Winch Launch Fatality

On Tue, 23 Jun 2009 09:10:28 -0700, T8 wrote:

On Jun 23, 11:14Â*am, Martin Gregorie
wrote:

Apart from anything else, your hand should be on the release knob
during the launch

This is surprising to me -- a non-winch-qualified pilot. Do you do the
same for aero tow?

Don't forget we're talking 30 seconds or so from when the glider first
moves until you're off the top of the cable, not several minutes, and no
trim changes should be needed during the launch.

And yes, because I learned to fly on the winch, I generally do keep my
hand on the release during an aero-tow. I leave the wheel down while on
tow, so in my Libelle there's never a need to take my left hand off the
release. If I'm flying anything else (e.g., a Puchacz for annual checks)
and need to re-trim, etc. I'll do that and then put my hand back on the
release.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

On Tue, 23 Jun 2009 09:03:01 -0700, T8 wrote:

On Jun 23, 11:14Â*am, Martin Gregorie
wrote:

Apart from anything else, your hand should be on the release knob
during the launch, so pulling it a couple of times immediately after
pushing over and just before letting go of it is an obvious move. That
is taught as SOP in my club.

That's surprising to me... a non-winch qualified guy. On an aero tow, I
would call that very risky business indeed.

On the winch there is a cable under tension connecting the glider's CG to
a few tonnes of winch. A consequence of this is that the glider is
unlikely to make sudden vertical movements before release - the main
effect of turbulence, thermals or gradient is to affect airspeed rather
than cause sudden vertical movements. This is quite unlike aero-tows.


Apart from that, exactly what you do with your release hand depends on
the cockpit arrangement in the glider:

- in the SZD Junior, where the T-shaped release grows out of the top left
of the panel on a stiff cable, you can put your left arm on the canopy
tail, straight fingers resting on the release. Closing the hand and
pulling is one fast, simple action.

- in a Libelle, where the release is on a relatively long cable between
your legs, your left arm is on your leg with fingers resting on the T-
shaped release. Again its simply a matter of close fingers and pull.

In both gliders rough ground or turbulence is unlikely to cause an
inadvertent release because (1) your hand isn't wrapped round the
release, (2) the cable isn't tight and (3) your arm ands hand is
supported. The situation isn't as clear-cut in, say, an ASK-21 with its
yellow ball dangling in mid-air, but you still want your hand very close
to it - touching but not grasping is good.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

On Tue, 23 Jun 2009 09:00:06 -0700, bildan wrote:

I don't think you made your case. I have seen LOTS of wire/rope breaks,
including weak link breaks, and nothing has ever stayed on the hook -
even with Schweizers.

I've seen several strops dropped when the pilot pulled the release after
a weak link broke. During a practice power fade the cable often stays on
through the push-over, so it follows that this is also likely if the
winch fails for real due to engine trouble or a fuel blockage.

The reason I brought this up is that I have seen many pilots nearly
bungle a recovery while pulling the release. Even with a hand on the
release, there's no guarantee a pilot will pull it - I've seen pilots
take their hand off the release and pull the spoilers. A launch failure
is no time to be multi-tasking.

I've never seen this. An ASW-19 or Pegase on finals with the wheel going
up and down, yes, but brakes opening after a cable break, never.

I want to see this priority list in order of decreasing urgency:

1. Nose way down NOW!
2. Get a safe airspeed ASAP!
3. Decide on the landing option (Straight or circle.)
4. Execute landing option - concentrate on airspeed and coordination.
5. Pull the release - maybe.

Move 5 up to 2 and I'll agree with your sequence. Three reasons:
(a) you're going to wait some seconds for the airspeed to build so
pulling it at this point doesn't delay any other actions.

(b) Your hand is on or very near the release, so just do it.

(c) As I said above, you may be faced with a power fade rather than
a cable break and the cable may still be on. Now, we know that
back-release works for a straight backward pull, but what if
its a high power fade and you get airspeed and turn. Would you
still expect the cable to back release at an angle to the flight
path?


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

1. Nose way down NOW!
2. Get a safe airspeed ASAP!
3. Decide on the landing option (Straight or circle.)
4. Execute landing option - concentrate on airspeed and coordination.
5. Pull the release - maybe.

