Safety of winch launch vrs. aero tow?

On Sun, 2 Nov 2003 00:05:21 -0000, "W.J. \(Bill\) Dean \(U.K.\)."
wrote:

There have been many accidents of the types described,
insufficient energy to avoid a heavy landing after a launch failure,
and a spin entry after stalling during the first part of the launch.

See this example:
http://www.alexburger.de/sf/seilriss.avi

Pilot suffered only minor injury.

Bye
Andreas

Marty, I'm going to top post here since I can't figure out which way this
thread is expanding.

In the first case, the weak link at the tug failed because the tugee
modified it without our knowledge or approval. In the second case the rope
itself was the weak link and it most likely failed because it was left
laying on the ground in the path of a landing 2-33 which cut some of the
strands with its razor sharp metal skid.

I know that in the first case, the glider was in perfect position - the link
just fell apart. In the second, the student was flying but was not badly
out of position. In both cases the failure was a complete surprise to the
CFI-G.

These incidents happened at different airports under different conditions
and operating procedures but to the same CFI-G in the same month. One could
argue, as I did, that the CFI-G shared responsibility with the tug pilot to
check the integrity of the rope and weak links . As we know, this is hard
to do for each flight at a busy operation and we rely on the operating
procedures and ground personnel to insure the rope is usable. Sometimes
your luck just runs out.

My original point was that with airtow stuff happens and sometimes you
aren't in position for a return to the runway. In winch launching, you are.

Bill Daniels

"Martin Eiler" wrote in message
...
Should we assume that these two rope breaks were during aero tow?
The next obvious question is how strong were the weak links and
why did they break.

The fact that this individual had two weak links break at a low enough
altitude that it resulted in his landing off field, does make us wonder
what the complete story is. Was he solo in a single place glider? Or
was it a result of letting a student get too far out of position?
Inquiring
minds would like to know.

M Eiler

More specifics please for those off-airport landings. Otherwise your
"1000
feet" may be taken by some as a bit of an exageration.
Jack


In my friends case, the first break came shortly after crossing the
field
boundary at about 50 feet. This was a case of insufficient climb angle
to
reach 200 feet while still in range of the runway. The other, as I
understand it, was at about 300 feet but still out of gliding range of
the
airport.

My comment about 1000 feet referred to a situation that happened to me
because the tug pilot turned downwind at 100 feet AGL with a heavy
glider
and strayed still further downwind as the air tow ground on despite
urgent
radio calls. It was only at 1000 feet AGL that I felt that I could
release
and get back. (and get another tug pilot) This has happened to me too
many
times to recall all of them.

Understand, I fly in an area where density altitude at takeoff can
exceed
10,000 feet. It takes a strong tug to keep a heavy two seater
constantly
in
range of the runway.

My point with the original post is that there is no guarantee that the
magic
200 feet AGL will always get you back.

Bill Daniels

Not always.

I learnt to fly at the London Gliding Club, Dunstable Downs some 40 years
ago, entirely on the winch, and on the T21b.

There was one run for which I was taught that the correct procedure for a
launch failure at a certain height was to land beyond the airfield boundary
in the farmer's field.

The point surely is that before the launch starts the pilot should have in
mind all the possible options to cope with any launch failure; this may
include an off-airfield landing for either a wire or an aerotow launch.

Incidentally, the London Club now has more land, and outlandings after a
winch launch failure are not now required.

W.J. (Bill) Dean (U.K.).
Remove "ic" to reply.


"Bill Daniels" wrote in message
nk.net...

snip

My original point was that with airtow stuff happens and sometimes you
aren't in position for a return to the runway. In winch launching, you
are.

Bill Daniels

The film clip posted by Andreas shows another sort of accident, i.e. it
seems not to have been caused by rotating too much and hence
insufficient energy to avoid a heavy landing. Instead it is one of the
accidents relatively common in winch launching - we do not see the
glider leaving the cable, but it clearly flies at an adequate airspeed
for some distance before spinning off a turn which is too steep, too
close to the ground, in the wind gradient, and too slow for that set of
circumstances. Without knowing the site one cannot say what the pilot
should have done instead, but it is rare for there not to be a "land
ahead" option with less serious potential after a low cable break or
launch failure.

As I remarked before, it is not the winch launch itself that usually
produces the accident, it is pilot mismanagement of the subsequent
flightpath.

The too-little-energy syndrome this thread had been discussing most
recently is pilot mismanagement during the launch - not having learned
properly how to avoid having too little energy to cope with any
eventuality.

Both kinds of pilot error seem hard to eradicate in civilian gliding
clubs, which leads to considerable numbers of "winch launch" related
statistics.

My understanding is that the Air Cadets in the UK, who do huge amounts
of winch launching, have a much better safety record. It is rumoured
that they achieve this by teaching in a more regimented fashion. However
they do it, it demonstrates that winch launching CAN be safe - the
problem is the human element, not the technology itself. The only way
the human element can be made safer is by better training etc.

If a wave of winch launching were to commence in the USA, I think it
would be difficult to avoid a wave of accidents following, unless the
training and conversion of pilots were done better than we often manage
in the UK civilian gliding world. I wish every success to the
instigators of the project, and I hope they can pick up enough know-how
to climb the learning curve safely.

Chris N.

Of course. When we say 200 feet, it's the first 199 that are
important. As a rule, you should only attempt to land in what you can
see up to 200 feet agl. You've already been planning your landing
during the tow, now you need only execute.

Above 200 feet you have more options, one of which is to recognize the
conditions (wind shear, sink, low airspeed, tailwind on takeoff, etc.)
which may not favor a rote return to the airfield. But above 200 you
can start planning landings to known fields that you cannot see (not
necessarily the airport).

