Soaring Safety

[[email protected]]

Last November, I chaired a panel at the local SSA affiliate (PASCO)'s
Soaring Safety Seminar entitled "Complacency: What Me Worry?" I wrote
up my part of that and made it available at

http://ee.stanford.edu/~hellman/soaring/PASCO_2007_talk.html

Just today, PASCO got a request from the Capetown S.A. soaring club to
reprint the article with the following explanation:

"The reason for writing to you is that my gliding club was unfortunate
to lose a member recently in a ridge accident. He was an extremely
experienced ridge pilot and only on his eighth flight in his brand new
DG808. Your PASCO Safety Seminar article titled "Complacency" is
therefore of particular relevance to our members."

My Soaring Safety page

http://ee.stanford.edu/~hellman/soaring/safety.html

has links to several other highly relevant articles. With respect to
ridge soaring and the too regular fatalities of "extremely experienced
ridge pilots" please see the links to Henry Combs article and JJ
Sinclair's. Gantenbrink's speech is a must read if you haven't seen
it, though I suspect most of you have. But, then again, it is worth
reading more than once.

Hoping this helps.

Martin
N56WT

[Andreas Maurer[_1_]]

On Wed, 13 Feb 2008 12:17:44 -0800 (PST), wrote:

>Last November, I chaired a panel at the local SSA affiliate (PASCO)'s
>Soaring Safety Seminar entitled "Complacency: What Me Worry?" I wrote
>up my part of that and made it available at

Very good article.
I just got the official statistics of Germany for 2007.

20 fatal accidents with German gliders involved (compared to 10 in
2006).
15 of them abroad, 12 in the French Alps.


German autorities suppose that the very bad weather in 2007 made
pilots with insufficient experience go to fly in better weather
conditions that can be found in the French Alps.
They also think that the competition situation due to the OLC might
have made some pilots accept higher risks.



Bye
Andreas

[Mike125]

Very good post and links. I consider myself a novice ridge flyer and,
despite having done a fair amount of reading on the subject, have
never seen this phenomenon addressed. Being low on ridge experience, I
tend to give the mountain a pretty wide berth but, as my confidence
level goes up and I start flying closer, the chances of encountering
this will increase. It has happened to me only a couple times at
altitude (once while still on tow) and, initially, scared me pretty
good each time. Being at what seems to be a 90 degree bank with full
opposite control inputs is a little disconcerting. A few seconds of
"What the*#!%?" followed by "Wow! Let me get back to that thermal!"
Great food for thought as the ridge season in the northeast
approaches.

Mike

[[email protected]]

On Feb 13, 12:17*pm, wrote:
> Last November, I chaired a panel at the local SSA affiliate (PASCO)'s
> Soaring Safety Seminar entitled "Complacency: What Me Worry?" I wrote
> up my part of that and made it available at
>
> http://ee.stanford.edu/~hellman/soaring/PASCO_2007_talk.html
>
> Just today, PASCO got a request from the Capetown S.A. soaring club to
> reprint the article with the following explanation:
>
> "The reason for writing to you is that my gliding club was unfortunate
> to lose a member recently in a ridge accident. *He was an extremely
> experienced ridge pilot and only on his eighth flight in his brand new
> DG808. Your PASCO Safety Seminar article titled "Complacency" is
> therefore of particular relevance to our members."
>
> My Soaring Safety page
>
> http://ee.stanford.edu/~hellman/soaring/safety.html
>
> has links to several other highly relevant articles. With respect to
> ridge soaring and the too regular fatalities of "extremely experienced
> ridge pilots" please see the links to Henry Combs article and JJ
> Sinclair's. Gantenbrink's speech is a must read if you haven't seen
> it, though I suspect most of you have. But, then again, it is worth
> reading more than once.
>
> Hoping this helps.
>
> Martin
> N56WT

In the Henry Combs article, what did happen to Chet Lymon?
He survived and so did/does he confirm his roll control authority was
overpowered?

