Nimbus 4DT accident 31 July 2000 in Spain.
W.J. (Bill) Dean (U.K.).
the UK registered Nimbus 4DT which crashed on 31st July 2000 near Toledo,
one of the British crew was killed.
The Spanish report in English translation may be found at
http://www.gliding.co.uk/accidents/reports/nimbus4dtreport.pdf (3MB).
The BGA report is at
http://www.gliding.co.uk/accidents/detail.php?acc_id=120&pageNum_AccidentSummary=0&totalRows_AccidentSummary=67 .
If this will not open, go to http://www.gliding.co.uk/accidents/login.php ,
Username user, Password risingmoon.
The similar accident to a Nimbus 4DM at Minden on 13th July 1999 ref:
LAX99MA251 may be found at http://www.ntsb.gov/publictn/2002/AAB0206.htm
brief report is at
http://www.ntsb.gov/NTSB/brief.asp?ev_id=20001212X19310&key=1 .
W.J. (Bill) Dean (U.K.).
Remove "ic" to reply.
Stefan
> The Spanish report in English translation may be found at
> http://www.gliding.co.uk/accidents/reports/nimbus4dtreport.pdf (3MB).
Thanks for the link. Very educational, indeed. I think this answers the
question whether spins and spiral dives should be demonstrated and
recovery should be regularly trained.
Stefan
M B
mentions anything about the ASI installed.
Were they the wrap-around types which cause
the pilot to not know if the glider is in a spin or
a spiral?
I personally have been in a spiral in a glider, and
not knowing it was a spin or spiral, have done the
spin recovery. Fortunately the glider performance
was low enough this wasn't a problem.
To verify this, I replicated the same situation twice
more
on the same flight. It was surprising how little
onformation I could get through windspeed noise.
I was relying on the ASI, and it was ambiguously
reading either 30kts or 100kts.
Only after landing and seeing the GPS info did I fully
believe that I was spiralling, and not spinning, even
though
I watched the ASI go only from 'fast' to 'really fast.'
Are these gliders regularly installed with
the wrap-around type ASIs? Could 1.8 seconds of confusion
be a contributing factor in these cases?
Of course, assume for the moment that the translation
to
english is awkward and the mention of 'spin' may
be mistranslated...
Has anyone else on this group ever looked at a
wrap-around ASI and wondered what it said?
Have you tried this with students, having them close
their eyes and violently shake their heads and then
try to recover the glider in an unusual attitude?
And have them get confused?
I certainly see the value of the wrap-around ASI and
the added precision it allows during normal flight,
but
I'm not terribly fond of them for spin vs.
spiral recognition. I don't trust my hearing as
an airspeed indicator during stressful situations.
At 22:42 20 June 2005, Stefan wrote:
>W.J. (Bill) Dean (U.K.). wrote:
>
>> The Spanish report in English translation may be found
>>at
>> http://www.gliding.co.uk/accidents/reports/nimbus4dtreport.pdf
>>(3MB).
>
>Thanks for the link. Very educational, indeed. I think
>this answers the
>question whether spins and spiral dives should be demonstrated
>and
>recovery should be regularly trained.
>
>Stefan
>
Mark J. Boyd
Stefan
> Neither this report nor the Minden report it references
> mentions anything about the ASI installed.
>
> Were they the wrap-around types which cause
> the pilot to not know if the glider is in a spin or
> a spiral?
I understand you're an instructor? I shudder at the thought that a
licensed pilot, let alone an instructor would rely on the ASI to tell
whether he's in a spin or a spiral.
Stefan
HL Falbaum
structural standpoint. A modern glider is more likely to progress to spiral
dive anyway. The pilot, by his own admission, did the wrong recovery for
either case.
However, since the Spanish report refers heavily to the Minden report, with
many similarities, I wonder if there is something peculiar about the Nimbus
4 DT. Both apparently departed into a stall and incipient spin in a strong
thermal. This pilot had sufficient recent flight experience, and total time,
to have developed good "survival" reflexes, including the "stick forward"
manuver. He had little time in the Nimbus 4, but quite enough in the Nimbus
3 to know how to fly it.
If it was purely the fault of very strong thermals, then the other gliders
in common use at places like Minden would also have similar accidents. This
does not seem to be the case.
Obviously, I have never flown a Nimbus of any kind. I have a few hours in
the Duo-Discus, but nothing larger. The Duo is certainly not malignant in
any way.
So my question is to those with Nimbus D experience. Is there some handling
characteristic that will bite a fairly experinced and competent, but
unsuspecting pilot?
I am thinking that the (biennial USA) Flight Review should include spiral
dive recovery routinely, in addition to the usual other "emergency"
maneuvers.
--
Hartley Falbaum
CFIG USA
"Stefan" <stefan@mus._INVALID_.ch> wrote in message
news:d97fts$rkt$1...@news.hispeed.ch...
Mark Wright
At 09:12 21 June 2005, M B wrote:
>Neither this report nor the Minden report it references
>mentions anything about the ASI installed.
>
>Were they the wrap-around types which cause
>the pilot to not know if the glider is in a spin or
>a spiral?
>
Mark Wright
Don Johnstone
from the accident report
The pilot realized that they had started to spin and
that, in order to come out of the spin, he pulled back
hard on the control stick and applied full flaps, without
regaining control (no surprise there then)..........the
glider quickly gathered speed (?)....and the flaps
got heavier and heavier.
...the flap position was 2 deg positive.
I fly an ASW17 and in my conversion brief I was told
that the first action is spin recovery was flaps to
neutral. If this action was not carried out then recovery
was not certain. It would appear from the exerpt from
the Nimbus manual that the same applied. It is to be
hoped that some of the above passage is the result
of iffy translation, if not it is a very strange sequence
of events.
The report conclusions do not help. I am no expert
on the 4DM but is it possible to exceed VNe in a spin?
Stefan
> It is to be
> hoped that some of the above passage is the result
> of iffy translation, if not it is a very strange sequence
> of events.
Perfectly correct translation. No strange sequence at all.
> The report conclusions do not help. I am no expert
Yes, they do. Know your airplane, know the emergency procedures and
particlarly know its behaviour in regading to spins. Practice spin
recoveries, practice spiral dive recoveries. And any pilot who is even
tempted to pull back the stick in a spin is not airworthy.
> on the 4DM but is it possible to exceed VNe in a spin?
Certainly not. But many gliders will not stay in the spin but go into a
spiral dive. Which was obviously the case here.
Stefan
Stefan
> It is to be
> hoped that some of the above passage is the result
> of iffy translation, if not it is a very strange sequence
> of events.
Perfectly correct translation. No strange sequence at all.
> The report conclusions do not help. I am no expert
Yes, they do. Know your airplane, know the emergency procedures and
particlarly know its behaviour in regading to spins. Practice spin
recoveries, practice spiral dive recoveries. And any pilot who is even
remotely tempted to pull back the stick in a spin is not airworthy.
> on the 4DM but is it possible to exceed VNe in a spin?
Certainly not. But many gliders will not stay in the spin but go into a
Bill Daniels
is anything sinister about the N4DM. They're just not built for diving.
Any time the nose is well below the horizon, they will pick up speed
rapidly. Don't do that.
Large span gliders will fly slowly and that means that there is a large
airspeed difference across their span when circling - my "little" Nimbus 2C
can develop a 15 knot difference. This, plus a thermal gust, can make them
roll into a spiral dive.
Recognizing this and taking prompt action when it happens is actually easy
once you experience it a few times. Just allow the speed to increase a bit
to increase control authority, then stop the turn and then recover normal
airspeed.
If the glider is allowed to progress into a full spiral dive, the options
narrow considerably. Only very gentle and precise control inputs will save
the day. Try not to apply large aileron and elevator inputs
simultaneously - bending and twisting the wing at the same time can break
it.
Reading the Spanish report made it seem that the pilot did not have complete
control of his glider. That's a shame when it's a two seater and there are
a lot of experienced pilots who would have been willing to ride with him and
help him master it.
Bill Daniels
"HL Falbaum" <hfal...@comcast.net> wrote in message
news:kMKdnZWBm5T...@comcast.com...
Don Johnstone
>Don Johnstone wrote:
>
>> It is to be
>> hoped that some of the above passage is the result
>> of iffy translation, if not it is a very strange sequence
>> of events.
>
>Perfectly correct translation. No strange sequence
>at all.
>
>> The report conclusions do not help. I am no expert
>
>Yes, they do. Know your airplane, know the emergency
>procedures and
>particlarly know its behaviour in regading to spins.
>Practice spin
>recoveries, practice spiral dive recoveries. And any
>pilot who is even
I agree entirely. But was this glider ever spinning?
The report does make the point that intentional spinning
of the 4DM is prohibited.
>
>> on the 4DM but is it possible to exceed VNe in a spin?
>
>Certainly not. But many gliders will not stay in the
>spin but go into a
>spiral dive. Which was obviously the case here.
I don't see that as obvious. How did it get from spin
to spiral dive. The action taken by the pilot would
not have prevented the auto-rotation, in fact it should
have ensured that it continued and that the glider
remained stalled. Stall plus autorotation =spin.
The question is was the glider ever in a spin. Reading
Bill's post that is a pertinent question? My point
about the conclusions not helping is that they say
that the structural failure was from a 'spiral dive
OR spin'. I have to accept that the recovery action
taken by the pilot was incorrect but what was he trying
to recover from?
>
>Stefan
>
Stefan
>> spiral dive. Which was obviously the case here.
> I don't see that as obvious.
