Wing Launch - Can it pull your wings off?

[ContestID67[_2_]]

I was sent this link from a UK soaring friend of mine about a death
when the wings came off of a glider during a winch tow.
http://www.dailymail.co.uk/news/article-1302215/Pilot-plunged-death-boyfriend-BOTH-wings-fell-glider.html

Sad story. A few things;

- My friend's thought was that the wing pins were left out. Howerver,
this was the second flight of the day. Both winch launches. So I
would think that the wing pins were installed but the wings failed
under a winch load. Which glider was it? Older? Wooden spars?
Never having had a winch launch, what happens if you don't release
back pressure at the top? Can you pull your wings off? Maybe
safeties on the pins were missed and the pins wiggled out on the
second flight after staying in for the first.

- I was under the impression that the BGA required parachutes for all
pilots. Wrong? 1000 ft should have been enough to get out in time
but who knows what was happening in the cockpit or if she was 1000 MSL
or AGL at the time.

Thanks.

- John DeRosa

[Tony[_5_]]

On Aug 12, 4:16*pm, ContestID67 > wrote:
> I was sent this link from a UK soaring friend of mine about a death
> when the wings came off of a glider during a winch tow.http://www.dailymail.co.uk/news/article-1302215/Pilot-plunged-death-b...
>
> Sad story. *A few things;
>
> - My friend's thought was that the wing pins were left out. *Howerver,
> this was the second flight of the day. *Both winch launches. *So I
> would think that the wing pins were installed but the wings failed
> under a winch load. *Which glider was it? *Older? *Wooden spars?
> Never having had a winch launch, what happens if you don't release
> back pressure at the top? *Can you pull your wings off? *Maybe
> safeties on the pins were missed and the pins wiggled out on the
> second flight after staying in for the first.
>
> - I was under the impression that the BGA required parachutes for all
> pilots. *Wrong? *1000 ft should have been enough to get out in time
> but who knows what was happening in the cockpit or if she was 1000 MSL
> or AGL at the time.
>
> Thanks.
>
> - John DeRosa

I suppose if you overload the structure you can rip the wings off
anything. No glider is immune from this.

[[email protected]]

On Aug 12, 5:16*pm, ContestID67 > wrote:
> I was sent this link from a UK soaring friend of mine about a death
> when the wings came off of a glider during a winch tow.http://www.dailymail.co.uk/news/article-1302215/Pilot-plunged-death-b...
>
> Sad story. *A few things;
>
> - My friend's thought was that the wing pins were left out. *Howerver,
> this was the second flight of the day. *Both winch launches. *So I
> would think that the wing pins were installed but the wings failed
> under a winch load. *Which glider was it? *Older? *Wooden spars?
> Never having had a winch launch, what happens if you don't release
> back pressure at the top? *Can you pull your wings off? *Maybe
> safeties on the pins were missed and the pins wiggled out on the
> second flight after staying in for the first.
>
> - I was under the impression that the BGA required parachutes for all
> pilots. *Wrong? *1000 ft should have been enough to get out in time
> but who knows what was happening in the cockpit or if she was 1000 MSL
> or AGL at the time.
>
> Thanks.
>
> - John DeRosa

There was a thread about this recently.
The Gist:
IF glider is in proper condition
AND correct weak link is used
THEN- you won't pull the wings off on launch.

And- 1000 ft is not much time to asess, open canopy, get out, and open
chute. Virtually no chance.
FWIW
UH

[Frank Whiteley]

On Aug 12, 3:16*pm, ContestID67 > wrote:
> I was sent this link from a UK soaring friend of mine about a death
> when the wings came off of a glider during a winch tow.http://www.dailymail.co.uk/news/article-1302215/Pilot-plunged-death-b...
>
> Sad story. *A few things;
>
> - My friend's thought was that the wing pins were left out. *Howerver,
> this was the second flight of the day. *Both winch launches. *So I
> would think that the wing pins were installed but the wings failed
> under a winch load. *Which glider was it? *Older? *Wooden spars?
> Never having had a winch launch, what happens if you don't release
> back pressure at the top? *Can you pull your wings off? *Maybe
> safeties on the pins were missed and the pins wiggled out on the
> second flight after staying in for the first.
>
> - I was under the impression that the BGA required parachutes for all
> pilots. *Wrong? *1000 ft should have been enough to get out in time
> but who knows what was happening in the cockpit or if she was 1000 MSL
> or AGL at the time.
>
> Thanks.
>
> - John DeRosa

It was a Foka 4.