[Mark Jardini]

This discussion brings to mind an episode I had relatively early in my
soaring life. After licensing at Tehachepi in a 2-33, I went to
Crystal to
transition to glass in their Grob 103's. After being cleared to solo I
was flying along the San Gabriel's in an area that had been shown to
me.
The lift was sketchy and I was flying long passes through bands of
weak lift, not very close to the mountain, (I was and still am quite
cowardly). After hitting a strengthening patch of lift through two
passes, I had the brilliant idea to try circling. I made two circles
just like it was any other thermal I had flown and then, between
heartbeats, It all went to schist. I heard a loud bang and instantly i
was no longer flying. the car keys in my shirt pocket were pinned
against the canopy and all the gravel and dust on the floor was
floating in front of me. my angle of bank entering into this was
shallow and I think both wings hit at the same time. If it had been
one wing only, I would have been vertical or inverted faster than I
could have moved the controls to react.
Luckily I was pointed away from the mountain, and recovery was to
simply nose down and pull out. My own personal recovery took
considerably longer. There is no skill in the world that could tame
that kind of sharp edged shear while rock polishing, in my estimation.

Mark Jardini

[JJ Sinclair]

Sadly, we lost Stew Kissel shortly after I wrote "Don't Smack the
Mountain-101", so we need to add yet another name to the list of
"Mysterious high energy impacts on the side of a mountain". I live by
the rules I stated and so far (35 years & 5000 hours in the Sierras &
Whites) they have kept me from impacting the mountain.
JJ

[[email protected]]

On Feb 14, 2:06*pm, wrote:
> In the Henry Combs article, what did happen to Chet Lymon?
> He survived and so did/does he confirm his roll control authority was
> overpowered?

I checked with my friend who knew Combs and gave me the article, but
so far he hasn't been able to provide an answer to the above question.
I did do a search of the NTSB database and found the report attached
below which says he encountered wind shear. The longer report lists
the wind as 270@13, so I suspect they really meant a thermally induced
wind shear. If that was the case, it wasn't quite the same mechanism
that Combs described but the point is still there. Anytime we fly
close to terrain, life is much more dangerous since there's less time
(no time sometimes) to recover from an anomaly -- be it a wing lifted
(as Combs describes), wind shear that causes a stall, etc.

Hope this helps.

Martin

NTSB Identification: LAX84FA315 .
The docket is stored on NTSB microfiche number 25291.
14 CFR Part 91: General Aviation
Accident occurred Saturday, May 26, 1984 in LLANO, CA
Aircraft: Bölkow PHOEBUS A-1, registration: N7700
Injuries: 1 Serious.
CIRCLING IN LIFT NEAR A HIGH RIDGE THE SAILPLANE ENCOUNTERED WHAT THE
PLT REFERRED TO AS WIND SHEAR. LOSING CONTROL, THE SAILPLANE COLLIDED
WITH A TREE BEFORE IMPACTING THE GROUND.

The National Transportation Safety Board determines the probable
cause(s) of this accident as follows:

WEATHER CONDITION..WINDSHEAR
AIRSPEED(VS)..NOT MAINTAINED..PILOT IN COMMAND

[Shawn[_5_]]

Mark Jardini wrote:
> This discussion brings to mind an episode I had relatively early in my
> soaring life. After licensing at Tehachepi in a 2-33, I went to
> Crystal to
> transition to glass in their Grob 103's. After being cleared to solo I
> was flying along the San Gabriel's in an area that had been shown to
> me.
> The lift was sketchy and I was flying long passes through bands of
> weak lift, not very close to the mountain, (I was and still am quite
> cowardly). After hitting a strengthening patch of lift through two
> passes, I had the brilliant idea to try circling. I made two circles
> just like it was any other thermal I had flown and then, between
> heartbeats, It all went to schist.

"Going to schist" When rock polishing goes bad.
Yeah, yeah, I know what your thinking "How gneiss."
;-)


Shawn

[tommytoyz]

I remember reading an article, I thought it was Henry Combs, but not
sure, about a technique of rolling inverted deliberately and moving
away from the mountain inverted, when encountering such a gust.

It made sense to me, if you roll authority is less than the strength
of the gust, then don't fight it and even reverse input and let
yourself go inverted. You can then turn away inverted, or at least not
into the mountain. Sounds like a Judo move to me.

Does anyone remember this article or concur with this technique?

[[email protected]]

On Feb 15, 12:39 pm, Shawn > wrote:
> Mark Jardini wrote:
> > This discussion brings to mind an episode I had relatively early in my
> > soaring life. After licensing at Tehachepi in a 2-33, I went to
> > Crystal to
> > transition to glass in their Grob 103's. After being cleared to solo I
> > was flying along the San Gabriel's in an area that had been shown to
> > me.
> > The lift was sketchy and I was flying long passes through bands of
> > weak lift, not very close to the mountain, (I was and still am quite
> > cowardly). After hitting a strengthening patch of lift through two
> > passes, I had the brilliant idea to try circling. I made two circles
> > just like it was any other thermal I had flown and then, between
> > heartbeats, It all went to schist.
>
> "Going to schist" When rock polishing goes bad.
> Yeah, yeah, I know what your thinking "How gneiss."
> ;-)
>
> Shawn

Oh, that's just marbelous.

