Wing Launch - Can it pull your wings off?

On Aug 13, 11:35*am, Frank Whiteley wrote:
On Aug 13, 10:56*am, Andy wrote:

On Aug 13, 8:30*am, bildan wrote:

Always use the EXACT weak link specified in the manual. *If a glider's
manual doesn't specify a winch launch weak link - you're going to be a
test pilot if you winch it.

What would be the consequence of using a link say 10% weaker than that
specified? *If I know the link is weaker I can fly a less agressive
climb profile and accept that I will get a lower launch altitude. *If
I forget and climb agressively the link will break - so what?

Andy

I've had experience as a winch driver with gliders using weaker links
resulting in frequent breakage. *In that case I would suggest the
pilot insisting on using the weaker link be held accountable for the
cost of broken link and any lost rigging. *Links are $7 (x4 in this
case) and I'm still looking for a missing strop, shackle, and ring set
($100). *Two went missing on a single day, with one having since been
recovered. *A few years ago a strop vanished and was found 4.5 years
later.

There are recommendations that if the correct value isn't specified or
known to use 1.3 x MAUW. *This is one reference to that formulahttp://tinyurl.com/258ba3j

Frank Whiteley

Again, Frank has provided a good analysis. Again I will add a few
points.

As frank says, a weaker than specified link will muck up the operation
when it breaks.

You really don't want it to break since you will then have to deal
with a launch failure - usually as you load the rope while rotating
into the climb. This, is NOT good.

If your glider was certified with an Approved Flight Manual, as all
JAR-22 gliders are, FAR's require you to operate in compliance with
that manual. That includes using the correct weak link - usually
specified to a + or - 10% tolerance. Incidentally, that also applies
to aero tow. The old 80-200% rule only applies to gliders without an
AFM. (i.e.Schweizers)

If you are being launched with one of the new Automatic Tension
Control winches, you must control your airspeed with pitch.
Attempting to climb at a lower angle will result in an over speed
condition.

The bottom line is you have no choice in weak links - you must use the
one specified in the manual.

On Aug 13, 12:00*pm, bildan wrote:

If your glider was certified with an Approved Flight Manual, as all
JAR-22 gliders are, FAR's require you to operate in compliance with
that manual.

Please be more specific. What particular FAR requires me to operate
my experimental (racing and exhibition) ASW-28 in compliance with the
flight manual?

The Experimental Operating Limitations contain specific extracts from
the flight manual that I am required to comply with. If content of
the flight manual was not extracted and included in the Experimental
Operating Limitations I am not aware that is has any regulatory
significance.

The flight manual extracts included in my limitations relate only to
maximum gross weight, allowable CG range, and maximum operating
speeds.

Sure, I recognize that it would be good practice to read and comply
with the flight manual, but that is not the same as being required to
do so by federal regulation.

Andy

On Aug 14, 5:28*pm, Andy wrote:
On Aug 13, 12:00*pm, bildan wrote:

If your glider was certified with an Approved Flight Manual, as all
JAR-22 gliders are, FAR's require you to operate in compliance with
that manual.

Please be more specific. *What particular FAR requires me to operate
my experimental (racing and exhibition) ASW-28 in compliance with the
flight manual?

The Experimental Operating Limitations contain specific extracts from
the flight manual that I am required to comply with. *If content of
the flight manual was not extracted and included in the Experimental
Operating Limitations I am not aware that is has any regulatory
significance.

The flight manual extracts included in my limitations relate only to
maximum gross weight, allowable CG range, and maximum operating
speeds.

Sure, I recognize that it would be good practice to read and comply
with the flight manual, but that is not the same as being required to
do so by federal regulation.

Andy

Every E&R Experimental operations limitations letter I've seen
requires operation in compliance with the AFM. FAR Part 91.9(a)
requires operation in compliance with an AFM if one is part of the
original airworthiness certification. (i.e JAR-22)

I'm very sure (based on FAA interpretations) if an E&R airworthiness
certificate is issued for a glider which had a standard airworthiness
certificate with AFM in it's country of origin, the mere issuance of a
US E&R airworthiness certificate does not excuse the owner of the
glider from compliance with the AFM.

On Aug 14, 6:37 pm, bildan wrote:

Every E&R Experimental operations limitations letter I've seen
requires operation in compliance with the AFM.

I can find no such requirement in mine. Does anyone else operating
experimental (racing/exhibition) have this requirement in their
operating limitations? If so, would you please email me a copy.

