May 12th 14, 06:04 AM

On Monday, May 12, 2014 3:44:51 PM UTC+12, Andrew wrote:
>One could say that a site
> where a straight-ahead landing from 200ft will certainly result in
> more than minor damage, is a site that should not be used.

Wait ... what?

Let's guess some numbers here...

300m for the tug to get off
200m more for it to get to climb speed
700m to climb to 200 ft (60m)
.... rope break ...
100m for the glider to slow to approach speed (while climbing 30m as well, making 90m)
600m for the glider to descend to ground level (worst case 7:1 glide angle with airbrakes)
100m to stop on the ground

Total: 2000m

And that's with a powerful tug, such as a Pawnee.

I've flown from places with such runway lengths (or empty fields beyond). But not many.

Your rule would eliminate at least 90% of the places that gliders fly -- without incident -- in this country.

At our home airfield (which by the way has scheduled Dash 8 flights on the sealed runway which is 1000m from stripes to stripes), gliders are given a 500m grass runway with about 300m more on either end to the fence. And yes, we're going over the fence at not much more than 100 ft if we don't have a headwind. Beyond that is nothing but houses. That's not "minor damage" to go into.

For a low break just after (or before) the boundary, the plan is definitely to turn towards and overfly the sealed runway. Any traffic there can take its chances!! (there are not supposed to be parallel operations) There is 300m width of unobstructed (though not particularly smooth) ground in that direction.

If you actually have the luxury of 200 ft when the rope breaks then better to turn the other way, over the houses, and land on the 300m long crosswind runway (which we use when 12+ knot crosswinds make the main runway too tricky for the tug (gliders cope fine)).

[email protected]

May 12th 14, 12:13 PM

Fortunately we don't have to 'guess' numbers as most gliders have high resolution GPS loggers in them! (Remember to use GPS altitude as your pressure altitude probably lags considerably)

From a random flight of my own (unballasted LS4) I observed I used 750m of grass strip to 200ft height, behind a Pawnee with a 9kt quartering headwind..

Where I fly the training process is, land ahead, land off field, turn around.

On Monday, May 12, 2014 3:04:29 PM UTC+10, Bruce Hoult wrote:
> On Monday, May 12, 2014 3:44:51 PM UTC+12, Andrew wrote:
>
> >One could say that a site
>
> > where a straight-ahead landing from 200ft will certainly result in
>
> > more than minor damage, is a site that should not be used.
>
>
>
> Wait ... what?
>
>
>
> Let's guess some numbers here...
>
>
>
> 300m for the tug to get off
>
> 200m more for it to get to climb speed
>
> 700m to climb to 200 ft (60m)
>
> ... rope break ...
>
> 100m for the glider to slow to approach speed (while climbing 30m as well, making 90m)
>
> 600m for the glider to descend to ground level (worst case 7:1 glide angle with airbrakes)
>
> 100m to stop on the ground
>
>
>
> Total: 2000m
>
>
>
> And that's with a powerful tug, such as a Pawnee.
>
>
>
> I've flown from places with such runway lengths (or empty fields beyond). But not many.
>
>
>
> Your rule would eliminate at least 90% of the places that gliders fly -- without incident -- in this country.
>
>
>
> At our home airfield (which by the way has scheduled Dash 8 flights on the sealed runway which is 1000m from stripes to stripes), gliders are given a 500m grass runway with about 300m more on either end to the fence. And yes, we're going over the fence at not much more than 100 ft if we don't have a headwind. Beyond that is nothing but houses. That's not "minor damage" to go into.
>
>
>
> For a low break just after (or before) the boundary, the plan is definitely to turn towards and overfly the sealed runway. Any traffic there can take its chances!! (there are not supposed to be parallel operations) There is 300m width of unobstructed (though not particularly smooth) ground in that direction.
>
>
>
> If you actually have the luxury of 200 ft when the rope breaks then better to turn the other way, over the houses, and land on the 300m long crosswind runway (which we use when 12+ knot crosswinds make the main runway too tricky for the tug (gliders cope fine)).

Bruce Hoult

May 12th 14, 12:54 PM

On Monday, May 12, 2014 11:13:14 PM UTC+12, wrote:
> From a random flight of my own (unballasted LS4) I observed I used 750m of grass strip to 200ft height, behind a Pawnee with a 9kt quartering headwind.

Unfortunately you didn't say how long that took, so we can't calculate how much air you went through. It's going to be a good 30 seconds though, which means probably 850-900m on a no wind day. In an unballasted single seater. My 1200m estimate for a glass twin doesn't seem too unreasonable.

And sometimes (not that infrequently, actually) we do a couple of takeoffs with a light tail wind (5 knots?) before changing ends.

glidergeek

May 13th 14, 03:45 PM

On Saturday, May 3, 2014 9:27:10 PM UTC-7, Waveguru wrote:
> Premature termination of the tow at 100ft. Did not complete the turn back to the runway.
>
>
>
> http://www.kathrynsreport.com/2014/05/wickenburg-maricopa-county-arizona.html?m=1
>
>
>
> Boggs

glidergeek

May 13th 14, 03:47 PM

kirk.stant

May 13th 14, 11:21 PM

What's wrong, too many interesting facts for you?

Instead of whining, add something!

Kirk
66

[email protected]

May 14th 14, 03:14 AM

>I've been into soaring since 1996 and he was the 7th I've known to be called to the other side.
>
>
>
> We try to learn from others' mistakes, but in this case, as there were no glider pilots who observed the event, little can be learned.
>
>
>
> My heart goes out to his family and friends.
>
>
>
> Bob T

Bob thanks.

Don Johnstone[_4_]

May 14th 14, 10:25 AM

At 02:14 14 May 2014, wrote: (snip)
>>I've been into soaring since 1996 and he was the 7th I've known to be
>called to the other side.

>> We try to learn from others' mistakes, but in this case, as there were
no
>glider pilots who observed the event, little can be learned.

>> Bob T
>
That is simply not true. Whilst not commenting on the specifics of this
accident the outcome has provoked a serious discussion on the procedure to
be adopted following a launch failure at low level.
There are those who have argued passionately, that a turn back, even from a
low starting height is a viable and safe option providing the best chance
of a good outcome. There has been a deal of opinion that in these
circumstances we should consider doing something, turning downwind at very
low level, which we would never ever consider doing in normal operations.
Observing a pilot making the 90 degree turn from base to finals at such a
low level would result in a very one sided conversation at many gliding
sites. Loss of control below 300 ft, let alone 200 ft, is only ever going
to end one way.
There are those who have argued that a much safer option in to land
straight ahead, or slightly to one side even if the terrain is difficult,
aiming to ensure that the fuselage survives the landing, even at the
expense of damage to other parts. The argument to support this is that a
controlled descent with wings level is far more likely to have a better
outcome than getting the low turn wrong. There are fewer items to
concentrate on with more time to monitor the basic need of keeping the
glider flying with sufficient airspeed to ensure a controlled landing. A
much simpler approach and one likely to be easier for low hours,
inexperienced and low currency pilots.
The basic questions to ask in deciding which is the best option is, "Will
pilots of ALL skill levels and currency be best served by a simple or
complicated procedure?" "Is creating a mindset that turning downwind is the
best option suitable for all conditions?" and "Does the procedure adopted
offer the best chance of survival of the pilot, even at the expense of
glider damage?". I think most gliding supervisors will be able to answer
those questions, the only question remaining is will they be able to make
the right decision to implement what they have learned.

My personal view is that the low turn back is one complication, if not
several, too many for an average pilot and flies in the face of the basic
Aviate, navigate, communicate mantra. The last two should only ever come
into play once the first has been achieved and off a very low launch
failure there may never be time to get to the secondary priorities. The
teaching of a low turn back places more emphasis on the secondary priority
to the detriment of the first and creates a mindset that may lead to a less
positive outcome than a much simpler procedure. There will always be
exceptions to any basic procedure, in a few situations the basic procedure
may not be an option so other options will have to be considered. Those
exceptions should only ever be applied where and when they are necessary,
which does not invalidate the preference for a simple basic procedure.
I also think that arguing amongst ourselves, while useful in reaching the
best conclusion, carries the danger of entrenchment when it should promote
the adoption of best practice.
To say there is little to be learned is just plain wrong.

David Salmon[_3_]

May 19th 14, 05:21 PM

At 09:25 14 May 2014, Don Johnstone wrote:
>At 02:14 14 May 2014, wrote: (snip)
>>>I've been into soaring since 1996 and he was the 7th I've known to be
>>called to the other side.
>
>>> We try to learn from others' mistakes, but in this case, as there were
>no
>>glider pilots who observed the event, little can be learned.
>
>>> Bob T
>>
>That is simply not true. Whilst not commenting on the specifics of this
>accident the outcome has provoked a serious discussion on the procedure
to
>be adopted following a launch failure at low level.
>There are those who have argued passionately, that a turn back, even from
a
>low starting height is a viable and safe option providing the best chance
>of a good outcome. There has been a deal of opinion that in these
>circumstances we should consider doing something, turning downwind at
very
>low level, which we would never ever consider doing in normal operations.
>Observing a pilot making the 90 degree turn from base to finals at such a
>low level would result in a very one sided conversation at many gliding
>sites. Loss of control below 300 ft, let alone 200 ft, is only ever going
>to end one way.
>There are those who have argued that a much safer option in to land
>straight ahead, or slightly to one side even if the terrain is difficult,
>aiming to ensure that the fuselage survives the landing, even at the
>expense of damage to other parts. The argument to support this is that a
>controlled descent with wings level is far more likely to have a better
>outcome than getting the low turn wrong. There are fewer items to
>concentrate on with more time to monitor the basic need of keeping the
>glider flying with sufficient airspeed to ensure a controlled landing. A
>much simpler approach and one likely to be easier for low hours,
>inexperienced and low currency pilots.
>The basic questions to ask in deciding which is the best option is, "Will
>pilots of ALL skill levels and currency be best served by a simple or
>complicated procedure?" "Is creating a mindset that turning downwind is
the
>best option suitable for all conditions?" and "Does the procedure adopted
>offer the best chance of survival of the pilot, even at the expense of
>glider damage?". I think most gliding supervisors will be able to answer
>those questions, the only question remaining is will they be able to make
>the right decision to implement what they have learned.
>
>My personal view is that the low turn back is one complication, if not
>several, too many for an average pilot and flies in the face of the basic
>Aviate, navigate, communicate mantra. The last two should only ever come
>into play once the first has been achieved and off a very low launch
>failure there may never be time to get to the secondary priorities. The
>teaching of a low turn back places more emphasis on the secondary
priority
>to the detriment of the first and creates a mindset that may lead to a
less
>positive outcome than a much simpler procedure. There will always be
>exceptions to any basic procedure, in a few situations the basic
procedure
>may not be an option so other options will have to be considered. Those
>exceptions should only ever be applied where and when they are necessary,
>which does not invalidate the preference for a simple basic procedure.
>I also think that arguing amongst ourselves, while useful in reaching the
>best conclusion, carries the danger of entrenchment when it should
promote
>the adoption of best practice.
>To say there is little to be learned is just plain wrong.
>
A good many years ago, my CFI had persuaded me to become an instructor, and
I confided in him that my only real concern, was allowing someone else to
be in control near the ground. He lent me Stick & Rudder by Wolfgang
Langewiesche, and suggested a chapter to read. This is not a gliding book,
but nevertheless there was lots of common interest. In particular was the
bit, actually written by someone else, and showing how forgiving aircraft
are when "crashing" under control. It is when they are not under control,
ie stalled or spinning when they hit the ground, that the occupants stand
the most chance of getting hurt, or worse.
The same lesson was passed onto me in my brief excursion into power
flying. In case of a relatively low engine failure, you land as near ahead
as possible, into whatever is available.
I can vouch for this from personal experience, having been in a straight
ahead aeroplane crash, not me flying it, I hasten to add, I was in the
back, and four of us walked away, as it went up in flames.
Dave

Bill D

May 19th 14, 08:40 PM

On Monday, May 19, 2014 10:21:26 AM UTC-6, David Salmon wrote:
> At 09:25 14 May 2014, Don Johnstone wrote:
>
> >At 02:14 14 May 2014, wrote: (snip)
>
> >>>I've been into soaring since 1996 and he was the 7th I've known to be
>
> >>called to the other side.
>
> >
>
> >>> We try to learn from others' mistakes, but in this case, as there were
>
> >no
>
> >>glider pilots who observed the event, little can be learned.
>
> >
>
> >>> Bob T
>
> >>
>
> >That is simply not true. Whilst not commenting on the specifics of this
>
> >accident the outcome has provoked a serious discussion on the procedure
>
> to
>
> >be adopted following a launch failure at low level.
>
> >There are those who have argued passionately, that a turn back, even from
>
> a
>
> >low starting height is a viable and safe option providing the best chance
>
> >of a good outcome. There has been a deal of opinion that in these
>
> >circumstances we should consider doing something, turning downwind at
>
> very
>
> >low level, which we would never ever consider doing in normal operations..
>
> >Observing a pilot making the 90 degree turn from base to finals at such a
>
> >low level would result in a very one sided conversation at many gliding
>
> >sites. Loss of control below 300 ft, let alone 200 ft, is only ever going
>
> >to end one way.
>
> >There are those who have argued that a much safer option in to land
>
> >straight ahead, or slightly to one side even if the terrain is difficult,
>
> >aiming to ensure that the fuselage survives the landing, even at the
>
> >expense of damage to other parts. The argument to support this is that a
>
> >controlled descent with wings level is far more likely to have a better
>
> >outcome than getting the low turn wrong. There are fewer items to
>
> >concentrate on with more time to monitor the basic need of keeping the
>
> >glider flying with sufficient airspeed to ensure a controlled landing. A
>
> >much simpler approach and one likely to be easier for low hours,
>
> >inexperienced and low currency pilots.
>
> >The basic questions to ask in deciding which is the best option is, "Will
>
> >pilots of ALL skill levels and currency be best served by a simple or
>
> >complicated procedure?" "Is creating a mindset that turning downwind is
>
> the
>
> >best option suitable for all conditions?" and "Does the procedure adopted
>
> >offer the best chance of survival of the pilot, even at the expense of
>
> >glider damage?". I think most gliding supervisors will be able to answer
>
> >those questions, the only question remaining is will they be able to make
>
> >the right decision to implement what they have learned.
>
> >
>
> >My personal view is that the low turn back is one complication, if not
>
> >several, too many for an average pilot and flies in the face of the basic
>
> >Aviate, navigate, communicate mantra. The last two should only ever come
>
> >into play once the first has been achieved and off a very low launch
>
> >failure there may never be time to get to the secondary priorities. The
>
> >teaching of a low turn back places more emphasis on the secondary
>
> priority
>
> >to the detriment of the first and creates a mindset that may lead to a
>
> less
>
> >positive outcome than a much simpler procedure. There will always be
>
> >exceptions to any basic procedure, in a few situations the basic
>
> procedure
>
> >may not be an option so other options will have to be considered. Those
>
> >exceptions should only ever be applied where and when they are necessary,
>
> >which does not invalidate the preference for a simple basic procedure.
>
> >I also think that arguing amongst ourselves, while useful in reaching the
>
> >best conclusion, carries the danger of entrenchment when it should
>
> promote
>
> >the adoption of best practice.
>
> >To say there is little to be learned is just plain wrong.
>
> >
>
> A good many years ago, my CFI had persuaded me to become an instructor, and
>
> I confided in him that my only real concern, was allowing someone else to
>
> be in control near the ground. He lent me Stick & Rudder by Wolfgang
>
> Langewiesche, and suggested a chapter to read. This is not a gliding book,
>
> but nevertheless there was lots of common interest. In particular was the
>
> bit, actually written by someone else, and showing how forgiving aircraft
>
> are when "crashing" under control. It is when they are not under control,
>
> ie stalled or spinning when they hit the ground, that the occupants stand
>
> the most chance of getting hurt, or worse.
>
> The same lesson was passed onto me in my brief excursion into power
>
> flying. In case of a relatively low engine failure, you land as near ahead
>
> as possible, into whatever is available.
>
> I can vouch for this from personal experience, having been in a straight
>
> ahead aeroplane crash, not me flying it, I hasten to add, I was in the
>
> back, and four of us walked away, as it went up in flames.
>
> Dave

Langewiesche's point is correct as far as it goes. If the only choice is between crashing with the aircraft under control and crashing while out of control, being in control is always better. Duh!