Foka-4 was a derivative of the Foka line
http://en.wikipedia.org/wiki/Foka_%28glider%29
Cobra was the next to last iteration, with 17m being the last.
http://en.wikipedia.org/wiki/SZD-36_Cobra_15
Note the comments on failures.

I don't know that the 4 had the same wing join design, but suspect it
was very similar.
There was a wing failure on a Cobra in the US and a sobering analysis.
http://www.sylacaugasoaring.com/SZD%20COBRA%20WARNING.htm

The SHK has an expanding vertical pin. There's an anecdotal story of
someone who used the right-hand to expand the pin, and finished the
job with left-hand, in the opposite direction. The wings reportedly
departed at the top of the launch. The pilot reportedly pulled the
tail chute on the way down.

I believe that some German studies found that successful egress and
parachute deployment below 600m is unlikely, of course there are
exceptions. The better emergency chutes are life saving from 100ft
agl at 100kts horizontal.

Wing failure on a winch launch is very rare. There was a K-7 at RAF
Dishforth in the UK a while back, but the investigation determined
there was prior damage to the spar which was not found following
another incident. There was a homebuilt in Colorado that had a wing
failure due to aileron flutter during a winch launch. After two weak
link breaks, the pilot doubled the weak link (unknown to the winch
crew). The described flight path was one of climb, level off, climb,
level off, climb, glider breakup, crash. The wing inspection hatch
was found early in the flight path. What did not appear in the NTSB
report was that the pilot was refused further tows at the local FBO
after the glider had suffered significant aileron flutter on aero tow.

I winched at RAF Bicester when it was the RAF/GSA Centre. Appropriate
weak links were always used, like any UK club. It's not a long run,
but easy enough to climb away on the thermal day.

Steel wire rope used in many places typically has a breaking strength
of 2800-3500lbs. The new UHMWPE 12-strand ropes (Spectra, Plasma,
Dyneema, Amsteel) now in common use are nominally 3500-5400lbs
breaking strength at similar diameters, thus use of correct weak links
are essential to avoid damaging a glider as some winches have
substantial power and there are also gusts and thermals to allow for.

Frank Whiteley

[bildan]

On Aug 12, 4:12*pm, Frank Whiteley > wrote:
> On Aug 12, 3:16*pm, ContestID67 > wrote:
>
>
>
> > I was sent this link from a UK soaring friend of mine about a death
> > when the wings came off of a glider during a winch tow.http://www.dailymail.co.uk/news/article-1302215/Pilot-plunged-death-b...
>
> > Sad story. *A few things;
>
> > - My friend's thought was that the wing pins were left out. *Howerver,
> > this was the second flight of the day. *Both winch launches. *So I
> > would think that the wing pins were installed but the wings failed
> > under a winch load. *Which glider was it? *Older? *Wooden spars?
> > Never having had a winch launch, what happens if you don't release
> > back pressure at the top? *Can you pull your wings off? *Maybe
> > safeties on the pins were missed and the pins wiggled out on the
> > second flight after staying in for the first.
>
> > - I was under the impression that the BGA required parachutes for all
> > pilots. *Wrong? *1000 ft should have been enough to get out in time
> > but who knows what was happening in the cockpit or if she was 1000 MSL
> > or AGL at the time.
>
> > Thanks.
>
> > - John DeRosa
>
> It was a Foka 4.
>
> Foka-4 was a derivative of the Foka linehttp://en.wikipedia.org/wiki/Foka_%28glider%29
> Cobra was the next to last iteration, with 17m being the last.http://en.wikipedia.org/wiki/SZD-36_Cobra_15
> Note the comments on failures.
>
> I don't know that the 4 had the same wing join design, but suspect it
> was very similar.
> There was a wing failure on a Cobra in the US and a sobering analysis.http://www.sylacaugasoaring.com/SZD%20COBRA%20WARNING.htm
>
> The SHK has an expanding vertical pin. *There's an anecdotal story of
> someone who used the right-hand to expand the pin, and finished the
> job with left-hand, in the opposite direction. *The wings reportedly
> departed at the top of the launch. *The pilot reportedly pulled the
> tail chute on the way down.
>
> I believe that some German studies found that successful egress and
> parachute deployment below 600m is unlikely, of course there are
> exceptions. *The better emergency chutes are life saving from 100ft
> agl at 100kts horizontal.
>
> Wing failure on a winch launch is very rare. *There was a K-7 at RAF
> Dishforth in the UK a while back, but the investigation determined
> there was prior damage to the spar which was not found following
> another incident. *There was a homebuilt in Colorado that had a wing
> failure due to aileron flutter during a winch launch. *After two weak
> link breaks, the pilot doubled the weak link (unknown to the winch
> crew). *The described flight path was one of climb, level off, climb,
> level off, climb, glider breakup, crash. *The wing inspection hatch
> was found early in the flight path. *What did not appear in the NTSB
> report was that the pilot was refused further tows at the local FBO
> after the glider had suffered significant aileron flutter on aero tow.
>
> I winched at RAF Bicester when it was the RAF/GSA Centre. *Appropriate
> weak links were always used, like any UK club. *It's not a long run,
> but easy enough to climb away on the thermal day.
>
> Steel wire rope used in many places typically has a breaking strength
> of 2800-3500lbs. *The new UHMWPE 12-strand ropes (Spectra, Plasma,
> Dyneema, Amsteel) now in common use are nominally 3500-5400lbs
> breaking strength at similar diameters, thus use of correct weak links
> are essential to avoid damaging a glider as some winches have
> substantial power and there are also gusts and thermals to allow for.
>
> Frank Whiteley

