Double Release Failure

[ZZ]

It is likely that the probability of an ACTUAL double release failure on
tow is what ever positive number is closest to zero. Of course that
doesn't mean that Mr.Murphy can't serve one of these up.

I would be interested in hearing any accounts of actual, non-instructor
induced double release failures which required either a landing on tow
or purposely breaking he rope to end the problem.

I would also be interested in any opinions regarding practicing landing
on tow to prepare oneself for this unlikely event. (I know that this is
or was a required maneuver in some European countries...but is it worth
the risk?)

Paul
ZZ

[mattm[_2_]]

On Sep 7, 9:05 pm, ZZ > wrote:
> It is likely that the probability of an ACTUAL double release failure on
> tow is what ever positive number is closest to zero. Of course that
> doesn't mean that Mr.Murphy can't serve one of these up.
>
> I would be interested in hearing any accounts of actual, non-instructor
> induced double release failures which required either a landing on tow
> or purposely breaking he rope to end the problem.
>
> I would also be interested in any opinions regarding practicing landing
> on tow to prepare oneself for this unlikely event. (I know that this is
> or was a required maneuver in some European countries...but is it worth
> the risk?)
>
> Paul
> ZZ

OK, I've got two True Stories, although I was not a pilot involved in
either
case.

In the first, an experienced pilot came back from a flight and said
he'd had
a double release failure. He said that he just put a lot of slack in
the rope and
broke it. No big deal.

In the second, an instructor at my current club tried to simulate this
situation
and tried to land on tow. During descent the towplane got too far
below the
glider while they were low and a long ways from the airport. When the
rope
broke from the excessive slack generated by the situation this fellow
had
no option except for landing in a farmer's field. We had no
functional
trailer for the L13, either, so the retrieve was quite interesting.

Personally, I've been flying gliders for over 20 years and have yet to
personally
experience a failure of the release or rope. I did witness another
glider have a
rope "break" (actually his tow hook came unhooked) at low altitude and
make
a successful return to the launch point though.

[Frank Whiteley]

On Sep 7, 7:05*pm, ZZ > wrote:
> It is likely that the probability of an ACTUAL double release failure on
> tow is what ever positive number is closest to zero. Of course that
> doesn't mean that Mr.Murphy can't serve one of these up.
>
> I would be interested in hearing any accounts of actual, non-instructor
> induced double release failures which required either a landing on tow
> or purposely breaking he rope to end the problem.
>
> I would also be interested in any opinions regarding practicing landing
> on tow to prepare oneself for this unlikely event. (I know that this is
> or was a required maneuver in some European countries...but is it worth
> the risk?)
>
> Paul
> ZZ

I had a release failure (mostly) on my Open Cirrus (CG hook) once. I
landed one thermal short of home plate at a neighboring glider club
(UK). I handed a cheque out the clear vision panel and took a
launch. When I got to altitude and distance, I pulled the release.
Nothing. I pulled another dozen times in rapid succession, nothing.
I called the tow plane on the radio, no answer. Called several more
time, nothing. I flew out to the left and waggled the wings, no
response from the tow plane. I was hoping he wasn't going to give me
the "bugger off" wing waggle and turn back. A few more pulls and it
let go thankfully. Next step would have been to put in the slack
and break it. Seemed a long time, but really only a few moments. The
TOST hook was replaced before the next flight. No broken springs,
just wear.

So, I guess it really depends on how you define release failure.

Frank Whiteley

[drbdanieli]

Paul,
I was fortunate enough to be trained in this procedure, albeit 35+
years ago. I was at summer camp that Fred Robinson had for kids at
Crystalaire. We're jarring a few cobwebs here but if I remember
correctly, the glider would decend to a low tow position and use the
spoilers for decent. The glider would touch down first but you had to
be careful not to stall and drop the towplane in with excessive
braking.

We had a 1-34 at the time that needed a radio installed. We didn't
have a trailer and the nearby radio shop was at a tower controlled
airport (KAPC). We called the tower and they suggested that the
glider land with the towplane that had a radio. I wasn't old enough
to fly powerplanes yet so my father flew the towplane and I flew the
glider. The airport was quite large and the flight was uneventful.

Bottom line, it's not as scary as it sounds but I would suggest proper
training before trying this on your own. Is anyone teaching this
anymore?

Barry

[[email protected]]

*Is anyone teaching this
> anymore?
>
> Barry

Sure. It's a good exercise for proficiency and confidence building.
Touch and goes, taxiing and even turning at runway intersection to
take off on a different runway. Good communication, experienced tow
pilots, proper conditions, FUN!

[Surfer!]

In message
>,
Frank Whiteley > writes
<snip>
>I flew out to the left and waggled the wings, no
>response from the tow plane.
<Snip>

I had that when learning to give the cannot release signal - it left me
wondering how much use it really is. BTW our tow plane has a retrieve
winch on the rope plus a guillotine for cutting the rope as the release.

--
Surfer!
Email to: ramwater at uk2 dot net

[Chris Rollings[_2_]]

Aside from the one anecdotal account in this thread, I don't recall that I
ever heard of a double failure, though doubtless it's happened somewhere
at some time.

So far as I know practicing landing on tow was never a requirement in any
European country, though I believe it was in Australia at one time.

We tried it a few times at Booker years back. As mentioned elsewhere, the
glider goes into low-tow and lands before the tow-plane. Not that
difficult but certainly not that safe and easy. I would expect a fair
number of accidents to result if it was introduced as part of normal
training and given that I'm not aware of any as a result of double
failures clearly not worth the risk.