However, I think your implied point is that if a pilot tries a turn, the aircraft will be out of control. Obviously, I disagree. If a pilot can't retain control while making a simple 180 degree turn, the situation was dire long before the emergency arose.

Now, lets define the "ground" you're going to crash into. Lets say there's a rock quarry off the departure end. Solid surfaces are vertical and all horizontal surfaces are water with no climb out options. The occupants will die in the crash or drown a few minutes later whether the aircraft crashed under control or not. My point is there are situations where no "straight ahead" option is available.

My situation isn't quite that bad - it's only water filled gravel pits. The only field proven landable is VERY small and requires a 90 degree turn at treetop level around a large tree. Turning back, when possible, is always the best option. It pays to be good at it.

The good news is gliders can turn back with generous safety margins. The wild card is the pilot.

Bruce Hoult

May 20th 14, 02:46 AM

On Tuesday, May 20, 2014 7:40:51 AM UTC+12, Bill D wrote:
> However, I think your implied point is that if a pilot tries a turn, the aircraft will be out of control. Obviously, I disagree. If a pilot can't retain control while making a simple 180 degree turn, the situation was dire long before the emergency arose.

Exactly.

> The good news is gliders can turn back with generous safety margins. The wild card is the pilot.

Let's just emphasise this again.

If the rope breaks at normal aerotow speed, you should be able to complete a 180º turn and be at normal safe final approach speed with as much or more height as the moment the rope broke.

The glider can. Easily.

[email protected]

May 20th 14, 09:11 PM

I dunno. I might be wary of a 180 at skosh altitude if the air was turbulent, ie a thermal off the end of the runway. That puts the variable of airspeed potentially outside my control.

Bill D

May 21st 14, 12:24 AM

On Tuesday, May 20, 2014 2:11:23 PM UTC-6, wrote:
> I dunno. I might be wary of a 180 at skosh altitude if the air was turbulent, ie a thermal off the end of the runway. That puts the variable of airspeed potentially outside my control.

Presumably, you, like most pilots, do steep turns in turbulent thermals every flight while keeping the airspeed within a narrow, safe margin.

BTW, define "skosh altitude" precisely.

[email protected]

May 22nd 14, 09:45 PM

Bill

I have had the experience while banked 45 deg in mountain thermal of having the glider stop flying and start falling in a split second. IE, the dirt came up of the floor and was pinned to the canopy.

Under those circumstances, I would define skosh altitude as anything less than enough to recover from a deep stall or early spin with enough reserve height then to direct the aircraft in a desirable direction.

Very sharp shear is possble at the borders of strong thermals. I don't think a steep bank would necessarily be as perfect a safeguard against a turbulent airflow as I would hope. Airflow across one wing could be erased in an instant under the wrong circumstances.

Mark

[email protected]

May 22nd 14, 10:41 PM

On Monday, May 19, 2014 8:40:51 PM UTC+1, Bill D wrote:
> On Monday, May 19, 2014 10:21:26 AM UTC-6, David Salmon wrote:
>
> > At 09:25 14 May 2014, Don Johnstone wrote:
>
> >
>
> > >At 02:14 14 May 2014, wrote: (snip)
>
> >
>
> > >>>I've been into soaring since 1996 and he was the 7th I've known to be
>
> >
>
> > >>called to the other side.
>
> >
>
> > >
>
> >
>
> > >>> We try to learn from others' mistakes, but in this case, as there were
>
> >
>
> > >no
>
> >
>
> > >>glider pilots who observed the event, little can be learned.
>
> >
>
> > >
>
> >
>
> > >>> Bob T
>
> >
>
> > >>
>
> >
>
> > >That is simply not true. Whilst not commenting on the specifics of this
>
> >
>
> > >accident the outcome has provoked a serious discussion on the procedure
>
> >
>
> > to
>
> >
>
> > >be adopted following a launch failure at low level.
>
> >
>
> > >There are those who have argued passionately, that a turn back, even from
>
> >
>
> > a
>
> >
>
> > >low starting height is a viable and safe option providing the best chance
>
> >
>
> > >of a good outcome. There has been a deal of opinion that in these
>
> >
>
> > >circumstances we should consider doing something, turning downwind at
>
> >
>
> > very
>
> >
>
> > >low level, which we would never ever consider doing in normal operations.
>
> >
>
> > >Observing a pilot making the 90 degree turn from base to finals at such a
>
> >
>
> > >low level would result in a very one sided conversation at many gliding
>
> >
>
> > >sites. Loss of control below 300 ft, let alone 200 ft, is only ever going
>
> >
>
> > >to end one way.
>
> >
>
> > >There are those who have argued that a much safer option in to land
>
> >
>
> > >straight ahead, or slightly to one side even if the terrain is difficult,
>
> >
>
> > >aiming to ensure that the fuselage survives the landing, even at the
>
> >
>
> > >expense of damage to other parts. The argument to support this is that a
>
> >
>
> > >controlled descent with wings level is far more likely to have a better
>
> >
>
> > >outcome than getting the low turn wrong. There are fewer items to
>
> >
>
> > >concentrate on with more time to monitor the basic need of keeping the
>
> >
>
> > >glider flying with sufficient airspeed to ensure a controlled landing. A
>
> >
>
> > >much simpler approach and one likely to be easier for low hours,
>
> >
>
> > >inexperienced and low currency pilots.
>
> >
>
> > >The basic questions to ask in deciding which is the best option is, "Will
>
> >
>
> > >pilots of ALL skill levels and currency be best served by a simple or
>
> >
>
> > >complicated procedure?" "Is creating a mindset that turning downwind is
>
> >
>
> > the
>
> >
>
> > >best option suitable for all conditions?" and "Does the procedure adopted
>
> >
>
> > >offer the best chance of survival of the pilot, even at the expense of
>
> >
>
> > >glider damage?". I think most gliding supervisors will be able to answer
>
> >
>
> > >those questions, the only question remaining is will they be able to make
>
> >
>
> > >the right decision to implement what they have learned.
>
> >
>
> > >
>
> >
>
> > >My personal view is that the low turn back is one complication, if not
>
> >
>
> > >several, too many for an average pilot and flies in the face of the basic
>
> >
>
> > >Aviate, navigate, communicate mantra. The last two should only ever come
>
> >
>
> > >into play once the first has been achieved and off a very low launch
>
> >
>
> > >failure there may never be time to get to the secondary priorities. The
>
> >
>
> > >teaching of a low turn back places more emphasis on the secondary
>
> >
>
> > priority
>
> >
>
> > >to the detriment of the first and creates a mindset that may lead to a
>
> >
>
> > less
>
> >
>
> > >positive outcome than a much simpler procedure. There will always be
>
> >
>
> > >exceptions to any basic procedure, in a few situations the basic
>
> >
>
> > procedure
>
> >
>
> > >may not be an option so other options will have to be considered. Those
>
> >
>
> > >exceptions should only ever be applied where and when they are necessary,
>
> >
>
> > >which does not invalidate the preference for a simple basic procedure.
>
> >
>
> > >I also think that arguing amongst ourselves, while useful in reaching the
>
> >
>
> > >best conclusion, carries the danger of entrenchment when it should
>
> >
>
> > promote
>
> >
>
> > >the adoption of best practice.
>
> >
>
> > >To say there is little to be learned is just plain wrong.
>
> >
>
> > >
>
> >
>
> > A good many years ago, my CFI had persuaded me to become an instructor, and
>
> >
>
> > I confided in him that my only real concern, was allowing someone else to
>
> >
>
> > be in control near the ground. He lent me Stick & Rudder by Wolfgang
>
> >
>
> > Langewiesche, and suggested a chapter to read. This is not a gliding book,
>
> >
>
> > but nevertheless there was lots of common interest. In particular was the
>
> >
>
> > bit, actually written by someone else, and showing how forgiving aircraft
>
> >
>
> > are when "crashing" under control. It is when they are not under control,
>
> >
>
> > ie stalled or spinning when they hit the ground, that the occupants stand
>
> >
>
> > the most chance of getting hurt, or worse.
>
> >
>
> > The same lesson was passed onto me in my brief excursion into power
>
> >
>
> > flying. In case of a relatively low engine failure, you land as near ahead
>
> >
>
> > as possible, into whatever is available.
>
> >
>
> > I can vouch for this from personal experience, having been in a straight
>
> >
>
> > ahead aeroplane crash, not me flying it, I hasten to add, I was in the
>
> >
>
> > back, and four of us walked away, as it went up in flames.
>
> >
>
> > Dave
>
>
>
> Langewiesche's point is correct as far as it goes. If the only choice is between crashing with the aircraft under control and crashing while out of control, being in control is always better. Duh!
>
>
>
> However, I think your implied point is that if a pilot tries a turn, the aircraft will be out of control. Obviously, I disagree. If a pilot can't retain control while making a simple 180 degree turn, the situation was dire long before the emergency arose.
>
>
>
> Now, lets define the "ground" you're going to crash into. Lets say there's a rock quarry off the departure end. Solid surfaces are vertical and all horizontal surfaces are water with no climb out options. The occupants will die in the crash or drown a few minutes later whether the aircraft crashed under control or not. My point is there are situations where no "straight ahead" option is available.
>
>
>
> My situation isn't quite that bad - it's only water filled gravel pits. The only field proven landable is VERY small and requires a 90 degree turn at treetop level around a large tree. Turning back, when possible, is always the best option. It pays to be good at it.
>
>
>
> The good news is gliders can turn back with generous safety margins. The wild card is the pilot.

Langewiesche's point is correct, period. Which option carries the best chance of retaining control, keeping the wings level or turning, especially at low level?
The primary concern is survival of the pilot, an undamaged glider is a long way below this fundamental priority.
We have all witnessed instructors who like to scare their pupils witless by carrying out risky procedures, such behavior has no place in responsible aviation, but we all know it survives because of the intransigence of those who refuse to accept that we are there to teach safe flying.

Ignore the KISS mantra at your peril.

Bill D

May 22nd 14, 11:23 PM

On Thursday, May 22, 2014 2:45:59 PM UTC-6, wrote:
> Bill
>
>
>
> I have had the experience while banked 45 deg in mountain thermal of having the glider stop flying and start falling in a split second. IE, the dirt came up of the floor and was pinned to the canopy.
>
So have I - many times - but the glider never got close to a stall. A typical Rocky Mountain flight will leave the tell-tales on the G-Meter at +2 and -1.
>

>
> Very sharp shear is possble at the borders of strong thermals. I don't think a steep bank would necessarily be as perfect a safeguard against a turbulent airflow as I would hope. Airflow across one wing could be erased in an instant under the wrong circumstances.

No one said a steep bank was a "perfect safeguard" against "turbulent airflow". It does increase the stall margin - even in "sharp shear".

Bill D

May 22nd 14, 11:28 PM

On Thursday, May 22, 2014 4:23:32 PM UTC-6, Bill D wrote:
> On Thursday, May 22, 2014 2:45:59 PM UTC-6, wrote:
>
> > Bill
>
> >
>
> >
>
> >
>
> > I have had the experience while banked 45 deg in mountain thermal of having the glider stop flying and start falling in a split second. IE, the dirt came up of the floor and was pinned to the canopy.
>
> >
>
> So have I - many times - but the glider never got close to a stall. A typical Rocky Mountain flight will leave the tell-tales on the G-Meter at +2 and -1.
>
> >
>
>
>
> >
>
> > Very sharp shear is possble at the borders of strong thermals. I don't think a steep bank would necessarily be as perfect a safeguard against a turbulent airflow as I would hope. Airflow across one wing could be erased in an instant under the wrong circumstances.
>
>
>
> No one said a steep bank was a "perfect safeguard" against "turbulent airflow". It does increase the stall margin - even in "sharp shear".

s

Bill D

May 22nd 14, 11:55 PM

On Thursday, May 22, 2014 3:41:14 PM UTC-6, wrote:
> On Monday, May 19, 2014 8:40:51 PM UTC+1, Bill D wrote:
>
> > On Monday, May 19, 2014 10:21:26 AM UTC-6, David Salmon wrote:
>
> >
>
> > > At 09:25 14 May 2014, Don Johnstone wrote:
>
> >
>
> > >
>
> >
>
> > > >At 02:14 14 May 2014, wrote: (snip)
>
> >
>
> > >
>
> >
>
> > > >>>I've been into soaring since 1996 and he was the 7th I've known to be
>
> >
>
> > >
>
> >
>
> > > >>called to the other side.
>
> >
>
> > >
>
> >
>
> > > >
>
> >
>
> > >
>
> >
>
> > > >>> We try to learn from others' mistakes, but in this case, as there were
>
> >
>
> > >
>
> >
>
> > > >no
>
> >
>
> > >
>
> >
>
> > > >>glider pilots who observed the event, little can be learned.
>
> >
>
> > >
>
> >
>
> > > >
>
> >
>
> > >
>
> >
>
> > > >>> Bob T
>
> >
>
> > >
>
> >
>
> > > >>
>
> >
>
> > >
>
> >
>
> > > >That is simply not true. Whilst not commenting on the specifics of this
>
> >
>
> > >
>
> >
>
> > > >accident the outcome has provoked a serious discussion on the procedure
>
> >
>
> > >
>
> >
>
> > > to
>
> >
>
> > >
>
> >
>
> > > >be adopted following a launch failure at low level.
>
> >
>
> > >
>
> >
>
> > > >There are those who have argued passionately, that a turn back, even from
>
> >
>
> > >
>
> >
>
> > > a
>
> >
>
> > >
>
> >
>
> > > >low starting height is a viable and safe option providing the best chance
>
> >
>
> > >
>
> >
>
> > > >of a good outcome. There has been a deal of opinion that in these
>
> >
>
> > >
>
> >
>
> > > >circumstances we should consider doing something, turning downwind at
>
> >
>
> > >
>
> >
>
> > > very
>
> >
>
> > >
>
> >
>
> > > >low level, which we would never ever consider doing in normal operations.
>
> >
>
> > >
>
> >
>
> > > >Observing a pilot making the 90 degree turn from base to finals at such a
>
> >
>
> > >
>
> >
>
> > > >low level would result in a very one sided conversation at many gliding
>
> >
>
> > >
>
> >
>
> > > >sites. Loss of control below 300 ft, let alone 200 ft, is only ever going
>
> >
>
> > >
>
> >
>
> > > >to end one way.
>
> >
>
> > >
>
> >
>
> > > >There are those who have argued that a much safer option in to land
>
> >
>
> > >
>
> >
>
> > > >straight ahead, or slightly to one side even if the terrain is difficult,
>
> >
>
> > >
>
> >
>
> > > >aiming to ensure that the fuselage survives the landing, even at the
>
> >
>
> > >
>
> >
>
> > > >expense of damage to other parts. The argument to support this is that a
>
> >
>
> > >
>
> >
>
> > > >controlled descent with wings level is far more likely to have a better
>
> >
>
> > >
>
> >
>
> > > >outcome than getting the low turn wrong. There are fewer items to
>
> >
>
> > >
>
> >
>
> > > >concentrate on with more time to monitor the basic need of keeping the
>
> >
>
> > >
>
> >
>
> > > >glider flying with sufficient airspeed to ensure a controlled landing. A
>
> >
>
> > >
>
> >
>
> > > >much simpler approach and one likely to be easier for low hours,
>
> >
>
> > >
>
> >
>
> > > >inexperienced and low currency pilots.
>
> >
>
> > >
>
> >
>
> > > >The basic questions to ask in deciding which is the best option is, "Will
>
> >
>
> > >
>
> >
>
> > > >pilots of ALL skill levels and currency be best served by a simple or
>
> >
>
> > >
>
> >
>
> > > >complicated procedure?" "Is creating a mindset that turning downwind is
>
> >
>
> > >
>
> >
>
> > > the
>
> >
>
> > >
>
> >
>
> > > >best option suitable for all conditions?" and "Does the procedure adopted
>
> >
>
> > >
>
> >
>
> > > >offer the best chance of survival of the pilot, even at the expense of
>
> >
>
> > >
>
> >
>
> > > >glider damage?". I think most gliding supervisors will be able to answer
>
> >
>
> > >
>
> >
>
> > > >those questions, the only question remaining is will they be able to make
>
> >
>
> > >
>
> >
>
> > > >the right decision to implement what they have learned.
>
> >
>
> > >
>
> >
>
> > > >
>
> >
>
> > >
>
> >
>
> > > >My personal view is that the low turn back is one complication, if not
>
> >
>
> > >
>
> >
>
> > > >several, too many for an average pilot and flies in the face of the basic
>
> >
>
> > >
>
> >
>
> > > >Aviate, navigate, communicate mantra. The last two should only ever come
>
> >
>
> > >
>
> >
>
> > > >into play once the first has been achieved and off a very low launch
>
> >
>
> > >
>
> >
>
> > > >failure there may never be time to get to the secondary priorities. The
>
> >
>
> > >
>
> >
>
> > > >teaching of a low turn back places more emphasis on the secondary
>
> >
>
> > >
>
> >
>
> > > priority
>
> >
>
> > >
>
> >
>
> > > >to the detriment of the first and creates a mindset that may lead to a
>
> >
>
> > >
>
> >
>
> > > less
>
> >
>
> > >
>
> >
>
> > > >positive outcome than a much simpler procedure. There will always be
>
> >
>
> > >
>
> >
>
> > > >exceptions to any basic procedure, in a few situations the basic
>
> >
>
> > >
>
> >
>
> > > procedure
>
> >
>
> > >
>
> >
>
> > > >may not be an option so other options will have to be considered. Those
>
> >
>
> > >
>
> >
>
> > > >exceptions should only ever be applied where and when they are necessary,
>
> >
>
> > >
>
> >
>
> > > >which does not invalidate the preference for a simple basic procedure.
>
> >
>
> > >
>
> >
>
> > > >I also think that arguing amongst ourselves, while useful in reaching the
>
> >
>
> > >
>
> >
>
> > > >best conclusion, carries the danger of entrenchment when it should
>
> >
>
> > >
>
> >
>
> > > promote
>
> >
>
> > >
>
> >
>
> > > >the adoption of best practice.
>
> >
>
> > >
>
> >
>
> > > >To say there is little to be learned is just plain wrong.
>
> >
>
> > >
>
> >
>
> > > >
>
> >
>
> > >
>
> >
>
> > > A good many years ago, my CFI had persuaded me to become an instructor, and
>
> >
>
> > >
>
> >
>
> > > I confided in him that my only real concern, was allowing someone else to
>
> >
>
> > >
>
> >
>
> > > be in control near the ground. He lent me Stick & Rudder by Wolfgang
>
> >
>
> > >
>
> >
>
> > > Langewiesche, and suggested a chapter to read. This is not a gliding book,
>
> >
>
> > >
>
> >
>
> > > but nevertheless there was lots of common interest. In particular was the
>
> >
>
> > >
>
> >
>
> > > bit, actually written by someone else, and showing how forgiving aircraft
>
> >
>
> > >
>
> >
>
> > > are when "crashing" under control. It is when they are not under control,
>
> >
>
> > >
>
> >
>
> > > ie stalled or spinning when they hit the ground, that the occupants stand
>
> >
>
> > >
>
> >
>
> > > the most chance of getting hurt, or worse.
>
> >
>
> > >
>
> >
>
> > > The same lesson was passed onto me in my brief excursion into power
>
> >
>
> > >
>
> >
>
> > > flying. In case of a relatively low engine failure, you land as near ahead
>
> >
>
> > >
>
> >
>
> > > as possible, into whatever is available.
>
> >
>
> > >
>
> >
>
> > > I can vouch for this from personal experience, having been in a straight
>
> >
>
> > >
>
> >
>
> > > ahead aeroplane crash, not me flying it, I hasten to add, I was in the
>
> >
>
> > >
>
> >
>
> > > back, and four of us walked away, as it went up in flames.
>
> >
>
> > >
>
> >
>
> > > Dave
>
> >
>
> >
>
> >
>
> > Langewiesche's point is correct as far as it goes. If the only choice is between crashing with the aircraft under control and crashing while out of control, being in control is always better. Duh!
>
> >
>
> >
>
> >
>
> > However, I think your implied point is that if a pilot tries a turn, the aircraft will be out of control. Obviously, I disagree. If a pilot can't retain control while making a simple 180 degree turn, the situation was dire long before the emergency arose.
>
> >
>
> >
>
> >
>
> > Now, lets define the "ground" you're going to crash into. Lets say there's a rock quarry off the departure end. Solid surfaces are vertical and all horizontal surfaces are water with no climb out options. The occupants will die in the crash or drown a few minutes later whether the aircraft crashed under control or not. My point is there are situations where no "straight ahead" option is available.
>
> >
>
> >
>
> >
>
> > My situation isn't quite that bad - it's only water filled gravel pits. The only field proven landable is VERY small and requires a 90 degree turn at treetop level around a large tree. Turning back, when possible, is always the best option. It pays to be good at it.
>
> >
>
> >
>
> >
>
> > The good news is gliders can turn back with generous safety margins. The wild card is the pilot.
>
>
>
> Langewiesche's point is correct, period. Which option carries the best chance of retaining control, keeping the wings level or turning, especially at low level?
--------------------
Neither or both depending solely on the ability of the pilot. Turns don't stall gliders - pilots do. Pilots with real flying ability have the "best chance" of retaining control.
>