FAR Part 91.9(a) requires operation in compliance with an AFM if one is part of the
original airworthiness certification. (i.e JAR-22)

My operating limitations do not require compliance with all of part
91. They reference very specific sections. In reference to 91.9 they
state in para 21 - This aircraft shall contain the placards.,
markings, etc. required by 91.9.

91.9 (a) states

a) Except as provided in paragraph (d) of this section, no person may
operate a civil aircraft without complying with the operating
limitations specified in the approved Airplane or Rotorcraft Flight
Manual, markings, and placards, or as otherwise prescribed by the
certificating authority of the country of registry.

It is my interpretation that "or as otherwise prescribed by the
certificating authority of the country of registry" means that the
details of the operating limitations specified by FAA (the
certificating authority in the country of registry) take precedence.
Those operating limitations make specific reference to the requirement
for placards and markings but make no reference to the AFM.

Why would the operating limitations pick out specific sections of part
91, and specific data from the AFM, for inclusion unless only those
included references/restrictions were applicable? It would be far
simpler to state that the aircraft is required to operate in
accordance with Part 91.

I'm very sure (based on FAA interpretations) if an E&R airworthiness
certificate is issued for a glider which had a standard airworthiness
certificate with AFM in it's country of origin, the mere issuance of a
US E&R airworthiness certificate does not excuse the owner of the
glider from compliance with the AFM.

Can you please give me references to, or email copies of, any
interpretation that requires compliance with the AFM when the
operating limitations do not. Do those interpretations also relate to
compliance with an approved maintenance manual?

thanks

Andy

The debate on the merits and technicalities of winch launching will
rage on ad infinitum as it has for years in the winch newsgroups.
However, in terms of winch safety the statistics for the UK and
Germany are very different. Winch launching on the Continent shows a
much lower accident rate than the British experience. In other cases a
mishandling of statistics paints an out-of-focus picture. For example
an article published in Soaring magazine a while back quoted
statistics from a very small sample group to make a point about winch
safety. The article was very much off-base and was a poor piece of
work based on insufficient data. The German study, however, does
appropriately apply statistical analysis to an appropriate sample
size.

I am surprised that no one has asked the question: Is it sensible to
winch launch a 50-year old wooden glider, in which the type has had
reported structural issues? A quick look at the UK winch accident
records seems to involve a disproportionate number of old gliders and
marginal winch equipment. Having flown at winch operations in both the
UK and Germany, my limited experience has been that the Germans
(generally speaking) are operating with better equipment than may be
the case in the UK. (Yes, of course there are some operations in the
UK with all the latest stuff and good procedures. But on the grand
average maybe not as good as on the Continent.)

So when the original question is asked, the first context should be –
Really? Winch launching 50-year old wood wing gliders?

Bob

On Aug 15, 5:03*pm, RL wrote:
The debate on the merits and technicalities of winch launching will
rage on ad infinitum as it has for years in the winch newsgroups.
However, in terms of winch safety the statistics for the UK and
Germany are very different. Winch launching on the Continent shows a
much lower accident rate than the British experience. In other cases a
mishandling of statistics paints an out-of-focus picture. For example
an article published in Soaring magazine a while back quoted
statistics from a very small sample group to make a point about winch
safety. The article was very much off-base and was a poor piece of
work based on insufficient data. *The German study, however, does
appropriately apply statistical analysis to an appropriate sample
size.

I am surprised that no one has asked the question: Is it sensible to
winch launch a 50-year old wooden glider, in which the type has had
reported structural issues? * A quick look at the UK winch accident
records seems to involve a disproportionate number of old gliders and
marginal winch equipment. Having flown at winch operations in both the
UK and Germany, my limited experience has been that the Germans
(generally speaking) are operating with better equipment than may be
the case in the UK. (Yes, of course there are some operations in the
UK with all the latest stuff and good procedures. But on the grand
average maybe not as good as on the Continent.)

So when the original question is asked, the first context should be –
Really? Winch launching 50-year old wood wing gliders?

Bob

If gliders are not capable of being winch launched using the correct
weak link, they are not airworthy. We winch launch vintage gliders all
the time in the UK as part of a very active Vintage Glider movement.


Derek C

The debate on the merits and technicalities of winch launching will
rage on ad infinitum as it has for years in the winch newsgroups.
However, in terms of winch safety the statistics for the UK and
Germany are very different. Winch launching on the Continent shows a
much lower accident rate than the British experience. In other cases a
mishandling of statistics paints an out-of-focus picture. For example
an article published in Soaring magazine a while back quoted
statistics from a very small sample group to make a point about winch
safety. The article was very much off-base and was a poor piece of
work based on insufficient data. *The German study, however, does
appropriately apply statistical analysis to an appropriate sample
size.