Frank's analysis is excellent.

I would only add that the wing spar loads incurred during a winch
launch is approximately that of a loop. If a glider is not approved
for loops or its age and condition is such you wouldn't loop it, don't
winch launch it.

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.

Bill Daniels

[Andy[_1_]]

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

[Frank Whiteley]

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 formula
http://tinyurl.com/258ba3j

Frank Whiteley

[Derek C]

On Aug 13, 5:56*pm, Andy > wrote:
>
> 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

The consequence of using a 10% weaker link would be a greater chance
of a broken weak link and a failed launch, which might be hazardous in
itself under some circumstances. If you use the correct link as
specified by the glider designer and the glider is in airworthy
condition, there should be no chance of a structural failure. All
gliders in the UK have to have an annual inspection and airworthiness
review. The glider that failed was a 30 year old wooden design. It has
been suggested that the tapered main pin might not have been fully
engaged, but the glider had survived a previous winch launch. My
sincere condolences to the family and friends of this young lady
pilot.

http://www.bbc.co.uk/news/uk-england-10949058

Derek C

[Derek C]

On Aug 13, 5:56*pm, Andy > wrote:
>
> 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

The consequence of using a 10% weaker link would be a greater chance
of a broken weak link and a failed launch, which might be hazardous in
itself under some circumstances. If you use the correct link as
specified by the glider designer and the glider is in airworthy
condition, there should be no chance of a structural failure. All
gliders in the UK have to have an annual inspection and airworthiness
review. The glider that failed was a 30 year old wooden design. It has
been suggested that the tapered main pin might not have been fully
engaged, but the glider had survived a previous winch launch. My
sincere condolences to the family and friends of this young lady
pilot.

http://www.bbc.co.uk/news/uk-england-10949058

Derek C

[bildan]

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.

[John Smith]

Derek C wrote:
> The consequence of using a 10% weaker link would be a greater chance
> of a broken weak link and a failed launch, which might be hazardous in
> itself under some circumstances.

No, never! A cable brake is routine and *never* hazardous in *any*
circumstances. If it is, then something in your operation is seriously
flawed.

But a cable brake (or weak link brake) is always an annoyance, as it
interrupts the operation.

[Derek C]

On Aug 14, 11:30*am, John Smith > wrote:
> Derek C wrote:
> > The consequence of using a 10% weaker link would be a greater chance
> > of a broken weak link and a failed launch, which might be hazardous in
> > itself under some circumstances.
>
> No, never! A cable brake is routine and *never* hazardous in *any*
> circumstances. If it is, then something in your operation is seriously
> flawed.
>
Depends on the size and nature of the airfield. Our site at Lasham in
the UK is large and flat, and gives you a wide range of options after
a winch launch failure. I have flown at a small sloping German site
where they launched without a weak link because having a weak link
failure was considered a serious hazard. Having said that the speed
control and quality of their winch launches was very good.