> We have all witnessed instructors who like to scare their pupils witless by carrying out risky procedures, such behavior has no place in responsible aviation, but we all know it survives because of the intransigence of those who refuse to accept that we are there to teach safe flying.
------------------
So, you say that instructors who teach a maneuver required by the FAA Practical Test Standards as covered in detail on page 8-11 of the FAA Glider Flying Handbook are "witlessly" carrying out "risky procedures" to "scare their pupils"? That's about as absurd as r.a.s ever gets - which is saying a lot. You better hope the instructor who gives you your next Flight Review didn't read your post.

WAVEGURU

May 23rd 14, 03:15 AM

I agree with Bill. If you are scared witless by an instructor pulling the release at 200ft you have no business flying a sailplane solo.

Boggs

[email protected]

May 23rd 14, 04:59 AM

Yes and no. Any competent instructor would NOT have pulled the handle at 200' in the conditions that were in existence at Samply Aguila airport the time of the fatal crash. I took off a few minutes ahead of Bob and my 200' countdown lasted WAY farther than it ever had before at that airport, and by the time I finally got that high I was out of range of a glide back, and my 17.6m Ventus has a 50:1 glide. Plus, the air down low was turbulent. I was uncomfortable with the idea of having to get back to the runway for a while after attaining that altitude. Normally, it looks like duck soup from 200'.

200' during a training flight in reasonable air is one thing, in gusty sinky air is another. This thread started out about an unfortunate PTT fatality, and now it has evolved into lots of opinions, math computations, etc.... all good for discussion, but there is / was far more to a turn around or go straight decision than just 200' altitude. Conditions (wind velocity and direction, rising or falling air, and turbulence) and distance to, or how far past, the runway end also fit into any scenario. 200' training has its place, when conditions and common sense prevail.

Plus, I suspect Bob's thousands of hours with engines that would help power around a turn and low time in a glider with no power to help probably / possibly had a hand in this particular event. Like so many things, we'll most likely never know. But, lots of folks will continue to want to throw in their 2 cents worth.

Fly safe.
Bob T.

[email protected]

May 23rd 14, 12:15 PM

On Thursday, May 22, 2014 11:55:44 PM UTC+1, Bill D wrote:
> On Thursday, May 22, 2014 3:41:14 PM UTC-6, wrote:
>
> > On Monday, May 19, 2014 8:40:51 PM UTC+1, Bill D wrote:
>
> >
>
> > > On Monday, May 19, 2014 10:21:26 AM UTC-6, David Salmon wrote:
>
> >
>
> > >
>
> >
>
> > > > At 09:25 14 May 2014, Don Johnstone wrote:
>
> >
>
> > >
>
> >
>
> > > >
>
> >
>
> > >
>
> >
>
> > > > >At 02:14 14 May 2014, wrote: (snip)
>
> >
>
> > >
>
> >
>
> > > >
>
> >
>
> > >
>
> >
>
> > > > >>>I've been into soaring since 1996 and he was the 7th I've known to be
>
> >
>
> > >
>
> >
>
> > > >
>
> >
>
> > >
>
> >
>
> > > > >>called to the other side.
>
> >
>
> > >
>
> >
>
> > > >
>
> >
>
> > >
>
> >
>
> > > > >
>
> >
>
> > >
>
> >
>
> > > >
>
> >
>
> > >
>
> >
>
> > > > >>> We try to learn from others' mistakes, but in this case, as there were
>
> >
>
> > >
>
> >
>
> > > >
>
> >
>
> > >
>
> >
>
> > > > >no
>
> >
>
> > >
>
> >
>
> > > >
>
> >
>
> > >
>
> >
>
> > > > >>glider pilots who observed the event, little can be learned.
>
> >
>
> > >
>
> >
>
> > > >
>
> >
>
> > >
>
> >
>
> > > > >
>
> >
>
> > >
>
> >
>
> > > >
>
> >
>
> > >
>
> >
>
> > > > >>> Bob T
>
> >
>
> > >
>
> >
>
> > > >
>
> >
>
> > >
>
> >
>
> > > > >>
>
> >
>
> > >
>
> >
>
> > > >
>
> >
>
> > >
>
> >
>
> > > > >That is simply not true. Whilst not commenting on the specifics of this
>
> >
>
> > >
>
> >
>
> > > >
>
> >
>
> > >
>
> >
>
> > > > >accident the outcome has provoked a serious discussion on the procedure
>
> >
>
> > >
>
> >
>
> > > >
>
> >
>
> > >
>
> >
>
> > > > to
>
> >
>
> > >
>
> >
>
> > > >
>
> >
>
> > >
>
> >
>
> > > > >be adopted following a launch failure at low level.
>
> >
>
> > >
>
> >
>
> > > >
>
> >
>
> > >
>
> >
>
> > > > >There are those who have argued passionately, that a turn back, even from
>
> >
>
> > >
>
> >
>
> > > >
>
> >
>
> > >
>
> >
>
> > > > a
>
> >
>
> > >
>
> >
>
> > > >
>
> >
>
> > >
>
> >
>
> > > > >low starting height is a viable and safe option providing the best chance
>
> >
>
> > >
>
> >
>
> > > >
>
> >
>
> > >
>
> >
>
> > > > >of a good outcome. There has been a deal of opinion that in these
>
> >
>
> > >
>
> >
>
> > > >
>
> >
>
> > >
>
> >
>
> > > > >circumstances we should consider doing something, turning downwind at
>
> >
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> > >
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> > > >
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> >
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> > >
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> > > > very
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> > >
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> > > >
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> > >
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> > > > >low level, which we would never ever consider doing in normal operations.
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> > >
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> > > >
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> > >
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> > > > >Observing a pilot making the 90 degree turn from base to finals at such a
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> > >
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> >
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> > > >
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> >
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> > >
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> > > > >low level would result in a very one sided conversation at many gliding
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> > >
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> >
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> > > >
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> >
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> > >
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> >
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> > > > >sites. Loss of control below 300 ft, let alone 200 ft, is only ever going
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> >
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> > >
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> >
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> > > >
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> >
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> > >
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> >
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> > > > >to end one way.
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> > >
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> > > >
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> > >
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> >
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> > > > >There are those who have argued that a much safer option in to land
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> > >
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> >
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> > > >
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> >
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> > >
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> > > > >straight ahead, or slightly to one side even if the terrain is difficult,
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> >
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> > >
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> >
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> > > >
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> >
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> > >
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> > > > >aiming to ensure that the fuselage survives the landing, even at the
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> >
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> > >
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> >
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> > > >
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> >
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> > >
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> >
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> > > > >expense of damage to other parts. The argument to support this is that a
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> >
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> > >
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> >
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> > > >
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> >
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> > >
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> >
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> > > > >controlled descent with wings level is far more likely to have a better
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> >
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> > >
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> >
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> > > >
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> >
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> > >
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> >
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> > > > >outcome than getting the low turn wrong. There are fewer items to
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> >
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> > >
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> >
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> > > >
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> >
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> > >
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> > > > >concentrate on with more time to monitor the basic need of keeping the
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> >
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> > >
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> > > >
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> > >
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> > > > >glider flying with sufficient airspeed to ensure a controlled landing. A
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> >
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> > >
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> >
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> > > >
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> >
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> > >
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> >
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> > > > >much simpler approach and one likely to be easier for low hours,
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> >
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> > >
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> >
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> > > >
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> > >
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> >
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> > > > >inexperienced and low currency pilots.
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> >
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> > >
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> > > >
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> > >
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> > > > >The basic questions to ask in deciding which is the best option is, "Will
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> >
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> > >
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> > > >
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> > >
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> > > > >pilots of ALL skill levels and currency be best served by a simple or
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> >
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> > >
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> >
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> > > >
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> >
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> > >
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> >
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> > > > >complicated procedure?" "Is creating a mindset that turning downwind is
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> >
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> > >
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> >
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> > > >
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> >
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> > >
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> > > > the
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> >
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> > >
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> > >
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> > > > >best option suitable for all conditions?" and "Does the procedure adopted
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> >
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> > >
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> >
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> > > >
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> >
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> > >
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> >
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> > > > >offer the best chance of survival of the pilot, even at the expense of
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> >
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> > >
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> >
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> > > >
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> >
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> > >
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> >
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> > > > >glider damage?". I think most gliding supervisors will be able to answer
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> >
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> > >
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> >
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> > > >
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> >
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> > >
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> >
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> > > > >those questions, the only question remaining is will they be able to make
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> >
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> > >
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> >
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> > > >
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> >
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> > >
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> >
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> > > > >the right decision to implement what they have learned.
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> >
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> > >
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> > > >
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> > >
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> >
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> > >
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> >
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> > > > >My personal view is that the low turn back is one complication, if not
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> >
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> > >
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> >
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> > > >
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> >
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> > >
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> >
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> > > > >several, too many for an average pilot and flies in the face of the basic
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> >
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> > >
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> >
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> > > >
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> >
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> > >
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> >
>
> > > > >Aviate, navigate, communicate mantra. The last two should only ever come
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> >
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> > >
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> >
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> > > >
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> >
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> > >
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> >
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> > > > >into play once the first has been achieved and off a very low launch
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> >
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> > >
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> >
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> > > >
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> >
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> > >
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> >
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> > > > >failure there may never be time to get to the secondary priorities.. The
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> >
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> > >
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> >
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> > > >
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> >
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> > >
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> >
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> > > > >teaching of a low turn back places more emphasis on the secondary
>
> >
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> > >
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> >
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> > > >
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> >
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> > >
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> >
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> > > > priority
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> >
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> > >
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> >
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> > > >
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> >
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> > >
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> >
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> > > > >to the detriment of the first and creates a mindset that may lead to a
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> >
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> > >
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> >
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> > > >
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> >
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> > >
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> >
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> > > > less
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> >
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> > >
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> >
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> > > >
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> >
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> > >
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> >
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> > > > >positive outcome than a much simpler procedure. There will always be
>
> >
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> > >
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> >
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> > > >
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> >
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> > >
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> >
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> > > > >exceptions to any basic procedure, in a few situations the basic
>
> >
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> > >
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> >
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> > > >
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> >
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> > >
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> >
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> > > > procedure
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> >
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> > >
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> >
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> > > >
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> >
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> > >
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> >
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> > > > >may not be an option so other options will have to be considered. Those
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> >
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> > >
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> >
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> > > >
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> >
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> > >
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> >
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> > > > >exceptions should only ever be applied where and when they are necessary,
>
> >
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> > >
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> >
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> > > >
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> >
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> > >
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> >
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> > > > >which does not invalidate the preference for a simple basic procedure.
>
> >
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> > >
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> >
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> > > >
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> >
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> > >
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> >
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> > > > >I also think that arguing amongst ourselves, while useful in reaching the
>
> >
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> > >
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> >
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> > > >
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> >
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> > >
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> >
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> > > > >best conclusion, carries the danger of entrenchment when it should
>
> >
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> > >
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> >
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> > > >
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> >
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> > >
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> >
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> > > > promote
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> >
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> > >
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> >
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> > > >
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> >
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> > >
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> >
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> > > > >the adoption of best practice.
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> >
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> > >
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> >
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> > > >
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> >
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> > >
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> >
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> > > > >To say there is little to be learned is just plain wrong.
>
> >
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> > >
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> >
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> > > >
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> >
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> > >
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> >
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> > > > >
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> > >
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> >
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> > > >
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> >
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> > >
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> >
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> > > > A good many years ago, my CFI had persuaded me to become an instructor, and
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> >
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> > >
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> >
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> > > >
>
> >
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> > >
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> >
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> > > > I confided in him that my only real concern, was allowing someone else to
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> >
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> > >
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> >
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> > > >
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> >
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> > >
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> >
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> > > > be in control near the ground. He lent me Stick & Rudder by Wolfgang
>
> >
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> > >
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> >
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> > > >
>
> >
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> > >
>
> >
>
> > > > Langewiesche, and suggested a chapter to read. This is not a gliding book,
>
> >
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> > >
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> >
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> > > >
>
> >
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> > >
>
> >
>
> > > > but nevertheless there was lots of common interest. In particular was the
>
> >
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> > >
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> >
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> > > >
>
> >
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> > >
>
> >
>
> > > > bit, actually written by someone else, and showing how forgiving aircraft
>
> >
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> > >
>
> >
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> > > >
>
> >
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> > >
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> >
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> > > > are when "crashing" under control. It is when they are not under control,
>
> >
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> > >
>
> >
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> > > >
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> >
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> > >
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> >
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> > > > ie stalled or spinning when they hit the ground, that the occupants stand
>
> >
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> > >
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> >
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> > > >
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> >
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> > >
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> >
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> > > > the most chance of getting hurt, or worse.
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> >
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> > >
>
> >
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> > > >
>
> >
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> > >
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> >
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> > > > The same lesson was passed onto me in my brief excursion into power
>
> >
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> > >
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> >
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> > > >
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> >
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> > >
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> >
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> > > > flying. In case of a relatively low engine failure, you land as near ahead
>
> >
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> > >
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> >
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> > > >
>
> >
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> > >
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> >
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> > > > as possible, into whatever is available.
>
> >
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> > >
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> >
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> > > >
>
> >
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> > >
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> >
>
> > > > I can vouch for this from personal experience, having been in a straight
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> >
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> > >
>
> >
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> > > >
>
> >
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> > >
>
> >
>
> > > > ahead aeroplane crash, not me flying it, I hasten to add, I was in the
>
> >
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> > >
>
> >
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> > > >
>
> >
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> > >
>
> >
>
> > > > back, and four of us walked away, as it went up in flames.
>
> >
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> > >
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> >
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> > > >
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> >
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> > >
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> >
>
> > > > Dave
>
> >
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> > >
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> >
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> > >
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> >
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> > >
>
> >
>
> > > Langewiesche's point is correct as far as it goes. If the only choice is between crashing with the aircraft under control and crashing while out of control, being in control is always better. Duh!
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > > However, I think your implied point is that if a pilot tries a turn, the aircraft will be out of control. Obviously, I disagree. If a pilot can't retain control while making a simple 180 degree turn, the situation was dire long before the emergency arose.
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > > Now, lets define the "ground" you're going to crash into. Lets say there's a rock quarry off the departure end. Solid surfaces are vertical and all horizontal surfaces are water with no climb out options. The occupants will die in the crash or drown a few minutes later whether the aircraft crashed under control or not. My point is there are situations where no "straight ahead" option is available.
>
> >
>
> > >
>
> >
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> > >
>
> >
>
> > >
>
> >
>
> > > My situation isn't quite that bad - it's only water filled gravel pits. The only field proven landable is VERY small and requires a 90 degree turn at treetop level around a large tree. Turning back, when possible, is always the best option. It pays to be good at it.
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > > The good news is gliders can turn back with generous safety margins. The wild card is the pilot.
>
> >
>
> >
>
> >
>
> > Langewiesche's point is correct, period. Which option carries the best chance of retaining control, keeping the wings level or turning, especially at low level?
>
> --------------------
>
> Neither or both depending solely on the ability of the pilot. Turns don't stall gliders - pilots do. Pilots with real flying ability have the "best chance" of retaining control.
>
> >
>
>
>
> > We have all witnessed instructors who like to scare their pupils witless by carrying out risky procedures, such behavior has no place in responsible aviation, but we all know it survives because of the intransigence of those who refuse to accept that we are there to teach safe flying.
>
> ------------------
>
> So, you say that instructors who teach a maneuver required by the FAA Practical Test Standards as covered in detail on page 8-11 of the FAA Glider Flying Handbook are "witlessly" carrying out "risky procedures" to "scare their pupils"? That's about as absurd as r.a.s ever gets - which is saying a lot. You better hope the instructor who gives you your next Flight Review didn't read your post.