"Meanwhile, the glider quickly gathered speed until it exceeded Vne."
(Page 2 of the report.)
> How did it get from spin
> to spiral dive.
By itself. Just as many gliders do.
> The question is was the glider ever in a spin.
I don't know (I'm tempted to say: nobody does) whether the glider was
technically ever in a spin or started right into the spiral dive. The
question is pretty pointless, pulling back the stick is a bad move in
either case.
Stefan
M B
I too started with the controls in a clasic spin entry,
and felt the stall, and then ended up in what
I could not discern was a spin or a spiral.
So I'd release the elevator pressure (assumed it
was a spin) and recover from the dive.
I did spins both before and after this in the
Blanik (with a non-wrap ASI) and they seemed
very easy to tell the difference from a spiral, and
quite easy to sustain as a spin for 4 turns or whatever
you wanted, with a subsequent quite well defined
spin recovery.
The spins in the other glider were at fairly forward
CG, so
after looking at it, I wasn't that surprised it didn't
stay in a spin.
I think Hartley was correct, that spins and spirals
ought
to be part of a flight review. From the report, however,
it seems this pilot got spin entry training. In all
of my spin entry training, this means crossed controls,
and a full stall, with recovery by flaps/dive brakes/power
to correct position, ailerons neutral, rudder opposite,
stick
pressure released or briefly forward to break the stall.
I can see value in doing full 2 turn spins left and
right,
however, instead of just spin entries (which can be
too mild,
or not give a good sense of spin vs. spiral indications).
I must think, however, that actually doing this in
some gliders
may be either prohibited or may damage the glider or
actually cause structural failure.
A slow reaction with flaps by the student might be
a
big problem. Likewise, practicing spins and recoveries
with
the engine extended in a motorglider might be
prohibited or damaging, but this might be exactly
the training needed to prevent a 180 turn back to the
airport from becoiming a stall/spin for example.
And how many instructors regularly spin a Nimbus or
a DG1000 with extensions or the like?
Honestly I don't know, since
I generally fly 18m or less spans myself...
What a shame to lose your own son though.
Geesh, what a tragedy.
At 13:24 21 June 2005, Stefan wrote:
>Don Johnstone wrote:
>
>> It is to be
>> hoped that some of the above passage is the result
>> of iffy translation, if not it is a very strange sequence
>> of events.
>
>Perfectly correct translation. No strange sequence
>at all.
>
>> The report conclusions do not help. I am no expert
>
>Yes, they do. Know your airplane, know the emergency
>procedures and
>particlarly know its behaviour in regading to spins.
>Practice spin
>recoveries, practice spiral dive recoveries. And any
>pilot who is even
>tempted to pull back the stick in a spin is not airworthy.
>
>> on the 4DM but is it possible to exceed VNe in a spin?
>
>Certainly not. But many gliders will not stay in the
>spin but go into a
>spiral dive. Which was obviously the case here.
>
>Stefan
>
Mark J. Boyd
Stefan
> to be part of a flight review. From the report, however,
> it seems this pilot got spin entry training. In all
Read it again. His last spin training was 20 years ago and he swore to
never do it again. A pilot who panics when he hears the S-word is not
airworthy. (Respect, yes. Panic, no.)
> of my spin entry training, this means crossed controls,
Then improve your spin training. Spin doesn't necessairily mean crossed
controls.
> I can see value in doing full 2 turn spins left and
> right,
> however, instead of just spin entries (which can be
> too mild,
> or not give a good sense of spin vs. spiral indications).
Which it doesn't need. At this early stage, recovery actions are the same.
> A slow reaction with flaps by the student might be
> a
> big problem.
Then the student needs more training.
> Likewise, practicing spins and recoveries
> with
> the engine extended in a motorglider might be
> prohibited or damaging, but this might be exactly
> the training needed to prevent a 180 turn back to the
> airport from becoiming a stall/spin for example.
You never explored how your glider drops the wing with the engine
extended/running? Gee, I wouldn't let my son be your student.
Stefan
Eric Greenwell
> To verify this, I replicated the same situation twice
> more
> on the same flight. It was surprising how little
> onformation I could get through windspeed noise.
> I was relying on the ASI, and it was ambiguously
> reading either 30kts or 100kts.
Don't the controls feel differently at 30 knots and 100 knots? That
should be a good clue as you begin the spin recovery.
--
Change "netto" to "net" to email me directly
Eric Greenwell
Washington State
USA
M B
>M B wrote:
>
>> to be part of a flight review. From the report, however,
>> it seems this pilot got spin entry training. In all
>
>Read it again. His last spin training was 20 years
>ago
Three months before the accident 'the pilot
had carried out some flights with the test pilot
(including diving at Vne and the start of spins.'
20 years ago may have been the last time he did fully
developed spins, but 'start of spins' sounds like
'spin entries' to me.
If your point was that his training was inadequate,
or
that perhaps the spin entries were demonstrated rather
than
trained, these are both possibilities, and I would
agree.
I recently had a student do some spin training with
me
and was happy to see him seek it out before flying
a very tautly spinning single-seater. I recommended
another
aerobatic glider instructor for further aerobatics
if
he wanted more interesting training. Some exposure
to aerobatics every so often seems to be good
for pilots.
>
>> I can see value in doing full 2 turn spins left and
>> right,
>> however, instead of just spin entries (which can be
>> too mild,
>> or not give a good sense of spin vs. spiral indications).
>
>Which it doesn't need. At this early stage, recovery
>actions >are the same.
I might have this out of context. Please elucidate.
Spiral and spin recovery actions are quite differently
spelled out in our US manuals. I've also found that
students
'get it' after doing some 2-turn or more spins, but
don't necessarily 'get it' after only spin entry
recoveries.
>
>> Likewise, practicing spins and recoveries
>> with
>> the engine extended in a motorglider might be
>> prohibited or damaging, but this might be exactly
>> the training needed to prevent a 180 turn back to
>>the
>> airport from becoiming a stall/spin for example.
>
>You never explored how your glider drops the wing with
>the engine
>extended/running? Gee, I wouldn't let my son be your
>student.
I do not plan to teach spins with the engine extended
in contravention to a flight manual, such as the DG500MB,
paragraph 2.9
I know you weren't suggesting teaching spins in contravention
to the flight manual. I certainly agree with exploring
non-prohibited edges of the
performance envelope to get a feel for the aircraft
(including the control stiffness felt at higher speeds).
But why don't you do this with your son yourself, Stephan,
aren't you an instructor?
>
>Stefan
>
Mark J. Boyd
M B
control pressure was definitely more than expected
at low airspeeds.
But WHEN I did it, I think the surprise of
looking at an ASI and having it tell me...
ambiguous garbage...
distracted my keenness to listen for airflow
or feel for control pressures.
The controls on this glider were quite light to
begin with. The airflow sound was actually
easier to detect for me than control pressures
in this (fairly noisy) glider.
I just distinctly remember it was the very
first time I had ever looked at an ASI where it
was impossible to read as a stand-alone indication
of airspeed. That was very, very strange for me.
Before that, I'd never flown any aircraft with a
wrap-around ASI and done intentional spins.
Part of why I'm writing this now is because the
was quite fascinating. I had to do it many times and
study the ASI to really believe I was in a spiral and
recovery and not a spin. The ASI needle whipped
around in a flash.
I tried spins later with further aft CG and was able
to
sustain spins, with the expected noise and control
feel
indications.
Mark J. Boyd
Stefan
> I recently had a student do some spin training with
> me
> and was happy to see him seek it out before flying
> a very tautly spinning single-seater.
We ask it from ours before transitioning them to the first single seater.
> I might have this out of context. Please elucidate.
> Spiral and spin recovery actions are quite differently
> spelled out in our US manuals.
Luckily, gliders cannot read. :-) Recovering from a developed spin is
certainly different from recovering from a developed spiral dive. But at
the early stage, when the glider just drops a wing and pitches forward,
your neither in a spiral nor in a spin yet. At this early stage,
corrective action is quite simple: Immediately stick forward and
opposite rudder. In most cases, this will do the trick just fine, and
you won't even know whether it would have developed into a spiral or a
spin. If a spin or spiral develops, you're in a different situation, of
course.
> I do not plan to teach spins with the engine extended
> in contravention to a flight manual, such as the DG500MB,
> paragraph 2.9
Dropping a wing with the engine extended is part of our "club syllabus"
for transitioning to the DG505M/22m. If you have never done it, it's a
real eye opener how aggessively the wing will drop. Of course, we don't
let the spin develop but take immediate action. (The glider will recover
after about a quarter of a turn.)
Try it! You don't need to cross the controls, just pitch up with the
engine running until the glider ceases to fly. It *will* drop a wing
then, you have no chance to hold it with the rudder. As I said, an eye
opener.
Stefan
Stefan
> But WHEN I did it, I think the surprise of
> looking at an ASI and having it tell me...
> ambiguous garbage...
I find it even more surprizing that somebody in this situation would
look at the ASI at all...
> I tried spins later with further aft CG and was able
> to
> sustain spins, with the expected noise and control
> feel
> indications.
See? You *can* tell a spin from a dive if you have familiarisized (?)
yourself with the glider. Which you should (must, according to the
legislation where I live and fly) in your first couple of flights, anyway.
Stefan
Mark Dickson
have been dismayed by your comments on recognising
and recovering from spins and spiral dives. Rather
than teaching these exercises and trying to impart
your 'knowledge' on this forum, you should have a bit
of remedial instruction yourself. Your reactions to
spinning should be automatic, there should be absolutely
no need to check your ASI to see if your spinning or
in a spiral dive. If you are in a spin you should
positively move the stick forward, not 'release the
back pressure'. Releasing the back pressure at the
buffet should prevent a spin developing.