At 01:05 08 September 2009, ZZ wrote:
>It is likely that the probability of an ACTUAL double release failure on

>tow is what ever positive number is closest to zero. Of course that
>doesn't mean that Mr.Murphy can't serve one of these up.
>
>I would be interested in hearing any accounts of actual, non-instructor
>induced double release failures which required either a landing on tow
>or purposely breaking he rope to end the problem.
>
>I would also be interested in any opinions regarding practicing landing
>on tow to prepare oneself for this unlikely event. (I know that this is
>or was a required maneuver in some European countries...but is it worth
>the risk?)
>
>Paul
>ZZ
>

[Ian]

On 8 Sep, 09:45, Chris Rollings > wrote:

> So far as I know practicing landing on tow was never a requirement in any
> European country, though I believe it was in Australia at one time.

I was told that it was a mandatory part of training in France, and we
certainly used to see it happen regularly at Le Blanc. However, I've
just checked my 1991/2 editions of "Manuel de Pilote Vol à Voile" and
"Réglementation de la Circulation Aérienne" (that's the official
French gliding manual and a summary of the relevant laws) and can see
no mention in either.

Ian

[John Cochrane]

>
> We tried it a few times at Booker years back. *As mentioned elsewhere, the
> glider goes into low-tow and lands before the tow-plane. *Not that
> difficult but certainly not that safe and easy. *

I tried it once, while at Tehachapi with no lift and nothing else to
do. It was part of their training program. The glider stayed in high
tow, not low. The thinking was, why do something unusual along with an
emergency. Open spoilers, slip as necessary, follow the towplane down
a shallow pattern, land normally, i.e. after the towplane. It was
very uneventful, but an experienced towpilot and a long runway
probably had a lot to do with that.

John Cochrane BB

[jeplane]

I too remember being trained doing this maneuver in France. It was
called "retour au sol" (back to ground)
You could always tell when someone was closed to solo, as this was
part of the curriculum back then.

You would open the speedbrakes full, drop down below the tow plane
wake turbulence, and wait for the tow pilot do its thing. I do not
remember being told that we could stall the glider on landing. Perhaps
it was because you would need to close the speed brakes while flaring.
You obviously don't need them full on very short final.

Interestingly, I also learned this maneuver later on as a tow pilot
itself. And let me tell you that this is where it is actually the most
challenging! We had to remember that there was a glider below you,
underneath that wake. So you would have to arrive much higher on
final, even higher than when you are just returning with the rope
only. Landing was uneventful, you would just have to remember to keep
taxiing a bit long, to give enough room for the glider behind you to
stop.

It's not an necessarily an unsafe maneuver and I was surprised while
flying in the US that a tow release failure is barely mentioned.

Richard
Phoenix,AZ

[FBCompton]

On Sep 7, 11:21*pm, wrote:
> **Is anyone teaching this
>
> > anymore?
>
> > Barry
>
> Sure. *It's a good exercise for proficiency and confidence building.
> Touch and goes, taxiing and even turning at runway intersection to
> take off on a different runway. *Good communication, experienced tow
> pilots, proper conditions, *FUN!


Why all CFIG's (in the USA) must discuss and teach this maneuver: It
appears in your FAA Practical Test Standards (PTS) for Glider
"checkrides" under the Area of Operation "Launches and Landings"/
"Abnormal Occurrences" / "Glider and towplane release
failure" (meaning both releases fail.) This is one of five listed
abnormal situations in your FAA PTS. FAA allows the Examiner to ask
you to perform this maneuver, as the Examiner may ask you to perform
any or all of the tasks under "Abnormal Occurrences." Most Examiners
just ask for the "towline break" demonstration and the "glider (only)
release failure" signal on tow, but "double release" is part of the
PTS, so be prepared to at least discuss the procedure on your
checkride.

Note to CFIG's: Just because a double release failure is rare does
not mean you can skip over it in the PTS. The FAA discusses double
release failure in the FAA Glider Flying Handbook, Chapter 7. Not
much of a discussion however, but there it is. Towpilots need to be
thoroughly briefed by a towpilot who has flown this maneuver. The
descent is very gradual at a proper approach airspeed. If the
approach doesn't look or feel right, the towpilot has the option to go
around and climb with glider still in tow.

Note to Readers: My discussion posted here is abbreviated and not
complete and not to be substituted or used for any aspect of your
ground and flight instruction. This post is discussion, not
instruction.

Regarding the glider in "low tow" position: Because the towplane is
gradually descending the wake is relatively higher, so the glider does
not need to be too low in relation to the towplane. The sight picture
is usually not as low as when you box the wake -- just enough to be
just under the wake, and with a full view of the towrope. Keep the
airbrakes unlocked and deployed as needed to keep a tight towrope at
all times. Overrunning the towplane is the dangerous part both in the
air and on the ground roll out. Be ready to release.

Important Timing Aspect: The glider (in low tow) must not touch down
much before the towplane -- this can be a hazardous aspect -- touching
down well before the towplane and stalling it. The glider wings are
still carrying the weight of the glider while it is flying. Once the
glider touches the wings stop lifting and the glider creates more
weight drag on the towplane, which if still well above the runway will
be slowed and may stall. If you try this maneuver, keep the glider
flying until the towplane is about one meter above the runway. Make
sure the towpilot keeps the towplane moving forward (no brakes) with
some power to help keep the rope tight. Glider pilot deploys nearly
full airbrake (spoiler) to keep from lifting off again and some wheel
brake, AFTER the towplane is on the ground. Just roll out and not be
in a hurry to stop. Both pilots should release if slack rope
develops. If lots of runway ahead a touch and go is possible. Long
runways and a good headwind make landing on tow a bit less
challenging. A long towrope may be a good idea.