Thankfully I will not have a problem. If a student on a "flight review" attempted a turn back from that height when there was a landable area ahead he would fail. As an instructor I would not be so stupid as to initiate a failure at that height without a safe landing area ahead, perhaps that is why I have survived 52 years of gliding. Quoting the FAA as an authority on gliding, that is a joke right?

Bill, just answer the 3 questions honestly:
"Will pilots of ALL skill levels and currency be best served by a simple or
complicated procedure?"
"Is creating a mindset that turning downwind is the best option suitable for all conditions?"
"Does the procedure adopted offer the best chance of survival of the pilot, even at the expense of glider damage?"

Bill D

May 23rd 14, 02:40 PM

On Friday, May 23, 2014 5:15:37 AM UTC-6, wrote:

> Thankfully I will not have a problem. If a student on a "flight review" attempted a turn back from that height when there was a landable area ahead he would fail. As an instructor I would not be so stupid as to initiate a failure at that height without a safe landing area ahead, perhaps that is why I have survived 52 years of gliding. Quoting the FAA as an authority on gliding, that is a joke right?

The joke is an 'instructor' who's obviously terrified of turns.

> Bill, just answer the 3 questions honestly:
>
> "Will pilots of ALL skill levels and currency be best served by a simple or
>
> complicated procedure?"

All skill levels? Pilots either meet the minimum skill level or they don't - and the minimum requires them to be able to return to the runway. If they can't demonstrate that level of skill, they don't fly.

In many, if not most cases, a return to the departure runway is the simplest solution. An off field landing dealing with trees, fences and unimproved ground is more often the complicated - and less safe - solution.

>
> "Is creating a mindset that turning downwind is the best option suitable for all conditions?"

No one suggests creating a "mindset" except to use good judgement in selecting the best option. No one is saying turn "downwind" - they are saying turn back for a downwind landing which is a different thing. No one in this absurd thread said "all conditions".
>
> "Does the procedure adopted offer the best chance of survival of the pilot, even at the expense of glider damage?"

Yes, in many if not most situations, landing on the departure runway does offer the best chance of survival.

Don Johnstone[_4_]

May 23rd 14, 03:22 PM

At 13:40 23 May 2014, Bill D wrote:
>On Friday, May 23, 2014 5:15:37 AM UTC-6, wrote:
>=20
>> Thankfully I will not have a problem. If a student on a "flight review"
>a=
>ttempted a turn back from that height when there was a landable area
ahead
>=
>he would fail. As an instructor I would not be so stupid as to initiate a
>f=
>ailure at that height without a safe landing area ahead, perhaps that is
>wh=
>y I have survived 52 years of gliding. Quoting the FAA as an authority on
>g=
>liding, that is a joke right?
>
>The joke is an 'instructor' who's obviously terrified of turns.
>=20
>> Bill, just answer the 3 questions honestly:
>>=20
>> "Will pilots of ALL skill levels and currency be best served by a
simple
>=
>or
>>=20
>> complicated procedure?"
>
>All skill levels? Pilots either meet the minimum skill level or they
>don't=
> - and the minimum requires them to be able to return to the runway. If
>th=
>ey can't demonstrate that level of skill, they don't fly.
>
>In many, if not most cases, a return to the departure runway is the
>simples=
>t solution. An off field landing dealing with trees, fences and
unimproved
>=
>ground is more often the complicated - and less safe - solution.
>
>
>>=20
>> "Is creating a mindset that turning downwind is the best option
>suitable=
> for all conditions?"=20
>
>No one suggests creating a "mindset" except to use good judgement in
>select=
>ing the best option. No one is saying turn "downwind" - they are saying
>tu=
>rn back for a downwind landing which is a different thing. No one in
this
>=
>absurd thread said "all conditions".
>>=20
>> "Does the procedure adopted offer the best chance of survival of the
>pil=
>ot, even at the expense of glider damage?"
>
>Yes, in many if not most situations, landing on the departure runway does
>o=
>ffer the best chance of survival.
>
Well all I can say is I am glad that I live and fly where common sense and
safe gliding prevails, and where the FAA is not.
I am not terrified of turns, I have done lots. I am not even terrified of
low turns, I avoid them if only to avoid setting a bad example to others.
Personally I would not have a problem turning back at 200 ft but I would
never do it or teach it if the land ahead option was available, even if off
airfield.
Your answer to the last question demonstrates your ignorance of safe
aviation but you are several thousand miles away from where I fly so I
should worry little.

BobW

May 23rd 14, 04:06 PM

Major snip...>

> ..."Will pilots of ALL skill
> levels and currency be best served by a simple or complicated procedure?"
> "Is creating a mindset that turning down adopted offer the best chance of
> survival of the pilot, even at the expense of glider damage?"
>

I could be wrong, but sometimes I sense a tendency to "reductio ad absurdum"
on the part of some folks - to convince others of their point of view? I
dunno...but as a non-instructor, glider-only pilot, I managed to
mostly-weekend-acquire ~2600 hours without ever contacting the ground "out of
control," to also safely and sans alarums demonstrate the proper response(s)
to simulated low-altitude, departure-end rope breaks, and I WAS surprised when
my ab-initio instructor (initially, verbally) introduced the concept of a
not-that-flight-pre-announced low-altitude rope break as a possibility for my
imminent future...and then who "immediately asked all the expected 'silly
questions'" of my instructor. That noted, nowhere along the line did I ever
get it into my head things like: 200' agl is an absolute go/no-go turnaround
altitude; or a downwind landing on the departure runway is ALWAYS to be
preferred; or that no judgment was required to safely and effectively respond
to a low-altitude rope break; or that it was "simple" (or, "complicated" for
that matter) to pilot my way through the post PTT attempt.

What I DID get into my head - and I can't remember if I did this entirely on
my own (out of fearful respect for the fragility of my "somewhat resilient
pink body") or through some combination of instruction, reading, cogitation,
etc. - was that it mattered VERY MUCH that I do certain things as PIC
"correctly" - for under certain (thin margin) circumstances I would not get a
second chance.

As many of my math instructors loved to say, It was "immediately obvious to
the most casual observer" that a low-altitude rope break was a thin margin
event, and it was up to me to "handle it right" - or else my frail pink bod
would be at higher risk than it needed to be.

IMHO, anyone who gets caught up in defending a stance I'd characterize as "do
it this way or you're wrong," when "this way" is procedurally based to the
discussional exclusion of maintaining solid flight control is missing the
point to a certain extent, and - yes - I understand the nature of instruction
and the need to instruct using "building blocks of knowledge"...which is the
way I've "forever" thought of "the magic 200 feet" concept. It's a great place
to start. It isn't fundamentally dangerous (from a control of the glider
perspective). It's not fundamentally difficult to pilot as Joe PIC. It's not
appropriate under all circumstances...while (in my view) "hitting the ground
under control" IS appropriate under all circumstances. The question then
becomes, "What ground?" That's where more judgement enters the picture.

As others have noted, it's not at all uncommon in the intermountain western
U.S. to aerotow launch from fields where accepting something other than a
downwind landing on the departure runway from 200' agl in the event of a
low-altitude rope break is (obviously, unarguably, inevitably, etc...) "the
best/safest thing to do."

Being 100% first-person-ignorant of the circumstances surrounding the tragic
crash sparking this (contains much food for thought) thread, several of my
operating conclusions are: 1) we can never know for sure what was in the
deceased pilot's mind; 2) he likely hit the ground "in a non-flying
condition"; 3) 2) is further evidence for me to "not do that." Tying the
preceding into "the magic 200' agl PTT altitude" is easy enough for me in that
if "in my judgment" I think 200' IS sufficient under the circumstances to
attempt a turn-around, then I'll do it; if not, then I'll do something
different...but whatever I do I'll work darned hard to ensure I maintain
control all the way to the ground. Duh???

Respectfully,
Bob W.

John L Fleming

May 24th 14, 03:21 PM

On Sunday, May 4, 2014 12:27:10 AM UTC-4, Waveguru wrote:
Premature termination of the tow at 100ft. Did not complete the turn back to the runway.

My sympathy to everyone touched by this tragedy.

Turning 180 back to the runway from only 100 feet AGL is unusual. I wonder why he did that.

I've been watching this thread from day one. I'm back here in New York and was a friend of Bob and am puzzled by the turn as he always had his ducks all in a row. I'm too am a glider pilot and I find it hard to believe he made a steep bank at 100 feet. Bob had accumilated 1000's of hours in both fighters and the two single engine aircraft he owned.
MAYBE, there was something wrong with the Zuni and he released because he couldn't control it?????? For instance........aileron linkage failure. I would be interested in others thoughts on this. John

Bob Whelan[_3_]

May 25th 14, 05:00 PM

On 5/24/2014 8:21 AM, John L Fleming wrote:
> son_of_flubber;883103 Wrote:
>> On Sunday, May 4, 2014 12:27:10 AM UTC-4, Waveguru wrote:-
>> Premature termination of the tow at 100ft. Did not complete the turn
>> back to the runway. -
>>
>> My sympathy to everyone touched by this tragedy.
>>
>> Turning 180 back to the runway from only 100 feet AGL is unusual. I
>> wonder why he did that.
>
> I've been watching this thread from day one. I'm back here in New York
> and was a friend of Bob and am puzzled by the turn as he always had his
> ducks all in a row. I'm too am a glider pilot and I find it hard to
> believe he made a steep bank at 100 feet. Bob had accumulated 1000's of
> hours in both fighters and the two single engine aircraft he owned.
> MAYBE, there was something wrong with the Zuni and he released because
> he couldn't control it?????? For instance........aileron linkage
> failure. I would be interested in others thoughts on this. John

My condolences for the loss of your friend. I hadn't been in aviation but two
or three years before personal aviation acquaintances and friends began dying
in aviation-related accidents. All I could do was mourn their passing, try and
extract lessons for myself (if any), rationalize that they died doing
something they loved, and take some decision(s) for my own future.

Many glider pilots often roll their eyes at "the obviousness" of NTSB probable
cause conclusions (e.g. pilot failed to maintain sufficient speed), but one
thing I think NTSB investigators are quite adept at is establishing control
connection continuity, particularly in the aftermath of low-speed accidents as
this (where wreckage is minimally disturbed from effects of the crash itself),
so probably the best answer to your puzzlement can be expected to come from
the final NTSB report on this crash.

Bob W.

Don Johnstone[_4_]

May 25th 14, 09:40 PM

At 15:06 23 May 2014, BobW wrote:
>Major snip...>
>
>> ..."Will pilots of ALL skill
>> levels and currency be best served by a simple or complicated
procedure?"
>> "Is creating a mindset that turning down adopted offer the best chance
>of
>> survival of the pilot, even at the expense of glider damage?"
>>
>
>I could be wrong, but sometimes I sense a tendency to "reductio ad
>absurdum"
>on the part of some folks - to convince others of their point of view? I
>dunno...but as a non-instructor, glider-only pilot, I managed to
>mostly-weekend-acquire ~2600 hours without ever contacting the ground
"out
>of
>control," to also safely and sans alarums demonstrate the proper
>response(s)
>to simulated low-altitude, departure-end rope breaks, and I WAS surprised
>when
>my ab-initio instructor (initially, verbally) introduced the concept of a

>not-that-flight-pre-announced low-altitude rope break as a possibility
for
>my
>imminent future...and then who "immediately asked all the expected 'silly

>questions'" of my instructor. That noted, nowhere along the line did I
ever
>
>get it into my head things like: 200' agl is an absolute go/no-go
>turnaround
>altitude; or a downwind landing on the departure runway is ALWAYS to be
>preferred; or that no judgment was required to safely and effectively
>respond
>to a low-altitude rope break; or that it was "simple" (or, "complicated"
>for
>that matter) to pilot my way through the post PTT attempt.
>
>What I DID get into my head - and I can't remember if I did this entirely
>on
>my own (out of fearful respect for the fragility of my "somewhat resilient

>pink body") or through some combination of instruction, reading,
>cogitation,
>etc. - was that it mattered VERY MUCH that I do certain things as PIC
>"correctly" - for under certain (thin margin) circumstances I would not
get
>a
>second chance.
>
>As many of my math instructors loved to say, It was "immediately obvious
to
>
>the most casual observer" that a low-altitude rope break was a thin margin

>event, and it was up to me to "handle it right" - or else my frail pink
bod
>
>would be at higher risk than it needed to be.
>
>IMHO, anyone who gets caught up in defending a stance I'd characterize as
>"do
>it this way or you're wrong," when "this way" is procedurally based to the

>discussional exclusion of maintaining solid flight control is missing the

>point to a certain extent, and - yes - I understand the nature of
>instruction
>and the need to instruct using "building blocks of knowledge"...which is
>the
>way I've "forever" thought of "the magic 200 feet" concept. It's a great
>place
>to start. It isn't fundamentally dangerous (from a control of the glider
>perspective). It's not fundamentally difficult to pilot as Joe PIC. It's
>not
>appropriate under all circumstances...while (in my view) "hitting the
>ground
>under control" IS appropriate under all circumstances. The question then
>becomes, "What ground?" That's where more judgement enters the picture.
>
>As others have noted, it's not at all uncommon in the intermountain
western
>
>U.S. to aerotow launch from fields where accepting something other than a

>downwind landing on the departure runway from 200' agl in the event of a
>low-altitude rope break is (obviously, unarguably, inevitably, etc...)
"the
>
>best/safest thing to do."
>
>Being 100% first-person-ignorant of the circumstances surrounding the
>tragic
>crash sparking this (contains much food for thought) thread, several of my

>operating conclusions are: 1) we can never know for sure what was in the
>deceased pilot's mind; 2) he likely hit the ground "in a non-flying
>condition"; 3) 2) is further evidence for me to "not do that." Tying the
>preceding into "the magic 200' agl PTT altitude" is easy enough for me in
>that
>if "in my judgment" I think 200' IS sufficient under the circumstances to

>attempt a turn-around, then I'll do it; if not, then I'll do something
>different...but whatever I do I'll work darned hard to ensure I maintain
>control all the way to the ground. Duh???
>
>Respectfully,
>Bob W.