Kilo Charlie
"Eric Greenwell" <flyg...@charter.netto> wrote in message
news:WOXte.7882$uS2....@fe03.lga...
>M B wrote:
> Don't the controls feel differently at 30 knots and 100 knots? That should
> be a good clue as you begin the spin recovery.
>
>
> --
> Change "netto" to "net" to email me directly
>
> Eric Greenwell
> Washington State
I am a partner in a Nimbus 3D. I have not had a lot of time in it but have
flown aircraft of all kinds for 36 years including hundreds of glider and
powered aerobatic hours. In order to get the Nimbus to go beyond the green
arc it takes a very large amount of forward stick even with the trim all the
way to the forward stop.....with flaps in -2. I absolutely disagree that it
would be easy to let it get away from you and end up in a spiral with the
exception of possibly entering it from a spin. The spin enty on the other
hand is docile and easy to recover from. As has been pointed out, if one is
clueless re incipient spins then the scenario in these 2 accidents might
easily unfold. Only education, planning and practice will prevent similar
accidents.
Casey Lenox
KC
Phoenix
mev
fiveni...@yahoo.com
I wonder at the thread though. Everyone discussing recognition of a
fully developed spin versus spiral dive.
Years ago, Al Blackburn pointed out to me that long span gliders need
to be treated gingerly at speed. His concern had to do with the
application of aileron during dive recovery. While he felt that most
pilots could manage the elevator to avoid structural damage, aileron
asymmetry (and the resulting squatcheloid assymetry) presented a
complicating factor. The longer the span, the more critical its
effects. Add a partial load of water, a yaw moment, and/or spoiler caps
deploying with wing bend and it's not hard to see how things might
quickly get to the breaking point.
For Example John Smith
What the heck is that?
Anything like the yeti dihedral?
<fiveni...@yahoo.com> wrote in message
news:1119444884....@z14g2000cwz.googlegroups.com...
Bert Willing
control inputs versus speed other than for a 15m glider.
What changes drastically with a long wing is the entry into a spin or a
spiral dive. The long wing makes that you can have large discrepancies of
effective angle of attack along the wingspan (which can make the spin entry
under g-load quite interesting). Long wings also have much more angular
momentum once the spin/spiral dive is developped - it can be as much as 5
times the angular momentum of a 15m glider, and that makes that recovery
will take a certain time even if correct counter procedures are undertaken.
And during that time, the glider will accelerate like hell so that you are
likely to operate you final recovery well beyond what's written in the
flight manual.
I think that training of instant recovery of a spin entry (or spiral dive
entry) is mandatory if you want to fly a 25+m ship safely. But in contrary
to short wings, it would be plain stupid to train the recovery of a fully
developed spin/spiral dive in these ships (beyond fligh testing for
certification) and that's the reason that a flight manual will usually call
it illegal.
Been there, done it, and don't feel that I want to get there again.
--
Bert Willing
ASW20 "TW"
<fiveni...@yahoo.com> a écrit dans le message de news:
1119444884....@z14g2000cwz.googlegroups.com...
Don Johnstone
explain?
M B
important, but covered adequately already on RAS and
elsewhere.
To me, I'm more interested in the less commonly discussed
human factors. Specifically what factors contribute
to accidents?
Both Eric and Bert's posts made me think about some
things
along with what Stefan and Casey wrote.
In my experience, I have seen and been a part of confusion
in
the cockpit. One pilot is saying one thing and the
other is
contradicting it. I've also had both pilots on the
controls at the same time, with opposite pressures
applied.
I've seen and felt myself during critical moments both
a
narrowing of perceptions and a loss of sense of time.
Seconds seem like hours and vice versa. In aerobatic
training,
the focus was not on control inputs, but correctly
applying
the RATE of control changes.
I've also noted that I use trim extensively when flying,
and this
reduces the feedback I get about airspeed from the
stiffness of
the elevator controls. Casey wrote about how trim
(and maybe flaps) change the behavior of a spin, and
require different control pressures. Flaps, water,
a second passenger, trim,
quite a different 'feel' depending on these factors.
Bert mentioned that training in fully developed spins
in one of these ships might be (ahem) hard to find.
And what ships are similar to these which ARE certified
for full spin training?
If I put all these observations into this accident,
the
post-accident debrief reads as a bit of fiction, none
of
which is in either of the real accident reports:
*****fictional report begins****
We were tight in a thermal, with my dad at the controls.
It was bumpy, and the vario was turned up loud and
beeping.
I was scanning for traffic over my shoulder, and my
dad
was telling a story. When I looked forward, we were
nose down.
I said 'I got it' and took the controls. I was trying
to pull back but something was stopping the stick,
so I paused
for a second. My dad said 'it's spinning!' again and
again very loud.
I think he may have been trying to push forward while
I was pulling.
Between the vario, his yelling, and me thinking about
the flap lever,
I don't remember hearing any airspeed indications.
I glanced at the wrap-around ASI, and couldn't tell
if we were stalling or
going through 140kts. I wasn't the one who'd done
the trim, so
I couldn't tell if the pressures were light on the
elevator or
if that was just trim. I was distracted by my Dad's
yelling.
It had been a while since I had done full spin training.
I flew with
the test pilot when I got the glider, but he didn't
demonstrate
any full spins or spiral dives with recovery. I did
some
wing drops, but nothing like a full spiral or spin
like this.
I think my dad finally let go of the stick, and when
he did
it came back. I thought I did it slowly, but I might
have done it faster than I should have, because there
was a loud
snap and then the glider was rotating violently. I
popped
off the canopy and parachuted out.
*******fictional report ends*****
From this made up sequence of events, if I were getting
training
for such a glider, I'd want to focus on
1. positive exchange of controls, with the control
change echoed back
2. CRM agreement that whoever is on the stick handles
the emergency
(assuming both are fairly similarly qualified pilots).
3. reduction of distractions (radio, vario volume,
wrap-around ASI)
4. training in a glider certified for full spins that
is as alike
the glider I want to fly as possible.
5. enough acro and unusual attitude training to control
my rate of
control inputs during recovery, without panic.
Is this fictional report what actually happened? Probably
not,
but it is a fusion of my own experiences and what I
have read in
various fatal accident reports in various aircraft.
I don't believe just going up and doing some spin/spiral
recovery
training is specific enough. CRM issues and distractions
have
happened enough to fully 'trained' and 'experienced'
airline
and aerobatic pilots that I think human factors are
as important as
time on the stick feeling the pressures and hearing
the wind.
All right, kids, flame away! For the rest, if you
have specific
constructive insights that are on topic, I'd like to
hear them.
Thank you to Bert and Eric and Stefan for your useful
discussions.
As far as my wrap-around ASI confusion theory goes,
I can't ell if it is a good one or not. Clearly these
pilots
either didn't accurately know their airspeed, or they
DID, and just
misapplied corrective action. There is a subtle
difference there...
At 04:48 22 June 2005, Kilo Charlie wrote:
>
>'Eric Greenwell' wrote in message
Mark J. Boyd
Stefan
> In my experience, I have seen and been a part of confusion
> in
> the cockpit. One pilot is saying one thing and the
> other is
> contradicting it. I've also had both pilots on the
> controls at the same time, with opposite pressures
> applied.
I'm more and more, well, surprized, what you have been experiencing
while flying. I've never seen, even less been part of such a thing.
Communicate before the flight, define the roles and adhere to it. Who
will do what? Who will fly in an emergency? Communicate during the
flight, and do so clearly.
And, you may ask, if the other pilot is doing something I don't like?
Well, if I don't trust the other pilot, I won't fly with him. If he
doesn't trust me, I don't want him to fly with me. Simple as that, very
basic CRM stuff. (It needn't be offensive when I say I don't like his
way of flying, because I'm not implying that he's a bad pilot, I'm just
saying our styles are incompatible.)
I'm surprized that, as it seems, you can become an instructor in the USA
without knowing such basic stuff.
Stefan
Bob Kuykendall
> I'm more and more, well, surprized,
> what you have been experiencing
> while flying.
I have seen all of this and much, much worse. I don't say that it's
good or right, because obviously it's suboptimal. But it is what it is,
and everybody has to come to terms with it one way or another.
> ...And, you may ask, if the other pilot
> is doing something I don't like?
> Well, if I don't trust the other
> pilot, I won't fly with him...
Hypothetical question: Suppose it's your _job_ to fly with this person?
Say, the person is your boss, and if you continue to decline then you
get fired with a bad fitness report that derails your flying career?
And, please, spare us the TS that such situations never happen, or that
they only happen in third-world countries. The records of the NTSB and
other national safety boards show that it happens with depressing
regularity.
I just finished reading an interesting book on the topic: "Darker Shade
of Blue," about rogue pilots in general and their effect on others. I
think it might go a bit over the top, since every pilot has a bit of
rogue to them, and sometimes it is that rogue element that carries the
day. But it is a valuable read regardless.
Furthermore, I'm pleased to see this thread directed more towards human
factors and the real world of soaring flight operations. I think it is
generally too easy to use "pilot error" as an excuse to not look deeper
into accidents and find their root causes. Peter Ladkin has a lot more
to say on that topic, and I generally agree with his assessments.
Following a slightly different tangent, as sailplanes become more
extreme in their complexity and dimension, the margins between early
adopters and the edges of the proven envelope will continue to shrink,
and will more often go negative in unexpected ways. Certification
doesn't _prove_ that a design is safe; it only demonstrates it under
carefully controlled conditions.