For the most comprehensive discussion and training on landing on tow,
along with purposely breaking the towrope, contact Cindy & Marty at
Caracole Soaring in California. They have developed this procedure to
be relatively safe, and fun.

Remember, I am not your personal Flight Instructor here. My
discussion posted here is abbreviated and not complete and not to be
used as part of your ground and flight instruction. For more
instruction in "abnormal occurrences" on tow consult with your local
Certificated Flight Instructor, one who is proficient in landing on
tow. You, your Flight Instructor, Towpilot, and FAA Examiner must
determine the level of acceptable risk when performing this or any
maneuver. You decide if you want to fly a "landing on tow", and don't
blame me if you screw it up.

[tstock]

I've heard some pilots say they would prefer to do an intentional rope
break than to try to land with the tow plane.

Tom

[bildan]

On Sep 7, 7:05*pm, ZZ > wrote:
> It is likely that the probability of an ACTUAL double release failure on
> tow is what ever positive number is closest to zero. Of course that
> doesn't mean that Mr.Murphy can't serve one of these up.
>
> I would be interested in hearing any accounts of actual, non-instructor
> induced double release failures which required either a landing on tow
> or purposely breaking he rope to end the problem.
>
> I would also be interested in any opinions regarding practicing landing
> on tow to prepare oneself for this unlikely event. (I know that this is
> or was a required maneuver in some European countries...but is it worth
> the risk?)
>
> Paul
> ZZ

It's probably worth mentioning that 'release failure' can also be an
uncommanded release. I've had a couple of those when the wing runner
didn't fully insert the Tost ring set into the hook but it somehow
partially engaged only to release on it's own later. Examination
showed nothing wrong with the hook.

I recall the story of a woman in a 1-26 who had the red ball come off
in her hand due to the steel cable breaking off inside the ball. She
looked at it for a moment, then reached under the panel and pulled on
the remaining cable activating the release. Cool head.

I've flown several training gliders which required an unusual amount
of pulling motion to effect a release - the usual 2" tug wouldn't do
it. Many pilots checking out in the glider would report a 'release
failure' and I'd have to say "pull further". The take home is that
you need to make sure you've fully actuated the release.

Final note: The FAA and NTSB seem to be taking a serious look at
release mechanisms, ring sets and weak links. If there's an accident
investigation, it probably isn't wise to be found to be using a chain
link in instead of a Tost ring set or a weak link at variance from
that specified in the POH.

I've been informed that the weak link, Tost hook and ring set are part
of a gliders airworthiness certificate documentation and substitutions
are judged to be an unauthorized modification from a regulatory and
enforcement perspective. Most JAR 22 gliders specify a weak link
strength + or - 10% (read your POH) for both aero tow and winch which
effectively requires a metal link made by Tost or equivalent. Rope
weak links can't meet that strength tolerance.

[bildan]

On Sep 8, 8:13*am, tstock > wrote:
> I've heard some pilots say they would prefer to do an intentional rope
> break than to try to land with the tow plane.
>
> Tom

That would be my preference - especially with a high performance
glider. Landing a 50:1 glider with marginal air/wheel brakes on tow
doesn't sound workable to me.

The breaking strength of the weak link only has to be exceeded for a
millisecond to break it. It's easy to do that using full spoilers
applied with slack in the rope while raising the nose. Neither the
glider pilot nor tuggee will feel more than a slight tug as the link
breaks - if you're using the correct weak link.

Student pilots break links/ropes all the time so it shouldn't be hard
to do it on purpose. Obviously, this works better with a heavy glider.

[Alex[_5_]]

