Winch Launch - Fatal

On Tue, 06 Dec 2016 08:27:58 -0800, Jonathan St. Cloud wrote:

What happened in this accident to cause the N3 to "flip over" in the
early stage of launch?

Read this:

https://assets.publishing.service.go...74a1317000923/
Schempp-Hirth_Nimbus-3_glider_G-EENN_06-13.pdf

Its the full AAIB report on this accident and contains full and useful
discussions about wing-drops during winch launches and of the importance
of cockpit layout with regard to interference between flying controls and
the hook release knob: both are relevant in this case.


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

On Tue, 06 Dec 2016 15:04:50 +0000, Jock Proudfoot wrote:

http://www.heraldscotland.com/news/1...pilot_killed_i
n_freak_accident_during_take_off/

This report has nothing to do with either of the recent fatal accidents.

It is about a Nimbus 3 winching accident at Portmoak in September 2012,
over four years ago.


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

There are few things in this world which arise out of nothing, The release location in schempp hirth gliders just inside the pilots left knee/thigh is at least as old as the austrias and the shk s. the later cirri and ventus , etc, were continuing a design feature which had worked in the past.
The potential interference may never have been reported due to the rare and lethal nature of the adverse event.
Scott.

No, the position changes subtly.

On my cirrus and N2 it is at the lower left of the stick box quadrant, on
the
N3 in question and later gliders it is in the upper left.

Please read the accident report and its conclusions.

At 02:17 09 December 2016, Scott Williams wrote:
There are few things in this world which arise out of nothing, The
release
=
location in schempp hirth gliders just inside the pilots left knee/thigh
is=
at least as old as the austrias and the shk s. the later cirri and
ventus
=
, etc, were continuing a design feature which had worked in the past.
The potential interference may never have been reported due to the rare
and=
lethal nature of the adverse event.
Scott.

At 08:24 09 December 2016, Pete Smith wrote:
No, the position changes subtly.

On my cirrus and N2 it is at the lower left of the stick box quadrant,
o
the
N3 in question and later gliders it is in the upper left.

Please read the accident report and its conclusions.

The accident described in the report was not so much of an issue
when Earlier ASW,17, 18,19,20 were designed and built. Same applied
to SH.
The accident is directly related to more powerful winches. The same
situation would develop with less powerful winches but it took much
much longer. There was more of a ground run to recognise the wing
on the ground and the acceleration was much less which meant that
when it went wrong it went wrong much slower with more time to
react. Not so with a modern powerful winch, when the problem occurs
it goes wrong very quickly, probably too quickly for any chance for a
meaningful reaction. What is described has always happened from time
to time, the only difference is that it did not start killing people until

the winches got powerful.

So how dangerous is wench launching compared to aero-tow? I only had enough wench launches to remove the "aero-tow only" off my ticket and that was years ago.

On Friday, December 9, 2016 at 7:45:05 AM UTC-8, Don Johnstone wrote:
At 08:24 09 December 2016, Pete Smith wrote:
No, the position changes subtly.

On my cirrus and N2 it is at the lower left of the stick box quadrant,
o
the
N3 in question and later gliders it is in the upper left.

Please read the accident report and its conclusions.

The accident described in the report was not so much of an issue
when Earlier ASW,17, 18,19,20 were designed and built. Same applied
to SH.
The accident is directly related to more powerful winches. The same
situation would develop with less powerful winches but it took much
much longer. There was more of a ground run to recognise the wing
on the ground and the acceleration was much less which meant that
when it went wrong it went wrong much slower with more time to
react. Not so with a modern powerful winch, when the problem occurs
it goes wrong very quickly, probably too quickly for any chance for a
meaningful reaction. What is described has always happened from time
to time, the only difference is that it did not start killing people until

the winches got powerful.

Pretty dangerous for the wench, I imagine. Depending on her weight, you might need a weak link.

The Soaring Safety Foundation (US) should have the best info on this https://www.soaringsafety.org/ This is a very good resource for safety training. There have been some European and UK studies out there since they tend to winch more than US. Aero-tow kills more tow pilots than winching kills wenches.

