Winch Launch Fatality

On Jun 24, 10:45*am, Del C wrote:
I knew that agreeing with Bill Daniels was too good to last!

Given a vaguely competent pilot, the most likely cause of a wing drop is a
gust, especially if there is a cross-wind component. That is what happened
in the series of photos that show a K13 standing on it's starboard
wingtip. I put a link into this in an earlier posting. Please note that
full opposite aileron and rudder is being applied throughout this
incident!

On the subject of not accidentally pulling the release knob as a result of
holding it, you need to arrange the cockpit so you are not holding the
release at full stretch.

Some glass single seaters are very good at hiding the release knob almost
out of reach somewhere below your crutch and behind the stick. On my own
glider I have extended the cable so it is easier to reach the knob (with
the approval of a BGA Inspector I hasten to add).

The last fatal cartwheel accident in the UK involved an ASW20L glider. If
you read the aaib report, they concluded that once the stick was hard over
to the left, which it would have been as it was the right wing that
dropped, it would have been almost impossible to get to the release knob
if you weren't holding it already!

Derek Copeland

At 15:29 24 June 2009, bildan wrote:

On Jun 23, 5:42=A0pm, Andy *wrote:
On Jun 23, 4:18=A0pm, 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. =A0What reasonably trained pilots would stuff the wing
into the ground and then continue to hold full aileron into the low
wing? =A0It 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. =A0Throw 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

It's realistic in the sense that the most likely way a wing would go
down is if the pilot does, in fact, "stuff it down". *Unfortunately,
you just have to watch a few takeoffs to see it happen. *One of my
frustrations is pilots who seem to have no idea where their ailerons
are until a wingtip hits the ground.

If the pilot consciously centers the ailerons as part of the pre-
takeoff checks and lets the wing runner balance the glider, the glider
will just stay balanced on its own for several seconds after the wing
runner lets go *- long enough to get aileron control on either aero
tow or winch. *That's good practice with any launch method.

What I see in that K-13 sequence is the parachute disappearing off the
left side of the frame after it was released. It gives the appearance
the glider was staged at least 30 degrees off the line of sight to the
winch. I also don't see any aileron or rudder applied in the first
frame with the wing on the ground indicating the pilot was WAAY behind
the glider.

Blaming this 100% on a gust seems a reach.

Fully agree with Derek, it stands to reason that an inadvertant cable
release at any moment in the launch is less risky that failure to release
instantly if things start to go wrong.

Its doesn't have to be white nuckle grip, but hlold it you must!

Eventualities before launch will cover the recovery scenario for the
launch ahead no matter it is a cable break or accidental/deliberate cable
release.

Even well away from the ground, the relative merit seems to remain.

David.

At 16:45 24 June 2009, Del C wrote:
I knew that agreeing with Bill Daniels was too good to last!

Given a vaguely competent pilot, the most likely cause of a wing drop is
a
gust, especially if there is a cross-wind component. That is what
happened
in the series of photos that show a K13 standing on it's starboard
wingtip. I put a link into this in an earlier posting. Please note that
full opposite aileron and rudder is being applied throughout this
incident!

On the subject of not accidentally pulling the release knob as a result
of
holding it, you need to arrange the cockpit so you are not holding the
release at full stretch.

Some glass single seaters are very good at hiding the release knob
almost
out of reach somewhere below your crutch and behind the stick. On my own
glider I have extended the cable so it is easier to reach the knob (with
the approval of a BGA Inspector I hasten to add).

The last fatal cartwheel accident in the UK involved an ASW20L glider.
If
you read the aaib report, they concluded that once the stick was hard
over
to the left, which it would have been as it was the right wing that
dropped, it would have been almost impossible to get to the release knob
if you weren't holding it already!

Derek Copeland


At 15:29 24 June 2009, bildan wrote:
On Jun 23, 5:42=A0pm, Andy wrote:
On Jun 23, 4:18=A0pm, 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. =A0What reasonably trained pilots would stuff the
wing
into the ground and then continue to hold full aileron into the low
wing? =A0It 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. =A0Throw 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

It's realistic in the sense that the most likely way a wing would go
down is if the pilot does, in fact, "stuff it down". Unfortunately,
you just have to watch a few takeoffs to see it happen. One of my
frustrations is pilots who seem to have no idea where their ailerons
are until a wingtip hits the ground.

If the pilot consciously centers the ailerons as part of the pre-
takeoff checks and lets the wing runner balance the glider, the glider
will just stay balanced on its own for several seconds after the wing
runner lets go - long enough to get aileron control on either aero
tow or winch. That's good practice with any launch method.

In message , Del C
writes
snip

Some glass single seaters are very good at hiding the release knob almost
out of reach somewhere below your crutch and behind the stick. On my own
glider I have extended the cable so it is easier to reach the knob (with
the approval of a BGA Inspector I hasten to add).