On Sep 8, 7:13*am, FBCompton > wrote:
> On Sep 7, 11:21*pm, wrote:
>
> > **Is anyone teaching this
>
> > > anymore?
>
> > > Barry
>
> > Sure. *It's a good exercise for proficiency and confidence building.
> > Touch and goes, taxiing and even turning at runway intersection to
> > take off on a different runway. *Good communication, experienced tow
> > pilots, proper conditions, *FUN!
>
> Why all CFIG's (in the USA) must discuss and teach this maneuver: *It
> appears in your FAA Practical Test Standards (PTS) for Glider
> "checkrides" under the Area of Operation "Launches and Landings"/
> "Abnormal Occurrences" / "Glider and towplane release
> failure" (meaning both releases fail.) *This is one of five listed
> abnormal situations in your FAA PTS. *FAA allows the Examiner to ask
> you to perform this maneuver, as the Examiner may ask you to perform
> any or all of the tasks under "Abnormal Occurrences." *Most Examiners
> just ask for the "towline break" demonstration and the "glider (only)
> release failure" signal on tow, but "double release" is part of the
> PTS, so be prepared to at least discuss the procedure on your
> checkride.
>
> Note to CFIG's: *Just because a double release failure is rare does
> not mean you can skip over it in the PTS. * The FAA discusses double
> release failure in the FAA Glider Flying Handbook, Chapter 7. *Not
> much of a discussion however, but there it is. * Towpilots need to be
> thoroughly briefed by a towpilot who has flown this maneuver. *The
> descent is very gradual at a proper approach airspeed. *If the
> approach doesn't look or feel right, the towpilot has the option to go
> around and climb with glider still in tow.
>
> Note to Readers: *My discussion posted here is abbreviated and not
> complete and not to be substituted or used for any aspect of your
> ground and flight instruction. *This post is discussion, not
> instruction.
>
> Regarding the glider in "low tow" position: *Because the towplane is
> gradually descending the wake is relatively higher, so the glider does
> not need to be too low in relation to the towplane. *The sight picture
> is usually not as low as when you box the wake -- just enough to be
> just under the wake, and with a full view of the towrope. *Keep the
> airbrakes unlocked and deployed as needed to keep a tight towrope at
> all times. Overrunning the towplane is the dangerous part both in the
> air and on the ground roll out. *Be ready to release.
>
> Important Timing Aspect: *The glider (in low tow) must not touch down
> much before the towplane -- this can be a hazardous aspect -- touching
> down well before the towplane and stalling it. *The glider wings are
> still carrying the weight of the glider while it is flying. *Once the
> glider touches the wings stop lifting and the glider creates more
> weight drag on the towplane, which if still well above the runway will
> be slowed and may stall. *If you try this maneuver, keep the glider
> flying until the towplane is about one meter above the runway. *Make
> sure the towpilot keeps the towplane moving forward (no brakes) with
> some power to help keep the rope tight. *Glider pilot deploys nearly
> full airbrake (spoiler) to keep from lifting off again and some wheel
> brake, AFTER the towplane is on the ground. *Just roll out and not be
> in a hurry to stop. *Both pilots should release if slack rope
> develops. *If lots of runway ahead a touch and go is possible. *Long
> runways and a good headwind make landing on tow a bit less
> challenging. *A long towrope may be a good idea.
>
> For the most comprehensive discussion and training on landing on tow,
> along with purposely breaking the towrope, contact Cindy & Marty at
> Caracole Soaring in California. *They have developed this procedure to
> be relatively safe, and fun.
>
> Remember, I am not your personal Flight Instructor here. *My
> discussion posted here is abbreviated and not complete and not to be
> used as part of your ground and flight instruction. * For more
> instruction in "abnormal occurrences" on tow consult with your local
> Certificated Flight Instructor, one who is proficient in landing on
> tow. *You, your Flight Instructor, Towpilot, and FAA Examiner must
> determine the level of acceptable risk when performing this or any
> maneuver. *You decide if you want to fly a "landing on tow", and don't
> blame me if you screw it up.

How much runway do you normally consume before both towplane and
glider come to a safe stop? I realize field elevation, density
altitude, wind,
obstructions, type of towplane and glider, are all variables. We have
a 3000ft dirt strip at 780ft MSL
field elevation, but have barbed wire fences to clear at both ends and
a ditch on one end. Is that enough to do it comfortably?

[Guy Byars[_2_]]

>
> That would be my preference - especially with a high performance
> glider. *Landing a 50:1 glider with marginal air/wheel brakes on tow
> doesn't sound workable to me.
>

Unless you're flying an ASW-12, most high performance sailplanes in
the 50:1 class have very effective airbrakes.

[Tom[_9_]]

> On Sep 8, 8:13*am, tstock > wrote:
>
> > I've heard some pilots say they would prefer to do an intentional rope
> > break than to try to land with the tow plane.

* * * * *
And what happens if the rope does NOT break? How is this rather benign
"emergency" magnified?
How many tow ropes /weak links (much) stronger than legal?

I am aware of one documented double release failure in the USA.


Tom Knauff

[bildan]

On Sep 8, 11:21*am, Tom > wrote:
> > On Sep 8, 8:13*am, tstock > wrote:
>
> > > I've heard some pilots say they would prefer to do an intentional rope
> > > break than to try to land with the tow plane.
>
> * ** ** ** **
> And what happens if the rope does NOT break? How is this rather
> benign "emergency" magnified?

It isn't 'magnified'.

A the correct way to attempt a deliberate rope break is gentle and
safe - far more so than a landing on tow. It's just the regular rope
slack maneuver taught to private pilots without the effort to take the
slack out smoothly plus opening the spoilers. You're aiming for about
10' of slack while in the normal center high-tow position. Once you
have that, open the spoilers and raise the nose as needed to maintain
normal tow position.

If it doesn't work, you still have the landing option. Why not try a
gentle, controlled, rope break first? You might find you have a rope
that breaks easily. If you try the landing option first and it goes
wrong you may never get the chance to break the rope.

> How many tow ropes /weak links (much) stronger than legal?

Probably less than the number of understrength ropes/weak links. But
that's a different issue being addressed by regulatory authorities.

>
> I am aware of one documented double release failure in the USA.

That 's one more than I was aware of.

[FBCompton]

>
> Probably less than the number of understrength ropes/weak links. *But
> that's a different issue being addressed by regulatory authorities.
>
>
Bill,

Which regulatory authorities and where are they doing the addressing?

[bildan]

On Sep 8, 1:16*pm, FBCompton > wrote:
> > Probably less than the number of understrength ropes/weak links. *But
> > that's a different issue being addressed by regulatory authorities.
>
> Bill,
>
> Which regulatory authorities and where are they doing the addressing?

The FAA & NTSB based on a conversation during a recent accident
investigation. The NTSB showed up at an accident site that would not
normally be on their radar - i.e. a minor accident with no in-flight
breakup, fire or fatality.

Their main interest was the weak link, ring set and release hook
maintenance/replacement records. They were obviously educating
themselves while building a data set for a report leading to further
action.