Move 5 up to 2 and I'll agree with your sequence. Three reasons:
(a) you're going to wait some seconds for the airspeed to build so
* * pulling it at this point doesn't delay any other actions.

(b) Your hand is on or very near the release, so just do it.

(c) As I said above, you may be faced with a power fade rather than
* * a cable break and the cable may still be on. Now, we know that
* * back-release works for a straight backward pull, but what if
* * its a high power fade and you get airspeed and turn. Would you
* * still expect the cable to back release at an angle to the flight
* * path?

--
martin@ * | Martin Gregorie
gregorie. | Essex, UK
org * * * |

OK, maybe, as long as it isn't priority 1 - but now you are
introducing a power fade which is a different animal. Power fades are
demonstrated and practiced along with simulated rope breaks just so
pilots know the difference. No one has ever said, "Wow, that's
confusing - how do you tell the difference?"

(C.) However, this one deserves serious consideration. A break is an
obvious "thump" and an upward surge. (Spectra/Dyneema rope generates
a much more obvious thump than steel.)

Assuming the pilot is monitoring airspeed, a power fade means the nose
will coming down and be down to a normal glide attitude and airspeed
as power is totally lost - just as at the top of a normal launch. It
will be managed as if it were a normal launch with a normal release
pull - just at a lower height. Just as with a normal launch, the
winch driver will be alert to the rope not detaching from the glider
and fire the guillotine

For a winch power loss to be confused with a rope break, the power
failure would need to be a rare kind - some sort of explosive loss of
mechanical integrity or seizing up of the winch. But, if the rope is
still attached at the winch, there won't be the upward surge.

In article a08530ef-b0e3-470d-a5ff-e8e7615fd300
@s1g2000prd.googlegroups.com, says...
On Jun 23, 9:14*am, Martin Gregorie
wrote:
On Tue, 23 Jun 2009 06:24:24 -0700, bildan wrote:
On Jun 23, 4:34*am, John Smith wrote:
ucsdcpc wrote:
The routine we are taught is as follows, all part of the pre-flight
eventualities check before each launch:

1. * *decide on appropriate approach speed for conditions

2. * *in the event of a launch failure (not just cable brake) lower
the nose to an appropriate attitude

Wrong, very wrong, very dangerous. The correct sequence is:

1. Push the stick forward and pull the release knob.

2. If possible, land ahead on the remaining runway.

3. If you're too high to land ahead, you have all the time to decide
your further actions. This can be an abbreviated circuit or a downwind
landing, depending on the circumstances.

And yes, doing a 180 too hasty will put you in a situation where you
don't have enough runway to land. So whatever you do, don't panic.
Everything else depends.

Please explain why pulling the release is priority one.

Apart from anything else, your hand should be on the release knob during
the launch, so pulling it a couple of times immediately after pushing
over and just before letting go of it is an obvious move. That is taught
as SOP in my club.

*Most likely the
remaining rope and parachute gear has already back released.

.... only if the cable break was down near the winch. If the break was
near the glider you could still have several meters of cable and the
furled drogue dangling trailing from the hook. Its even more likely that
you'll still have the cable attached if the problem is a power fade at
the winch rather than a cable break.

Diverting attention to the release knob when other critical decisions
are pending seems odd when you think about it.

It should be in your hand already, so no attention diversion is needed.

Note to Schweizer operators: *Schweizer CG hooks require MUCH more force
to back release than the Tost release so you folks should pull.

There's the other answer: never train somebody to use a technique that is
unsafe on some types of glider. Murphy pretty much mandates they'll
forget to check the cable is gone when they're flying a type where it
matters.

--
martin@ * | Martin Gregorie
gregorie. | Essex, UK
org * * * |

I don't think you made your case. I have seen LOTS of wire/rope
breaks, including weak link breaks, and nothing has ever stayed on the
hook - even with Schweizers. But, even if pulling the release is
justified on the assumption that something MIGHT be on the hook AND
assuming that something on the hook would cause damage (It won't kill
you), why a priority?

The reason I brought this up is that I have seen many pilots nearly
bungle a recovery while pulling the release. Even with a hand on the
release, there's no guarantee a pilot will pull it - I've seen pilots
take their hand off the release and pull the spoilers. A launch
failure is no time to be multi-tasking. Screw the release - FLY THE
GLIDER!

