At 20:08 06 October 2013, John Galloway wrote:
At 15:34 06 October 2013, Bill D wrote:
On Sunday, October 6, 2013 2:53:16 AM UTC-6, Don
Johnstone wrote:


http://www.aaib.gov.uk/cms_resources.cfm?
file=3D/Schempp-Hirth%20Nimbus-3=
%20glider%20G-EENN%2006-13.pdf

There are so many bonehead screw-up's in this report it
makes one want to
c=
ry.

A few:

1. Not staging the glider so it points exactly at the winch.
2. A VERY long, slow, wobbly takeoff roll despite a 15kt
headwind
component=
..
3. A failure of the launch crew to stop the launch when a wing
went down.
4. Not releasing when it was clear the ground roll wasn't
precisely normal.

A dry Nimbus 3 launching into a 15 knot wind would likely
have aileron
cont=
rol BEFORE the roll began and should have been airborne in
around one
secon=
d after rolling about a glider length. Obvious point: Once
airborne,
there=
's no danger of dragging a wing.

At least you Brits are good at writing accident reports.


This tragic accident happened to one of my club colleagues.
With reference to the comments above:

1) There is nothing in the AAIB report to suggest that the glider
was not pointing at the winch. It was situated 30m from the
position that the cables had been drawn to and so the cable
would have been pulled over to the glider. It may have been
better to point the glider away from the winch and somewhat
towards the line of the cable. (Better still to have minimized
the bow in the cable by positioning the glider closer to the cable
and pulling the cable as straight as possible.)

2)There is nothing in the report to suggest "a very long, slow,
wobbly takeoff roll". I can report from personal experience of
many launches from the winch and professional winch-driver
involved that this is a very powerful rapidly accelerating winch.
The AAIB report makes direct reference to the fact that the
winch was operated correctly according to the manufacturer.
The cable released at 4 seconds from the start of the launch
with the glider already airborne and unrecoverable so that
leaves no time for a takeoff roll as characterised above.

3) There is no suggestion in the AAIB report of a "failure" by the
ground crew to stop the launch. This point is specifically
addressed:

"On this occasion both the wing holder and the launch signaller
saw the wing touch the ground but events then developed
quickly, so it is unlikely that either of them had time to consider
and make a ‘stop’ signal. Therefore, the responsibility to
release the cable would have to rest with the pilot"

4) Agreed - to release the cable as soon as the wing cannot be
kept level is vital.

John Galloway

All John says is absolutely correct. The sad fact is that this type of
accident occurs on a fairly regular basis and as yet no one has come up
with a plausible cause. What is clear that the wing drop is a symptom and
requires that the glider is released very early which is why the hand
should be on the release. A similar accident happened at my club a month
back involving a Discus, in that case the pilot was unhurt but the glider
was written off.
What is clear is that once the glider starts to yaw nothing on this earth
is going to stop it except contact with the ground so early release, to
mitigate the inevitable accident, is essential.