Another point which arose in that discussion is that if your POH says
you need a 650 KG weak link with a + or - 10% tolerance for both winch
and aero tow, the old 80 - 200% rule doesn't satisfy that
requirement. In most cases, the POH value falls within the 80-200%
range. but if it doesn't, the POH weak link value trumps the 80-200%
rule.

[JS]

We lost Captain Curt in Blairstown to a tug upset. Preferring to
stay away from that possibility. I have done quite a few landings on
tow and would gladly do one in about anything I'm familiar with.
Perhaps people who believe that landings on tow are dangerous haven't
done one?
After one LOT in an AS-K21 (during my Commercial check ride prep
with the instructor in the back seat) with tension still on the rope,
the rope would not release from the glider. It turned out the ring was
smaller diameter than standard and the release didn't open enough to
go past center. It would have released in flight, but sitting still it
wouldn't. How far from an in-flight problem was that? New Tost rings
were ordered, and the release cable adjusted.
Jim

[Chad[_2_]]

Just to add two thoughts- 1) the wake is more mild as the tug is
generating less power, 2) it worked best for me (and this is how I was
taught) if the sailplane controls the descent rate and the towplane
controls the speed. This division of duties prevents the towplane from
landing too short. Also, at towplane final approach speed, the glider
will be well above stall and clearly not ready to land. Thus it is
natural for the glider pilot to keep it flying and apply just enough
spoilers are needed at this point to keep the rope taught. The
maneuver is uneventful if properly planned out, but it does eat up lot
of runway.

Chad
4Z

[[email protected]]

Aarrgh! Not this subject again! Winter must be coming:) There have
been monsterous threads about this subject but a search sadly yielded
nada.

First, ZZ, what is the "additional risk" as compared to a departure,
other than the fact that the Landing On Tow ("LOT") is losing energy
(altitude + airspeed) and a takeoff is gaining energy? LOT is just
another phase of tow, a descending one, culminating in a touchdown.

Second, other than the incident JS mentions and the double failure Tom
Knauff alludes to, I am not aware of any dual failures. These
statistics do no support LOT's as preparation for such an event.
However, I DO believe they have value and are worth the perceived risk
in terms of confidence building and (heaven forbid) Fun and
Excitement. I think the military calls such events "motivational".
Skylark used to employ this event as a pre-solo wind-up for students.
A sortie consisted of a CFI demo'd touch-and-go followed by a student
touch-and-go and finally a student full stop. The post-flight grin
and swagger exhibited by the student was indeed worth it. Earned
Confidence is a Good Thing, as is Fun and Excitement.

Nothing special is required of the glider pilot and very little of the
Tuggie to LOT: After steering the flight to overhead the airport at
more than 1500 ft agl and after exchanging appropriate signals, the
glider pilot pulls full brakes (no wheel brakes!) and continues to fly
the standard high tow position. The Tuggie needs to keep the
formation in glide range of the field. Who touches down first is not
important. Just land your aircraft. The glider need only flair and
land as usual and just keep the rope taught on the ground using wheel
brake as the tug brakes to a stop. As conducted at Skylark, the
Tuggie maintained an approach of 65 kts for 2-33 and 70 kts for glass
and was shooting for 4-5 kt descent rate by adjusting power. Power
was smoothly and slowly reduced as the ground came up and the Tug
wheel-landed. Short of locking the brakes,wrecking the tug, and/or
loss of glider wheel brakes, it is highly unlikely that the glider
will overrun the Tug. If it occurs, the glider clears to the right
per standard procedure. If the approach becomes unacceptable, the
Tuggies applies full power to initiate the go around and the glider
puts the brakes away as the descent stops. If the glider puts the
brakes away at any point in the approach, the tuggie initiates a go-
around and transitions to a standard climb. I have never observed a
rejected approach.

100's (1000's?) of these have been flown at Skylark, many (most) with
pre-solo pilots flying. The only problem I observed in 20 years of
doing these was when the glider pilot decided to ignore the briefed
procedures and began modulating the dive brakes in a Blanik, thus
destabilizing the approach. Typical field length used was about 3000
ft (of 5K ft available), over a 30 ft (?) obstacle at 4200 ft msl.
Typical density altitudes are probably in the 5000 ft msl range.

I have also observed (as the Tuggie) intentional rope breaks ("IRB")
performed by experts and, as others have mentioned, it is also not a
big deal. I have also experienced attempts by Noobs that were
decidedly unpleasant, to the point of punching them off. My biggest
issue with IRB's is the difficulty in maintaining proficiency; how
many ropes / weak links is an operator going to allow each pilot to
break per year?

LOT's in summary:

* More dangerous than a departure tow? Maybe slightly more - mostly
due to a lack of practice and experience.

* Necessary preparation for a real emergency? Definitely not worth
it.

* Valuable for improving pilot skills and inspiring self-confidence?
Invaluable!

A good tool in the toolbox for cruise descents on X-C tows?
Invaluable!

* Fun and Exciting? Absolutely!

[Jim Beckman[_2_]]

At 04:41 09 September 2009, wrote:
>
>Nothing special is required of the glider pilot and very little of the
>Tuggie to LOT: After steering the flight to overhead the airport at
>more than 1500 ft agl and after exchanging appropriate signals, the
>glider pilot pulls full brakes (no wheel brakes!) and continues to fly
>the standard high tow position.

Hadn't thought about this much, but what's the procedure when I'm
flying my 1-35? About the same, I suppose, although the transition from
zero to full flaps while on tow might be sort of entertaining. Full flaps
right away, or keep a bit in reserve? I wonder what the glider attitude
would look like while running along at tow speed with all the flaps out?
Has anybody tried this in such a glider?