I think everyone agrees on those three words as priority 1.

--
Duncan

On Tue, 23 Jun 2009 14:42:24 -0700, bildan wrote:

OK, maybe, as long as it isn't priority 1 - but now you are introducing
a power fade which is a different animal.

They aren't taught as distinct happenings here - just as winch launch
failures. I agree that they are seldom confused, but the actions to be
taken after a cable break or after a power fade is recognised are the
same: (1) nose down to establish approach speed, (2) make sure cable is
off (3).....

No one has ever said, "Wow, that's confusing - how do you
tell the difference?"

....and I didn't say or imply that anybody confuses the two.

(C.) However, this one deserves serious consideration. A break is an
obvious "thump" and an upward surge. (Spectra/Dyneema rope generates a
much more obvious thump than steel.)

Even when it breaks at the winch end? I wouldn't know - I've not yet
flown on the stuff.

Assuming the pilot is monitoring airspeed, a power fade means the nose
will coming down and be down to a normal glide attitude and airspeed as
power is totally lost - just as at the top of a normal launch.

If its a slow fade the airspeed may easily be lower than approach speed.
IME a slow fade is harder to recognize and deal with than a sudden cut or
a break.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

have a look at the simulation videos on the BGA website

http://www.gliding.co.uk/bgainfo/saf...nch-safety.htm

you don't have a lot of time to find the release knob if a wing drops



T8 wrote:
On Jun 23, 11:14 am, Martin Gregorie
wrote:

Apart from anything else, your hand should be on the release knob during
the launch

This is surprising to me -- a non-winch-qualified pilot. Do you do
the same for aero tow?

-T8

On Jun 23, 4:18*pm, ucsdcpc wrote:
have a look at the simulation videos on the BGA website

http://www.gliding.co.uk/bgainfo/saf...nch-safety.htm

you don't have a lot of time to find the release knob if a wing drops



Maybe not, but it's hard to believe the wing drop simulations are
representative. What reasonably trained pilots would stuff the wing
into the ground and then continue to hold full aileron into the low
wing? It would be interesting to see the same scenario simulated with
an external upset causing the wing drop and full recovery aileron
being applied at and after wing tip contact. Throw in various amounts
of drag on the low wing tip to simulate short grass, long grass, etc
and then introduce pilot release before, at, and after wing tip
contact, and I'd start to believe it was a useful training aid.


Andy

Subject changed. As J.May wrote: "We are speculating which is wrong.
Lets not insult the guys that paid a terrible price in the name of a
sport we all love". That said, don't let me stop you guys from
debating the cable break procedure....

At 02:41 23 June 2009, bildan wrote:

Might I ask that you actually read what I wrote before correcting me. What
I said is exactly what you have said but in two or three lines.

On Jun 22, 6:15=A0pm, Don Johnstone wrote:
Much has been said and written about winch launch failures and here is
my
"Guide to Surviving a launch failure"

Launch fails

1 Pitch the nose down, at least approach attitude - snip

I have to take issue since anyone following this advice might/will get
hurt.

Rubbish


If you stop the pitch down at 'approach attitude' from an initial
attitude of 30 - 45 degrees nose up, you will be stalled - the nose
must be pushed far below 'approach attitude" to achieve prompt
airspeed recovery.

I said at least approach attitude, not stop at. "at least" means more
may be needed but it should never be less.

This is easy to demonstrate without a winch. At an altitude that
allows safe spin recovery, zoom up at a 45 degree nose-up attitude.
When the airspeed drops to 65 knots, pretend you have a rope break and
push over to 'approach attitude' and stop the pitch down there. Note
the airspeed - it will be around 20 knots. If you turn you will
spin. This is a classic killer on a winch.

I then said, ask the question is the speed at least approach speed only if
the answer to this is yes do you go to stage two which considers turning
only after considering a landing ahead.

There is no counting involved, no waiting, just checking to see if the
relevant conditions apply to allow the procedure to move on.

It is even better to demonstrate off a simulated launch failure and the
more you do the better.

I agree that starting a turn before the airspeed has increased is very bad
news which is why I emphasised that you do not even make the decision
between landing ahead and turning, let alone doing it until the airspeed
is up.