Winch Launch Fatality

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

In message
,
toad writes
snip

There is one less Discus in the world because the pilot had his hand
on the release on a bumpy day. He "in-advertently" pulled the release
at low altitude and crashed into the trees. The pilot was not
injured, but the glider was totaled. If you want to keep your hand on
the release, then hold it some way that prevents turbulence from
releasing it for you.

Since a launch can fail at any point, inadvertently releasing shouldn't
lead to totalling the glider...

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

Once a wing drops onto the ground, the glider will almost inevitably veer
off in the same direction due to ground friction, which is what you see
here and what you also see in my video of a wing drop. The photographer
didn't quite catch the start of this incident, and I am sure that the
glider would have been lined up correctly.

The wing tip runner for the K13 was a very experienced pilot and an ex
syndicate partner of mine. He told me that it was a cold, windy and very
blustery day and that none of our runways lined up with the wind
direction, so there was about a 30 degree cross wind from the right. The
chain of events started with a violent gust that caused the wing to drop
as he let go. The instructor tried to pull off, but his gloved hand
slipped round the round release knob, twice in fact. He was successful at
the third attempt, but reported that it took a lot more force than he
expected to release under tension. By this time he was airborne, so had to
take over and fight the glider back onto the ground somehow. What was
interesting was the the eventual landing direction was at right angles to
the start direction, once the rudder was taken off. The student pilot may
not have dealt with the dropping wing very well, but there is no evidence
that he contributed to it.

After this incident, our CFI wanted to fit T handle releases to our K13s,
but EASA said no because it counted as a major modification and would
require full design approval (very expensive). Bureaucracy gone mad or
what!

Derek Copeland


At 18:54 24 June 2009, bildan wrote:
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.

At 19:50 24 June 2009, Surfer! wrote:
In message , Del C
writes


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!


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.


Either way, it's not a desirable design feature.!!!

Derek C

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.....

What is particularly interesting in both the video and the photographs is
the direction the glider is pointing relative to the cable. In the video
the glider can be seen to yaw as the cable tightens and then further yaw
as the it starts to move.
In the photographs it is clear that the glider is pointing to the right of
the direction of the cable AND stangely is pointed in the same direction as
the K13 parked behind it, a co-incidence perhaps. In both cases it would
appear possible that the glider was not lined up with the cable prior to
launch so that as soon as the cable moved yaw was induced. With a CofG
hook the glider will be more unstable about the yaw axis than was the case
with the more forward release on older gliders. Perhaps that might explain
why this appears to be a "new" phenomenon.


At 21:45 24 June 2009, Derek Copeland wrote:
Once a wing drops onto the ground, the glider will almost inevitably
veer
off in the same direction due to ground friction, which is what you see
here and what you also see in my video of a wing drop. The photographer
didn't quite catch the start of this incident, and I am sure that the
glider would have been lined up correctly.

The wing tip runner for the K13 was a very experienced pilot and an ex
syndicate partner of mine. He told me that it was a cold, windy and very
blustery day and that none of our runways lined up with the wind
direction, so there was about a 30 degree cross wind from the right. The
chain of events started with a violent gust that caused the wing to drop
as he let go. The instructor tried to pull off, but his gloved hand
slipped round the round release knob, twice in fact. He was successful
at
the third attempt, but reported that it took a lot more force than he
expected to release under tension. By this time he was airborne, so had
to
take over and fight the glider back onto the ground somehow. What was
interesting was the the eventual landing direction was at right angles
to
the start direction, once the rudder was taken off. The student pilot
may
not have dealt with the dropping wing very well, but there is no
evidence
that he contributed to it.

After this incident, our CFI wanted to fit T handle releases to our
K13s,
but EASA said no because it counted as a major modification and would
require full design approval (very expensive). Bureaucracy gone mad or
what!

Derek Copeland


At 18:54 24 June 2009, bildan wrote:
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.

The apparent cable offset was because we were using a retrieve winch.
However the cable always pulled approximately straight under tension as
the launch commenced. It was normal to place the launch queue on the
downwind side of the retrieve winch, so that any slight weather-cocking at
the start of the launch if anything further reduced the angle between the
cable and the glider, and also reduced the possibility of the wind getting
under the upwind wing. The gliders would have been set up to point at the
main winch, or just slightly upwind of it to reduce any yaw at the start.


IMHO the use of a retrieve winch actually reduces the possibility of a
wing drop, and was not a factor in either case. Particularly in the video,
the glider was running straight before the wing drop occured, and was
probably due to the student pilot failing to do anything positive to keep
the wings level in a slight cross wind from the right, plus a late
take-over by a very newly qualified (at the time) instructor.

Derek Copeland


At 01:00 25 June 2009, Don Johnstone wrote:
What is particularly interesting in both the video and the photographs
is
the direction the glider is pointing relative to the cable. In the video
the glider can be seen to yaw as the cable tightens and then further yaw
as the it starts to move.
In the photographs it is clear that the glider is pointing to the right
of
the direction of the cable AND stangely is pointed in the same direction
as
the K13 parked behind it, a co-incidence perhaps. In both cases it would
appear possible that the glider was not lined up with the cable prior to
launch so that as soon as the cable moved yaw was induced. With a CofG
hook the glider will be more unstable about the yaw axis than was the
case
with the more forward release on older gliders. Perhaps that might
explain
why this appears to be a "new" phenomenon.