Jim Beckman

[Jim Beckman[_2_]]

At 14:13 08 September 2009, FBCompton wrote:
>
>Important Timing Aspect: The glider (in low tow) must not touch down
>much before the towplane -- this can be a hazardous aspect -- touching
>down well before the towplane and stalling it. The glider wings are
>still carrying the weight of the glider while it is flying. Once the
>glider touches the wings stop lifting and the glider creates more
>weight drag on the towplane, which if still well above the runway will
>be slowed and may stall.

This seems counterintuitive to me. When the wings stop lifting, the
induced drag goes away, so the drag on the towplane should decrease. The
only added drag is friction in the glider's main gear. What am I missing
here?

Jim Beckman

[JS]

Sounds like it's time for a Landings On Tow Soar-O-Rama on El Mirage
dry lake!
Jim

[ZZ]

wrote:
> Aarrgh! Not this subject again! Winter must be coming:) There have
> been monsterous threads about this subject but a search sadly yielded
> nada.
>
> First, ZZ, what is the "additional risk" as compared to a departure,
> other than the fact that the Landing On Tow ("LOT") is losing energy
> (altitude + airspeed) and a takeoff is gaining energy? LOT is just
> another phase of tow, a descending one, culminating in a touchdown.
>
> Second, other than the incident JS mentions and the double failure Tom
> Knauff alludes to, I am not aware of any dual failures. These
> statistics do no support LOT's as preparation for such an event.
> However, I DO believe they have value and are worth the perceived risk
> in terms of confidence building and (heaven forbid) Fun and
> Excitement. I think the military calls such events "motivational".
> Skylark used to employ this event as a pre-solo wind-up for students.
> A sortie consisted of a CFI demo'd touch-and-go followed by a student
> touch-and-go and finally a student full stop. The post-flight grin
> and swagger exhibited by the student was indeed worth it. Earned
> Confidence is a Good Thing, as is Fun and Excitement.
>
> Nothing special is required of the glider pilot and very little of the
> Tuggie to LOT: After steering the flight to overhead the airport at
> more than 1500 ft agl and after exchanging appropriate signals, the
> glider pilot pulls full brakes (no wheel brakes!) and continues to fly
> the standard high tow position. The Tuggie needs to keep the
> formation in glide range of the field. Who touches down first is not
> important. Just land your aircraft. The glider need only flair and
> land as usual and just keep the rope taught on the ground using wheel
> brake as the tug brakes to a stop. As conducted at Skylark, the
> Tuggie maintained an approach of 65 kts for 2-33 and 70 kts for glass
> and was shooting for 4-5 kt descent rate by adjusting power. Power
> was smoothly and slowly reduced as the ground came up and the Tug
> wheel-landed. Short of locking the brakes,wrecking the tug, and/or
> loss of glider wheel brakes, it is highly unlikely that the glider
> will overrun the Tug. If it occurs, the glider clears to the right
> per standard procedure. If the approach becomes unacceptable, the
> Tuggies applies full power to initiate the go around and the glider
> puts the brakes away as the descent stops. If the glider puts the
> brakes away at any point in the approach, the tuggie initiates a go-
> around and transitions to a standard climb. I have never observed a
> rejected approach.
>
> 100's (1000's?) of these have been flown at Skylark, many (most) with
> pre-solo pilots flying. The only problem I observed in 20 years of
> doing these was when the glider pilot decided to ignore the briefed
> procedures and began modulating the dive brakes in a Blanik, thus
> destabilizing the approach. Typical field length used was about 3000
> ft (of 5K ft available), over a 30 ft (?) obstacle at 4200 ft msl.
> Typical density altitudes are probably in the 5000 ft msl range.
>
> I have also observed (as the Tuggie) intentional rope breaks ("IRB")
> performed by experts and, as others have mentioned, it is also not a
> big deal. I have also experienced attempts by Noobs that were
> decidedly unpleasant, to the point of punching them off. My biggest
> issue with IRB's is the difficulty in maintaining proficiency; how
> many ropes / weak links is an operator going to allow each pilot to
> break per year?
>
> LOT's in summary:
>
> * More dangerous than a departure tow? Maybe slightly more - mostly
> due to a lack of practice and experience.
>
> * Necessary preparation for a real emergency? Definitely not worth
> it.
>
> * Valuable for improving pilot skills and inspiring self-confidence?
> Invaluable!
>
> A good tool in the toolbox for cruise descents on X-C tows?
> Invaluable!
>
> * Fun and Exciting? Absolutely!
>


I agree with your assessments Mark. I have only done three LOTs and they
were all easy and great fun.

A current student of mine asked me how common the double release failure
is and I did not have a good answer for him so I decided to poll the
masses. The answer to that one seems to be either zero or one.

Regarding the question of should we be practicing these, I am currently
bucking a political tide trying to get LOTs into Flight Reviews
for those pilots that want to widen their horizons. So far, no dice.

I especially liked your point about cruise descents on X-C tows.
Descending on tow is not something we do normally and while not
difficult, requires some thought and care.

Paul
ZZ

[Alan[_6_]]

In article > ZZ > writes:

>I agree with your assessments Mark. I have only done three LOTs and they
>were all easy and great fun.
>
>A current student of mine asked me how common the double release failure
>is and I did not have a good answer for him so I decided to poll the
>masses. The answer to that one seems to be either zero or one.
>
>Regarding the question of should we be practicing these, I am currently
>bucking a political tide trying to get LOTs into Flight Reviews
>for those pilots that want to widen their horizons. So far, no dice.


