Nimbus 4DT accident 31 July 2000 in Spain.

I'm not as interested in spins and spirals. This is
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
...
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



Mark J. Boyd

M B 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'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

Earlier, Stefan wrote:

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.

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.

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.)

On Thu, 23 Jun 2005 16:18:58 UTC, Don Johnstone
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

Ian Johnston wrote:
On Thu, 23 Jun 2005 16:18:58 UTC, Don Johnstone
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

Has anyone mentioned the yaw string on these wide birds? What's it doing
during incipient diving vs. spinning?

Bob

On Thu, 23 Jun 2005 16:34:41 -0500, Bob Johnson
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

Ian Johnston wrote:

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

Ian Johnston wrote:

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
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

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.

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
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