Thanks, and best regards to all
Bob K.
Kilo Charlie
Thanks for herding the discussion toward more science and less emotion.
I apologize to anyone that may have been offended by my comments above re
"clueless". One person wrote a nice note pointing out that the family is
grieving enough without that type of thing.
The point I was trying to make was that those of us that choose to fly these
very long winged aircraft need to be keenly aware of impending problems and
react to them immediately should they begin to develop. If you decide to
thermal in turbulent conditions at just above stall speed then you should be
on edge every second you are doing so and if a gust begins to push you into
a spin or spiral then you should execute your already planned out and
hopefully second nature, correction. If you haven't thought of this plan or
possibility then you have no business flying at those speeds in that
aircraft.
Will having a plan ALWAYS get you out of trouble? No. But as others have
pointed out, in these birds you only have a very short time before there is
not any amount of skill that will save the aircraft.
Sorry to digress Chris.....I'd still really like to hear more about the
aerodynamic reasons that things go awry.....can only help to formulate the
best plan of action!
Casey
Ian Johnston
> I wonder at the thread though. Everyone discussing recognition of a
> fully developed spin versus spiral dive.
Isn't it generally more useful to recognize the difference between a
just-developing spin and a just-developing spiral dive?
Which reminds me of Johnston's Test Question for BGA Instructors
Number Three:
"The offical recovery from a stall with wing drop is different from
the official recovery from a spin. At what point do you, personally,
transition from one to the other?"
Ian
--
Ian Johnston
wrote:
> And any pilot who is even
> remotely tempted to pull back the stick in a spin is not airworthy.
I suspect that many or all of us are to some extent tempted to do just
that. That's why we need training and practice in the right thing ...
Ian
--
Bill Daniels
"Ian Johnston" <ian.g...@btinternet.com> wrote in message
news:dzZo7CxomoOm-pn2-39ddFD9pBSKp@localhost...
As often happens, the BGA comes through with some useful wisdom. Thanks,
Ian.
As for the difference in sensations between an incipient spin and incipient
spiral, the former seems to me to be like an uncommanded yaw and the later
like an uncommanded roll. To me, at least, they clearly say that if the
situation is allowed to continue without intervention, the uncommanded yaw
will become a spin and the uncommanded roll will become a spiral.
I wish I could capture the sensations and record them. They would be very
useful in training.
As for a spinable trainer with similar characteristics, the venerable IS28b2
would do a creditable job of either spin or spiral and build up speed like
crazy in the ensuing dive. It had the requisite large inertia about all
axes. I found it taught me a lot about how to fly a Nimbus.
Bill Daniels
Bill Gribble
>> "The offical recovery from a stall with wing drop is different from
>> the official recovery from a spin. At what point do you, personally,
>> transition from one to the other?"
I'm curious. Although in practical terms I'm quite confident (through
practice) that I can tell one from the other and react and recover
accordingly, but how would you phrase the answer to that?
--
Bill Gribble
http://www.scapegoatsanon.demon.co.uk
- Learn from the mistakes of others.
- You won't live long enough to make all of them yourself.
Don Johnstone
action is to reduce the AoA, move the stick forward
to unstall the wing.
The action for a spin is: opposite rudder (to stop
the yaw/rotation) and then move the stick progressively
forward to unstall the wing. The recovery from there
is the same.
The important point is that with the wing down stall
the stick forward comes first and rudder may be used
to conteract any yaw present. With the spin the rudder
MUST come first.
In flapped gliders the first action should be flaps
to neutral, well with my flapped glider it should be.
At 16:18 23 June 2005, T O D D P A T T I S T wrote:
>Bill Gribble
>wrote:
>
>>>> 'The offical recovery from a stall with wing drop
>>>>is different from
>>>> the official recovery from a spin. At what point do
>>>>you, personally,
>>>> transition from one to the other?'
>>
>>I'm curious. Although in practical terms I'm quite
>>confident (through
>>practice) that I can tell one from the other and react
>>and recover
>>accordingly, but how would you phrase the answer to
>>that?
>
>I'd phrase my answer in terms of pitch down and rotation
>angles.
>
>T o d d P a t t i s t - 'WH' Ventus C
>(Remove DONTSPAMME from address to email reply.)
>
Ian Johnston
<REMOVE_TO_REPLY...@yahoo.co.uk> wrote:
> The answer is simple: Stall with a wing drop the first
> action is to reduce the AoA, move the stick forward
> to unstall the wing.
> The action for a spin is: opposite rudder (to stop
> the yaw/rotation) and then move the stick progressively
> forward to unstall the wing. The recovery from there
> is the same.
Of course. But how far does the wing have to drop - how much does the
glider have to roll at the stall - before you take spin recovery
action rather than stall with wing drop recovery action?
In real life, on the final turn, you have approximately 0.3 seconds to
answer this question ...
ian
Don Johnstone
A stall with wing drop is just that and provided action
is taken to solve that problem, unstall the wing, the
a spin will be prevented. A spin is the result of failure
at the first step for whatever reason. Everyone properly
trained will know the difference.
I would suggest that if you get to the point of a fully
developed spin on the final turn the chances of recovery
before the ground gets in the way are very remote,
unless you final turn above 600 feet that is, so you
better recognise and deal with that stall\wing drop.
I have thought about this and decided that if I ever
get to the point where I do get to a fully developed
spin at final turn height I am going to spin in, rather
that than tent peg half way through the recovery. My
philosophy teaches recognition of the approach of the
problem so it can be prevented and this is still not
given sufficient emphasis in training. Yes train people
to recover from fully developed spins but if you do
the job right and train so that they recognise the
approach and take the correct preventative action they
will never need to recover from a spin.
Now here's a question. Given the answer above why when
the wing drops at the start of a take off run (winch
or aero-tow) does everyone almost without exception
try and lift the downgoing wing with aileron?
At 20:42 23 June 2005, Ian Johnston wrote:
>On Thu, 23 Jun 2005 16:18:58 UTC, Don Johnstone
Bob Johnson
Has anyone mentioned the yaw string on these wide birds? What's it doing
during incipient diving vs. spinning?
Bob
Ian Johnston
<REMOVE_TO_REPLY...@yahoo.co.uk> wrote:
> The answer is again simple and goes to recognition.
> A stall with wing drop is just that and provided action
> is taken to solve that problem, unstall the wing, the
> a spin will be prevented. A spin is the result of failure
> at the first step for whatever reason. Everyone properly
> trained will know the difference.
OK, so how would you described the difference. How far does the wing
have to drop before /you/ use spin recovery rather than stall
recovery? I'm genuinely interested: it's not supposed to be a trick
question in any way.
Ian
Ian Johnston
<REMOVE_TO_REPLY...@yahoo.co.uk> wrote:
> Now here's a question. Given the answer above why when
> the wing drops at the start of a take off run (winch
> or aero-tow) does everyone almost without exception
> try and lift the downgoing wing with aileron?
Define "drops". How do you keep your wings level on the takeoff run?
Ian
--
nimbusgb
I suspect that keeping the wing off the ground with aileron in the
initial part of the ground run works because with the tailwheel/ skid
on the deck the effects of adverse yaw & secondary effect roll are
negated.
There is no way on Gods earth that the rudder of the Nimbus is going to
accelerate a dropping wing at the beginning of the ground run.
Personally I thing the rudder of the
Nimbus is there because us pilot types wouldnt but an hairyplane
without one :)
Ian
Don Johnstone
that. Spinning is more than stalling with the wing
down or indeed with wing drop. A spin involves the
aircraft autorotating with yaw, roll and pitch movement.
I suppose you could say that if there significant yaw
present then that needs to be stopped. I think the
important point is that the angle of attack needs to
be reduced. If that can be achieved by use of the elevator
then that is all that is required.
I am not sure that I can explain satisfactorily in
words, but I could definitely demonstrate the difference.
At 22:24 23 June 2005, Ian Johnston wrote:
>On Thu, 23 Jun 2005 21:27:25 UTC, Don Johnstone
Andreas Maurer
wrote:
>Has anyone mentioned the yaw string on these wide birds? What's it doing
>during incipient diving vs. spinning?
During lots of spin training flights (that include spiral dives to
show the difference) I *never* looked at the yaw string. Even in a big
bird the diffrence between a dive and a stall/spin is easy to detect
(and recover) if you have a little experience in this glider and
halfways correct spin training.
Frankly spoken, pulling the stick back hard enough to break off the
wings shows that the pilot was lacking the most basic skills to fly
that bird.
Bye
Andreas
Andreas Maurer
<REMOVE_TO_REPLY...@yahoo.co.uk> wrote:
>Now here's a question. Given the answer above why when
>the wing drops at the start of a take off run (winch
>or aero-tow) does everyone almost without exception
>try and lift the downgoing wing with aileron?
... because it works in 99 percent of the cases?
Bye
Andreas
Robert William
>On Thu, 23 Jun 2005 16:34:41 -0500, Bob Johnson
>
>Frankly spoken, pulling the stick back hard enough
>to break off the
>wings shows that the pilot was lacking the most basic
>skills to fly
>that bird.
>
>
you could either go through Vd or pull back what would
YOU do?
jonnyboy
Bob Johnson:
> pulling the stick back hard enough to break the wings
> shows pilot .. lacking .. skills to fly that bird.
> >
Robert William wrote:
>> having got to the position where you could either go
>> through Vd or pull back what would YOU do?
Is, 'Not getting into that position', an allowed response?
Jon.