No reason to put them in flight reviews, since the trend is to make the
flight review more closely match the PTS. Now, I think that making the
flight review be matched to the Practical Test Standards is stupid, and it
makes a lot more sense to use the time working on something *different*,
and let the evaluation of general competency be incidental --- a good
instructor should be able to tell if the pilot is generally competent
fairly quickly, without having to go through a re-running of the checkride.

For example, it would make more sense for me to spend a bunch of flight
review time under a hood, since I am not instrument rated, so I have not
practiced that lately. Or, perhaps do it on a soft/grass field, since
most of my flying has been on pavement. Doing it in a different sort of
airplane would be another option.

Landing on tow as one option for a flight review is fine. It should
*not* be a standard part, however.

Putting specific items in the flight review is a bad idea. Doing something
different, gaining new experience, is better than re-doing the same experience.

Alan

[Alan[_6_]]

In article > Jim Beckman > writes:
>At 14:13 08 September 2009, FBCompton wrote:
>>
>>Important Timing Aspect: The glider (in low tow) must not touch down
>>much before the towplane -- this can be a hazardous aspect -- touching
>>down well before the towplane and stalling it. The glider wings are
>>still carrying the weight of the glider while it is flying. Once the
>>glider touches the wings stop lifting and the glider creates more
>>weight drag on the towplane, which if still well above the runway will
>>be slowed and may stall.
>
>This seems counterintuitive to me. When the wings stop lifting, the
>induced drag goes away, so the drag on the towplane should decrease. The
>only added drag is friction in the glider's main gear. What am I missing
>here?
>
>Jim Beckman

It seems backwards to me, too, but I have asked tow pilots about this,
and I was told that they feel the drag decrease when the glider comes off
the ground on the takeoff roll.

I guess those wheels have a lot of drag.

Alan

[Frank Whiteley]

On Sep 10, 2:37*am, (Alan) wrote:
> In article > Jim Beckman > writes:
> >At 14:13 08 September 2009, FBCompton wrote:
>
> >>Important Timing Aspect: *The glider (in low tow) must not touch down
> >>much before the towplane -- this can be a hazardous aspect -- touching
> >>down well before the towplane and stalling it. *The glider wings are
> >>still carrying the weight of the glider while it is flying. *Once the
> >>glider touches the wings stop lifting and the glider creates more
> >>weight drag on the towplane, which if still well above the runway will
> >>be slowed and may stall. *
>
> >This seems counterintuitive to me. *When the wings stop lifting, the
> >induced drag goes away, so the drag on the towplane should decrease. *The
> >only added drag is friction in the glider's main gear. *What am I missing
> >here?
>
> >Jim Beckman
>
> * It seems backwards to me, too, but I have asked tow pilots about this,
> and I was told that they feel the drag decrease when the glider comes off
> the ground on the takeoff roll.
>
> * I guess those wheels have a lot of drag.
>
> * * * * Alan

Behind less powerful tow planes, I generally note a 3-5 knot jump in
airspeed immediately following glider lift off.

Frank Whiteley

[bildan]

On Sep 10, 8:27*am, Frank Whiteley > wrote:
> On Sep 10, 2:37*am, (Alan) wrote:
>
>
>
> > In article > Jim Beckman > writes:
> > >At 14:13 08 September 2009, FBCompton wrote:
>
> > >>Important Timing Aspect: *The glider (in low tow) must not touch down
> > >>much before the towplane -- this can be a hazardous aspect -- touching
> > >>down well before the towplane and stalling it. *The glider wings are
> > >>still carrying the weight of the glider while it is flying. *Once the
> > >>glider touches the wings stop lifting and the glider creates more
> > >>weight drag on the towplane, which if still well above the runway will
> > >>be slowed and may stall. *
>
> > >This seems counterintuitive to me. *When the wings stop lifting, the
> > >induced drag goes away, so the drag on the towplane should decrease. *The
> > >only added drag is friction in the glider's main gear. *What am I missing
> > >here?
>
> > >Jim Beckman
>
> > * It seems backwards to me, too, but I have asked tow pilots about this,
> > and I was told that they feel the drag decrease when the glider comes off
> > the ground on the takeoff roll.
>
> > * I guess those wheels have a lot of drag.
>
> > * * * * Alan
>
> Behind less powerful tow planes, I generally note a 3-5 knot jump in
> airspeed immediately following glider lift off.
>
> Frank Whiteley

Brake pucks and shoes are always in light contact with the disks or
drums to eliminate 'lost motion' so as to provide immediate braking
action. Although small, this friction is not negligible.

Aircraft tires are made from natural rubber which has very good wet
and dry traction but also has higher rolling resistance than synthetic
rubber. A single glider tire is also loaded heavily - sometimes
beyond the load rating limit which increases rolling resistance still
further.

It's reasonable to expect these taken together would result in
noticeable rolling resistance.

On a slightly different tack, I've had badly worn drum brakes lock up
on touchdown all on their own without input from me. Normally, this
is not a problem and serves as a reminder to service the brakes. If
the brake locked and/or a tire blew while landing on tow, the results
might be 'interesting'.