I cannot argue against the above. From what I have read in this thread I
have gained the impression that in the event of a launch failure at 200 ft
or above the recommended procedure is to turn back to the runway. This is
completely different from what I have taught for 45 years. In the event of
any launch failure the question that should be asked is "Can I land ahead"
If the answer is "yes" then land ahead, height does not come into it at
all. If, and only if the answer is "No" or "Not sure" should another action
be considered and executed.
In any event I would never simulate a launch failure at 200 ft if there was
not room to land ahead. I would and do simulate launch failures at 300ft
and above if there is no room to land ahead and allow students to practice
this, turning back as necessary. The reason is simple, while a pilot may be
faced with having to turn back at 200 ft the risks in doing so are not
justified in training, in the same way that we do not practice very low
winch launch failures, just after liftoff, or practice groundloops to avoid
obstacles both of which are covered by briefings. We do set up the ultra
low level launch failure situation from a normal approach but we never
simulate it off the launch because of the dangers involved.
There will always be circumstances where the "normal" procedure is not
possible but we do stress that the important part of the outcome is that
the pilot has the best chance of survival, an undamged glider is not a
priority in these circumstances.

Chris Rollings[_2_]

May 26th 14, 07:44 AM

At 16:00 25 May 2014, Bob Whelan wrote:
>On 5/24/2014 8:21 AM, John L Fleming wrote:
>> son_of_flubber;883103 Wrote:
>>> On Sunday, May 4, 2014 12:27:10 AM UTC-4, Waveguru wrote:-
>>> Premature termination of the tow at 100ft. Did not complete the turn
>>> back to the runway. -
>>>
>>> My sympathy to everyone touched by this tragedy.
>>>
>>> Turning 180 back to the runway from only 100 feet AGL is unusual. I
>>> wonder why he did that.
>>
>> I've been watching this thread from day one. I'm back here in New York
>> and was a friend of Bob and am puzzled by the turn as he always had his
>> ducks all in a row. I'm too am a glider pilot and I find it hard to
>> believe he made a steep bank at 100 feet. Bob had accumulated 1000's
of
>> hours in both fighters and the two single engine aircraft he owned.
>> MAYBE, there was something wrong with the Zuni and he released because
>> he couldn't control it?????? For instance........aileron linkage
>> failure. I would be interested in others thoughts on this. John
>
>My condolences for the loss of your friend. I hadn't been in aviation but
>two
>or three years before personal aviation acquaintances and friends began
>dying
>in aviation-related accidents. All I could do was mourn their passing,
try
>and
>extract lessons for myself (if any), rationalize that they died doing
>something they loved, and take some decision(s) for my own future.
>
>Many glider pilots often roll their eyes at "the obviousness" of NTSB
>probable
>cause conclusions (e.g. pilot failed to maintain sufficient speed), but
one
>
>thing I think NTSB investigators are quite adept at is establishing
control
>
>connection continuity, particularly in the aftermath of low-speed
accidents
>as
>this (where wreckage is minimally disturbed from effects of the crash
>itself),
>so probably the best answer to your puzzlement can be expected to come
from
>
>the final NTSB report on this crash.
>
>Bob W.
>

Some years ago I witnessed a fatal spin-in following a launch failure. It
was a winch launch, the cable broke at about 150 feet agl. There was
plenty of room to land ahead on the airfield but the glider started a turn
to the left, flying obviously rather slowly. It completed about two thirds
of a 360 degree turn and then spun, went down into some trees a few yards
from the airfield boundary on ground about 20 feet lower than the airfield.
I was one of those that extracted the badly injured pilot from the
wreckage (he died in the ambulance before it left the airfield).

In the UK it is almost universal practice to set QFE not QNH on glider
altimeters (most gliding sites are less than 1,000 feet amsl), I noticed
that the altimeter in the wrecked glider was reading about plus 260 feet.
Later investigation showed that the millibar sub-scale setting was
consistent with the pressure on the previous day on which the glider had
flown. It seemed highly likely to me that the pilot had omitted to reset
the altimeter before take-off and, when the launch failed, saw over 400
feet on the altimeter and reacted to that.

Bruce Hoult

May 26th 14, 12:51 PM

On Monday, May 26, 2014 6:44:41 PM UTC+12, Chris Rollings wrote:
> Some years ago I witnessed a fatal spin-in following a launch failure. It
> was a winch launch, the cable broke at about 150 feet agl. There was
> plenty of room to land ahead on the airfield but the glider started a turn

Well, that's clearly stupid.

The place I normally fly is short (but long enough we have 150 ft or so over the fence on a normal day, less if dead calm, more if a decent headwind) and the options are houses houses and houses, or turn back.

If you've got "cross the boundary fence and take the next paddock" that's a different matter.

And if you've got a km of runway still in front of you then turning back from 150 ft is utterly stupid. I don't think anyone here is arguing for that.

> In the UK it is almost universal practice to set QFE not QNH on glider
> altimeters (most gliding sites are less than 1,000 feet amsl), I noticed

Um. Who the heck looks at the *altimeter* at a time like that? Look out the window!

A couple of years ago the field I usually fly from got a flight information service. They can't tell us what to do, in every regard except one. When we arrived back and joined the circuit they'd (along with wind etc) tell us the QNH and EXPECT US TO REPEAT IT BACK. And presumably expect us to set the altimeter to it.

It's been a long process, but we seem to have finally convinced them that by the time we've made the decision to land and made the downwind call we are no longer interested in the altimeter, what it says, or what the QNH is. That was useful 20 or 30 km out, but from this point on we're ignoring the altimeter and looking out the window.

Bob Whelan[_3_]

May 26th 14, 05:04 PM

On 5/25/2014 2:40 PM, Don Johnstone wrote:
> At 15:06 23 May 2014, BobW wrote:
>> <Major snip...>
>>

> I cannot argue against the above. From what I have read in this thread I
> have gained the impression that in the event of a launch failure at 200 ft
> or above the recommended procedure is to turn back to the runway. This is
> completely different from what I have taught for 45 years. In the event of
> any launch failure the question that should be asked is "Can I land ahead"
> If the answer is "yes" then land ahead, height does not come into it at
> all. If, and only if the answer is "No" or "Not sure" should another action
> be considered and executed.

From my U.S.-centric, non-instructing perspective, perhaps this is one of
those nuanced differences between FAA-driven-instruction and BGA-driven
instruction?

What I think I remember of my instruction - and what I think I've seen ever
since then from observing others' instruction - was that "considering all
alternatives" before executing a reversing turn from nominally 200' agl in a
glider "is no big deal" and ought to be in the glider pilot's bag of tricks.
I've never thought the conceptual approach in any way fundamentally marginal
in a life-threatening (mine!) sense.

That's not to say the sensibility of the BGA approach wasn't - hadn't already
- been hammered home...as in I'd already internalized that Joe Glider-pilot's
Rule Number One is to never be beyond safe gliding distance to a safe landing
field. In my experience, the ONLY exception to Rule No. 1 has been those
(mostly western U.S.) fields where there may be a short time window when the
"reach a safe field" option simply doesn't exist for whatever reason(s).
That's when "fly the plane into/through the arrival" becomes more than a
mental concept.

> In any event I would never simulate a launch failure at 200 ft if there was
> not room to land ahead.

This certainly has been my training/recurrency experience(s)..."merely
goes-without-saying common-sense" IMO. I might be wrong in this surmise -
chime in instructors - but I doubt even our FAA has felt it necessary to
provide instructional guidelines "to this degree of obviousness."

> I would and do simulate launch failures at 300ft
> and above if there is no room to land ahead and allow students to practice
> this, turning back as necessary. The reason is simple, while a pilot may be
> faced with having to turn back at 200 ft the risks in doing so are not
> justified in training, in the same way that we do not practice very low
> winch launch failures, just after liftoff, or practice groundloops to avoid
> obstacles both of which are covered by briefings. We do set up the ultra
> low level launch failure situation from a normal approach but we never
> simulate it off the launch because of the dangers involved.

FWIW, my takeaway from decades of avid personal interest and absorbing every
flight crunch writeup available to me, is that the risk in these sorts of
situations is essentially U.S.-invisible when considering training
incidents/accidents. The crunches sticking in my mind have been those
involving single-pilots for the most part. I suppose an argument can be made
about the longer-term efficacy and mental retention of training, if my
memories are valid, but not so much from a training perspective. In any event,
I don't think MY personal risk was increased from this aspect of my training.

> There will always be circumstances where the "normal" procedure is not
> possible but we do stress that the important part of the outcome is that
> the pilot has the best chance of survival, an undamaged glider is not a
> priority in these circumstances.
>

I 100% agree!!!

Respectfully,
Bob W.

June 15th 14, 07:09 AM

On Thursday, May 8, 2014 5:55:27 PM UTC-7, Bill D wrote:
> On Thursday, May 8, 2014 6:39:06 PM UTC-6, 2G wrote:
>
>
>
> > The other issue is that a tow rope break requires immediate lowering of the nose.
>
>
>
> Why would anyone lower the nose? The glider is presumably at aero tow speed - 65 - 70 knots which is way above the pattern speed. A better plan is to use the excess airspeed to maintain height while turning until airspeed drops to pattern speed.
>
>
>
>
>
> This is done routinely at altitude, but at low altitude this means pointing the glider's nose uncomfortably down at the ground while executing a steep banked turn. If the ground is rising, as it is at Sampley, the picture seen by the pilot is even more disturbing. All that it takes is a momentary hesitation in this reflex and the outcome can be fatal.
>
>
>
> The nose is not "uncomfortably down". The turn back is a normal turn.
>
> >
>
> >
>
> >
>
> > As an aside, I once did a wind mill start in my DG400 below 1000' (over a runway). This maneuver requires achieving in excess of 90 kt airspeed. Because the engine & prop act like dive brakes, you feel like you are standing on your rudder pedals when you do this close to the ground. I got to this airspeed and the prop still didn't rotate. This meant that I had to steepen the descent even more. All of my instincts said no, but my brain said yes, which is what I did. The engine started, but I decided that this maneuver really needs to be started at a higher altitude.
>
>
>
> Aha! You're really a motor glider pilot, not an aero tow pilot which explains your misconceptions.

PLEASE stop with the sanctimonious crap! I have done hundreds of aerotows. You need to lower the nose because you are in a climb attitude and need to transition to a glide attitude. On your next tow note where the horizon is on the canopy and compare it to where it is after release at the same airspeed.

Tom

Bruce Hoult

June 15th 14, 12:31 PM

On Sunday, June 15, 2014 6:09:22 PM UTC+12, 2G wrote:
> PLEASE stop with the sanctimonious crap! I have done hundreds of aerotows.. You need to lower the nose because you are in a climb attitude and need to transition to a glide attitude. On your next tow note where the horizon is on the canopy and compare it to where it is after release at the same airspeed.

While the nose ends up lower, you don't lower the nose. The decrease in airspeed does that for you, and the movement of the stick is rearward, to prevent the nose falling through into a dive and again attaining the aerotow airspeed.

John Firth[_4_]

June 15th 14, 01:21 PM

Whether or not positive action is required to maintain airspeed
depends on the trim; this will be different for nose and belly hooks. A
belly hook on some ( older ) gliders requires
nose down trim to balance the rope force.
JMF

At 11:31 15 June 2014, Bruce Hoult wrote:
>On Sunday, June 15, 2014 6:09:22 PM UTC+12, 2G wrote:
>> PLEASE stop with the sanctimonious crap! I have done hundreds of
>aerotows=
>.. You need to lower the nose because you are in a climb attitude and
need
>t=
>o transition to a glide attitude. On your next tow note where the horizon
>i=
>s on the canopy and compare it to where it is after release at the same
>air=
>speed.
>
>While the nose ends up lower, you don't lower the nose. The decrease in
>air=
>speed does that for you, and the movement of the stick is rearward, to
>prev=
>ent the nose falling through into a dive and again attaining the aerotow
>ai=
>rspeed.
>
>

Bruce Hoult

June 15th 14, 04:01 PM

On Monday, June 16, 2014 12:21:16 AM UTC+12, firsys wrote:
> Whether or not positive action is required to maintain airspeed
> depends on the trim; this will be different for nose and belly hooks. A
> belly hook on some ( older ) gliders requires
> nose down trim to balance the rope force.

Yes, I have 60 or 70 hours PIC from aerotow (and a few flights on a winch) in an original model Janus, with only a belly hook. To be honest the only time it is really noticeable on aerotow is if you have slack rope and it comes tight with a jerk. It pays to be ready with forward stick, or even anticipate it.

But in any case, the removal of that nose-up force at tow release makes it even more certain that you'll be moving the stick rearwards after release.

That model is far more of a handfull on the winch, as the hook is really too far forward for good winching. It takes a lot of up elevator to keep the climb steep enough. The all moving tailplane means that it's easily possible to over do it and stall the elevator. And if you get a premature release then you're sitting there nose up with the stick most of the way back. *Definitely* need a positive check forward to neutral stick in that situation!

