Keep your hand off the release handle during aero tows!

On Sunday, October 6, 2013 2:53:16 AM UTC-6, Don Johnstone wrote:

http://www.aaib.gov.uk/cms_resources...NN%2006-13.pdf

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

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 control BEFORE the roll began and should have been airborne in around one second 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.

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

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.

On Sunday, October 6, 2013 2:08:30 PM UTC-6, 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

I'm not basing this entirely on the AAIB report - I can read between the lines and I have other sources. No, the AAIB didn't address those issues although they certainly should have.

Instead, they ignored a wealth of obvious facts and blamed the accident on the release position which has worked just fine in literally millions of releases. Even so, if the owner, or a maintenance shop, thought there was a problem, adding a flexible release extension is SOP. Such an extension is even shown in Figure 5 with the release T-handle BEHIND the stick. Figure 6 showing a 'pilot' with his RIGHT hand blocked from reaching a release is grossly misleading. I hope the AAIB doesn't risk its reputation by presenting this argument in court.

Independent sources the glider was not pointing at the winch and, John, even you suggest that's acceptable. I say the rope must be dead straight and the glider pointed exactly at the winch - no exceptions. This accident is a great example of why.

I've been officially involved in very similar accidents where the launch crew had far less time yet DID stop a launch in time to save a pilot who failed to release. Your crew had plenty of time to stop the launch. If the signaling system didn't permit such a timely signal, that's yet another problem that needs to be addressed.

Clearly the acceleration was VERY slow and the wing did drag so the roll was wobbly. Rolling 29m (95 feet) into a 15 knot headwind component proves it. A dry N3 with flaps set for winch launch lifts off below 33 knots so with the headwind, the winch only had to add 18 knots which requires less than one G for less than one second over a distance of less than 20 feet.

All winches, even a Skylaunch, have throttles so the phrase "very powerful rapidly accelerating winch" is meaningless. Acceleration depends only on the throttle setting.

So, what could have prevented this accident?
In order of importance:

1. Faster acceleration. Get a glider airborne and climbing before a wing can drop.

2. Insist every launch have the rope exactly straight and the glider pointed exactly at the winch.

3. Better communications. Maybe someone at the launch point should have a thumb hovering over a button that lights a big, bright "EMERGENCY STOP" sign in the winch cab. Better yet, have that button trigger the guillotine.

This accident report will serve as a classroom example for many years including a "can you find the screw-ups?" exercise. If you suspended the Imperial arrogance long enough, you might hear the groans and forehead slapping from the Continent and around the world - and if you listened to what they're saying you might start improving your miserable accident record.

Not a single instructor, check pilot or examiner I flew with in England and Germany ever suggested/required holding the release on a winch launch. I was always told to keep my hand close, but not wrapped around the knob.

Worked well every time.

At 02:06 05 October 2013, Bill T wrote:
Winch tow, hand on release? Not a good idea?

Asking a question? Making a statement? Sarcasm? What?

Jerk acceleration from some slack or something in the line and you
inadvertently pull the release.

HAD VERY MANY WINCH LAUNCHES?

All Out in my country means you take up the slack and launch. What slack
then?

"Or something else in the line". Like what, Gremlins tight rope walking?

HAVE MUCH WINCH EXPERIENCE?

What DOES cause slack in the ground roll or climb-

1. Pretty rare to have a tail wind gradient change as you climb or no wind
create momentary slack rope, but it happens.

So what? Then the trained winch driver gives more kts. Enough acceleration
to cause so severe a jerk and a premature detach because you were holding
the release? Pretty hard to fathom.

2. Poor pilot winch technique or not timely enough reactions, cause your
own slack, line catches up and a hard jerk? Not so. Thousands of feet of
line are very nice at cushioning shock, if not, maybe you should be
releasing and start over anyway.

3. EXPERIENCED winch pilots know instead, that with even a momentary slack,
usually a chute does you a favor, opens and an auto back release on a Tost
hook. If not, my left palm is right there on the left knee and left pinky
on the yellow knob for as fast as I can pull.

4. Hit severe sink on the way up, some slack (usually just a bow in the
line), recover as above or abort. Where's the jerk?

5. Novice winch driver or one with a lead foot on the accelerator and no
line tension control, brief cough in the motor, too fast a start can cause
slack in a stretched elastic line or break a weak link or both. Imagine all
the possible senarios. Prudence says immediately release and land straight
ahead, not react with a harder pull, steeper rotation to risk stall or back
release at a high AOA, or possibly break the weak link at not enough meters
high to have time, airspeed and elevator authority to aim back at the
ground and flare. (Maybe this is the type of situation where one can get so
excited and pull whatever he is holding on to.)

My hand (or part of it) is on (or near) the let-go mechanism.