[noel.wade]

One thing I've wondered is whether some of these "wing lift" incidents
are actually *wing drop* incidents. I don't have much ridge-time in
full-scale gliders, but I have already experienced some good amounts
of turbulence.

There's nothing that says a turbulent parcel of air couldn't hit the
wing that's closer to the ridge. After all, the wing closer to the
ridge is also closer to the ground. Accordingly, that wing is
possibly more exposed to turbulence caused by ground features - these
can extend downwind (i.e. up-slope) to a distance of 10 or 20 times
the height of the original object. For example, a 100-foot-tall tree
can create turbulence over 1000 feet downwind of it. When I did slope-
soaring with R/C gliders, we used to have to be VERY cautious of this
- so its always in my mind when I visually scan the ridge ahead of me
when in my cockpit.

So imagine a situation where you're getting rocked by lift and
turbulence, and all of a sudden the ridge-facing wing drops. Could
you confidently distinguish that from a wing-lift on the opposite side
if you're going through pulses of lift and sink, or turbulent roiling
air?

Of course, there's a BIG difference in what might be the best way to
recover from those two different situations. With a wing-drop, you
have a stalled condition - giving the aircraft full aileron to lower
the upwind wing just increases the angle of attack on the stalled wing
and doesn't make the situation any better. And if we're close to
terrain we might subconsciously be pulling on the stick, too (again,
not helpful to a stalled wing).

....Just some food for thought that a relative newbie like me wonders
about at midnight (being a night-owl I tend to be obsessing over
gliders at that time quite frequently *grin*).

Take care,

--Noel

[tommytoyz]

Noel,
You do make in interesting point in making that distinction. In that
situation , rolling inverted so as not to stall the mountain side wing
would seem the best way out alive without stalling or more probably
spinning in.

The main hindrance I think is most pilot's reluctance to actually
deliberately go inverted and steer from that position and without
stalling while inverted.

I'm interested in thoughts on this issue, am I nuts?

[noel.wade]

On Feb 15, 11:43 pm, tommytoyz > wrote:
> The main hindrance I think is most pilot's reluctance to actually
> deliberately go inverted and steer from that position and without
> stalling while inverted.
>
> I'm interested in thoughts on this issue, am I nuts?

Its been proven how much lower the survival rate is for people who
haven't had spin training and get into a spin.

Do you really want to advocate that people should go into an unusual
attitude that they are neither used to nor is their glider rated for,
in a moment of confusion and stress? Can we expect them to stay
oriented? Can we expect their aircraft to perform well invertted?
Can we expect their aircraft to hold together under negative "G" loads
while invertted? (especially if this is a rough/strong day on a
mountain ridge)?

--Noel

[Dan Silent]

Any chance of getting a link to the source of these
numbers.

>I just got the official statistics of Germany for 2007.
>20 fatal accidents with German gliders involved
>(compared to 10 in 2006).
>15 of them abroad, 12 in the French Alps.
------------------



Daniel Scopel
Silent 2 Targa
C-GODY serial 2027
Volez souvent et soyez prudent.
http://pages. videotron. com/dscopel/

[JJ Sinclair]

I actually saw Tom Madigan hit the Whites just east of Bishop. Most
of us thought he had experienced heat prostration, but after re-
reading Henry Combs explanation I can see that Tom might have placed
his sailplane in exactly the wrong position relative to the mountain.
It was the second day of the 1985 regionals and hotter than hell, like
105! About 12:30 we started towing to the Whites which weren't working
very well because the sun hadn't been hitting the western slopes very
long. Several of us were slope-soaring back and forth without much
success. Then I saw a ship circling and immediately headed for his
location, figuring he had finally snagged a thermal. Just before
getting there I saw the ship CRASH on a small plateau! The terrain was
about 30 degrees up slope with a small plateau of maybe 100 feet
across, then the mountain continued on up the 30 degree slope. Tom
obviously turned because he had hit lift, lets say 300 fpm. Using
Henry's explanation, that thermal would have been kicked off when
rising hot air hit the edge of the plateau. When Tom's ship got
between the thermal and the air coming down the mountain feeding his
thermal, he may have been in exactly the wrong place at the wrong
time. Let's say he had 300 fpm UP air under his LEFT wing and 200 fpm
DOWN air on top of his RIGHT wing. Old Tom might not have had the
aileron AUTHORITY to make the ship do his bidding?