Derek C

[Bob Kuykendall]

On Aug 14, 3:30*am, John Smith > wrote:

> No, never! A cable brake is routine and *never* hazardous in *any*
> circumstances...

I do envy your faith in the ubiquity of human competence.

Thanks, Bob K.

[John Smith]

Derek C wrote:
> On Aug 14, 11:30 am, John > wrote:

>> No, never! A cable brake is routine and *never* hazardous in *any*
>> circumstances. If it is, then something in your operation is seriously
>> flawed.
>>
> Depends on the size and nature of the airfield. Our site at Lasham in
> the UK is large and flat, and gives you a wide range of options after
> a winch launch failure. I have flown at a small sloping German site
> where they launched without a weak link because having a weak link
> failure was considered a serious hazard.

Hmmmmm... I've experienced firsthand a fair number of rope brakes on the
winch (but interestingly not a single weak link break), and hence
consider a rope break pretty much SOP when winching. So I'm not sure I'd
want to fly at that German site. I have no problem with an airfield
where a cable brake puts me in a difficult situation which requires
special procedures but a cable brake shall never be hazardous.

[bildan]

On Aug 14, 9:36*am, Bob Kuykendall > wrote:
> On Aug 14, 3:30*am, John Smith > wrote:
>
> > No, never! A cable brake is routine and *never* hazardous in *any*
> > circumstances...
>
> I do envy your faith in the ubiquity of human competence.
>
> Thanks, Bob K.

Bob, John Smith is correct. If a cable break appears hazardous for a
particular pilot, then that pilot is seriously under-trained. Almost
90% of winch training is directed to safely handling rope breaks and a
good winch instructor just won't sign a pilot off until a safe outcome
is assured. Note that I said "rope" since steel cable is no longer
insurable in the US.

Breaks should be totally routine and pilots should handle them
instinctively.

[Andy[_1_]]

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

[bildan]

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.

[Bob Whelan[_3_]]

On 8/14/2010 8:17 AM, Derek C wrote:
> On Aug 14, 11:30 am, John > wrote:
>> Derek C wrote:
>>> The consequence of using a 10% weaker link would be a greater chance
>>> of a broken weak link and a failed launch, which might be hazardous in
>>> itself under some circumstances.
>>
>> No, never! A cable break is routine and *never* hazardous in *any*
>> circumstances. If it is, then something in your operation is seriously
>> flawed.
>>
> Depends on the size and nature of the airfield. Our site at Lasham in
> the UK is large and flat, and gives you a wide range of options after
> a winch launch failure. I have flown at a small sloping German site
> where they launched without a weak link because having a weak link
> failure was considered a serious hazard. Having said that the speed
> control and quality of their winch launches was very good.
>
> Derek C

Out of genuine curiosity, can you share more details of "small sloping...site"?

I have difficulty imagining a winch site unsuitable for either a straight
ahead landing following an 'early-early' launch problem not also suitable for
a 360-to-a-return-at-the-launch-point for a 'later-in-time' launch problem. I
am assuming a 'reasonably powered winch' of course, which I imagine is the
German norm. Short of an anemic winch with the winch/line stashed down a road
in a copse of woods, my imagination fails me here.

My experience in the western U.S. (generally >5000' msl) is any field
considered 'distance-suitable' for (even marginal) aerotowing is - in a
launch-emergency sense - far more 'emergency-option-friendly' than aerotowing,
because you never get dragged at low altitude over completely unlandable
terrain...which is definitely *not* the case in these parts with aerotowing.
Are there folks winch launching from postage-stamp-sized-fields surrounded by
unlandable terrain using a beyond-the-boundary-winch?

Curiously,
Bob W.

[Bob Kuykendall]

On Aug 14, 3:43*pm, bildan > wrote:

> Bob, John Smith is correct. *If a cable break appears hazardous for a
> particular pilot, then that pilot is seriously under-trained. *Almost
> 90% of winch training is directed to safely handling rope breaks and a
> good winch instructor just won't sign a pilot off until a safe outcome
> is assured. *Note that I said "rope" since steel cable is no longer
> insurable in the US.
>
> Breaks should be totally routine and pilots should handle them
> instinctively.

