Soaring Safety

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/soar...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

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

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

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

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?

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

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

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

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

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/soar...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?