I'm not basing this entirely on the AAIB report - I can read between the
li=
nes and I have other sources. No, the AAIB didn't address those issues
alt=
hough they certainly should have. =20

Instead, they ignored a wealth of obvious facts and blamed the accident
on
=
the release position which has worked just fine in literally millions of
re=
leases. Even so, if the owner, or a maintenance shop, thought there was
a
=
problem, adding a flexible release extension is SOP. Such an extension
is
=
even shown in Figure 5 with the release T-handle BEHIND the stick.
Figure
=
6 showing a 'pilot' with his RIGHT hand blocked from reaching a release
is
=
grossly misleading. I hope the AAIB doesn't risk its reputation by
present=
ing this argument in court.

OK, try sitting in a Schemp Hirth or even and ASW 17/19/20 with the stick
full to the left and try finding the release knob if you do not actually
have your hand on it. The time you have to realise you have a problem and
react is very short, trying to find the release will take longer than the
time you have.

Independent sources the glider was not pointing at the winch and, John,
eve=
n you suggest that's acceptable. I say the rope must be dead straight
and
=
the glider pointed exactly at the winch - no exceptions. This accident is
a=
great example of why.

Actually the glider should point down the direction if the initial cable
run, of course that should be the same as the direct line to the winch.

I've been officially involved in very similar accidents where the launch
cr=
ew had far less time yet DID stop a launch in time to save a pilot who
fail=
ed to release. Your crew had plenty of time to stop the launch. If the
si=
gnaling system didn't permit such a timely signal, that's yet another
probl=
em that needs to be addressed.=20

Not so, anyone with any experience of winch launching would know that the
time taken for a stop signal to be sent, received by the winch driver and
reacted on is way more than the time taken for the event you are trying to
prevent being over.

Clearly the acceleration was VERY slow and the wing did drag so the roll
wa=
s wobbly. Rolling 29m (95 feet) into a 15 knot headwind component proves
i=
t. A dry N3 with flaps set for winch launch lifts off below 33 knots so
wi=
th the headwind, the winch only had to add 18 knots which requires less
tha=
n one G for less than one second over a distance of less than 20 feet.
=20

All winches, even a Skylaunch, have throttles so the phrase "very
powerful
=
rapidly accelerating winch" is meaningless. Acceleration depends only on
t=
he throttle setting.

So, what could have prevented this accident?
In order of importance:

1. Faster acceleration. Get a glider airborne and climbing before a wing
c=
an drop.

Wing drop is not the cause of the problem, it is a symptom. The primary
problem is yaw and increased acceleration will exacerbate this.

2. Insist every launch have the rope exactly straight and the glider
pointe=
d exactly at the winch.

3. Better communications. Maybe someone at the launch point should have
a
=
thumb hovering over a button that lights a big, bright "EMERGENCY STOP"
sig=
n in the winch cab. Better yet, have that button trigger the guillotine.

This accident report will serve as a classroom example for many years
inclu=
ding a "can you find the screw-ups?" exercise. If you suspended the
Imperi=
al arrogance long enough, you might hear the groans and forehead slapping
f=
rom the Continent and around the world - and if you listened to what
they'r=
e saying you might start improving your miserable accident record.

Nothing like a bit of ignorance to provoke a complete misunderstanding of
reality. To a certain extent this type of accident is an operating hazard
which can be mitigated by making sure that at the very least a pilot is
immediately able to terminate the launch. To suggest that a chain of people
outside the aircraft can react in time to effect the chain of events, given
the total time over which the situation becomes irrecoverable, shows an
incredible depth of ignorance.
I have absolutely no doubt that over the years pilots in the UK have
avoided death or injury by having their hand on the release from the time
the cable is attached until complete control is gained in the launch. No,
it does not work every time, you have to actually pull it when it goes
wrong but part of the problem is that it may not be immediately apparent
that it is going wrong until it is to late for anything other than
mitigation.
The real point is that having your hand on the release may save your life,
to me that is a complete no brainer.

Re winch launching. You guy's might like to check out the very
useful Safe winching leaflet and associated information put out by
the BGA after much thought and refinement of the process's. This
has resulted in a significant reduction in the number of
accidents/injury's in the UK from winch launching.

http://www.gliding.co.uk/bgainfo/saf...hlaunching.htm

Regards

Andy

Re winch launching. You guy's might like to check out the very
useful Safe winching leaflet and associated information put out by
the BGA after much thought and refinement of the process's. This
has resulted in a significant reduction in the number of
accidents/injury's in the UK from winch launching.

http://www.gliding.co.uk/bgainfo/saf...hlaunching.htm

Regards

Andy

Re winch launching. You guy's might like to check out the very
useful Safe winching leaflet and associated information put out by
the BGA after much thought and refinement of the process's. This
has resulted in a significant reduction in the number of
accidents/injury's in the UK from winch launching.

http://www.gliding.co.uk/bgainfo/saf...hlaunching.htm

Regards

Andy