Food for thought, this would explain how a relatively weak 'first
thermal' could have overpowered Tom's ship and also the Phoebus
example in Henry's article which crashed about 10:45 in the morning
JJ






On Feb 15, 9:29*pm, "noel.wade" > wrote:
> One thing I've wondered is whether some of these "wing lift" incidents
> are actually *wing drop* incidents. *I don't have much ridge-time in
> full-scale gliders, but I have already experienced some good amounts
> of turbulence.
>
> There's nothing that says a turbulent parcel of air couldn't hit the
> wing that's closer to the ridge. *After all, the wing closer to the
> ridge is also closer to the ground. *Accordingly, that wing is
> possibly more exposed to turbulence caused by ground features - these
> can extend downwind (i.e. up-slope) to a distance of 10 or 20 times
> the height of the original object. *For example, a 100-foot-tall tree
> can create turbulence over 1000 feet downwind of it. *When I did slope-
> soaring with R/C gliders, we used to have to be VERY cautious of this
> - so its always in my mind when I visually scan the ridge ahead of me
> when in my cockpit.
>
> So imagine a situation where you're getting rocked by lift and
> turbulence, and all of a sudden the ridge-facing wing drops. *Could
> you confidently distinguish that from a wing-lift on the opposite side
> if you're going through pulses of lift and sink, or turbulent roiling
> air?
>
> Of course, there's a BIG difference in what might be the best way to
> recover from those two different situations. *With a wing-drop, you
> have a stalled condition - giving the aircraft full aileron to lower
> the upwind wing just increases the angle of attack on the stalled wing
> and doesn't make the situation any better. *And if we're close to
> terrain we might subconsciously be pulling on the stick, too (again,
> not helpful to a stalled wing).
>
> ...Just some food for thought that a relative newbie like me wonders
> about at midnight (being a night-owl I tend to be obsessing over
> gliders at that time quite frequently *grin*).
>
> Take care,
>
> --Noel

[Jim White]

At 16:24 16 February 2008, Jj Sinclair wrote:
> I actually saw Tom Madigan hit the Whites just east
>of Bishop.

I dont think anyone has discussed airspeed in this
thread. My glider has crap airelon authority at 50kts
but at Va it is very good. Isn't safety near rocks
a factor of speed? If you are belting along at a Va
would you not be able to pull up / fly away from the
cliff if you needed to?

Jim

[JJ Sinclair]

On Feb 16, 9:04*am, Jim White >
wrote:
> At 16:24 16 February 2008, Jj Sinclair wrote:
>
> > I actually saw Tom Madigan hit the Whites just east
> >of Bishop.
>
> I dont think anyone has discussed airspeed in this
> thread. My glider has crap airelon authority at 50kts
> but at Va it is very good. Isn't safety near rocks
> a factor of speed? If you are belting along at a Va
> would you not be able to pull up / fly away from the
> cliff if you needed to?
>
> Jim

Sure Jim, but these guys were trying to climb and flying fairly slow
in weak slope lift ond/or trying to work weak thermals. You bring up a
good point though, I never slow down below 65 knots on my first pass
across a piece of ridge that I haven't made at least one pass by to
check for squirrely air.
JJ

[kirk.stant]

On Feb 16, 12:43*am, tommytoyz > wrote:
> Noel,
> You do make in interesting point in making that distinction. In that
> situation , rolling inverted so as not to stall the mountain side wing
> would seem the best way out alive without stalling or more probably
> spinning in.
>
> The main hindrance I think is most pilot's reluctance to actually
> deliberately go inverted and steer from that position and without
> stalling while inverted.
>
> I'm interested in thoughts on this issue, am I nuts?

Have you ever had any aerobatic training in a glider? Or a power
plane?

I have. What you suggest is extremely dangerous, and unlikely to work
with a glider due to their extremely slow roll rate and extreme
negative angle of attack needed when inverted - combined with limited
elevator authority. As well as being extremely disorienting.

In addition, while most gliders are extremely spin resistant right
side up, they will spin in a heartbeat inverted (think anhedral and
wash-in).