In article , F.L. Whiteley
writes
There once was a non-BGA soaring site/club in East Anglia in the UK. The
operator was named Fred, but the surname escapes me and I believe he passed
away in the 1980's. By all accounts he operated a steam winch though I
never met him nor saw it in action. I believe that operation was dwindling
and may have ceased operations about 1980. Any stories out there?

Frank Whiteley

In the 60s there was an instructor at the Midland GC who had the idea of
building a steam winch.

Because the Long Mynd is largely peat, we thought we might use the
terrain as a fuel source.

The project never got off the ground; we never got any steam driven,
Mynd fuelled launches.


--
Mike Lindsay
n

"Chris Nicholas" wrote in message
...
The film clip posted by Andreas shows another sort of accident, i.e. it
seems not to have been caused by rotating too much and hence
insufficient energy to avoid a heavy landing. Instead it is one of the
accidents relatively common in winch launching - we do not see the
glider leaving the cable, but it clearly flies at an adequate airspeed
for some distance before spinning off a turn which is too steep, too
close to the ground, in the wind gradient, and too slow for that set of
circumstances. Without knowing the site one cannot say what the pilot
should have done instead, but it is rare for there not to be a "land
ahead" option with less serious potential after a low cable break or
launch failure.

As I remarked before, it is not the winch launch itself that usually
produces the accident, it is pilot mismanagement of the subsequent
flightpath.

The too-little-energy syndrome this thread had been discussing most
recently is pilot mismanagement during the launch - not having learned
properly how to avoid having too little energy to cope with any
eventuality.

Both kinds of pilot error seem hard to eradicate in civilian gliding
clubs, which leads to considerable numbers of "winch launch" related
statistics.

My understanding is that the Air Cadets in the UK, who do huge amounts
of winch launching, have a much better safety record. It is rumoured
that they achieve this by teaching in a more regimented fashion. However
they do it, it demonstrates that winch launching CAN be safe - the
problem is the human element, not the technology itself. The only way
the human element can be made safer is by better training etc.

If a wave of winch launching were to commence in the USA, I think it
would be difficult to avoid a wave of accidents following, unless the
training and conversion of pilots were done better than we often manage
in the UK civilian gliding world. I wish every success to the
instigators of the project, and I hope they can pick up enough know-how
to climb the learning curve safely.

Chris N.


Chris makes a good point.

There does seem to be a condition experienced by some people who find it
hard to make fast mental adjustments from one set of conditions to another.
One moment they are setting on the ground and 35 seconds later then are high
in the sky at the controls of a glider and struggling to cope. The rush of
a winch launch may create a sensory overload beyond their ability to manage.

This may be analogous to a well known condition experienced by some
motorists who enter a high speed expressway and find it hard to adjust to
the fast traffic for a while. (and, of course, the reverse when leaving the
expressway and entering slow surface traffic.) I have never experienced
this and know of relatively few who do.

If we were more alert to this possibility we might intervene and ask a pilot
showing these symptoms to get a little more recurrent training. Perhaps
this is something we instructors should emphasize in training. Instructors
should be alert to sensory overload in their students and pace their lessons
accordingly but things do happen quickly in a winch launch.

Bill Daniels

In article , "Adrian Jansen"
writes:

I was lucky enough to get a kite launch one day. We had about 35 Kts of
wind on the ground, and someone suggested we try a launch. An instructor
and I climbed into a Blanick L13, launched ( *very* short run ! ) and
climbed to 4300 ft still on the wire. Of course we needed the expert
cooperation of the winch driver, who eased off the power as we got about 500
ft, then payed out cable to let us climb. At the end, it was mostly the
weight of cable ( single strand high tensile steel wire ) which determined
the max height, although there wasnt much wire left on the drum.

Yessss, but!!

I suggest you now estimate the wing loading with 4300 ft of high tensile steel
plus the down pull of the winch. Because you cannot feel the "G" loading on a
winch does not mean it is not there and two effects occur.

1) Your stalling speed increases with the weight of cable dangling below you,
and,

2) the G loading increases by the weight of cable attached to your glider so
you MAY be far exceding your all up "weight".

Beware, whilst this may be great fun, you get much closer to the envelope
limits than you know.Care is needed.

Barney
UK

On Sun, 02 Nov 2003 15:03:18 GMT, "Bill Daniels"
wrote:


There does seem to be a condition experienced by some people who find it
hard to make fast mental adjustments from one set of conditions to another.
One moment they are setting on the ground and 35 seconds later then are high
in the sky at the controls of a glider and struggling to cope. The rush of
a winch launch may create a sensory overload beyond their ability to manage.

Hmmm... I never saw this during a winch launch yet. The work load
during a winch launch is very low compared to an aerotow - the only
thing you really need to watch is airspeed and the "bang" of a rope
break.

The situation you describe (when the pilot gets behind the plane)
happens much more often during very low maneuvering (like low
approaches) - suddenly pilot looses track of airspeed and stalls, for
example (just as the clip I posted shows).



Bye
Andreas

On Sun, 02 Nov 2003 15:03:18 GMT, "Bill Daniels"
wrote:

There does seem to be a condition experienced by some people who find it
hard to make fast mental adjustments from one set of conditions to another.
One moment they are setting on the ground and 35 seconds later then are high
in the sky at the controls of a glider and struggling to cope. The rush of
a winch launch may create a sensory overload beyond their ability to manage.

Hmm... If their sensory is overloaded so easily, then they should
consider to quit flying immediately.

Stefan