Stefan
> In real life, on the final turn, you have approximately 0.3 seconds to
> answer this question ...
I've always wondered about those "final turn spins". Yes, I know they
happen. I'm wondering nonetheless. It has been hammered in my heat right
from day one to watch that approach speed and to stay coordinated on
approach. Tolerance on the slow side: None. We won't let a student solo
before we are absolutely, positively sure he can and will acomplish
this. And when he gets his license, this will have become second nature
to him (just as not pulling back in a spin).
I'm not a great pilot and I'm making mistakes all the time. I can think
of a lot of ways how I could loose my life in a glider. But I'm
absolutely, positively sure that stalling/spinning in the final turn
will *not* be one of them.
Stefan
Stefan
> In real life, on the final turn, you have approximately 0.3 seconds to
> answer this question ...
I've always wondered about those "final turn spins". Yes, I know they
happen. I'm wondering nonetheless. It has been hammered into my head
Bill Gribble
>The answer is again simple and goes to recognition.
I think that was the point of the BGA's question ;)
>A stall with wing drop is just that and provided action is taken to
>solve that problem, unstall the wing, the a spin will be prevented. A
>spin is the result of failure at the first step for whatever reason.
>Everyone properly trained will know the difference.
I know the theoretical and practical difference between a spin and a
stall with or without a wing drop, and understand the difference in
recovery for each. However,
The BGA Instructor's Course question asked:
>> "The offical recovery from a stall with wing drop is different from
>> the official recovery from a spin. At what point do you, personally,
>> transition from one to the other?"
At what point do you NOT put the stick forward to reduce AoA and
alleviate the stall and instead centre the controls then kick a boot
full of opposite rudder in to stop the spin? Assuming no flaps, that
is...
Or is the question, and the suggestion that you transit from one
recovery procedure through to the other at some definite point in time,
intrinsically wrong? Should it be, "What is the difference between a
stall with wing drop and a fully developed spin?"
>I have thought about this and decided that if I ever get to the point
>where I do get to a fully developed spin at final turn height I am
>going to spin in, rather that than tent peg half way through the
>recovery.
Presumably working on the grounds that impacting at the lower, stable
velocity of a spin is going to hurt less than doing so at the higher,
increasing velocity of the initial part of the recovering dive? I can
appreciate the sense in that argument, though personally I doubt I could
accept the inevitability of the impact without putting up a struggle and
trying to recover despite the futility of the situation.
> My philosophy teaches recognition of the approach of the problem so it
>can be prevented and this is still not given sufficient emphasis in
>training.
It was in mine. Repeatedly hammered into me through graphic description
and demonstration by a number of different instructors throughout the
period of my training.
>Yes train people to recover from fully developed spins but if you do
>the job right and train so that they recognise the approach and take
>the correct preventative action they will never need to recover from a
>spin.
Though that overlooks the other essential advantage of spin training. It
teaches familiarity and confidence with the aircraft in unusual and
discomforting attitudes, which, IMHO, makes you far less likely to panic
and make a potentially bad situation terminally worse if you ever find
yourself there, whether through fault of your own or otherwise.
Besides which, as one of my favourite instructors was once quoted as
saying when asked why he had spun on a certain occasion; "Well, it's
just about one of the most exiting things you can do in a glider".
That is, of course, unless the glider concerned is a Fox ;)
Don Johnstone
the 1% tend to be spectacular, and stings a bit.
At 02:06 24 June 2005, Andreas Maurer wrote:
>On 23 Jun 2005 21:27:25 GMT, Don Johnstone
> wrote:
>
>
>>Now here's a question. Given the answer above why when
>>the wing drops at the start of a take off run (winch
>>or aero-tow) does everyone almost without exception
>>try and lift the downgoing wing with aileron?
>
>.... because it works in 99 percent of the cases?
>
>
>Bye
>Andreas
>
Edward Lockhart
snip
>OK, so how would you described the difference. How
>far does the wing
>have to drop before /you/ use spin recovery rather
>than stall
>recovery? I'm genuinely interested: it's not supposed
>to be a trick question in any way.
>
>Ian
Its not about how far the wing has dropped, its about
whether the glider has started to rotate about the
dropped wing.
A wing drop stall has a lot of roll, some pitch but
not much yaw so your first action is to unstall the
wings by moving the stick forward.
If you've been slow to intiate the recovery, the glider
will start to yaw/rotate around the dropped wing and
once this has happened, your first action should be
full opposite rudder.
Ed
>
Bill Gribble
>Its not about how far the wing has dropped, its about whether the
>glider has started to rotate about the dropped wing.
I think //that's// the answer the question was looking for.
>If you've been slow to intiate the recovery, the glider will start to
>yaw/rotate around the dropped wing and once this has happened, your
>first action should be full opposite rudder.
Or the nose drop self-corrects the stall and the glider develops into a
spiral dive, in which case centring the controls and kicking in a
boot-full of opposite rudder is only going to delay recovery in the face
of a now rapidly approaching Vne.
Despite knowing the difference, being practised and familiar with the
characteristics, recovery and differences of both, it's the prospect of
mistaking a spiral dive for a spin in the adrenaline rush of the moment
that actually still scares me, despite the fact that I quite enjoy being
upside down in a glider ;)
HL Falbaum
experinced pilots did. The owner P1 was a famous glider pilot, and P2 was a
WW II trained Naval Aviator, also famous. Eyewitness reports (in the NTSB
report) stated that the rotation had stopped, the glider nosed down, then
the wings bent up to about 45 deg, then failed. The spoilers were found
actuated. The wings broke just outboard of the spoiler. The report refers to
an interconnction between the flaps and the spoiler, full spoiler also
produces full flap. The report also states time for the glider to accelerate
to Vne and Vd, indicating quite rapid acceration.
Further in the report it is indicated that the N4DM was certified by JAR
with exceptions for stall/spin behavior.
The implication is that the pilot(s) stopped the yaw, the glider dropped
it's nose and started accelerating as expected, and then at or above Vd,
spoilers were actuated, and the wings broke. Neither pilot got out.
The Spanish accident reports notes that the spoilers were found in the
locked position.
So, in summary, one pilot pulled the stick and broke the aircraft, and one
pilot pulled the spoilers and broke the aircraft. Faced with going through
Vd and breaking the aircraft, or trying to recover and breaking the
aircraft--maybe the best chioce is to jump while it's still intact?
--
Hartley Falbaum
"Robert William" <REMOVE_TO_RE...@hotmail.com> wrote in message
news:3i1rskF...@individual.net...
Stephen
What do we think about picking up the wing with rudder when in a stall with
wing drop? It's not the BGA method and I'm troubled by someone who
recommends it.
Stephen
fiveni...@yahoo.com
disagree in practice if not in principle. Bending and twisting moments
are much greater with increasing span. And a certain degree of symmetry
is assumed in measuring load limits. Contol inputs will significanly
change the lift distribution across the span (the squatcheloid). So
will twist in the wing. Al Blackburn's point, and I take it to heart,
is that design requirements don't look at failure modes under a variety
of assymetric lift distributions.
Consider the deployment of one spoiler cap during the spiral dive
recovery with deflected ailerons to recover from a steep bank.
The lesson I take away is to be very thoughful in applying the controls
under high load.
Stefan
> Further in the report it is indicated that the N4DM was certified by JAR
> with exceptions for stall/spin behavior.
How so? You cannot get a glider certificated without adhering to all JAR
22 requirements.
> So, in summary, one pilot pulled the stick and broke the aircraft, and one
> pilot pulled the spoilers and broke the aircraft.
Wrong. Neither of the two would have done any damage. They broke the
glider by doing both things at the same time.
Stefan
fiveni...@yahoo.com
the spin is a product of yaw moment at departure, you can prevent a
spin with coordinated controls alone. IE, modern aircraft must be
"helped" into the spin. (Put another way, the vertical stabilizer
creates enough yaw dampening to prevent autorotaion at stall so long no
pro spin control imputs are made. Since there are two yaw controls,
that would mean pro rudder or anti stick.) Thus, any prestall or
initial departure that is met with a release of back pressure and use
of coordinated controls to level the wings will produce the desired
effect before a spin or spiral dive can develop. Even if you choose not
to release back pressure, you shouldn't spin. Instead, you might find
yourself in a secondary stall. The longer it takes to apply these
simple actions, the less likely that it will produce an immediate
remedy, as the aircraft will continue into either a spin or spiral dive.
fiveni...@yahoo.com
the high Sierra during the winter. It would be much more manageable (if
not entirely polite), if they hitched their rides in pairs.
Bill Gribble
>What do we think about picking up the wing with rudder when in a stall
>with wing drop? It's not the BGA method and I'm troubled by someone
>who recommends it.
I'm not sure I understand what you mean. Say, right wing drops in a
stall so this "method" would advocate kicking in left rudder as you move
the stick forwards to alleviate the stall?
Personally, the last thing I'd do when the aircraft was in a stalled
state, whether or not a wing drop was involved, would be to
intentionally use the rudder in an uncoordinated fashion. That is,
unless I actually wanted to spin.
Andrew Warbrick
all evidence points to the brakes not being deployed,
at all.
Bill Gribble
>Wrong. Neither of the two would have done any damage. They broke the
>glider by doing both things at the same time.
