Glider accident while filming commercial in 2011. NTSB Report updated

In article Bill D writes:

I'm positive that if it's done right, winch launch is far safer than aero t=
ow. Germans suffer one accident on average every 180,000 winch launches wh=
ile we suffer one every 24,000 aero tows. I know there are cultural differ=
ences but, presumably, we're pretty good at aero tow and they're at least a=
s good at winch launch so the comparison is probably valid.

But, what is the severity of these accidents? An article (referenced below)
lists 18 fatal+36 serious injury out of 380 winch launch accidents (14.2 percent).
Aerotow had 1 fatal+2 serious injury out of 103 launch accidents (2.9 percent).

See http://www.soaringsafety.org/ssf-06/articles.html - the articles from
November 2006 report a higher rate of winch accidents than aerotow, and a 7.2
times ratio of winch fatalities vs aerotow once adjusted for number of tows of
each type.

The Feb 2008 column revisits it with few additional numbers.

It's natural for familiar things like aero tow to seem safe and unfamiliar =
things like winch launch to look unsafe but the numbers tell a different st=
ory.

The numbers I found in the November 2006 article appear to favor
aerotow for safety, both in accidents per launch, and in severity of
the accident once it has happened.

Alan

At 00:28 22 June 2013, Frank Whiteley wrote:


Hard to say from the report images whether the rope had any worry marks,
bu=
t there are some discolorations in the break area. It appears to be
reason=
able quality rope, but nylon just is not the right media and is very low
wo=
rking limit for it's breaking strength and diameter. The recoil of the
rop=
e in the video is pretty interesting as the bulk of the rope bunches up
in
=
a clump only a few fuselage lengths behind the glider. If the rope had
pre=
viously recoiled toward the release on the car during earlier launches,
it'=
s possible it was compromised by impacting the car or release hardware
(hen=
ce the marks). One witness described seeing 6-8 inches of rope remaining
a=
t the car end.



Ropes may be expected to break, but choice of rope makes a big
difference.

Frank Whiteley

We use skyrope, which is nylon rope on our winch and the failure rate is
much less than with wire rope

On Saturday, June 22, 2013 1:41:41 AM UTC-6, Alan wrote:
In article Bill D writes:



I'm positive that if it's done right, winch launch is far safer than aero t=

ow. Germans suffer one accident on average every 180,000 winch launches wh=

ile we suffer one every 24,000 aero tows. I know there are cultural differ=

ences but, presumably, we're pretty good at aero tow and they're at least a=

s good at winch launch so the comparison is probably valid.



But, what is the severity of these accidents?

The severity is exactly the same for both aero tow and winch. The German LBU accident statistics are available on-line just as the NTSB data is. I suggest you verify them yourself.

I have no idea where the SSF got their numbers but it may have been the UK since no translations are required. 2011 data shows the UK suffers one accident every 16,000 launches while Germany suffers one every 180,000. German numbers are roughly comparable to the rest of continental Europe. The SSF needs to take another, wider look.

On 6/21/2013 1:14 PM, Frank Whiteley wrote:
Some have said there's nothing new in this report.
Indeed there remain some missing details, but there
is also a new fact that I don't recall from the prior reports and
my inquiries, including discussion with the observer in the back of
the launch vehicle.

If the facts are correct, anyone involved in ground launching should have zeroed in on the rope.

And on that previously taped-over damage to the wing leading edge! In
my (very limited) experience with leading edge damage, that's possibly
sufficient to cause a wicked wing drop in a deep stall. So it could
have contributed to the accident, even though the NTSB report didn't
seem to give it much significance.

There is no way that glider was legally airworthy with that unrepaired
wing damage.

See the examination report with pictures he
http://dms.ntsb.gov/pubdms/search/do...9&mkey=8205 9


Or:http://preview.tinyurl.com/m6ul7gq

A few weeks ago a German visitor told me that it's now unlawful in Germany
to air tow with a CG release. Four of my five gliders have had CG hooks
only and most of my launches are by air tow. Frankly I don't see the
problem (I know the physics) - simply fly the glider and who needs the
self-righting forces of a nose hook?


"Bill D" wrote in message
...
On Friday, June 21, 2013 9:49:00 AM UTC-6, Dan Marotta wrote:
I just started reviewing your training guide, Bill, and I must say,

"Excellent!"

Thanks for the kind word. My only objective is to promote safe winch
launch.

I'm positive that if it's done right, winch launch is far safer than aero
tow. Germans suffer one accident on average every 180,000 winch launches
while we suffer one every 24,000 aero tows. I know there are cultural
differences but, presumably, we're pretty good at aero tow and they're at
least as good at winch launch so the comparison is probably valid.