[Bruce]

bildan wrote:
> On Sep 10, 8:27 am, Frank Whiteley > wrote:
>> On Sep 10, 2:37 am, (Alan) wrote:
>>
>>
>>
>>> In article > Jim Beckman > writes:
>>>> At 14:13 08 September 2009, FBCompton wrote:
>>>>> Important Timing Aspect: The glider (in low tow) must not touch down
>>>>> much before the towplane -- this can be a hazardous aspect -- touching
>>>>> down well before the towplane and stalling it. The glider wings are
>>>>> still carrying the weight of the glider while it is flying. Once the
>>>>> glider touches the wings stop lifting and the glider creates more
>>>>> weight drag on the towplane, which if still well above the runway will
>>>>> be slowed and may stall.
>>>> This seems counterintuitive to me. When the wings stop lifting, the
>>>> induced drag goes away, so the drag on the towplane should decrease. The
>>>> only added drag is friction in the glider's main gear. What am I missing
>>>> here?
>>>> Jim Beckman
>>> It seems backwards to me, too, but I have asked tow pilots about this,
>>> and I was told that they feel the drag decrease when the glider comes off
>>> the ground on the takeoff roll.
>>> I guess those wheels have a lot of drag.
>>> Alan
>> Behind less powerful tow planes, I generally note a 3-5 knot jump in
>> airspeed immediately following glider lift off.
>>
>> Frank Whiteley
>
> Brake pucks and shoes are always in light contact with the disks or
> drums to eliminate 'lost motion' so as to provide immediate braking
> action. Although small, this friction is not negligible.
>
> Aircraft tires are made from natural rubber which has very good wet
> and dry traction but also has higher rolling resistance than synthetic
> rubber. A single glider tire is also loaded heavily - sometimes
> beyond the load rating limit which increases rolling resistance still
> further.
>
> It's reasonable to expect these taken together would result in
> noticeable rolling resistance.
>
> On a slightly different tack, I've had badly worn drum brakes lock up
> on touchdown all on their own without input from me. Normally, this
> is not a problem and serves as a reminder to service the brakes. If
> the brake locked and/or a tire blew while landing on tow, the results
> might be 'interesting'.
Very interesting - the white stripe on the runway costs about $100/m...
(Pictures available)

Tost Lilliput 4" rim failed radially around the pressed in liner as I
touched down in my Std Cirrus. Air pressure forced the two parts apart
against the frame. Instant locked wheel.
The tar ate a hole right through the Tost 4.00x4 that I could fit a
thumb through.

Certainly the only time the Lilliput ever stopped 66 fast though - can't
have gone much more than 50" ground roll.

Have adjusted the replacement rim to give the normal useless level of
braking force.

Bruce

[Uncle Fuzzy]

On Sep 9, 9:27*am, JS > wrote:
> Sounds like it's time for a Landings On Tow Soar-O-Rama on El Mirage
> dry lake!
> Jim

Yeehaa! Confidence building, fun and entertaining, useful for XC
tows. I'm up for the LOT Soar-O-Rama (followed of course by awesome
dry lake food, campfire, and telling of lies), but probably not at El
Mirage. Last time I was there, the lakebed was being patrolled by 6
Big Land Mothers in large SUV's. Not the same atmosphere as it was in
the 60's and 70's. How about Roach?

[Jonathon May[_2_]]

At 19:58 10 September 2009, Uncle Fuzzy wrote:
>On Sep 9, 9:27=A0am, JS wrote:
>> Sounds like it's time for a Landings On Tow Soar-O-Rama on El Mirage
>> dry lake!
>> Jim
>
>Yeehaa! Confidence building, fun and entertaining, useful for XC
>tows. I'm up for the LOT Soar-O-Rama (followed of course by awesome
>dry lake food, campfire, and telling of lies), but probably not at El
>Mirage. Last time I was there, the lakebed was being patrolled by 6
>Big Land Mothers in large SUV's. Not the same atmosphere as it was in
>the 60's and 70's. How about Roach?
>

OK so what is a Big Land Mother?
Jon

[Uncle Fuzzy]

On Sep 10, 2:45*pm, Jonathon May > wrote:
> At 19:58 10 September 2009, Uncle Fuzzy wrote:
>
> >On Sep 9, 9:27=A0am, JS *wrote:
> >> Sounds like it's time for a Landings On Tow Soar-O-Rama on El Mirage
> >> dry lake!
> >> Jim
>
> >Yeehaa! *Confidence building, fun and entertaining, useful for XC
> >tows. *I'm up for the LOT Soar-O-Rama (followed of course by awesome
> >dry lake food, campfire, and telling of lies), but probably not at El
> >Mirage. *Last time I was there, the lakebed was being patrolled by 6
> >Big Land Mothers in large SUV's. Not the same atmosphere as it was in
> >the 60's and 70's. *How about Roach?
>
> OK *so what is a Big Land Mother?
> Jon

BLM - Bureau of Land Management. It's not as bad as I had thought,
but it is a "Fee" area now, and I wouldn't go there to do the things I
did when I was a teenager (a very long time ago!)
http://www.blm.gov/ca/st/en/fo/barstow/mirage.html

[Bob Gibbons[_2_]]

On Mon, 7 Sep 2009 20:46:08 -0700 (PDT), drbdanieli
> wrote:

>... text deleted ...
>Bottom line, it's not as scary as it sounds but I would suggest proper
>training before trying this on your own. Is anyone teaching this
>anymore?
>
>Barry

I don't know about today, but AC Williams and his instructors at
Southwest Soaring outside Dallas, TX would frequently do the landing
behind the towplace with his Grob 103's during flight reviews. I did a
few during BFRs in the late 80's and 90's. Mostly a non-event. The
only difficult part I found was coordinating the ground deceleration
so as to avoid overrunning the towrope on the rollout.

Bob