The last fatal cartwheel accident in the UK involved an ASW20L glider. If
you read the aaib report, they concluded that once the stick was hard over
to the left, which it would have been as it was the right wing that
dropped, it would have been almost impossible to get to the release knob
if you weren't holding it already!
Snip

I might be wrong but I think they also concluded that having the left
hand where it could reach the release knob would have made full left
aileron impossible. My own glider has similarities with an ASW20 and
also has a short extension on the release pull.

--
Surfer!
Email to: ramwater at uk2 dot net

On Wed, 24 Jun 2009 08:29:22 -0700 (PDT), bildan
wrote:

It's realistic in the sense that the most likely way a wing would go
down is if the pilot does, in fact, "stuff it down". Unfortunately,
you just have to watch a few takeoffs to see it happen. One of my
frustrations is pilots who seem to have no idea where their ailerons
are until a wingtip hits the ground.

If the pilot consciously centers the ailerons as part of the pre-
takeoff checks and lets the wing runner balance the glider, the glider
will just stay balanced on its own for several seconds after the wing
runner lets go - long enough to get aileron control on either aero
tow or winch. That's good practice with any launch method.


Hi Bill,

I'm not sure if your observation is correct.

During aerotows you often see the wing runner working hard to keep the
wing perfectly balanced, the pilot keeps ailerons centered, wing
runner lets go - and the wing tip hits the ground immediately before
the pilot has time to apply aileron. A typical crosswind situation.

The problem is that the pilot cannot sense the wing-drop tendency (and
apply opposite aileron) as long as the wing runner keeps the wing
level.
The better technique is if the wing runner follows the wing-drop
tendency, not trying to keep the wings level - the pilot is going to
feel one wing going down (although still held by the wing runner,
hence no danger of the wing tip touching the ground) and will apply
aileron immediately. This usually works like a charm.


And then there were those open class ships in crosswind situations
where you have to apply full aileron to the lee side from the
beginning of the aerotow (even if this wing drops)... because despite
full aileron this side it's going to come up again.....

On Jun 24, 4:38*pm, Andreas Maurer wrote:
On Wed, 24 Jun 2009 08:29:22 -0700 (PDT), bildan
wrote:

It's realistic in the sense that the most likely way a wing would go
down is if the pilot does, in fact, "stuff it down". *Unfortunately,
you just have to watch a few takeoffs to see it happen. *One of my
frustrations is pilots who seem to have no idea where their ailerons
are until a wingtip hits the ground.

If the pilot consciously centers the ailerons as part of the pre-
takeoff checks and lets the wing runner balance the glider, the glider
will just stay balanced on its own for several seconds after the wing
runner lets go *- long enough to get aileron control on either aero
tow or winch. *That's good practice with any launch method.

Hi Bill,

I'm not sure if your observation is correct.

During aerotows you often see the wing runner working hard to keep the
wing perfectly balanced, the pilot keeps ailerons centered, wing
runner lets go - and the wing tip hits the ground immediately before
the pilot has time to apply aileron. A typical crosswind situation.

The problem is that the pilot cannot sense the wing-drop tendency (and
apply opposite aileron) as long as the wing runner keeps the wing
level.
The better technique is if the wing runner follows the wing-drop
tendency, not trying to keep the wings level - the pilot is going to
feel one wing going down (although still held by the wing runner,
hence no danger of the wing tip touching the ground) and will apply
aileron immediately. This usually works like a charm.

And then there were those open class ships in crosswind situations
where you have to apply full aileron to the lee side from the
beginning of the aerotow (even if this wing drops)... because despite
full aileron this side it's going to come up again.....

If the wing runner balances the glider into the crosswind while the
pilot holds neutral aileron it will work just fine, but the two have
to work together. The wing runner should feel for the tilt into the
wind that balances the glider so it's a tossup which wing would fall
if he let go but he can only do this if the ailerons are neutral.
Another instructor and I worked this out long ago. Since we often ran
wings for each other it was easy to teach the technique to our
students. (Ailerons neutral until the wing runner lets go - then fly
the glider with the same bank into the wind as the wing runner gave
you.)

If the wing runner just "holds the wing level" it may well drop to the
ground when he lets go. If the pilot is wagging the ailerons around,
the wing runner can't do anything to help.

BTW, there's another 'gotcha' you often see with aero tow takeoffs in
crosswinds. A crosswind will blow the tugs propeller blast downwind
so it hits the gliders downwind wing. The glider encounters the prop
blast after rolling about half the towrope length. Usually by then
the pilot is holding into-the-wind aileron which together with the
prop blast will slam the upwind wing into the ground before the pilot
reacts. If you are ready for it, you can handle it OK but it catches
many pilots unaware.