I'm sorry, Bill, I'm still not buying it. It's the word "never" that
rings my bell. I don't much hold with either "always" or "never."

All dangers are relative. The added hazards of a cable break may be
fairly low, but I am confident that rigorous analysis will demonstrate
them to be statistically significant.

Even the most competent pilots have their off days and off minutes,
and the intersection of those times and trying circumstances can and
too often will be troublesome.

Note that I do not argue that winch launching is to any great degree
dangerous. That is not the case. I believe that, when executed
conscientiously, winch launching can equal or better the safety record
of aerotow.

What I do argue is that every soaring operation entails non-trivial
risk, and that those risks can only be greater when things do not go
as planned or expected.

Thanks, Bob K.

[Derek C]

On Aug 14, 5:24*pm, John Smith > wrote:
> Derek C wrote:
> > On Aug 14, 11:30 am, John > *wrote:
> >> No, never! A cable brake is routine and *never* hazardous in *any*
> >> circumstances. If it is, then something in your operation is seriously
> >> flawed.
>
> > Depends on the size and nature of the airfield. Our site at Lasham in
> > the UK is large and flat, and gives you a wide range of options after
> > a winch launch failure. I have flown at a small sloping German site
> > where they launched without a weak link because having a weak link
> > failure was considered a serious hazard.
>
> Hmmmmm... I've experienced firsthand a fair number of rope brakes on the
> winch (but interestingly not a single weak link break), and hence
> consider a rope break pretty much SOP when winching. So I'm not sure I'd
> want to fly at that German site. I have no problem with an airfield
> where a cable brake puts me in a difficult situation which requires
> special procedures but a cable brake shall never be hazardous.

The site in question is a narrow strip 800 metres long, sloping
downhill at about 1 in 10, on top of a hill and totally surrounded by
small unlandable vineyards. They always launched downhill,
irrespective of wind direction. Once above about 200ft, but below
circuit height, the only cable break option to get back onto site was
a 180 degree turn (teardrop circuit) to land back uphill. The
alternatives were a controlled crash into a vineyard or a water
landing on the local river.

I have also winch launched at a very small UK site called Sandhill
Farm near Shrivenham in Wiltshire, which wasn't much better. At
certain heights you only option was to land in one of the surrounding
fields. They have since given up winch launching as they felt that the
risk to reward (700-800ft launches) ratio was too great.

The only problem with winch launching (of which I am a great fan) is
that you need a reasonable large airfield to get decent heights and to
do it safely without presenting pilots with extremely critical
judgement decisions in the event of a launch failure.

Derek C

[John Smith]

Bob Kuykendall wrote:
>> Breaks should be totally routine and pilots should handle them
>> instinctively.
>
> I'm sorry, Bill, I'm still not buying it. It's the word "never" that
> rings my bell.

I stand by my words: A rope break shall *never* be hazardous as such. Of
course, every pilot may screw up, but that's a completely different
question and not limited to rope breaks.

[John Smith]

Derek C wrote:
> The site in question is a narrow strip 800 metres long, sloping
> downhill at about 1 in 10, on top of a hill and totally surrounded by
> small unlandable vineyards. They always launched downhill,
> irrespective of wind direction. Once above about 200ft, but below
> circuit height, the only cable break option to get back onto site was
> a 180 degree turn (teardrop circuit) to land back uphill.

And where's the problem?

[Bruce Hoult]

On Aug 15, 2:23*pm, Bob Whelan > wrote:
> Are there folks winch launching from postage-stamp-sized-fields surrounded by
> unlandable terrain using a beyond-the-boundary-winch?

The site where I converted to winch launching was like that. It's
"Jury Hill", at Greytown, near Wellington NZ.

There is a quite long north/south runway, but the interesting
conditions are often in westerly winds. The westerly runway starts
from the southern end of the main runway and at the time I was flying
there had a length of around 300 - 400 m. The winch run was something
like 1200 m with the remainder of the distance to the winch crossing a
mixture of swamp and low "sand dunes" (not actually sand, but
similarly lumpy). The cable retrieve vehicle used a not terribly
straight path through the lumps, including crossing a farm track and
one or two small streams.