Don Johnstone[_4_]

June 15th 14, 07:20 PM

At 11:31 15 June 2014, Bruce Hoult wrote:
>On Sunday, June 15, 2014 6:09:22 PM UTC+12, 2G wrote:
>> PLEASE stop with the sanctimonious crap! I have done hundreds of
>aerotows=
>.. You need to lower the nose because you are in a climb attitude and
need
>t=
>o transition to a glide attitude. On your next tow note where the horizon
>i=
>s on the canopy and compare it to where it is after release at the same
>air=
>speed.
>
>While the nose ends up lower, you don't lower the nose. The decrease in
>air=
>speed does that for you, and the movement of the stick is rearward, to
>prev=
>ent the nose falling through into a dive and again attaining the aerotow
>ai=
>rspeed.
>
The expression you are looking for is "select the approach attitude". That
should be the case after ALL launch failures. With the correct attitude
selected the speed will eventually decay or increase to the correct value.
By selecting the approach attitude you will ensure that the speed is less
likely to reduce below the desired value in any turn. Of course if the
failure occurs at height it may be that normal glide attitude is more
appropriate and this can be selected at the appropriate time but the
initial selection should always be approach attitude.
KISS

Bill D

June 15th 14, 10:18 PM

On Sunday, May 25, 2014 2:40:01 PM UTC-6, Don Johnstone wrote:
> At 15:06 23 May 2014, BobW wrote:
>
> >Major snip...>
>
> >
>
> >> ..."Will pilots of ALL skill
>
> >> levels and currency be best served by a simple or complicated
>
> procedure?"
>
> >> "Is creating a mindset that turning down adopted offer the best chance
>
> >of
>
> >> survival of the pilot, even at the expense of glider damage?"
>
> >>
>
> >
>
> >I could be wrong, but sometimes I sense a tendency to "reductio ad
>
> >absurdum"
>
> >on the part of some folks - to convince others of their point of view? I
>
> >dunno...but as a non-instructor, glider-only pilot, I managed to
>
> >mostly-weekend-acquire ~2600 hours without ever contacting the ground
>
> "out
>
> >of
>
> >control," to also safely and sans alarums demonstrate the proper
>
> >response(s)
>
> >to simulated low-altitude, departure-end rope breaks, and I WAS surprised
>
> >when
>
> >my ab-initio instructor (initially, verbally) introduced the concept of a
>
>
>
> >not-that-flight-pre-announced low-altitude rope break as a possibility
>
> for
>
> >my
>
> >imminent future...and then who "immediately asked all the expected 'silly
>
>
>
> >questions'" of my instructor. That noted, nowhere along the line did I
>
> ever
>
> >
>
> >get it into my head things like: 200' agl is an absolute go/no-go
>
> >turnaround
>
> >altitude; or a downwind landing on the departure runway is ALWAYS to be
>
> >preferred; or that no judgment was required to safely and effectively
>
> >respond
>
> >to a low-altitude rope break; or that it was "simple" (or, "complicated"
>
> >for
>
> >that matter) to pilot my way through the post PTT attempt.
>
> >
>
> >What I DID get into my head - and I can't remember if I did this entirely
>
> >on
>
> >my own (out of fearful respect for the fragility of my "somewhat resilient
>
>
>
> >pink body") or through some combination of instruction, reading,
>
> >cogitation,
>
> >etc. - was that it mattered VERY MUCH that I do certain things as PIC
>
> >"correctly" - for under certain (thin margin) circumstances I would not
>
> get
>
> >a
>
> >second chance.
>
> >
>
> >As many of my math instructors loved to say, It was "immediately obvious
>
> to
>
> >
>
> >the most casual observer" that a low-altitude rope break was a thin margin
>
>
>
> >event, and it was up to me to "handle it right" - or else my frail pink
>
> bod
>
> >
>
> >would be at higher risk than it needed to be.
>
> >
>
> >IMHO, anyone who gets caught up in defending a stance I'd characterize as
>
> >"do
>
> >it this way or you're wrong," when "this way" is procedurally based to the
>
>
>
> >discussional exclusion of maintaining solid flight control is missing the
>
>
>
> >point to a certain extent, and - yes - I understand the nature of
>
> >instruction
>
> >and the need to instruct using "building blocks of knowledge"...which is
>
> >the
>
> >way I've "forever" thought of "the magic 200 feet" concept. It's a great
>
> >place
>
> >to start. It isn't fundamentally dangerous (from a control of the glider
>
> >perspective). It's not fundamentally difficult to pilot as Joe PIC. It's
>
> >not
>
> >appropriate under all circumstances...while (in my view) "hitting the
>
> >ground
>
> >under control" IS appropriate under all circumstances. The question then
>
> >becomes, "What ground?" That's where more judgement enters the picture.
>
> >
>
> >As others have noted, it's not at all uncommon in the intermountain
>
> western
>
> >
>
> >U.S. to aerotow launch from fields where accepting something other than a
>
>
>
> >downwind landing on the departure runway from 200' agl in the event of a
>
> >low-altitude rope break is (obviously, unarguably, inevitably, etc...)
>
> "the
>
> >
>
> >best/safest thing to do."
>
> >
>
> >Being 100% first-person-ignorant of the circumstances surrounding the
>
> >tragic
>
> >crash sparking this (contains much food for thought) thread, several of my
>
>
>
> >operating conclusions are: 1) we can never know for sure what was in the
>
> >deceased pilot's mind; 2) he likely hit the ground "in a non-flying
>
> >condition"; 3) 2) is further evidence for me to "not do that." Tying the
>
> >preceding into "the magic 200' agl PTT altitude" is easy enough for me in
>
> >that
>
> >if "in my judgment" I think 200' IS sufficient under the circumstances to
>
>
>
> >attempt a turn-around, then I'll do it; if not, then I'll do something
>
> >different...but whatever I do I'll work darned hard to ensure I maintain
>
> >control all the way to the ground. Duh???
>
> >
>
> >Respectfully,
>
> >Bob W.
>
>
>
> I cannot argue against the above. From what I have read in this thread I
>
> have gained the impression that in the event of a launch failure at 200 ft
>
> or above the recommended procedure is to turn back to the runway. This is
>
> completely different from what I have taught for 45 years. In the event of
>
> any launch failure the question that should be asked is "Can I land ahead"
>
> If the answer is "yes" then land ahead, height does not come into it at
>
> all. If, and only if the answer is "No" or "Not sure" should another action
>
> be considered and executed.
>
> In any event I would never simulate a launch failure at 200 ft if there was
>
> not room to land ahead. I would and do simulate launch failures at 300ft
>
> and above if there is no room to land ahead and allow students to practice
>
> this, turning back as necessary. The reason is simple, while a pilot may be
>
> faced with having to turn back at 200 ft the risks in doing so are not
>
> justified in training, in the same way that we do not practice very low
>
> winch launch failures, just after liftoff, or practice groundloops to avoid
>
> obstacles both of which are covered by briefings. We do set up the ultra
>
> low level launch failure situation from a normal approach but we never
>
> simulate it off the launch because of the dangers involved.
>
> There will always be circumstances where the "normal" procedure is not
>
> possible but we do stress that the important part of the outcome is that
>
> the pilot has the best chance of survival, an undamged glider is not a
>
> priority in these circumstances.

What you were taught relates to winch launch only. Different rules apply to aero tow. With aero tow at 200' AGL on departure it is almost never possible to land ahead on the runway. Either turn or land in whatever terrain is available off the end of the runway. In many aero tow only airfields, that terrain is not suitable for a safe landing.

Bill D

June 15th 14, 10:22 PM

On Monday, May 26, 2014 12:44:41 AM UTC-6, Chris Rollings wrote:
> At 16:00 25 May 2014, Bob Whelan wrote:
>
> >On 5/24/2014 8:21 AM, John L Fleming wrote:
>
> >> son_of_flubber;883103 Wrote:
>
> >>> On Sunday, May 4, 2014 12:27:10 AM UTC-4, Waveguru wrote:-
>
> >>> Premature termination of the tow at 100ft. Did not complete the turn
>
> >>> back to the runway. -
>
> >>>
>
> >>> My sympathy to everyone touched by this tragedy.
>
> >>>
>
> >>> Turning 180 back to the runway from only 100 feet AGL is unusual. I
>
> >>> wonder why he did that.
>
> >>
>
> >> I've been watching this thread from day one. I'm back here in New York
>
> >> and was a friend of Bob and am puzzled by the turn as he always had his
>
> >> ducks all in a row. I'm too am a glider pilot and I find it hard to
>
> >> believe he made a steep bank at 100 feet. Bob had accumulated 1000's
>
> of
>
> >> hours in both fighters and the two single engine aircraft he owned.
>
> >> MAYBE, there was something wrong with the Zuni and he released because
>
> >> he couldn't control it?????? For instance........aileron linkage
>
> >> failure. I would be interested in others thoughts on this. John
>
> >
>
> >My condolences for the loss of your friend. I hadn't been in aviation but
>
> >two
>
> >or three years before personal aviation acquaintances and friends began
>
> >dying
>
> >in aviation-related accidents. All I could do was mourn their passing,
>
> try
>
> >and
>
> >extract lessons for myself (if any), rationalize that they died doing
>
> >something they loved, and take some decision(s) for my own future.
>
> >
>
> >Many glider pilots often roll their eyes at "the obviousness" of NTSB
>
> >probable
>
> >cause conclusions (e.g. pilot failed to maintain sufficient speed), but
>
> one
>
> >
>
> >thing I think NTSB investigators are quite adept at is establishing
>
> control
>
> >
>
> >connection continuity, particularly in the aftermath of low-speed
>
> accidents
>
> >as
>
> >this (where wreckage is minimally disturbed from effects of the crash
>
> >itself),
>
> >so probably the best answer to your puzzlement can be expected to come
>
> from
>
> >
>
> >the final NTSB report on this crash.
>
> >
>
> >Bob W.
>
> >
>
>
>
> Some years ago I witnessed a fatal spin-in following a launch failure. It
>
> was a winch launch, the cable broke at about 150 feet agl. There was
>
> plenty of room to land ahead on the airfield but the glider started a turn
>
> to the left, flying obviously rather slowly. It completed about two thirds
>
> of a 360 degree turn and then spun, went down into some trees a few yards
>
> from the airfield boundary on ground about 20 feet lower than the airfield.
>
> I was one of those that extracted the badly injured pilot from the
>
> wreckage (he died in the ambulance before it left the airfield).
>
>
>
> In the UK it is almost universal practice to set QFE not QNH on glider
>
> altimeters (most gliding sites are less than 1,000 feet amsl), I noticed
>
> that the altimeter in the wrecked glider was reading about plus 260 feet.
>
> Later investigation showed that the millibar sub-scale setting was
>
> consistent with the pressure on the previous day on which the glider had
>
> flown. It seemed highly likely to me that the pilot had omitted to reset
>
> the altimeter before take-off and, when the launch failed, saw over 400
>
> feet on the altimeter and reacted to that.

It sounds like this pilot lacked even basic airmanship skills. Quibbling over altimeter settings and low turns is beside the point. The real question is why he was allowed to fly at all.

Bill D

June 15th 14, 10:54 PM

On Sunday, May 25, 2014 2:40:01 PM UTC-6, Don Johnstone wrote:
"we do not practice very low winch launch failures, just after liftoff"

That's one of several reasons why the UK has such a terrible safety record on winch launch. I watched a UK 'trained' instructor destroy a glider and put himself in the hospital from a real low failure because he didn't know what to do next. Lacking training, he simply continued the rotation into the climb until the glider stalled.

I insist on simulated low failures just after lift-off. Given a pilot with minimum airmanship skills, there is no danger whatsoever. It's exactly like flying a bungee launch.

"In any event I would never simulate a launch failure at 200 ft if there was
not room to land ahead."

Nor would I - on a winch launch. On aero tow, where rules are different, a 200' failure will be beyond the departure end of the runway where there is often no choice but to turn back. Pilots trained to do so have a better chance of survival.

Bill D

June 15th 14, 11:11 PM

On Sunday, June 15, 2014 12:09:22 AM UTC-6, 2G wrote:

> PLEASE stop with the sanctimonious crap! I have done hundreds of aerotows.. You need to lower the nose because you are in a climb attitude and need to transition to a glide attitude. On your next tow note where the horizon is on the canopy and compare it to where it is after release at the same airspeed.
---------------------------
Raise, lower or leave the nose where it is - this is an energy management maneuver. The pilot is trying to make the most of the energy he has available when the rope breaks not follow some rote procedure.

If the glider remains at the climb attitude the airspeed will be trending down which is just fine for the moment since the tow airspeed is very likely to have been well above best L/D or even pattern speed. Until safe return to the runway is assured, stabilizing the airspeed at best L/D is the target. Once return is assured, the pilot may elect to accelerate to pattern speed.

The basic airmanship skill is monitoring airspeed trends while simultaneously maneuvering the glider for landing. Once stabilized at best L/D, if the airspeed is climbing, the nose is too low. If the airspeed is falling, it's too high.

Don Johnstone[_4_]

June 15th 14, 11:14 PM

At 21:18 15 June 2014, Bill D wrote:

>> I cannot argue against the above. From what I have read in this thread
I
>> have gained the impression that in the event of a launch failure at
200ft
>> or above the recommended procedure is to turn back to the runway. >>This
is completely different from what I have taught for 45 years. In the
>>event of
>> any launch failure the question that should be asked is "Can I land
>ahead"
>> If the answer is "yes" then land ahead, height does not come into it at
>> all. If, and only if the answer is "No" or "Not sure" should another
>action be considered and executed.=20

>> In any event I would never simulate a launch failure at 200 ft if there
>was
>> not room to land ahead. I would and do simulate launch failures at
300ft

>> and above if there is no room to land ahead and allow students to
>practice
>> this, turning back as necessary. The reason is simple, while a pilot
may
>be
>> faced with having to turn back at 200 ft the risks in doing so are not
>> justified in training, in the same way that we do not practice very low
>> winch launch failures, just after lift off, or practice ground loops to
>avoid
>> obstacles both of which are covered by briefings. We do set up the
ultra
>> low level launch failure situation from a normal approach but we never
>> simulate it off the launch because of the dangers involved.=20
>> There will always be circumstances where the "normal" procedure is not
>> possible but we do stress that the important part of the outcome is
that
>> the pilot has the best chance of survival, an undamaged glider is not a
>> priority in these circumstances.
>
>What you were taught relates to winch launch only. Different rules apply
>t=
>o aero tow. With aero tow at 200' AGL on departure it is almost never
>poss=
>ible to land ahead on the runway. Either turn or land in whatever
terrain
>=
>is available off the end of the runway. In many aero tow only airfields,
>t=
>hat terrain is not suitable for a safe landing.

No, what I was taught and what I teach applies to ALL launch failures,
winch, auto tow, and aerotow as detailed above. The first action is to
select the appropriate attitude, at least approach attitude and make sure
that you have a minimum of approach speed. Then ask the question, "Can I
land ahead" If and ONLY if the answer is NO or NOT SURE should any other
action be considered.
>

Tom Claffey

June 16th 14, 01:18 AM

While I agree that landing straight ahead is best if there is room, your
sequence of events is wrong. On an aerotow the question whether to land
ahead or turn should be made on every launch! "Then ask the question" will

lead to overload and grief! On tow, once you have decided you cannot land
ahead then it may be a turn to an off-field landing if possible, followed
by a
180 turn back to runway when safe. (That will invariably be at least 200')

I repeat: after a failure is not the time to be thinking about where to
go!

Tom

>
>No, what I was taught and what I teach applies to ALL launch failures,
>winch, auto tow, and aerotow as detailed above. The first action is to
>select the appropriate attitude, at least approach attitude and make sure
>that you have a minimum of approach speed. Then ask the question, "Can I
>land ahead" If and ONLY if the answer is NO or NOT SURE should any other
>action be considered.
>>
>
>

June 16th 14, 02:45 AM

On Sunday, June 15, 2014 3:11:29 PM UTC-7, Bill D wrote:
> On Sunday, June 15, 2014 12:09:22 AM UTC-6, 2G wrote:
>
>
>
> > PLEASE stop with the sanctimonious crap! I have done hundreds of aerotows. You need to lower the nose because you are in a climb attitude and need to transition to a glide attitude. On your next tow note where the horizon is on the canopy and compare it to where it is after release at the same airspeed.
>
> ---------------------------
>
> Raise, lower or leave the nose where it is - this is an energy management maneuver. The pilot is trying to make the most of the energy he has available when the rope breaks not follow some rote procedure.
>
>
>
> If the glider remains at the climb attitude the airspeed will be trending down which is just fine for the moment since the tow airspeed is very likely to have been well above best L/D or even pattern speed. Until safe return to the runway is assured, stabilizing the airspeed at best L/D is the target. Once return is assured, the pilot may elect to accelerate to pattern speed.
>
>
>
> The basic airmanship skill is monitoring airspeed trends while simultaneously maneuvering the glider for landing. Once stabilized at best L/D, if the airspeed is climbing, the nose is too low. If the airspeed is falling, it's too high.

Come on, get REAL! If this were the case there would be no such accidents!

Actual pilots, when confronted with actual emergencies, do not always respond the way they are taught. Why do pilots stall AT ALL if they did what you suggested? Your arm chair analytical review is NOT WORKING!

I am strongly suggesting that there are irrational emotional factors that influence pilots to do things completely contrary to their training. I know this for a fact; disregarding this reality is to put your head into the sand.

At least you have stopped denigrating my motorglider experience.

Tom

Jim White[_3_]

June 16th 14, 08:15 AM

May I offer a practical tip? Talk to yourself all the way up the launch to
a safe height (perhaps 500ft), deciding where you will go at every moment
should the rope / tug break. Should it then happen you already have the
decision made and only have to execute it well.

If you, or your trainee, start to do this every launch you will be amazed
at what poor decisions you would make to begin with. These get better with
the doing of it.