So yes, in this case, you are nuts! ;>)

But please, if you get a chance, get some glider acro training and see
for yourself, at a safe altitude, in a proper acro glider (which most
XC ships are definitely not).

Cheers,

Kirk
66

[tommytoyz]

Ok Kirk,
I concede it is a very dangerous and likely nutty idea. But when
you're roll authority is gone, is smacking into the mountain a better
alternative? Maybe the chances of coming out are not good, but isn't
it better than certain doom?

When you're suddenly looking at the mountain slope and the mountain
side wing is going down, despite full input to the opposite, what is
the best alternative? We have discussed how to avoid getting into this
situation, my suggestion is what do you do when you encounter it
despite all efforts not to get into one.

This may not even be an idea to pursue, but just maybe it's a chance
to NOT crash into a mountain in an emergency situation.

Like I said, it may not be a good idea nor am I advocating people do
this. But those who say it's nutty, of those I ask, what is the better
alternative is the exact same situation?
Tom

[Andreas Maurer[_1_]]

On 16 Feb 2008 12:59:45 GMT, Dan Silent
> wrote:

>Any chance of getting a link to the source of these
>numbers.

As far as I know they are not on the web yet, unfortunately - I got
them during an CFI training one week ago on paper only directly from
one of the German fligt safety commisioners.

They are going to be published on bfu-web.de - please send me a
reminder if you cannot find them there within a couple of weeks (the
site is in German only).




Bye
Andreas

[kirk.stant]

On Feb 16, 8:00*pm, tommytoyz > wrote:
> Ok Kirk,
> I concede it is a very dangerous and likely nutty idea. But when
> you're roll authority is gone, is smacking into the mountain a better
> alternative? Maybe the chances of coming out are not good, but isn't
> it better than certain doom?

The problem is that in this situation you are already too close for
this "option" to have any chance of working. If you try to roll with
the upset, assuming you have any better roll authority in that
direction (not certain, the whole wing could be stalled), what will
happen is that you will end up hitting the ridge head on inverted
pointed almost straight down - which will probably not increase your
chance of surviving!

Again, if you haven't tried it - the half roll to inverted flight,
then turning inverted, is one of the hardest maneuvers to learn in a
glider (and may not even be possible in a normal 15 m racing/xc
glider). It's not just a matter of pushing the stick over! And
compared to an acro ship, takes forever. Time that you don't have on
the ridge during an upset.

> When you're suddenly looking at the mountain slope and the mountain
> side wing is going down, despite full input to the opposite, what is
> the best alternative? We have discussed how to avoid getting into this
> situation, my suggestion is what do you do when you encounter it
> despite all efforts not to get into one.

My response (easy to come up with sitting here at my computer, of
course) would be to try to accellerate by unloading and diving towards
the ridge, and hope to regain roll control before hitting the rocks.
It that doesn't happen, then try to hit the softest thing in front of
me. But realistically, you may have put yourself in a non-recoverable
situation, and you just killed yourself. Pretty stupid, that!

Now, there is one situation where continueing the roll might work: if
the upset is next to a vertical cliff face, you could continue the
roll while pulling - to try a rolling split-s away from the mountain.
You would need lots of room underneath, and keep a lot of positive G
on the glider to avoid blasting through VNE, but it could work. I
doubt there are many areas of the US with the terrain that would allow
that option, though.

> This may not even be an idea to pursue, but just maybe it's a chance
> to NOT crash into a mountain in an emergency situation.

You are on the right track to what-if this kind of situation - but the
"Derry Roll" solution just won't work with most gliders. (A Derry
Roll is a 270 degree roll underneath to initiate a turn in the
opposite direction). Now if you were ridge soaring in a Swift or a
Fox, it might just work!

> Like I said, it may not be a good idea nor am I advocating people do
> this. But those who say it's nutty, of those I ask, what is the better
> alternative is the exact same situation?

It sounds like a platitude, but the way to avoid this situation is to
not get into it in the first place - that means always having room to
get away from the ridge. Giving up that safety buffer means accepting
the risk of not being able to always avoid hitting the rocks if things
go wrong. We all make that decision when we get on the ridge and push
hard.

Kirk

[tommytoyz]

I hate to drag up this topic again, because I know it is
controversial. But I can't stop thinking about it. This is an issue I
actively think about when flying in the mountains, which I mostly do.