With a glider with good brakes (e.g. Ka7, ASK13) and a bit of a
headwind (and you wouldn't use that runway unless there was too much
crosswind for the other one) you could land straight ahead from a
cable break at 200 or 250 ft and make some kind of circuit from 200 ft
or less, so there was always either one good option or else two
reasonable ones for the same runway, plus the option of simply turning
right 90 degrees onto the 1000+ m runway and land with a crosswind.

[Bruce]

Bias disclaimer -
I learned to fly on a winch. First two flights in gliders were aerotow -
Never took an aero tow again until 3 years post solo. So you might say I
have a primacy bias towards winch feeling right and consequently
perceived as safe.

That said -
The BGA statistics, taken from the UK and continental Europe,
unfortunately are unequivocal that winch launching was responsible for a
disproportionate number of fatalities. Note I said disproportionate - so
corrected for the relatively higher percentage of winch launches.

Having run a formal program to remove unsafe practices and to understand
the dynamics of what happens when it goes wrong, the recent statistics
are very good. It turns out that winch launching IS actually very safe
as long as best practice is followed. AND as long as everyone involved -
including the winch driver knows what to do.

So - anyone who considers a launch failure to be an emergency, is in
need of some "upskilling" it should be "ops-normal". But, to say that a
cable break is never dangerous is denial. Any cable break involves
danger - handling it correctly should be standard unexciting practice -
but denial of risk is the most dangerous thing in flying...

For me - there are few things more stressful in all my glider flying
that being dragged at low level by some anaemic tug - full of water -
over the "select a hazard of your choice - rocks, shacks, water, trees,
power lines..."

Conversely - winch launching lets you get into trouble VERY quickly.

Whichever way you launch , there is no substitute for awareness and
having a plan for what to do if things go wrong. For my part - If I have
to chose a launch emergency I would far rather have the winch failure -
you generally have more alternatives for mitigating that risk.

Bruce

On 2010/08/15 6:22 AM, Bob Kuykendall wrote:
> On Aug 14, 3:43 pm, > wrote:
>
>> Bob, John Smith is correct. If a cable break appears hazardous for a
>> particular pilot, then that pilot is seriously under-trained. Almost
>> 90% of winch training is directed to safely handling rope breaks and a
>> good winch instructor just won't sign a pilot off until a safe outcome
>> is assured. Note that I said "rope" since steel cable is no longer
>> insurable in the US.
>><Snip>

--- news://freenews.netfront.net/ - complaints: ---

[bildan]

> "The BGA statistics, taken from the UK and continental Europe,
> unfortunately are unequivocal that winch launching was responsible for a
> disproportionate number of fatalities"

BGA statistics on Continental Europe are seriously in error. You're
just trying to say that everybody else is a bad as the UK - they
aren't.

I have obtained accident statistics from Germany for 2009. More than
1.5 million winch launches resulted in just 17 accidents (13 of which
were really landing accidents since the glider was in a position for a
safe landing with good height and airspeed.) There were three
fatalities.

That's an absolutely extraordinary safety record - far, far better
than aero tow in the US or winch launch in the UK. The SSF says the
US lost 12 people on aero tow in 2009.

If winch launch is done competently, as it is in Germany, it's orders
of magnitude safer than aero tow as practiced in the US. I strongly
advise adopting the training methods and operating techniques used in
Germany.

John Smith's point is not about the infallibility of pilots, (fools
will find a way) it's that a winch operation should never put a pilot
in a situation where more than basic flying ability is required to
recover from a rope break. This goes for aero tow operations as well.

As an instructor, I can tell if a pilot has to think through a
recovery or is doing it instinctively. I train until it's
instinctive. If they maintain that level of competency, rope breaks
will never be a hazard for them.

[Andy[_1_]]

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

[Alex Potter]

On Sun, 15 Aug 2010 07:34:22 -0700, bildan wrote:

> As an instructor, I can tell if a pilot has to think through a recovery
> or is doing it instinctively.

As a pilot, one never knows whether one will get to the top of a winch
launch. During my training, at HUSBOS, simulated cable breaks were very
much in evidence. Recovery does become instinctive, and rather fun.

--
Alex

[RL]

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

[Derek C]

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

[sisu1a]

> 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

[Bruce]

Be careful of statistics - but agreed that recent winch safety has been
excellent for most of Europe (at least it appears to be so from what we
can see reported.)