Glad you brought this up, I also didn't like that article. My main
problem was less the sample data size, but rather the timeframe it
represented. It lumps all the statistics going back to the 60s into
single figures when it should really be separated into at least 2 or 3
different 'eras' for that same timeframe, when various gliding
authorities and groups identified common problems and implemented
standardized solutions that were game changers. Also, modern winches
are orders of magnitude more powerful and more importantly quite
controllable. That combined with material advances (UHMW etc) further
separate modern winching from it's roots.

Modern winching is pretty much a science and has come a long way since
the 60s so it does not do the soaring community (US at least...) a
favor to combine it all into single raw statistics cause it paints a
negative biased picture based on irrelevant data. It would be like
combining accident data from the era before seatbelts and airbags with
modern car accident statistical data, and then using that to form
statistics/articles to help potential future drivers decide how safe
cars are.

-Paul

On Sun, 15 Aug 2010 10:29:49 -0700 (PDT), sisu1a
wrote:


Modern winching is pretty much a science and has come a long way since
the 60s so it does not do the soaring community (US at least...) a
favor to combine it all into single raw statistics cause it paints a
negative biased picture based on irrelevant data.


Hmmm... I beg to differ.
Modern winching has very much in common with winching in the 60s.
The only difference is that the winches grew stronger in accordance to
the rising weight and speed of the gliders, but otherwise -at least in
Germany- very little has changed. Apart from the stronger engines the
rest of the equipment as well as the procedures are still the same as
fifty years ago.

It is not necessary (Bill - I know you are going to cry out now to
have the latest state-of-the-art gizmos (telemetry, plastic cables,
advanced speed control) to perform a perfectly safe and satisfactory
winch launch.

Cheers
Andreas

On Aug 15, 8:55*am, Andy wrote:
On Aug 14, 6:37 pm, bildan wrote:

Every E&R Experimental operations limitations letter I've seen
requires operation in compliance with the AFM.

I can find no such requirement in mine. *Does anyone else operating
experimental (racing/exhibition) have this requirement in their
operating limitations? *If so, would you please email me a copy.

FAR Part 91.9(a) requires operation in compliance with an AFM if one is part of the
original airworthiness certification. *(i.e JAR-22)

My operating limitations do not require compliance with all of part
91. *They reference very specific sections. *In reference to 91.9 they
state in para 21 - This aircraft shall contain the placards.,
markings, etc. required by 91.9.

91.9 (a) states

a) Except as provided in paragraph (d) of this section, no person may
operate a civil aircraft without complying with the operating
limitations specified in the approved Airplane or Rotorcraft Flight
Manual, markings, and placards, or as otherwise prescribed by the
certificating authority of the country of registry.

It is my interpretation that *"or as otherwise prescribed by the
certificating authority of the country of registry" means that the
details of the operating limitations specified by FAA (the
certificating authority in the country of registry) *take precedence.
Those operating limitations make specific reference to the requirement
for placards and markings but make no reference to the AFM.

Why would the operating limitations pick out specific sections of part
91, and specific data from the AFM, for inclusion unless only those
included references/restrictions were applicable? *It would be far
simpler to state that the aircraft is required to operate in
accordance with Part 91.

I'm very sure (based on FAA interpretations) if an E&R airworthiness
certificate is issued for a glider which had a standard airworthiness
certificate with AFM in it's country of origin, the mere issuance of a
US E&R airworthiness certificate does not excuse the owner of the
glider from compliance with the AFM.

Can you please give me references to, or email copies of, any
interpretation that requires compliance with the AFM when the
operating limitations do not. *Do those interpretations also relate to
compliance with an approved maintenance manual?

thanks

Andy

Andy, all you have to do is call your FSDO and ask for an opinion. If
you ask, "Do I have to comply with my glider's AFM if I have an E&R
airworthiness certificate?", you already know what the answer will be.

On Aug 15, 7:58*pm, bildan wrote:

Andy, all you have to do is call your FSDO and ask for an opinion. *If
you ask, "Do I have to comply with my glider's AFM if I have an E&R
airworthiness certificate?", you already know what the answer will be.


The person that issued my operating limitations has retired so I
cannot ask him for any interpretation. I will operate under the
limitations as issued, which are unambiguous in this regard, until
such time as the new FSDO staff decide to revoke them.

Thank you for your assistance in providing the applicable regulations
and precedent that support your position and for being so willing to
have a reasoned discussion of the issue.