At 21:45 24 June 2009, Derek Copeland wrote:
Once a wing drops onto the ground, the glider will almost inevitably
veer
off in the same direction due to ground friction, which is what you see
here and what you also see in my video of a wing drop. The photographer
didn't quite catch the start of this incident, and I am sure that the
glider would have been lined up correctly.

The wing tip runner for the K13 was a very experienced pilot and an ex
syndicate partner of mine. He told me that it was a cold, windy and
very
blustery day and that none of our runways lined up with the wind
direction, so there was about a 30 degree cross wind from the right.
The
chain of events started with a violent gust that caused the wing to
drop
as he let go. The instructor tried to pull off, but his gloved hand
slipped round the round release knob, twice in fact. He was successful
at
the third attempt, but reported that it took a lot more force than he
expected to release under tension. By this time he was airborne, so had
to
take over and fight the glider back onto the ground somehow. What was
interesting was the the eventual landing direction was at right angles
to
the start direction, once the rudder was taken off. The student pilot
may
not have dealt with the dropping wing very well, but there is no
evidence
that he contributed to it.

After this incident, our CFI wanted to fit T handle releases to our
K13s,
but EASA said no because it counted as a major modification and would
require full design approval (very expensive). Bureaucracy gone mad or
what!

Derek Copeland


At 18:54 24 June 2009, bildan wrote:
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.

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.

On Jun 24, 7:00*pm, Don Johnstone wrote:
What is particularly interesting in both the video and the photographs is
the direction the glider is pointing relative to the cable. In the video
the glider can be seen to yaw as the cable tightens and then further yaw
as the it starts to move.
In the photographs it is clear that the glider is pointing to the right of
the direction of the cable AND stangely is pointed in the same direction as
the K13 parked behind it, a co-incidence perhaps. In both cases it would
appear possible that the glider was not lined up with the cable prior to
launch so that as soon as the cable moved yaw was induced. With a CofG
hook the glider will be more unstable about the yaw axis than was the case
with the more forward release on older gliders. Perhaps that might explain
why this appears to be a "new" phenomenon.

Nope, they lined it up at an angle to the wire then all the other
stuff compounded the problem. There are other videos from Lasham with
the gliders improperly staged which show a similar wobbly takeoff. If
the gilder isn't pointing at the winch, the takeoff will be
'interesting'. Unfortunately, some people in the US are showing the
k-13 photo sequence as proof that winches are too dangerous to use.
This actually forced me to add a paragraph in my winch training
syllabus cautioning pilots to aim gliders at the winch - which any kid
launching a balsa glider with a rubber band would understand without
being told.

To be fair, there very well could have been a wind event that we, in a
dustier climate, would call a "dust devil" which couldn't be seen in
lush green England. We would see it coming and stand down until the
thing passed - then launch and go chase it for the lift it marks.

For Christs sake Bill! Lasham is the largest and most professional gliding
club in the UK and we do about 10,000 winch launches per year, 9,999 of
which go without incident. We do know what we are doing. We either point
the glide directly at the main winch, or just slightly upwind of it in a
crosswind to reduce any initial yaw due to weather cocking.

The K13 incident was caused by a gust, and the glider was landed without
damage or injury. A similar wing drop during an aerotow would be
considered quite unremarkable. The correct thing to do is to pull off if a
wing drops during a winch launch.

Derek Copeland

At 03:42 26 June 2009, bildan wrote:
On Jun 24, 7:00=A0pm, Don Johnstone wrote:
What is particularly interesting in both the video and the photographs
is
the direction the glider is pointing relative to the cable. In the
video
the glider can be seen to yaw as the cable tightens and then further
yaw
as the it starts to move.
In the photographs it is clear that the glider is pointing to the
right
o=
f
the direction of the cable AND stangely is pointed in the same
direction
=
as
the K13 parked behind it, a co-incidence perhaps. In both cases it
would
appear possible that the glider was not lined up with the cable prior
to
launch so that as soon as the cable moved yaw was induced. With a CofG
hook the glider will be more unstable about the yaw axis than was the
cas=
e
with the more forward release on older gliders. Perhaps that might
explai=
n
why this appears to be a "new" phenomenon.

Nope, they lined it up at an angle to the wire then all the other
stuff compounded the problem. There are other videos from Lasham with
the gliders improperly staged which show a similar wobbly takeoff. If
the gilder isn't pointing at the winch, the takeoff will be
'interesting'. Unfortunately, some people in the US are showing the
k-13 photo sequence as proof that winches are too dangerous to use.
This actually forced me to add a paragraph in my winch training
syllabus cautioning pilots to aim gliders at the winch - which any kid
launching a balsa glider with a rubber band would understand without
being told.

To be fair, there very well could have been a wind event that we, in a
dustier climate, would call a "dust devil" which couldn't be seen in
lush green England. We would see it coming and stand down until the
thing passed - then launch and go chase it for the lift it marks.