At 16:19 09 December 2016, Jonathan St. Cloud wrote:
So how dangerous is wench launching compared to aero-tow? I only
had enough
wench launches to remove the "aero-tow only" off my ticket and that
was
years ago.

I do not have the figures but my answer would be as safe as any other
method of launching.
I do not know but I suspect the number of winch launches in the UK
runs to many thousands per year. Accidents like the one described are
very rare, the last recorded 4 years ago.
Aerotows tend to be more of a gotcha for tuggies but there are a lot
less of them so they are even less frequent.
Bungee launching tends to involve lighter gliders but has it's share of
accidents, very few fatal.
Winching is not for the unwary and less forgiving of errors than other
methods, more so since the introduction of modern powerful winches
with the ability to accelerate very very quickly.

Wench launching can be very dangerous, especially if she's heavy and
your aim is poor...

On 12/9/2016 9:19 AM, Jonathan St. Cloud wrote:
So how dangerous is wench launching compared to aero-tow? I only had enough wench launches to remove the "aero-tow only" off my ticket and that was years ago.

On Friday, December 9, 2016 at 7:45:05 AM UTC-8, Don Johnstone wrote:
At 08:24 09 December 2016, Pete Smith wrote:
No, the position changes subtly.

On my cirrus and N2 it is at the lower left of the stick box quadrant,
o
the
N3 in question and later gliders it is in the upper left.

Please read the accident report and its conclusions.

The accident described in the report was not so much of an issue
when Earlier ASW,17, 18,19,20 were designed and built. Same applied
to SH.
The accident is directly related to more powerful winches. The same
situation would develop with less powerful winches but it took much
much longer. There was more of a ground run to recognise the wing
on the ground and the acceleration was much less which meant that
when it went wrong it went wrong much slower with more time to
react. Not so with a modern powerful winch, when the problem occurs
it goes wrong very quickly, probably too quickly for any chance for a
meaningful reaction. What is described has always happened from time
to time, the only difference is that it did not start killing people until

the winches got powerful.

--
Dan, 5J

On Friday, December 9, 2016 at 8:45:05 AM UTC-7, Don Johnstone wrote:
At 08:24 09 December 2016, Pete Smith wrote:
No, the position changes subtly.

On my cirrus and N2 it is at the lower left of the stick box quadrant,
o
the
N3 in question and later gliders it is in the upper left.

Please read the accident report and its conclusions.

The accident described in the report was not so much of an issue
when Earlier ASW,17, 18,19,20 were designed and built. Same applied
to SH.
The accident is directly related to more powerful winches. The same
situation would develop with less powerful winches but it took much
much longer. There was more of a ground run to recognise the wing
on the ground and the acceleration was much less which meant that
when it went wrong it went wrong much slower with more time to
react. Not so with a modern powerful winch, when the problem occurs
it goes wrong very quickly, probably too quickly for any chance for a
meaningful reaction. What is described has always happened from time
to time, the only difference is that it did not start killing people until

the winches got powerful.

Muddled thinking, Don.

All winches have throttles so they produce no more power than the winch operator chooses. If the winch seems too powerful, you're problem is with the winch operator, not the winch.

Did "powerful" winches cause a wing drop and subsequent ground loop? Highly unlikely. The problem is far more likely to be with pilot training and general winch operations.

Wings go down on winch launch for three main reasons.

One, excessively slow acceleration allows a wing drop before the pilot gains aileron control - same as with aero tow. The difference is with a CG hook an ensuing ground loop is going to be more violent. It's much safer to get the glider up to aileron control airspeed in the minimum time.

Two, with a fast accelerating winch, should the pilot begin the ground roll with aileron input, they will take effect suddenly forcing a wing tip to the ground before the pilot can react - consciously centering the stick before the launch starts is critical. Avoiding over-controlling ailerons is equally important.

Three, wing "runners" sometimes mishandle the situation. If they are accustomed to aero tow, they will be surprised how quickly the tip must be released.