Jim

At 00:18 16 June 2014, Tom Claffey wrote:
>While I agree that landing straight ahead is best if there is room, your
>sequence of events is wrong. On an aerotow the question whether to land
>ahead or turn should be made on every launch! "Then ask the question"
will
>
>lead to overload and grief! On tow, once you have decided you cannot land

>ahead then it may be a turn to an off-field landing if possible, followed
>by a
>180 turn back to runway when safe. (That will invariably be at least
200')
>
>I repeat: after a failure is not the time to be thinking about where to
>go!
>
>Tom
>
>
>
>>
>>No, what I was taught and what I teach applies to ALL launch failures,
>>winch, auto tow, and aerotow as detailed above. The first action is to
>>select the appropriate attitude, at least approach attitude and make
sure
>>that you have a minimum of approach speed. Then ask the question, "Can I
>>land ahead" If and ONLY if the answer is NO or NOT SURE should any other
>>action be considered.
>>>
>>
>>
>
>

Z Goudie[_2_]

June 16th 14, 09:13 AM

At 07:15 16 June 2014, Jim White wrote:
>May I offer a practical tip? Talk to yourself all the way up the launch t
>a safe height (perhaps 500ft), deciding where you will go at every momen
>should the rope / tug break. Should it then happen you already have th
>decision made and only have to execute it well.

I thought that was supposed to be part of the training!

Fred Bear

June 16th 14, 10:44 AM

On 6/15/2014 8:18 PM, Tom Claffey wrote:
> While I agree that landing straight ahead is best if there is room, your
> sequence of events is wrong. On an aerotow the question whether to land
> ahead or turn should be made on every launch! "Then ask the question" will
>
> lead to overload and grief! On tow, once you have decided you cannot land
> ahead then it may be a turn to an off-field landing if possible, followed
> by a
> 180 turn back to runway when safe. (That will invariably be at least 200')
>
> I repeat: after a failure is not the time to be thinking about where to
> go!
>
> Tom
>
>
>
>>
>> No, what I was taught and what I teach applies to ALL launch failures,
>> winch, auto tow, and aerotow as detailed above. The first action is to
>> select the appropriate attitude, at least approach attitude and make sure
>> that you have a minimum of approach speed. Then ask the question, "Can I
>> land ahead" If and ONLY if the answer is NO or NOT SURE should any other
>> action be considered.
>>>
>>
>>
>
That's how I was taught - first immediate action - fly the glider. Then
assess.

I was sent solo in a T21 at Portmoak, flying off winch from the SW end,
accompanied by a sandbag in the RH seat. Two 360 degree turns and a good
landing. Woohoo.

Ok - now for the second solo flight - cable break at 300 feet. All I
remember of my thought processes at the time was to get the nose down
out of full climb immediately before speed bled off, get rid of cable
and then assess - unsure about straight ahead (20/20 hindsight - full
spoiler and land would have worked), too low for short circuit (maybe),
so I made a 90 degree left turn to get some room, turned back to right
and landed across the main onto the alternative area across from the
hangars, passing in front of the winch.

I explained my thought process to the instructor and we reviewed what I
had done - got a slow nod and a well done lad. Good enough for me and a
credit to my instructors. Was sent back up once we had towed the T21
back to the launch point.

Don Johnstone[_4_]

June 16th 14, 12:43 PM

At 09:44 16 June 2014, Fred Bear wrote:
>On 6/15/2014 8:18 PM, Tom Claffey wrote:
>> While I agree that landing straight ahead is best if there is room,
your
>> sequence of events is wrong. On an aerotow the question whether to land
>> ahead or turn should be made on every launch! "Then ask the question"
>will
>>
>> lead to overload and grief! On tow, once you have decided you cannot
land
>> ahead then it may be a turn to an off-field landing if possible,
followed
>> by a
>> 180 turn back to runway when safe. (That will invariably be at least
>200')
>>
>> I repeat: after a failure is not the time to be thinking about where to
>> go!
>>
>> Tom
>>
>>
>>
>>>
>>> No, what I was taught and what I teach applies to ALL launch failures,
>>> winch, auto tow, and aerotow as detailed above. The first action is to
>>> select the appropriate attitude, at least approach attitude and make
>sure
>>> that you have a minimum of approach speed. Then ask the question, "Can
I
>>> land ahead" If and ONLY if the answer is NO or NOT SURE should any
other
>>> action be considered.

Spot on, run away to the south field, worked for me too

>>>>
>>>
>>>
>>
>That's how I was taught - first immediate action - fly the glider. Then
>assess.
>
>I was sent solo in a T21 at Portmoak, flying off winch from the SW end,
>accompanied by a sandbag in the RH seat. Two 360 degree turns and a good
>landing. Woohoo.
>
>Ok - now for the second solo flight - cable break at 300 feet. All I
>remember of my thought processes at the time was to get the nose down
>out of full climb immediately before speed bled off, get rid of cable
>and then assess - unsure about straight ahead (20/20 hindsight - full
>spoiler and land would have worked), too low for short circuit (maybe),
>so I made a 90 degree left turn to get some room, turned back to right
>and landed across the main onto the alternative area across from the
>hangars, passing in front of the winch.
>
>I explained my thought process to the instructor and we reviewed what I
>had done - got a slow nod and a well done lad. Good enough for me and a
>credit to my instructors. Was sent back up once we had towed the T21
>back to the launch point.
>

Fred Bear

June 16th 14, 03:44 PM

On 6/16/2014 4:13 AM, Z Goudie wrote:
> At 07:15 16 June 2014, Jim White wrote:
>> May I offer a practical tip? Talk to yourself all the way up the launch t
>> a safe height (perhaps 500ft), deciding where you will go at every momen
>> should the rope / tug break. Should it then happen you already have th
>> decision made and only have to execute it well.
>
> I thought that was supposed to be part of the training!
>

Z - the very man who sent me solo at Portmoak all those years ago.

Jonathon May

June 16th 14, 05:06 PM

At 14:44 16 June 2014, Fred Bear wrote:
>On 6/16/2014 4:13 AM, Z Goudie wrote:
>> At 07:15 16 June 2014, Jim White wrote:
>>> May I offer a practical tip? Talk to yourself all the way up the
launch
>t
>>> a safe height (perhaps 500ft), deciding where you will go at every
momen
>>> should the rope / tug break. Should it then happen you already have th
>>> decision made and only have to execute it well.
>>
>> I thought that was supposed to be part of the training!
>>
>
>
>Z - the very man who sent me solo at Portmoak all those years ago.
>

The thing that concerns me is the change to rotax tugs.
On Sunday I watched one tow a skylark up,perfect ,but 2 fat pilots in a
duo full of water and we are talking curve of the earth,assuming you can
get it rolling in the first place.Historicly we had accidents and learned
how to not have them.
But heavier gliders,weaker tugs and steam comes from my ears when I see the
launch point set up 1/3 of the way down the runway,because its easier to
get passengers to the glider and you can land behind.Explain that to the
family after Joe pilot coudn't land ahead because it was more convenient.
Rant over,my sinsera condolances to the family of the pilot who started
this at a terrible price.

Bruce Hoult

June 16th 14, 08:05 PM

On Tuesday, June 17, 2014 4:06:19 AM UTC+12, Jonathon May wrote:
> At 14:44 16 June 2014, Fred Bear wrote:
> But heavier gliders,weaker tugs and steam comes from my ears when I see the
> launch point set up 1/3 of the way down the runway,because its easier to
> get passengers to the glider and you can land behind.

Yeah, we did that recently when we had an away weekend at a 6500 ft strip on a dairy farm instead of our usual 2000 ft strip in the middle of a town. Definitely convenient.

Andrew[_13_]

June 17th 14, 07:46 AM

In the event of a launch failure (or a bounce on landing) I was
taught to 'adopt the attitude that you would be at that height
during a normal approach', which I think is a clear and good
description of the 'appropriate attitude' that Don recommends. I
completely agree with Don's advice about then checking speed,
and landing ahead as the first choice.

I was worried by writers in this thread who have mentioned
aerotowing at sites where a straight ahead landing from a low PT3
could not be safely made. Single-engine power pilots often accept
catastrophic risks (e.g. from engine failures) but we glider pilots
don't have to. If the PT3 danger is only to the glider, I guess that's
ok, if the owners and their insurance company have no objection.
But if personal injury is risked by PT3, I hope everyone agrees that
such sites should not be used for aerotowing gliders.

At 22:14 15 June 2014, Don Johnstone wrote:

>
>No, what I was taught and what I teach applies to ALL launch
failures,
>winch, auto tow, and aerotow as detailed above. The first action
is to
>select the appropriate attitude, at least approach attitude and
make sure
>that you have a minimum of approach speed. Then ask the
question, "Can I
>land ahead" If and ONLY if the answer is NO or NOT SURE should
any other
>action be considered.
>>
>
>

Bruce Hoult

June 17th 14, 10:17 AM

On Tuesday, June 17, 2014 6:46:14 PM UTC+12, Andrew wrote:
> I was worried by writers in this thread who have mentioned
> aerotowing at sites where a straight ahead landing from a low PT3
> could not be safely made. Single-engine power pilots often accept
> catastrophic risks (e.g. from engine failures) but we glider pilots
> don't have to. If the PT3 danger is only to the glider, I guess that's
> ok, if the owners and their insurance company have no objection.
> But if personal injury is risked by PT3, I hope everyone agrees that
> such sites should not be used for aerotowing gliders.

I disagree.

Options in the event of a tow failure include:

1) land ahead
2) land cross wind
3) do a (approx) 180 and land downwind
4) do a (approx) 180, enter an abbreviated downwind leg, land crosswind
5) do a (approx) 180, enter an abbreviated downwind leg, land upwind
6) do a (approx) 180, do a normal downwind leg, land upwind

As long as at least *one* of those options is available at all times the site is fine.

Which ones are appropriate does change according to conditions. For example 3) is likely to be a bad idea in all but the lightest winds. But as the wind strength picks up the opportunities for the others increases quickly.

Bill D

June 17th 14, 03:58 PM

On Tuesday, June 17, 2014 3:17:59 AM UTC-6, Bruce Hoult wrote:
> On Tuesday, June 17, 2014 6:46:14 PM UTC+12, Andrew wrote:
>
> > I was worried by writers in this thread who have mentioned
>
> > aerotowing at sites where a straight ahead landing from a low PT3
>
> > could not be safely made. Single-engine power pilots often accept
>
> > catastrophic risks (e.g. from engine failures) but we glider pilots
>
> > don't have to. If the PT3 danger is only to the glider, I guess that's
>
> > ok, if the owners and their insurance company have no objection.
>
> > But if personal injury is risked by PT3, I hope everyone agrees that
>
> > such sites should not be used for aerotowing gliders.
>
>
>
> I disagree.
>
>
>
> Options in the event of a tow failure include:
>
>
>
> 1) land ahead
>
> 2) land cross wind
>
> 3) do a (approx) 180 and land downwind
>
> 4) do a (approx) 180, enter an abbreviated downwind leg, land crosswind
>
> 5) do a (approx) 180, enter an abbreviated downwind leg, land upwind
>
> 6) do a (approx) 180, do a normal downwind leg, land upwind
>
>
>
> As long as at least *one* of those options is available at all times the site is fine.
>
>
>
> Which ones are appropriate does change according to conditions. For example 3) is likely to be a bad idea in all but the lightest winds. But as the wind strength picks up the opportunities for the others increases quickly.

I agree with Bruce. However, all those actions require the pilot to have at least basic airmanship abilities which is clearly missing in some posts to this thread.

When applied to flight training, I find terms like "KISS" and "lowest common denominator" to be infuriating. Aviation is not simple and never will be.

When I read "KISS, I'm reminded of Forrest Gump: "Stupid is as stupid does". Rather than aiming to accommodate the "lowest common denominator" in students, demand excellence.

CindyB[_2_]

June 18th 14, 01:47 AM

On Monday, June 16, 2014 12:15:07 AM UTC-7, Jim White wrote:
> May I offer a practical tip? Talk to yourself all the way up the launch to
>
> a safe height (perhaps 500ft), deciding where you will go at every moment
>
> should the rope / tug break. Should it then happen you already have the
>
> decision made and only have to execute it well.
>
>
>
> If you, or your trainee, start to do this every launch you will be amazed
>
> at what poor decisions you would make to begin with. These get better with
>
> the doing of it.
>
>
>
> Jim
>

Delightful. Since it was about a hundred posts ago I offered the same concept, may I say, "Thank you."
I am heartened to know that there are others out there who prefer to be prepared and updating their situational awareness during launch, rather than becoming off-launch and then begin 'assessing' the choices.

If the assessment is ongoing, the execution of the 'best choice' becomes pretty relaxed. And if we fly to the landing, it is so much more likely to be survivable than falling to an impact.

Thanks, Jim.
Cindy B

Bruce Hoult

June 18th 14, 02:18 AM

On Wednesday, June 18, 2014 12:47:20 PM UTC+12, CindyB wrote:
> On Monday, June 16, 2014 12:15:07 AM UTC-7, Jim White wrote:
> > May I offer a practical tip? Talk to yourself all the way up the launch to
> > a safe height (perhaps 500ft), deciding where you will go at every moment
>
> Delightful. Since it was about a hundred posts ago I offered the same concept, may I say, "Thank you."

!!!!

It would never have occurred to me that this was not assumed by all in the conversation.

Here in NZ, students are frequently asked "where would you go now?"

Andrew[_13_]

June 18th 14, 05:51 AM

At 01:18 18 June 2014, Bruce Hoult wrote:
>
>Here in NZ, students are frequently asked "where would you go
now?"
>

Hi Bruce, can you tell us what the teaching is in NZ is about this? Do
you teach 180 degree turns at 200ft?

Bruce Hoult

June 18th 14, 08:38 AM

On Wednesday, June 18, 2014 4:51:46 PM UTC+12, Andrew wrote:
> At 01:18 18 June 2014, Bruce Hoult wrote:
> >Here in NZ, students are frequently asked "where would you go
> now?"
>
> Hi Bruce, can you tell us what the teaching is in NZ is about this? Do
> you teach 180 degree turns at 200ft?

The Gliding NZ training syllabus requires the instructor demonstrating a low level launch failure. It doesn't require the student flying one. (the same applies to fully developed spins, by the way ... the student only has to demonstrate incipient spin, recognition, recovery).

I don't think there is mention of any particular height. Our students are doing 180 and 360 degree turns 200 ft above ridges all the time, and constantly have "safe speed near the ground" drummed into them.

250 ft is the common simulated launch failure height, with an expectation that you'll be able to turn onto a downwind and then evaluate whether to land crosswind (probably) or into wind.

Further information:

One of Gliding NZ's A certificate oral questions and model answer:

Q: What is the pilot's first priority immediately following a launch failure on a winch launch and an aerotow launch?

A: Winch launch: Lower the nose to attain "Safe Speed Near The Ground".
Aerotow launch at low level: Raise the nose to convert excess speed to height but never fly slower than "Safe Speed Near The Ground".

For winch launching, the instructor's manual recommends landing ahead if you are less than half way down the strip and with less height than 1/10th of the total strip length. It recommends 400 ft as the minimum for doing a full circuit and normal landing. (it also recommends 4000 ft as the minimum length for winch launching, so that is internally consistent)

If you will always deliberately release if you find yourself halfway down the strip at less than 400 ft then there can never be a situation where you'd want to turn 180 and land downwind. At least, on a strip where the entire length is landable. I've flown from sites with a 5000 or 6000 feet run for the winch cable, but only a few hundred yards of landable area ... different guidelines will apply.

For aerotow launching, no specific advice is given as to heights. It does say "Unlike winch launching, aerotowing often involves entering the non-manoeuvring area." and "Beware the low-level turnback--if in doubt, land out", but without any definition of what is low level.

Certainly at our site -- a commercial airport with scheduled Dash 8 flights, surrounded by dense housing on all sides -- any off field landing is going to have very severe consequences. The seal is 1500m, but the grass we use is only about 600m. In one direction, we have the option of stepping sideways onto the main runway and landing ahead. In the other direction, grass and seal hit the fence at essentially the same point, but there is an old X'd tarsealed runway parallel and close to the fence that will serve in an emergency with only a 90º turn if 180º doesn't seem advisable.

Jim White[_2_]

June 18th 14, 12:06 PM

At 01:18 18 June 2014, Bruce Hoult wrote:
>On Wednesday, June 18, 2014 12:47:20 PM UTC+12, CindyB wrote:
>> On Monday, June 16, 2014 12:15:07 AM UTC-7, Jim White wrote:
>> > May I offer a practical tip? Talk to yourself all the way up the
launch
>to
>> > a safe height (perhaps 500ft), deciding where you will go at every
>moment
>>
>> Delightful. Since it was about a hundred posts ago I offered the same
>concept, may I say, "Thank you."
>
>!!!!
>
>It would never have occurred to me that this was not assumed by all in
the
>conversation.
>
>Here in NZ, students are frequently asked "where would you go now?"
>
Bruce, one would hope that this is how most people do it, but my experience
is different. I am not a full instructor but do coach xc soaring to people
who have already got their wings. When I suggest this to the people I fly
with I usually get "that's a good idea, I never thought of that" so I
presume it is not generally taught.