No. With the Spanish tragedy the pilots didn't open the airbrakes but
the P1 broke the wings by pulling back too hard. Presumably it wasn't
necessarily Vne that broke the wings but excessive load (pulling back
too hard in a panic) once past maximum maneuvouring speed? Given the
P1's self-confessed lack of currency in spin-training (paraphrased from
memory; "did it once twenty years ago and swore never again") is it fair
to say that without the panic from an unpractised situation the spin and
resulting dive recovery might not have broken the wings? Limiting your
spin recovery to just pulling back hard is going to have unfortunate
consequences which ever way it turns out. That said, it was a terrible
thing to happen and my heart really does go out to the pilot and his
family.
The Minden tragedy involved opened airbrakes which in turn contributed
to breaking the wing. Still from pulling back too hard, but in quite
different circumstances where "too hard" might not have been so apparent
because of the reduction in wing area and thus perceived wing-loading.
But had the airbrakes not been out the wing might have sustained the
load. Though Vne may then have been passed.
So it would seem the answer is to not open the airbrakes but respect the
yellow band on your ASI when loading the aircraft with g. Even if this
means passing through Vne?
Or, if you do open the airbrakes in a last ditch attempt to avoid
breaching Vne be even more respectful with the loading when pulling out
of the dive. But, between the devil and the deep blue sea you're better
off not having stepped out onto the gunwale in the first place :(
Stefan
> No, in the accident in Spain which started this thread,
> all evidence points to the brakes not being deployed,
> at all.
Please read the thread before commenting. HLF, to whom I was responding,
was explicitely referring to the Minden accident.
Stefan
Stefan
> But, between the devil and the deep blue sea you're better
JAR 22 requires that a glider can be recovered from a spin of at least 5
full turns (or the number at which the spin transfers to a spiral, if
that number is smaller) by applying the "standard procedure" and without
exceeding the load limits. Last I've heard there are a couple of Nimbi
4DT registered in Germany and other European countries. Which means they
are JAR certificated, hence...
Stefan
Chris Reed
into the spin". There are some circumstances when a spin entry can be
made without any "odd" control inputs at all.
One of my favourite exercises for my annual checkouts as a UK Basic
Instructor is the spin off a simulated winch launch (only try this at
height with an appropriate instructor with you!). Simulate a winch
launch by diving to 90 kt and then pulling up at 45 degrees. As the
speed drops to about 60 kt cry "BANG - cable break", and push over into
the normal flying attitude. The moment normal attitude is reached, begin
a co-ordinated turn.
All will be fine for a second or so, as you are flying at reduced G.
However, once the G comes back on many gliders will roll smoothly (no
buffeting) into a spin so fast that there is little you can do about it
(though the purpose of the exercise is to show the spin entry and then a
recovery, so I've not tried reducing back pressure as the wing drops).
The Puchacz is excellent for this.
My understanding is that although everything looks fine, in fact you are
flying below 1G stall speed (possible because of the reduced G resulting
from the pushover, which is why BGA training requires you to push over
beyond the normal attitude after a cable break, monitor the airspeed and
not turn until a safe speed is regained). When 1G is restored the wings
stall, but because you're already in a turn the down wing stalls earlier
and autorotation ensues.
If you think about it, an aggressive pull up into a thermal coupled with
turning a little later than normal might produce similar effects.
I believe there are a number of other modes of spin entry without
unusual control movements, though you would need a far more experienced
pilot than me to explain them.
This is not to say that a glider in normal flight will depart into a
spin without abuse of the controls, but I think it important to
recognise that co-ordinated flight is not an *absolute* protection and
to understand when extra precautions are required (and what those
precautions are).
Don Johnstone
The damger from exceeding VNe is flutter and flutter
WILL break the aircraft. I think the last paragraph
is the only option.
The only time a pilot (test pilots excepted) is likely
to experience a spin in a big wing aeroplane is if
it happens accidentally. Non aerobatic means no deliberate
spinning (in the UK anyway) which means there is no
opportunity to practice. Makes prevention and early
recognition even more vital.
At 16:00 24 June 2005, Bill Gribble wrote:
>Stefan writes
>of the dive. But, between the devil and the deep blue
>sea you're better
fiveni...@yahoo.com
length. However, I will not recover to see if it really is a spin. I
suspect I'll see it become a spiral dive based on previous flight
testing in this regime. But experimentation will tell.
By the way, I do this often, though not in quite the order you state or
for the same reason. I enjoy pointing the nose up 60 degrees or so,
then letting it park. The stall and pitch through is typically well
past vertical. Great fun, and completely self recovering after the
stall break. And much, much more exciting than a wing over.
Andrew Warbrick
the thread more carefully before flaming people. Enough
said.
fiveni...@yahoo.com
possible to stall a glider while coordinated. No epiphany there. If you
stall in a bank, you are likely to have the low wing drop, for the
reasons Chris gave. This, however, should not result in a spin.
UNLESS... given the variables Chris has introduced, we have a glider
that is potentially flying well below its 1G stall speed. This means
that the force available to the vertical stabilizer to dampen a yawing
motion is significantly diminished. So then is the power of the rudder.
Adverse yaw of the ailerons is increased at the stall. Harmonization
(ie, required pilot control inputs to maintain coordinated flight)
changes as the horizontal stab is now operating at less than design
speeds. Interesting. There would seem to be a crossover in this regime,
where even if the contols are harmonized (given the relative torques
available to VS and ailerons), there simply may not be enough
weathervaning potential in the VS to prevent autorotation if a stall
develops at the wingtip.
Is it safe to say that winch launching is an aerobatic maneuver, and
therefore requires very specific training techniques since the glider
is likely to be flown outside its design limits? Also, it seems the key
to avoiding this situation is to avoid the stall, which means no sudden
snatching back of the stick (even to neutral) once a "normal" attitude
is achieved. Since this situation is likely to occur near the ground,
where the horizon is not a particularly useful airspeed indicator, do
you teach close monitoring of airspeed throughout the recovery? And a
complicating factor... if there is already a bank during the recovery,
how do you address it? You've noted that AOA differential is enough to
snap the glider into a spin. Attempting to level the wings would seem
to only aggrevate any impending tip stall.
I'm not unfamiliar with this regime. Though I typically don't turn at
the top of a hard pull into a thermal (I generally start the turn
during the pull, if I'm going to turn at all), I do on occasion decide
that I've misjudged the thermal's size and its worth a turn. However,
the glider's roll is typically so slow, I find myself moving the stick
well forward (and sometimes dumping flaps) to increase the roll rate...
a normal reaction to sluggish controls near the stall. So again, I'm
wondering that the pilot isn't introducing an aggrevating factor
(misuse of the elevator), though admittedly, I hadn't considered this
narrow flight band when addressing the first, best recovery to an
unaticipated loss of control.
Bill Daniels
<fiveni...@yahoo.com> wrote in message
news:1119704062....@g14g2000cwa.googlegroups.com...
> Is it safe to say that winch launching is an aerobatic maneuver, and
> therefore requires very specific training techniques since the glider
> is likely to be flown outside its design limits?
Absolutely not true. Winch launch and the associated maneuvers are well
within the design limits of any modern glider. Winch launch is not an
aerobatic maneuver.
>
> Chris Reed wrote:
> > One of my favourite exercises for my annual checkouts as a UK Basic
> > Instructor is the spin off a simulated winch launch (only try this at
> > height with an appropriate instructor with you!). Simulate a winch
> > launch by diving to 90 kt and then pulling up at 45 degrees. As the
> > speed drops to about 60 kt cry "BANG - cable break", and push over into
> > the normal flying attitude. The moment normal attitude is reached, begin
> > a co-ordinated turn.
One of my favorites too but it needs to be understood that, in Chris Reed's
example, the glider is at a very high AOA and deeply stalled, or will be as
soon as 1G is re-established. The ASI will only be indicating 10 - 15
knots. Initiating a turn while in a deep stall will cause a wing drop and a
spin entry - no surprise here. This 'feels' normal only because of the
normal glide attitude. It is a variant of an accelerated stall.
This maneuver is for instructors so they can anticipate the results if a
student botches a wire break recovery. I've sometimes used it with student
to demonstrate WHY the nose needs to be well down and the airspeed seen to
be above best L/D and increasing before initiating a turn. In all cases,
this practice maneuver is done at a safe altitude.
To further explain, if a wire break occurs during the nose high part of a
winch launch, it's very likely that the best landing option is straight
ahead. When the glider is high enough that a turn is needed, the nose
attitude will be lower and the height AGL will be much greater.
Bill Daniels
Chris Gadsby
> Chris Reed wrote:
>
>>> > One of my favourite exercises for my annual checkouts as a UK Basic
>>> > Instructor is the spin off a simulated winch launch (only try this at
>>> > height with an appropriate instructor with you!). Simulate a winch
>>> > launch by diving to 90 kt and then pulling up at 45 degrees. As the
>>> > speed drops to about 60 kt cry "BANG - cable break", and push over into
>>> > the normal flying attitude. The moment normal attitude is reached, begin
>>> > a co-ordinated turn.
I've recently been doing this as a student and personally I found it a very
valuable lesson as (a) it required no "forcing" from the instructor to initiate
the spin and (b) it makes you realise how quickly you can transition from an
apparently normal flying attitude into a serious situation.
Chris Gadsby
fiveni...@yahoo.com
In fact, at least according to US regs, a winch launch IS an aerobatic
manuever. But that wasn't my point. If normal recovery from a normal
operation places the pilot on the ragged edge of a deep stall, then I
think it best to characterize the operation as "ab"normal., requiring
reactions unique to that environment. And thus my toying with the term
aerobatic.
There remains a problem with this argument, however. Maybe the subject
of a different thread.
BTW, have you demonstrated this maneuver without revocery? IE, have you
left the controls in place to let the spin fully develop?
