Nimbus 4DT accident 31 July 2000 in Spain.

Don Johnstone wrote:

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

During my experiments with the wrap-around ASI,
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

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 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

At 17:12 21 June 2005, Stefan wrote:
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 wrote:

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

AFTER I did it, yes I thought back and yes, the
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.

At 17:24 21 June 2005, Eric Greenwell wrote:
M B wrote:

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

Mark J. Boyd

M B wrote:

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

I've read your entries, MB, and, in common with Stefan,
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.

Crap Mark, do you think before you press *send*? It rarely seems so.


Mark Dickson wrote:
I've read your entries, MB, and, in common with Stefan,
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.

I see nothing crap in Mark's post. Could you perhaps
explain?

At 04:48 22 June 2005, Mev wrote:
Crap Mark, do you think before you press *send*? It
rarely seems so.


Mark Dickson wrote:
I've read your entries, MB, and, in common with Stefan,
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.