Know let's simulate this for a second. Walk along any wall 1-2 feet
away or less - that's you flying along a mountain below ridge level.
Now something upsets you and start turning into the wall. What do you
do to not smack into it? What do you do if normal control inputs can
not correct in time?

Asking myself this, I simulated what it would take to make a quick
steep turn away from the mountain. Firstly, as we all know, making a
steep quick turn requires a steep bank angle, the more the better - so
long as we have the airspeed to do it.

So I figured that if my mountain side wing was pushed 45 degrees down
by the upset, I would only need another 46 degrees in the some
direction to be able to turn the other way, by pushing the stick. This
would only take maybe 2 seconds (maybe less if your being turned that
way anyway) in a 15 M ship with good airspeed, that should be carried
in close proximity to terrain anyway.

So the previous objections that it would take too long or be
disorienting, I find not a little overblown. However, once turned away
from the mountain, one would need to be careful in regaining a normal
flight position.

I'll be trying this with an aerobatic instructor and see what happens.
I just can't see any other way out of that situation when you are
asked - what do you do? when you're facing the mountain with a wing
down and probably tail high or rising.

Continuing the rotation another 46 degrees or more and pushing on the
stick to increase the angle of attack to turn, should turn the ship
away from the mountain quickest.

[fredsez]

On Feb 28, 3:08*pm, tommytoyz > wrote:
> I hate to drag up this topic again, because I know it is
> controversial. But I can't stop thinking about it. This is an issue I
> actively think about when flying in the mountains, which I mostly do.
>
> Know let's simulate this for a second. Walk along any wall 1-2 feet
> away or less - that's you flying along a mountain below ridge level.
> Now something upsets you and start turning into the wall. What do you
> do to not smack into it? What do you do if normal control inputs can
> not correct in time?
>
> Asking myself this, I simulated what it would take to make a quick
> steep turn away from the mountain. Firstly, as we all know, making a
> steep quick turn requires a steep bank angle, the more the better - so
> long as we have the airspeed to do it.
>
> So I figured that if my mountain side wing was pushed 45 degrees down
> by the upset, I would only need another 46 degrees in the some
> direction to be able to turn the other way, by pushing the stick. This
> would only take maybe 2 seconds (maybe less if your being turned that
> way anyway) in a 15 M ship with good airspeed, that should be carried
> in close proximity to terrain anyway.
>
> So the previous objections that it would take too long or be
> disorienting, I find not a little overblown. However, once turned away
> from the mountain, one would need to be careful in regaining a normal
> flight position.
>
> I'll be trying this with an aerobatic instructor and see what happens.
> I just can't see any other way out of that situation when you are
> asked - what do you do? when you're facing the mountain with a wing
> down and probably tail high or rising.
>
> Continuing the rotation another 46 degrees or more and pushing on the
> stick to increase the angle of attack to turn, should turn the ship
> away from the mountain quickest.

Soaring safety... more than anyone thinks, is a function of the pilots
mental control and reaction when things go wrong.

I may be more familiar with the mountains near Crystalair than almost
anyone except Henry Combs. Mr. Combs is a thinker and very deliberate
pilot. He reviews plans for his flights and mentally stores a flight
plan in his lower concioness. When something in his flight plan
happens he is mentally prepared to deal with it.
He has tried to get me to teach his recovery tecnique but I either
didn't understand it well enough to teach it or in most cases most of
our students are taught to maintain extra control speed, to be aware
that at 9,000 on a hot day, the glider will not have the same turn
radius and end up without enough room.

The mountains have claimed more airplane pilots than glider pilots
around here. Mountain flying is very rewarding but also very
demanding.

The atmosphere flowing over mountains is somewhat like water flow over
rocks...except that it is compressible. The compression and heating,
along with expansion makes the air flowing over and between ridges
hard to predict. It is a facinating subject to spend a lifetime to
master.

My advice is to learn as much as you can from an old hand, study how
the air flows, understand density and forever mentally be prepared for
the unexpected and have a preplanned escape route. I've been in sudden
upsets but always had room to recover without aerobatic skills.
Fortunately the number of spins and rolls I have done makes me more
comfortable, but I doubt that any of that skill would have saved me
from a sudden upset near terrain. Do some ridge soaring, but leave
room for the unexpected.