Bill Daniels
<fiveni...@yahoo.com> wrote in message
news:1119787040....@z14g2000cwz.googlegroups.com...
> Bill,
>
> In fact, at least according to US regs, a winch launch IS an aerobatic
> manuever.
I believe you are referring to the +-30 degrees pitch and +-45 degrees bank
definition of aerobatics. I believe there is an exclusion for aircraft for
which these are normal maneuvers. Gliders routinely exceed these values
thus they are not considered aerobatic for gliders.
> But that wasn't my point. If normal recovery from a normal
> operation places the pilot on the ragged edge of a deep stall, then I
> think it best to characterize the operation as "ab"normal., requiring
> reactions unique to that environment. And thus my toying with the term
> aerobatic.
Normal winch operation does not place the glider on the ragged edge of a
stall. A normal launch places the max AOA very near that for best L/D. A
wire break handled properly with a prompt pushover is flown at a still lower
AOA with the airspeed not dropping below 1.3 x Vs or so. The margin is even
greater when you consider that the pushover is at less than one G so the
stall airspeed is lower.
The wire break training maneuver described by Chris is to show an instructor
candidate what can happen if the student is allowed to mis-handle the wire
break and is WAY outside normal operation.
The whole point is to drum into the instructors who will then insist that
his students learn that the nose must be promptly lowered well below normal
glide and the airspeed seen to be at a safe value and increasing before any
thought is given to a turn. This is to establish and maintain a large
safety margin. In many cases no turn is necessary and the glider lands on
the remaining runway.
>
>
> BTW, have you demonstrated this maneuver without recovery? IE, have you
> left the controls in place to let the spin fully develop?
Yes, It is a normal spin with a normal recovery at least with the trainers
in common use.
The wire break recovery being discussed here is safer and less dramatic than
the equivalent airtow maneuver consisting of a 200 foot AGL release on
departure and a turn back to the runway.
Bill Daniels
fiveni...@yahoo.com
What interests me is that recovery from a cable break, if misapplied,
appears to place the pilot in a very unusual situation. This flight
condition was presented to put into question the abolutism of some
simple control movements that should keep pilots out of danger of loss
of control. So my question becomes one of instructional emphasis. Since
some problems evolve so quickly that thoughtful consideration isn't
always a best first course, some absolutes are needed. But if you are
flying outside normal flight conditions (IE, aerobatics or cable break
recoveries), those absolutes might not apply. Yanking the stick back to
neutral to fix the horizon on the canopy at the top of a cable break
recovery qualifies as departing from normal flight conditions. But I
certainly see the problem you face. We train pilots to take note of a
stick well aft as one sign of an imminent stall. They might not so
quickly recognize that the glider can be stalled with the stick at
neutral under these conditions. Nor might they realize that
coordination of ailerons and rudder has changed at extremely low
airpseed. Thus the opportunity to enter a wing low stall with your
hands and feet in a position that should normally signal safe flight.
All that said, I spent about 15 minutes on Sunday afternoon
experimenting with this maneuver. The results weren't as previously
published, so I'll need to take some time to write up the results. I'll
start this as a new thread.
Stefan
> But if you are
> flying outside normal flight conditions (IE, aerobatics or cable break
> recoveries),
A cable brake during a winch launch is a perfectly normal flight
condition, and as such, is regulariliy trained. Maybe I'm wrong, but it
seems you didn't do many winch launches, did you?
Stefan
Don Johnstone
where the nose is well up above the horizon, airspeed
rapidly decaying with the possibility of increase wing
load from hanging cable can be described as 'normal'.
It is a situation we train pilots to recover from but
it also goes against the normal training in that the
reference to the horizon means less than normal.
During the launch the attitude to of the glider to
the relative airflow is within the normal parameters.
As soon as the launch fails, for whatever reason, the
situation becomes abnormal. Lowering the nose to an
attitude relative to the horizon will not result in
instant recovery.
My way of teaching was for the student to carry out
the corrective action and then ask a simple questions.
Do I have the approach attitude? Answer no, correct,
answer yes then 'Do I have the approach airspeed? answer
no, check response to answer yes, if that is still
yes then wait until the answer to the airspeed question
is yes. When the answer to both questions is yes, then
and only then decide on the most appropriate course
of action and implement.
Works for me and I have survived 10000 winch launches
Bill Daniels
<fiveni...@yahoo.com> wrote in message
news:1119872303.1...@z14g2000cwz.googlegroups.com...
Yanking the stick back to
> neutral to fix the horizon on the canopy at the top of a cable break
> recovery qualifies as departing from normal flight conditions.
We agree. This is the reason for the training scenario which teaches
avoidance of this situation.
> But I certainly see the problem you face. We train pilots to take note of
a
> stick well aft as one sign of an imminent stall. They might not so
> quickly recognize that the glider can be stalled with the stick at
> neutral under these conditions.
To stop the nose at the normal gliding attitude after a wire break requires
a powerful elevator and full back stick. This is definitely a pilot induced
stall resulting from a mis-use of the elevator. However, accident records
show that this has occasionally been the cause of a spin accident so the
training scenario was added. To repeat what I wrote earlier, this is merely
a slight variant of an accelerated stall. If the stick were held neutral,
the nose would fall through to a steep nose down attitude. This is not the
best technique but it wouldn't result in a deep stall.
Bill Daniels
Andreas Maurer
>In fact, at least according to US regs, a winch launch IS an aerobatic
>manuever. But that wasn't my point. If normal recovery from a normal
>operation places the pilot on the ragged edge of a deep stall, then I
>think it best to characterize the operation as "ab"normal., requiring
>reactions unique to that environment. And thus my toying with the term
>aerobatic.
LMAO.
Bye
Andreas
Stefan
> Sorry I do not see that finding yourself in a condition
> where the nose is well up above the horizon, airspeed
> rapidly decaying with the possibility of increase wing
> load from hanging cable can be described as 'normal'.
We can argue the meaning of the word normal. For me, everything which
happens from time to time and is no surprize is normal. In winch
launches, cable breakes do occur and are to be expected. So they are
normal me, just a variant. But there's no need to argue about this word.
> It is a situation we train pilots to recover from but
> it also goes against the normal training in that the
> reference to the horizon means less than normal.
Again, what is normal? In flat land, during normal flight, the horizon
is the reference, so that's normal. In mountains, having no natural
horizon but only an imaginary one is normal. And in a winch launch, not
referring to the horizon is normal, at least to me.
> Lowering the nose to an
> attitude relative to the horizon will not result in
> instant recovery.
Exactly, that's why, after a cable break (or after "normal" release, for
that matter), ist "normal" not to refer to the horizon in the same way
as during free flight. Different conditions, different techniques.
Nothing abnormal.
> My way of teaching was for the student to carry out
I'm sure you instruct your students correctly. The only thing I jumped
on was the statement that there was something "abnormal" in a winch
launch. Again, different conditions require different techniques, which
means different normalities.
This is the approach I take: Normality depends on cirumstance, so
broaden your view and your repertoire of techniques.
Stefan
fiveni...@yahoo.com
BTW,
For the purposes of this section, aerobatic flight means an intentional
maneuver involving an abrupt change in an aircraft's attitude, an
abnormal attitude, or abnormal acceleration, not necessary for normal
flight. This is from the US FARs. While we can discuss ad nauseum
whether a winch launch is an aerobatic maneuver... (and really it
isn't), it clearly requries control motions that constitute aerobatic
flight, and as such represent a "special" set of circumstances.
Note that Chris introduced me to a manuever which can be accurately
described as outside the parameters of normal flight (IE, abrupt change
in aircraft attitude). In preparing to defend the efficacy of winch
launching, you're missing my point. There is a disconnect between the
control actions required for safe recovery from a cable break and the
correction of a stall and/or dropping wing during normal flight. My
point is that the cable break recovery is a special case and needs to
be discussed in depth, and differentiated from the "normal" control
movements to establish and maintain controlled flight. But I digress.
This is the subject of new thread.
BTW, I learned to winch launch under the tutelage of a BGA instructor
in Britain. This concern of the snap spin was never discussed. Recovery
of airspeed, certainly, but no warning against starting a turn.
Per the particulars of earlier notes in this thread, I'll offer some
opinions at length based on what I experienced in my glider yesterday,
but it'll be a few days before I can take the time to document them.
Bill Daniels
stepping in here.
I am fighting a lonely battle to convince my fellow USA pilots that winch
launch is a perfectly normal way to launch gliders and not some invention of
the devil. Those few US pilots who have experienced a winch launch have
most likely done so using horrendously inadequate equipment that would not
have been allowed to operate in your countries. There is no standard
training manuals so each instructor makes up their own. The results range
from hilarious to deadly.
With oil prices exceeding $60US/barrel in the last few days, and aviation
fuel prices heading into uncharted territory, the viability of our 'air tow
only' soaring operations comes into question. If oil prices continue on to
$100/barrel, as the world bank and many investment houses predict, the US
soaring community is in for some rough times if we don't quickly adopt a
more fuel efficient launch method.
To quickly shift to winch launch means that we will have to adopt the best
practices of other countries who have developed winch launch to a high level
of performance and safety.
I appreciate your continued inputs.
Bill Daniels
fiveni...@yahoo.com
park the nose on the horizon. Very couterintuitive (for me, at least),
though I can see how any pilot at low altitude might let a canopy full
of terrain misinform his better judgement.