It's natural for familiar things like aero tow to seem safe and unfamiliar
things like winch launch to look unsafe but the numbers tell a different
story.

I would venture a guess that we (in the USA) are trained for the most part
in aero tow and are very accustomed to it. Winch launching is a novelty
here whereas in Europe it's much more prevalent and the pilots there are
more familiar with the winch.


"Alan" wrote in message
...
In article Bill D
writes:

I'm positive that if it's done right, winch launch is far safer than aero
t=
ow. Germans suffer one accident on average every 180,000 winch launches
wh=
ile we suffer one every 24,000 aero tows. I know there are cultural
differ=
ences but, presumably, we're pretty good at aero tow and they're at least
a=
s good at winch launch so the comparison is probably valid.

But, what is the severity of these accidents? An article (referenced
below)
lists 18 fatal+36 serious injury out of 380 winch launch accidents (14.2
percent).
Aerotow had 1 fatal+2 serious injury out of 103 launch accidents (2.9
percent).

See http://www.soaringsafety.org/ssf-06/articles.html - the articles
from
November 2006 report a higher rate of winch accidents than aerotow, and a
7.2
times ratio of winch fatalities vs aerotow once adjusted for number of
tows of
each type.

The Feb 2008 column revisits it with few additional numbers.

It's natural for familiar things like aero tow to seem safe and unfamiliar
=
things like winch launch to look unsafe but the numbers tell a different
st=
ory.

The numbers I found in the November 2006 article appear to favor
aerotow for safety, both in accidents per launch, and in severity of
the accident once it has happened.

Alan

On Saturday, June 22, 2013 4:02:59 AM UTC-6, Don Johnstone wrote:
At 00:28 22 June 2013, Frank Whiteley wrote:





Hard to say from the report images whether the rope had any worry marks,

bu=

t there are some discolorations in the break area. It appears to be

reason=

able quality rope, but nylon just is not the right media and is very low

wo=

rking limit for it's breaking strength and diameter. The recoil of the

rop=

e in the video is pretty interesting as the bulk of the rope bunches up

in

=

a clump only a few fuselage lengths behind the glider. If the rope had

pre=

viously recoiled toward the release on the car during earlier launches,

it'=

s possible it was compromised by impacting the car or release hardware

(hen=

ce the marks). One witness described seeing 6-8 inches of rope remaining

a=

t the car end.







Ropes may be expected to break, but choice of rope makes a big

difference.



Frank Whiteley



We use skyrope, which is nylon rope on our winch and the failure rate is

much less than with wire rope



The technical specifications would be more helpful than the hyberbole
http://www.skylaunchuk.com/proddetai...prod=CC-9-1200

Can you point to something more useful about this product?

Frank

Dan M wrote: “Frankly I don't see the problem (I know the physics) - simply fly the glider and who needs the self-righting forces of a nose hook?”

The small number of pilots who killed a tug pilot by kiting did, and the larger number who nearly have, including some quite recently. We are having a campaign in the UK to try to stop it again, but humans being what they are . . .


Chris M

On Saturday, June 22, 2013 3:56:46 PM UTC-6, Chris Nicholas wrote:
Dan M wrote: “Frankly I don't see the problem (I know the physics) - simply fly the glider and who needs the self-righting forces of a nose hook?”



The small number of pilots who killed a tug pilot by kiting did, and the larger number who nearly have, including some quite recently. We are having a campaign in the UK to try to stop it again, but humans being what they are . . .





Chris M

Chris, the accident record shows pilots using a nose hook are quite capable of killing a tow pilot by kiting. The concern about CG hooks is understandable but I doubt outlawing them for aero tow will make much difference.

The bottom line is aero tow is a lot more dangerous than people think. I once heard it described as, "Formation flight between two grossly mis-matched aircraft tied together by a 200 foot rope - something no sane person would approve as an air-show act."

Bill, I entirely agree that it is not the only factor - we have
identified 6 factors as the most notable circumstances, of which
belly hooks are one. It is a fact that the first such UK fatality was
with a belly hook (and also turbulence, and probably
recency/currency, were others in that case).

Dan’s point AIUI was you only have to fly the glider. My main point
was too many people didn’t, and over here at least are starting not
to again. Another of my points is that by education and supervision,
we are trying to address the re-emergence of the issue.

Our policy is that you should not have more than two, if that, of the
factors present on any one launch. Had that been known, adopted
and followed, the first such fatality would probably not have
happened.

By the way, another factor not in the list of 6 is distraction, which
has emerged recently in incident reports.

Regards - Chris