Winch Launch Fatality

At 18:34 23 June 2009, bildan wrote:
On Jun 23, 11:14=A0am, John Smith wrote:
bildan wrote:
Answer the question: =A0WHY A PRIORITY?

Because it's automatic and then it's done and you can fully
concentrate
on more important things like speed, coordinated flight and where to
land. And, surprise, your glider flies better without that chute
dangling in the wind, which may make the difference between a
non-event
and an event.

But I understand that you're fully absorbed by staring at your AOA
indicator and therefore don't have any capacity left to pull the
release
knob.



Do it because it's automatic! That's no reason at all.

Do it so you can get it out of the way and get on with the important
stuff like saving your life! Are you really thinking about what
you're writing?

If the drag of a parachute/rope is great enough a glider 'flies
significantly better without it', it will back release because of that
very drag. In fact, a parachute pulled by its apex has little drag.
Either way, it's a non-issue.

What we've done, without really thinking about it, is put a relatively
unimportant action - pulling the release - ahead of a series of very
urgent steps the pilot must take to avoid a serious accident. This
has almost certainly made an unfortunate contribution to the overall
accident record.

The first step in writing ANY EMERGENCY CHECKLIST is to eliminate all
actions that do not contribute to a safe outcome and then to
prioritize the remaining steps with the most urgent at the top.
Pulling the release does not contribute materially to a safe outcome
and, in any event, is not urgent enough to be anywhere near the top of
the list.

As for an AOA indicator, you're damn right I'd be looking at it - and
flying a much safer recovery as a result.


When the parachute covers the canopy, the AOA will be all that you have to
look at. This happened to me once on a winch launch. I'll take the extra
5 sec to get rid of the cable.

I saw a K13 in the UK have 1/4 of it tailplane removed, and at same club
the parachute somehow got on top of the wing. The instructor rolled
towards the cable to try to get it to slide off, only to have it catch in
the alieron. ####! This was many years ago and i forget how the cable
finally freed, but in both cases glider landed in a controlled fashion.
Root cause was discoved after second accident - parachute too big.

Two real points,
#1 winch or aerotow, hand on cable release at least until clear of the
ground, the benefit to release instantly is greater than risk of an
accidental release.

#2 winch/auto-tow cable break,

establish the appropriate nose down attitude quickly (as discussed here,
this depends on the stage of launch, but the recipricol of the climb is a
good approximation) but quickly, quickly, quickly, so this may mean close
to zero g as the nose goes down, and this needs practice to convince pilot
to quickly establish and maintain appropriate attitude, despite the
"stalled" sensations that will be induced, but note the wing is never
stalled particularly if you are appropriatly quick to establish the
correct attitude.

When the apropriate attitude is established it may still take several
seconds to establish the appropiate speed. Now is the time to dump the
cable and take a deep breath and "aviate" ...
Here is is simple, low? land ahead, space to land ahead? land ahead,
If no space to land ahead you will be high enough to implenet the
"eventualites" preparred before take off.

This youtube demonstrates incorrect attitude & pilot fully asleep

http://www.youtube.com/watch?v=jvK1O...e=channel_page

This youtube shows even a slight negative g (watch straps and stuff fly
up) as apropriate attitude is achieved, quickly quickly quickly , ...

http://www.youtube.com/watch?v=4csksheL-o4

Cable breaks happen often, none need be dangerous.

David.




At 20:00 23 June 2009, Ed Gaddy wrote:
At 18:34 23 June 2009, bildan wrote:
On Jun 23, 11:14=A0am, John Smith wrote:
bildan wrote:
Answer the question: =A0WHY A PRIORITY?

Because it's automatic and then it's done and you can fully
concentrate
on more important things like speed, coordinated flight and where to
land. And, surprise, your glider flies better without that chute
dangling in the wind, which may make the difference between a
non-event
and an event.

But I understand that you're fully absorbed by staring at your AOA
indicator and therefore don't have any capacity left to pull the
release
knob.



Do it because it's automatic! That's no reason at all.

Do it so you can get it out of the way and get on with the important
stuff like saving your life! Are you really thinking about what
you're writing?

If the drag of a parachute/rope is great enough a glider 'flies
significantly better without it', it will back release because of that
very drag. In fact, a parachute pulled by its apex has little drag.
Either way, it's a non-issue.

What we've done, without really thinking about it, is put a relatively
unimportant action - pulling the release - ahead of a series of very
urgent steps the pilot must take to avoid a serious accident. This
has almost certainly made an unfortunate contribution to the overall
accident record.

The first step in writing ANY EMERGENCY CHECKLIST is to eliminate all
actions that do not contribute to a safe outcome and then to
prioritize the remaining steps with the most urgent at the top.
Pulling the release does not contribute materially to a safe outcome
and, in any event, is not urgent enough to be anywhere near the top of
the list.

As for an AOA indicator, you're damn right I'd be looking at it - and
flying a much safer recovery as a result.


When the parachute covers the canopy, the AOA will be all that you have
to
look at. This happened to me once on a winch launch. I'll take the
extra
5 sec to get rid of the cable.

Ed Gaddy wrote:

I'll take the extra 5 sec to get rid of the cable.

Surely this is a typo and you've meant 0.5 Seconds.

At 21:18 23 June 2009, John Smith wrote:
Ed Gaddy wrote:

I'll take the extra 5 sec to get rid of the cable.

Surely this is a typo and you've meant 0.5 Seconds.


Yes I left out the .