BTW, throughout a dozen or more of these maneuvers, the glider never
spun. I'll give details. And remember, the point of the exercise wasn't
to show how misapplied controls might cause a sudden spin (this was
more than clear throughout the maneuver), but what would happen if I
paid accute attention to coordination.
fiveni...@yahoo.com
I too am amused by the risks we accept through habituation. I regularly
take off in tailwinds exceeding 15 knots, with water, on a runway only
2,600 feet long. I'm used to it, and accept the risk as a byproduct of
where I fly. Most pilots would consider these practices insane. As a
result, I stood in a amazement at a US Nationals when pilots were
showing grave concern over the safety of a launch with less than 7
miles per hour of tail wind.
For pilots who winch launch regularly, the definition of normal flight
attitudes is greatly expanded. But I think you'll all agree that it is
a highly specialized type of flying (even if you are used to it). Pull
on the stick to go faster. Push to go slower. If the cable breaks, no
messing around... stick right forward until the nose is well below the
horizon, then ease it back gently, paying attention to your airspeed.
Abrupt control motions, significantly reduced g, large angles of nose
up and nose down, close to the ground, special considerations regarding
turns... sounds to me like a pretty threatening environment, sort of
like taking off downwind at gross from a short runway. Deserves some
special consideration. And occasional reexamination to prevent the
complacency of experience.
Chuckle.
OC
Bill Gribble
>I'm sure you instruct your students correctly. The only thing I jumped
>on was the statement that there was something "abnormal" in a winch
>launch. Again, different conditions require different techniques, which
>means different normalities.
I think we're generally agreed that the conditions during a routine
winch launch are quite "normal" for a glider and its usual modes of
flight.
The assertion, which I agree with, is that the conditions of a launch
failure are abnormal to the normal modes of operation for the glider and
so need peculiar training and discipline to handle safely. But that's no
more a slur against winch launching than the risk of a turbulence
induced incipient spin is a discouragement to thermalling a glider. As
long as you know better than to just "pull back hard on the stick" to
prevent the spin developing and don't try to scratch away from stupidly
low heights it's a non-issue.
>This is the approach I take: Normality depends on cirumstance, so
>broaden your view and your repertoire of techniques.
However, the obvious extension of such a relativistic view is to argue
that abnormality is a fabrication of perception and that everything can
be termed "normal" within the context of itself. Which may be all well
and good but is catastrophically useless when it comes to defining
anything in terms that are any more than halfway useful.
That said, I can't say I don't agree with you ;)
fiveni...@yahoo.com
of what you are used to. A 200 foot rope break in the absence of
strong winds or turbulence is completely benign, at least for me,
having done hundreds of them.
What I'm finding interesting is the need to make fairly dramatic
motions of the controls as part of a cable break recovery. So again,
I'll flirt with the term aerobatic, not as a maneveur designed to
thrill and excite and audience or a passenger, but as a way to
differentiate use of the controls given these circumstances.
Even if you fail to observe the moment the rope breaks on aerotow, and
only become aware of it as you fail to maintain position behind the tow
plane, use of the controls is not nearly so dramatic as post cable
break. Nor, apparently, quite as critical. Though I think we can both
agree that they each represent real emergencies demanding preplanned
action.
Don Johnstone
launching holds no fear for me. On the other hand a
rope break on aero tow is something that I have little
experience of. I do however have a plan and that I
believe is the key.
Understanding the problems, the differences if you
like is what training should all be about. In many
ways with the right training winch launching is safer
than aero tow, if it goes wrong you always have the
airfield to land on.
Stefan
> What I'm finding interesting is the need to make fairly dramatic
> motions of the controls as part of a cable break recovery. So again,
> I'll flirt with the term aerobatic,
Last weekend I flew in the mountains. Conditions were rough and I had to
make fairly dramatic motions of the controls to keep the blue side up.
I'll log it as an aerobatic flight, then.
> Even if you fail to observe the moment the rope breaks on aerotow, and
> only become aware of it as you fail to maintain position behind the tow
> plane,
Awareness and prompt reaction are indispensable to survive which
launches. A winch launch *is* dangerous, in the way as there is a very
small margin for errors and it asks for your full focus.
Stefan
Ian Johnston
<REMOVE_TO_REPLY...@yahoo.co.uk> wrote:
: I know we are getting off the original thread but winch
: launching holds no fear for me.
It bleeding terrifies me - but I think that's pretty healthy!
I spend quite a lot of time each year introducing children to the joys
of soldering. After I have explained how hot the iron is, how
important it is not to touch the metal bits, and so on, I ask if
anyone is scared. A few timid hands always go up - at which point I
say "Well done! You've been listening - there are some things in life
which it is right to be scared of, and soldering is one of them".
"Anything to do with aviation, and especially winch launching" is one
of the others, I suggest!
Ian
--
Stefan
> I am fighting a lonely battle to convince my fellow USA pilots that winch
> launch is a perfectly normal way to launch gliders and not some invention of
> the devil.
Just three things to consider:
A which launch brings you to a certain altitude above the site. At some
places, this gives you enough options to find a thermal, at other sites,
it does not.
A winch operation doesn't mix well with other traffic. It's doable, if
everybody is willing.
And, most important: If done correctly, a winch launch is safe. But
there is an extremely small margin for errors. I love winch launches,
but they are dead serious, literally.
Stefan
Ian Johnston
wrote:
: Last weekend I flew in the mountains. Conditions were rough and I had to
: make fairly dramatic motions of the controls to keep the blue side up.
: I'll log it as an aerobatic flight, then.
All this seems to hinge on what's meant by "aerobatic". Frankly, it
seems like a pretty pointless term to me, since it seems to depend on
the intention of the pilot rather on the manoevres flown. Why, for
example, is a loop aerobatic yet a tight thermalling turn, involving
similar stresses on the glider, is not?
To me, it makes more sense to categorize manoevres as high load / low
load and high risk / low risk, where "load" relates to forces on the
glider and "risk" relates to the speed with which things will go wrong
if the pilot misreacts.
That gives four permutations:
1) low load / low risk (normal flight)
2) low load / high risk (inverted flight)
3) high load / low risk (loop, tight thermalling)
4) high load / high risk (spin or spiral dive recovery)
This is off the top of my head, and I am sure we could argue about the
categories (should there be a "medium" in each case?) and
categorisations (how hard is a loop) for ages.
However, I think I would put many display aerobatic manoevres and
winch launching together in the high load / high risk category: it's
not that winch launching is aerobatic (whatever that means) but it is
also a time when the glider is being flown with higher than normal
structural loadings and when pilot error can cause things to go very
nasty very quickly.
I'd put mountain flying, from the little I have done, in the low load
/ high risk category at the very least, and probably high / high on
rough days.
Ian
--
fiveni...@yahoo.com
I like your train of thought. As well as decoupling from a term that
has such strong connotations.
Kilo Charlie
"Bill Daniels" <bil...@comcast.net> wrote in message
news:GfGdnQg2O7j...@comcast.com...
>I want to thank Don and Stefan and others from Europe and the UK for
> stepping in here.
>
> I am fighting a lonely battle to convince my fellow USA pilots that winch
> launch is a perfectly normal way to launch gliders and not some invention
> of
> the devil.
Bill-
I think that you have a chip on your shoulder re winch launches. I have not
seen a single thread that tries to make winch launches sound like they are
an "invention of the devil". Chris' (OC)point is only pertaining to the
aerodynamics unique to the situation that a glider may be in during a winch
launch cable break. He does not seem to be making any a priori assumptions
that anything is dangerous about winch launching. I think that the
discussion re that unique situation is not only interesting but may also
possibly pertain to some other scenarios such as a hard pull and turn into a
thermal, so would like to have a more detailed understanding of it.
Casey Lenox
KC
Phoenix
Andreas Maurer
>
>For pilots who winch launch regularly, the definition of normal flight
>attitudes is greatly expanded. But I think you'll all agree that it is
>a highly specialized type of flying (even if you are used to it). Pull
>on the stick to go faster. Push to go slower. If the cable breaks, no
>messing around... stick right forward until the nose is well below the
>horizon, then ease it back gently, paying attention to your airspeed.
>Abrupt control motions, significantly reduced g, large angles of nose
>up and nose down, close to the ground, special considerations regarding
>turns... sounds to me like a pretty threatening environment, sort of
>like taking off downwind at gross from a short runway. Deserves some
>special consideration. And occasional reexamination to prevent the
>complacency of experience.
Well...
1. Have you ever flown a model glider without radio control? The one
that you pull up with a rope, simulating a winch launch?
Works like a charm. In *any* halfways correctly trimmed real-size
glider you can let go the stick - and your glider will do the launch
for you. Try that in an aerotow.
How many tow pilots did you say have been victims due to
overcontrolled gliders in the last 50 years?
2. It looks as if you are simply afraid of winch launching due to lack
of training/experience. Having more winch launches than I care to
count, my experience is that *any* student pilot learns winch
launching a lot easier than aerotowing.
3. I had more than enough aerotows where any engine problem of the tow
plane would have led to a bad crash because we were low over an
unlandable area. I prefer by far the winch launch where the complete
airfield is head of me in case of a low cable-break.
4. Recovery from cable-breaks is an extremely straight forward
procedure. Very easy to perform with some training.
What did you say you are doing if you have a rope break in an aerotow
at the end of the runway in 100 ft with unlandable area in front of
you?
5. Sure a winch launch is a highly specialized type of flying. But
isn't flying without any engine at all even more highly specialized?
Imagine that - no engine means that you cannot perform a go-around if
you misjudged your landing approach...
6. Accident statistics definitely prove that winch launching is by far
one of the less risky things you can do if you fly gliders.
Bye
Andreas