Fred Robinson








t

[kirk.stant]

On Feb 28, 5:08*pm, tommytoyz > wrote:
> I hate to drag up this topic again, because I know it is
> controversial. But I can't stop thinking about it. This is an issue I
> actively think about when flying in the mountains, which I mostly do.
>
> Know let's simulate this for a second. Walk along any wall 1-2 feet
> away or less - that's you flying along a mountain below ridge level.
> Now something upsets you and start turning into the wall. What do you
> do to not smack into it? What do you do if normal control inputs can
> not correct in time?
>
> Asking myself this, I simulated what it would take to make a quick
> steep turn away from the mountain. Firstly, as we all know, making a
> steep quick turn requires a steep bank angle, the more the better - so
> long as we have the airspeed to do it.
>
> So I figured that if my mountain side wing was pushed 45 degrees down
> by the upset, I would only need another 46 degrees in the some
> direction to be able to turn the other way, by pushing the stick. This
> would only take maybe 2 seconds (maybe less if your being turned that
> way anyway) in a 15 M ship with good airspeed, that should be carried
> in close proximity to terrain anyway.
>
> So the previous objections that it would take too long or be
> disorienting, I find not a little overblown. However, once turned away
> from the mountain, one would need to be careful in regaining a normal
> flight position.
>
> I'll be trying this with an aerobatic instructor and see what happens.
> I just can't see any other way out of that situation when you are
> asked - what do you do? when you're facing the mountain with a wing
> down and probably tail high or rising.
>
> Continuing the rotation another 46 degrees or more and pushing on the
> stick to increase the angle of attack to turn, should turn the ship
> away from the mountain quickest.

It's always good to think of possible accident scenarios before hand.

In the specific situation you are describing - upset next to a sheer
mountain face - the quickest way to get clear might be just to stuff
the stick forward to unload the wing and accelerate, then roll away
from the mountain as you regain roll authority, pulling hard g as soon
as your lift vector is paralles or away from the mountain. You might
exceed Vne, but not by much.

Trying to roll underneath will result in a vertical dive unless you
push hard from the beginning. Extemely uncomfortable and disorienting
without training and practice. And again, what kind of glider are you
in? A 1-26 (might work) or a Nimbus 3 (no way)?

If the upset is so severe that you end up pointing straight down, then
you don't want to push, since your negative g limit is a lot lower
(usually). So you are back to rolling the quickest way away from the
mountain, then pulling as hard as you can.

This assumes you are going slow to begin with. If you are fast, you
will probably have enough control authority to stop the upset.

Acro training is great! Let us know what you think of it - I think
you will be surprised at what you can (and can't) do in a glider.

Cheers,

Kirk
66

[gliderman]

On Feb 28, 8:09*pm, fredsez > wrote:
> On Feb 28, 3:08*pm, tommytoyz > wrote:
>
>
>
>
>
> > I hate to drag up this topic again, because I know it is
> > controversial. But I can't stop thinking about it. This is an issue I
> > actively think about when flying in the mountains, which I mostly do.
>
> > Know let's simulate this for a second. Walk along any wall 1-2 feet
> > away or less - that's you flying along a mountain below ridge level.
> > Now something upsets you and start turning into the wall. What do you
> > do to not smack into it? What do you do if normal control inputs can
> > not correct in time?
>
> > Asking myself this, I simulated what it would take to make a quick
> > steep turn away from the mountain. Firstly, as we all know, making a
> > steep quick turn requires a steep bank angle, the more the better - so
> > long as we have the airspeed to do it.
>
> > So I figured that if my mountain side wing was pushed 45 degrees down
> > by the upset, I would only need another 46 degrees in the some
> > direction to be able to turn the other way, by pushing the stick. This
> > would only take maybe 2 seconds (maybe less if your being turned that
> > way anyway) in a 15 M ship with good airspeed, that should be carried
> > in close proximity to terrain anyway.
>
> > So the previous objections that it would take too long or be
> > disorienting, I find not a little overblown. However, once turned away
> > from the mountain, one would need to be careful in regaining a normal
> > flight position.
>
> > I'll be trying this with an aerobatic instructor and see what happens.
> > I just can't see any other way out of that situation when you are
> > asked - what do you do? when you're facing the mountain with a wing
> > down and probably tail high or rising.
>
> > Continuing the rotation another 46 degrees or more and pushing on the
> > stick to increase the angle of attack to turn, should turn the ship
> > away from the mountain quickest.
>
> Soaring safety... more than anyone thinks, is a function of the pilots
> mental control and reaction when things go wrong.
>
> I may be more familiar with the mountains near Crystalair than almost
> anyone except Henry Combs. Mr. Combs is a thinker and very deliberate
> pilot. He reviews plans for his flights and mentally stores a flight
> plan in his lower concioness. When something in his flight plan
> happens he is mentally prepared to deal with it.
> He has tried to get me to teach his recovery tecnique but I either
> didn't understand it well enough to teach it or in most cases most of
> our students are taught *to maintain extra control speed, to be aware
> that at 9,000 on a hot day, the glider will not have the same turn
> radius and end up without enough room.
>
> The mountains have claimed more airplane pilots than glider pilots
> around here. Mountain flying is very rewarding but also very
> demanding.
>
> The atmosphere flowing over mountains is somewhat like water flow over
> rocks...except that it is compressible. The compression and heating,
> along with expansion makes the air flowing over and between ridges
> hard to predict. It is a facinating subject to spend a lifetime to
> master.
>
> My advice is to learn as much as you can from an old hand, study how
> the air flows, understand density and forever mentally be prepared for
> the unexpected and have a preplanned escape route. I've been in sudden
> upsets but always had room to recover without aerobatic skills.
> Fortunately the number of spins and rolls I have done makes me more
> comfortable, but I doubt that any of that skill would have saved me
> from a sudden upset near terrain. Do some ridge soaring, but leave
> room for the unexpected.
>
> Fred Robinson
>
> t- Hide quoted text -
>
> - Show quoted text -