Asking 'where would you go' does not demonstarte that your pupil is doing
this, he may just be good enough to come up with a sensible answer on the
fly, that time. Asking him to tell you where he would go all the way up to
a safe height would tell you, the instructor, very much more about what his
thought processes are and how well he could handle an emergency.

Just my penny's worth.

Rob Brown[_3_]

July 15th 14, 10:52 PM

On 2014-05-11,
> wrote:
> On Saturday, May 10, 2014 10:51:36 PM UTC-7, wrote:
>> ... get to a laudable spot in go shape to land.
> ...get to a landable spot in good shape to land.

a laudible goal

flgliderpilot[_2_]

July 18th 14, 05:10 AM

On Tuesday, May 6, 2014 4:41:23 PM UTC-4, Don Johnstone wrote:
> While in no way do I wish to speculate on the cause of this accident or
>
> indeed suggest that my comments in any way address the cause of this
>
> accident.
>
> I feel that comment is needed on some of the things said here. We have a
>
> rule here in the UK, launch failure on aerotow below 300ft a landing should
>
> be made ahead, or slightly to one side. No attempt should be made to turn
>
> back below this height.
>
> The reason is simple, a controlled crash into difficult terrain is likely
>
> to result in a better outcome than an uncontrolled arrival on the airfield.
>
> The important bit to keep intact is the bit you are sitting in, the rest of
>
> the glider does not really matter too much. The best chance of achieving
>
> that is flying to the ground with the wings level. It has only happened to
>
> me once, there was a field ahead but it was full of the Tiger Moth tug that
>
> had landed in the middle. I discovered that there was just enough space for
>
> a Skylark 2 as well. I have no doubt that a turn back would have resulted
>
> in an accident. I was at 250ft agl max.
>
> If there really is nowhere to land ahead you should really ask the
>
> question, "should I be taking a launch".
>
> Frankly I would be horrified to be required to conduct a turn back at
>
> 200ft, I would suggest that this is one of those occasions where the danger
>
> of practice is to great to justify.

Sometimes it's hard to face the fact that the glider must be destroyed to survive. Trying to save the device could be a deadly decision.

Again, I don't know what actually happened, best guess, inadvertent unintentional release. Whether he tried to turn back, or just plain didn't get the nose down quick enough during a 90 degree or lesser turn, who knows.

The only way to practice rope breaks at 100' is on a simulator (condor).

waremark

July 19th 14, 03:47 AM

Don's suggestion that there is a rigid rule about turn back heights in the UK is a surprise to me (I am an instructor). Select the least bad option at the time. Prepare students for it by (at an earlier stage) saying 'from here I would..'. Later asking 'if the tow fails here, where would you go?'

In most circumstances from 200 foot I would turn back.

Chris Rollings[_2_]

July 19th 14, 07:20 AM

Quite right, individual clubs may have had a minimum turn back height as
advice or even a rule, the BGA has not. I write as the ex-National Coach
who produced the BGA Instructor's Manual.

At 02:47 19 July 2014, waremark wrote:
>Don's suggestion that there is a rigid rule about turn back heights in
the
>=
>UK is a surprise to me (I am an instructor). Select the least bad option
>at=
> the time. Prepare students for it by (at an earlier stage) saying 'from
>he=
>re I would..'. Later asking 'if the tow fails here, where would you go?'
>
>In most circumstances from 200 foot I would turn back.
>

Bob T

September 9th 16, 10:58 PM

On Saturday, May 3, 2014 at 10:27:10 PM UTC-6, Waveguru wrote:
> Premature termination of the tow at 100ft. Did not complete the turn back to the runway.
>
> http://www.kathrynsreport.com/2014/05/wickenburg-maricopa-county-arizona.html?m=1
>
> Boggs

A really scary comment in the NTSB final report: "Postaccident examination of the glider's release system revealed that it was missing a spring, which likely resulted in the cable not engaging in the detent and caused the premature release from the tow line." http://www.ntsb.gov/_layouts/ntsb.aviation/brief.aspx?ev_id=20140504X34426&key=1

It was a bumpy day. I took off about 10 minutes of Bob and hit strong turbulence and sink over the last few hundred yards of the runway. My 200 foot countdown took much longer than usual, but, as I continued on tow, finally got up and found a good thermal and left the area, unaware of the crash that had occurred behind me.

Bob was a very experienced jet pilot with thousands of hours, but had just gotten into gliding and had only recently purchased the glider. Having his glider release itself because of a faulty release mechanism in turbulence only 100 ft. AGL and only desert trees ahead, our newbe pilot made the unfortunate fatal decision to turn back and spun in.

When was the last time YOU had your release checked by a professional???

BobW

September 10th 16, 12:39 AM

On 9/9/2016 3:58 PM, Bob T wrote:
<Snip>
>
> A really scary comment in the NTSB final report: "Postaccident examination
> of the glider's release system revealed that it was missing a spring, which
> likely resulted in the cable not engaging in the detent and caused the
> premature release from the tow line."
> http://www.ntsb.gov/_layouts/ntsb.aviation/brief.aspx?ev_id=20140504X34426&key=1
>
> It was a bumpy day. I took off about 10 minutes of Bob and hit strong
> turbulence and sink over the last few hundred yards of the runway. My 200
> foot countdown took much longer than usual, but, as I continued on tow,
> finally got up and found a good thermal and left the area, unaware of the
> crash that had occurred behind me.
>
> Bob was a very experienced jet pilot with thousands of hours, but had just
> gotten into gliding and had only recently purchased the glider. Having his
> glider release itself because of a faulty release mechanism in turbulence
> only 100 ft. AGL and only desert trees ahead, our newbe pilot made the
> unfortunate fatal decision to turn back and spun in.
>
> When was the last time YOU had your release checked by a professional???
>

"Right on!" regarding "known-good release health."

Philosophical agreement aside...if (big "if") the release was an original
Aerotek release, I've a hard time getting my head around the NTSB's "missing
spring" possibility (though if it happens, it must be possible).

So far as I'm aware, every Zuni left the factory with a clone of Dick
Schreder's dirt-simple HP release (used in every HP I've examined, including
up to HP-16's and one HP-18).

The original release uses a single spring, easily visible (assuming the
cockpit-side of the release wasn't subsequently enclosed by some sort of
doghouse). But more to the point, without the spring the original release
simply doesn't *work* properly - as in, requiring active, precise-and-fiddly,
action (on-the-rope-connnector-person's-part), to make a tension-holding
connection. I know because I tried both my HP-14 and Zuni (S/N 3)releases
sans-spring, on the ground, just out of curiosity. As it was, even with a
properly functioning release, part of my pre-launch routine was describing to
(almost!) every rope-connecting-person how to connect the rope (a task Joe
Pilot could not assist with from within the cockpit). Whereas having "Joe
Average Connector Person" make a successful connection with a functioning
spring is "verbally trivial" from Joe Pilot's perspective, I doubt I could
have talked through J.A.C. Person into making a(n apparently) secure
connection in the absence of a spring. Memory says that doing so requires two
hands, one with access to the interior/cockpit side of the release.

Now if the spring failed or somehow came loose, I'd expect an immediate back
release the instant the rope lost tension for any reason.

Bob W.

Ernst

September 12th 16, 03:34 PM

Go to the accident docket and read the MATERIALS LABORATORY FACTUAL REPORT.
My conclusion is that the pawl spring had been missing for some time.

Ernst

Bob Whelan[_3_]

September 13th 16, 04:09 AM

On 9/12/2016 8:34 AM, Ernst wrote:
> Go to the accident docket and read the MATERIALS LABORATORY FACTUAL
> REPORT. My conclusion is that the pawl spring had been missing for some
> time.
>
> Ernst
>

I found the 7-page Factual Report, which includes the statement, "A detailed
examination report for the glider release mechanism is contained in the
Materials Laboratory factual report located in the public docket."

I've been unable to find the "Materials Laboratory factual report." Pointer
help will be Seriously Appreciated!

Meanwhile, I'm still finding it hard to believe the accident aircraft was
successfully operated for ~26 hours without the release spring, though I can
believe the (light-in-tension) spring *might* leave very little in the way of
witness marks on the I.D. of the pawl's through hole.

Thanks very much.

Bob W.

Bob Kuykendall

September 13th 16, 04:21 AM

On Monday, September 12, 2016 at 8:09:10 PM UTC-7, Bob Whelan wrote:

> ...I've been unable to find the "Materials Laboratory factual report." Pointer
> help will be Seriously Appreciated!

The Docket Management System (DMS) has many good detail photos of broken aircraft. It is (or should be) every detail designer's go-to resource:

http://dms.ntsb.gov/pubdms/search/hitlist.cfm?docketID=58737

Thanks, Bob K.

BobW

September 13th 16, 03:34 PM

On 9/12/2016 9:21 PM, Bob Kuykendall wrote:
> On Monday, September 12, 2016 at 8:09:10 PM UTC-7, Bob Whelan wrote:
>
>> ...I've been unable to find the "Materials Laboratory factual report."
>> Pointer help will be Seriously Appreciated!
>
> The Docket Management System (DMS) has many good detail photos of broken
> aircraft. It is (or should be) every detail designer's go-to resource:
>
> http://dms.ntsb.gov/pubdms/search/hitlist.cfm?docketID=58737
>
> Thanks, Bob K.
>

Many thanks!

Just to (sorta) complete the train of thought in my (bemused) posts preceding
this one. The photos of the release mechanism from the accident aircraft seem
to (pretty much) match my (oldish) memories of how it functions, the "pretty
much" exception being I remembered the hook retraction spring as a simple
tension spring (and not the dual-sided, probably custom-bent) coil type. It
was THAT spring force to which I referred when writing I couldn't understand
how the hook could have sensibly functioned in its absence. That force serves
dual purposes: 1) maintaining the hook cover against the back side of the
opening slot while in flight (while also allowing a back release in the event
of loss of rope tension combined with a Big Bow), and 2) (by
through-transmittal of the hook-opening-cover force) retracting the entire
hook mechanism after the pawl is released from the flat-plate/cable-hook
detent by the pilot pulling the release knob/cable.

As for the report's claimed missing pawl spring...I must be getting dense in
my old age, since I'm still puzzled by the intended function and line of force
of that implicated piece of (missing?) hardware. Using Figure 8 by way of
illustrating my puzzlement, it seems to me such a spring could either serve to
decrease or increase the pawl's contact force against the hook plate.
Decreasing the contact force would appear to be counter-productive, while
increasing it (arguably) might have served to make the incomplete contact
condition shown in Figure 9 even more likely.

In any event, my current working hypothesis is the hook likely back released
(as intended, for better or for worse) from a bow in the rope (gusty sink
being reported in that vicinity by the previously-towed pilot) at an
unfortunate/ugly towing-location, followed by loss of control. Having had two
such back releases during gnarly tows (one nearly too low to warrant an
attempted return, above head-high sagebrush, but fortunately not occurring
until later that same tow), I can relate. Whether or not the incomplete
contact condition between pawl and cable hook detent (shown in Figure 9) was a
contributor, I have no idea.

Back to the hook design - what am I missing? Thanks!

Bob W.

Dave Nadler

September 13th 16, 04:26 PM

On Tuesday, September 13, 2016 at 10:34:20 AM UTC-4, BobW wrote:
> As for the report's claimed missing pawl spring...I must be getting dense in
> my old age, since I'm still puzzled by the intended function and line of force
> of that implicated piece of (missing?) hardware.
> Back to the hook design - what am I missing? Thanks!
>
> Bob W.

If I understand correctly, the missing spring pushes the pawl
in the direction opposite of pulling the release knob.
Otherwise, the pawl is not secured in the "latched" position,
except by a bit of friction with the hook plate (from the
spring that is present and any rope tension).

Do I understand correctly??

BobW

September 13th 16, 06:28 PM

On 9/13/2016 9:26 AM, Dave Nadler wrote:
> On Tuesday, September 13, 2016 at 10:34:20 AM UTC-4, BobW wrote:
>> As for the report's claimed missing pawl spring...I must be getting dense
>> in my old age, since I'm still puzzled by the intended function and line
>> of force of that implicated piece of (missing?) hardware. Back to the
>> hook design - what am I missing? Thanks!
>>
>> Bob W.
>
> If I understand correctly, the missing spring pushes the pawl in the
> direction opposite of pulling the release knob. Otherwise, the pawl is not
> secured in the "latched" position, except by a bit of friction with the
> hook plate (from the spring that is present and any rope tension).
>
> Do I understand correctly??
>

Quite possibly. I suppose such a spring fairly might be considered the
"suspenders" to the hook-retract-spring's "belt." It's not obvious from the
photos (Figure 1 shows it best), but installed-geometry, plus gravity, in the
pawl's as-installed position/angle work "against" the pawl remaining
detent-seated...i.e. the pawl pivoting by itself (no other physical contacts)
would tend to flop its "business end" *away* from the detent due to the longer
cable-attach arm's length compared to the detent-engagement arm's length
(unequal length teeter-totter).

Nonetheless, whether the absence of a compression spring between the pawl and
receptacle/pawl-spring-housing was a crucial element in this accident is
debatable; it would take very little force on the rope to rotate the cable
hook from the barely-engaged position (Figures 9) to the fully engaged
position (Figure 8). Once there, further testing definitely required to
determine whether the design would be more or less prone to back-releasing in
the absence of the pawl spring, in the presence of a rope bow...

That said - and since a number of these hooks have been installed into the
noses of German-built ships originally entering the USA with only a CG hook -
owners of ships with these hooks SHOULD (and easily can) VERIFY the
presence/absence of such a compression spring by checking to see if the pawl
is positively forced against the rotating piece of the cable hook throughout
its rotation range. Positive engagement => spring-present. (Note that the
spring itself is hidden in the hook's assembled state...and might easily
escape unnoticed in the event of the hook being disassembled for any reason.)

Bob W.

Don Johnstone[_4_]

September 13th 16, 11:24 PM

At 17:28 13 September 2016, BobW wrote:
>On 9/13/2016 9:26 AM, Dave Nadler wrote:
>> On Tuesday, September 13, 2016 at 10:34:20 AM UTC-4, BobW
wrote:
>>> As for the report's claimed missing pawl spring...I must be
getting
>dense
>>> in my old age, since I'm still puzzled by the intended function
and line
>>> of force of that implicated piece of (missing?) hardware. Back
to the
>>> hook design - what am I missing? Thanks!
>>>
>>> Bob W.
>>
>> If I understand correctly, the missing spring pushes the pawl in
the
>> direction opposite of pulling the release knob. Otherwise, the
pawl is
>not
>> secured in the "latched" position, except by a bit of friction with
the
>> hook plate (from the spring that is present and any rope
tension).
>>
>> Do I understand correctly??
>>
>
>Quite possibly. I suppose such a spring fairly might be considered
the
>"suspenders" to the hook-retract-spring's "belt." It's not obvious
from the
>
>photos (Figure 1 shows it best), but installed-geometry, plus
gravity, in
>the
>pawl's as-installed position/angle work "against" the pawl
remaining
>detent-seated...i.e. the pawl pivoting by itself (no other physical
>contacts)
>would tend to flop its "business end" *away* from the detent due
to the
>longer
>cable-attach arm's length compared to the detent-engagement
arm's length
>(unequal length teeter-totter).
>
>Nonetheless, whether the absence of a compression spring
between the pawl
>and
>receptacle/pawl-spring-housing was a crucial element in this
accident is
>debatable; it would take very little force on the rope to rotate the
cable
>hook from the barely-engaged position (Figures 9) to the fully
engaged
>position (Figure 8). Once there, further testing definitely required
to
>determine whether the design would be more or less prone to
back-releasing
>in
>the absence of the pawl spring, in the presence of a rope bow...
>
>That said - and since a number of these hooks have been installed
into the
>noses of German-built ships originally entering the USA with only
a CG hook
>-
>owners of ships with these hooks SHOULD (and easily can) VERIFY
the
>presence/absence of such a compression spring by checking to
see if the
>pawl
>is positively forced against the rotating piece of the cable hook
>throughout
>its rotation range. Positive engagement => spring-present. (Note
that the
>spring itself is hidden in the hook's assembled state...and might
easily
>escape unnoticed in the event of the hook being disassembled for
any
>reason.)
>
>Bob W.

I am now confused by the "installed in German" part. Is the release
you are talking about a TOST release?