I agree with everyting Fred said, but I think it's important that
students need to be made aware of the definition of "faster".
Each pilot must judge the situation and correctly understand that
going faster than what you need to maintain control authority reduces
the amount of reaction time that you have. You need to fly a little
further from the ridge as your speed increases over this "control
authority speed." Like my father once told me "When you are close to
the ground, add a little airspeed for the wife and kids".

Paul Gravance

[tommytoyz]

I would like to know what Henry's recovery technique is. Anyway,
thinking this over some more, I'm thinking that so long as I have good
airspeed near terrain, vertical or horizontal (which I have always
practiced), and (here's the new part for me):

I don't fly into the corner of L shaped terrain

Flying close to vertical or horizontal terrain is OK with airspeed and
being prepared to recover from an upset. There is a place to go. But
flying into the corner of L shaped terrain is not recoverable in an
upset, not matter what. There is no room to the side nor bellow. I'm
boxed in.

Perhaps looking back at glider accidents in the mountains, we can look
if the accidents occurred close to the corner of L shaped terrain.

[tommytoyz]

Kirk,
You made me realize that the recovery is even simpler and faster than
I thought, starting from the upset position putting me turning into
the mountain with the mountain wing low. The fastes way away from the
mountain is just to push the stick forward so the negative angle of
attack on the wings will instantly turn the glider away from the
mountain. Of course this is an inverted turn, but a very quick one,
the speed of which is dependent on elevator authority. So this could
work even with 26M wingspans. The wings never have to change their
bank angle at all. If the tail is lifted up, as Henry and others have
stated most likely would happen, the glider would move away from the
mountain even faster.

It's only in the recovery from the inverted turn that wings would have
to change their bank angle significantly.

Airspeed will increase but I think can be held in check by applying
rudder, like in any turn. Recovery after that depends on the terrain
but at that point, I'm upside down - without even having deflected the
ailerons and away from the mountain face.

This is a very unique situation, but I don't want to be caught with my
pants down should it ever happen. For now, I'm keeping a lookout for
the corners of L shaped terrain.

I know most of this sounds crazy, but the situation is a crazy one to
find oneself in.

I'm not advocating anything, just discussing possibilities here.

[[email protected]]

On Feb 16, 9:04*am, Jim White >
wrote:

> I dont think anyone has discussed airspeed in this
> thread. My glider has crap airelon authority at 50kts
> but at Va it is very good. Isn't safety near rocks
> a factor of speed? If you are belting along at a Va
> would you not be able to pull up / fly away from the
> cliff if you needed to?

Combs' article says that your ailerons will not be able to overcome
the rolling tendency produced by 500 fpm differential lift on your
wings. He doesn't say at what speed that is, but even if it's at 60
kts and you're flying 80, there will be some differential lift you
cannot overcome. It pushes you further out on the bell shaped curve
(or whatever shape that curve takes), but it doesn't say it cannot
happen. It just happens less frequently.

If anyone has data for modern sailplanes at different speeds, please
chime in.

Martin