Interestingly my club includes a lot of expatriate Germans, and a
similar group of expatriate English pilots. I have not seen any major
difference between them in approach or safety.

Glad to see we agree on the rest - primacy is important. When something
puts pressure on a pilot we tend to revert to what we first learned.
Make sure it is sensible.

Interestingly I wonder how much of the relative safety of launches in
the USA vs Germany / France/ England is the way soaring is administered.
The US way of licensing and having the proficiency standards and
examinations mandated and by the FAA is not ideal. Tom Knauf makes a
strong argument for doing it better.

As to the safety aspect - all launch methods intrinsically involve risk,
and decisions about how much risk to accept, and how you manage the risk
you take. Some communities take higher risk, and have consequentially
higher incident rates. (For example the one way strip in the vineyards)
The take away for me is to be aware of the situation and make sure you
have thought through the possible eventualities, and what you can and
should do in the event one of them occurs. Instinctive responses are
very useful up to a point. In an unusual situation, they had better be
tempered by rational processes. Attitude and preparation are most
important. The flying skill required should not be unusual - but the
necessary speed of decision making can exceed peoples capabilities. I
helps to have thought things through.

Cheers
Bruce

On 2010/08/15 4:34 PM, bildan wrote:
>
>> "The BGA statistics, taken from the UK and continental Europe,
>> unfortunately are unequivocal that winch launching was responsible for a
>> disproportionate number of fatalities"
>
> BGA statistics on Continental Europe are seriously in error. You're
> just trying to say that everybody else is a bad as the UK - they
> aren't.
>
> I have obtained accident statistics from Germany for 2009. More than
> 1.5 million winch launches resulted in just 17 accidents (13 of which
> were really landing accidents since the glider was in a position for a
> safe landing with good height and airspeed.) There were three
> fatalities.
>
> That's an absolutely extraordinary safety record - far, far better
> than aero tow in the US or winch launch in the UK. The SSF says the
> US lost 12 people on aero tow in 2009.
>
> If winch launch is done competently, as it is in Germany, it's orders
> of magnitude safer than aero tow as practiced in the US. I strongly
> advise adopting the training methods and operating techniques used in
> Germany.
>
> John Smith's point is not about the infallibility of pilots, (fools
> will find a way) it's that a winch operation should never put a pilot
> in a situation where more than basic flying ability is required to
> recover from a rope break. This goes for aero tow operations as well.
>
> As an instructor, I can tell if a pilot has to think through a
> recovery or is doing it instinctively. I train until it's
> instinctive. If they maintain that level of competency, rope breaks
> will never be a hazard for them.


--- news://freenews.netfront.net/ - complaints: ---

[brianDG303[_2_]]

On Aug 15, 7:34*am, bildan > wrote:

That's an absolutely extraordinary safety record - far, far better
than aero tow in the US or winch launch in the UK. The SSF says the
US lost 12 people on aero tow in 2009.

I have no opinion on this topic and am just reading it to for
background, but the statement above is very much in error, I suspect.
The NTSB lists 7 glider fatals for 2009, of which one is not really a
glider as we think of it (a 'light-sport' type float kit machine that
took off on water without enough room to miss the trees at the shore).
Of the 6 remaining, one was a winch launch, one spun off the (aero)
tow line at ~300" and one released, spun, and crashed. So worst case
there are 2 aero tow fatalities and one winch fatality in the US in
2009. NTSB was unable to determine the cause of either aero tow
related incident, there was some speculation about cardic events, but
sounds like we'll never know.

As a low hour pilot I don't have an opinion on the topic except to
mention that every January I do 3 to 5 simulated rope breaks. My
reason for that is when making a high bank turn below 200' the ground
being so near tends to freak me out, and the simulated rope breaks get
me used to the sight picture and helps me stay calm.

Brian

[Andreas Maurer]

On Sun, 15 Aug 2010 10:12:03 +0200, John Smith
> wrote:

>Derek C wrote:
>> The site in question is a narrow strip 800 metres long, sloping
>> downhill at about 1 in 10, on top of a hill and totally surrounded by
>> small unlandable vineyards. They always launched downhill,
>> irrespective of wind direction. Once above about 200ft, but below
>> circuit height, the only cable break option to get back onto site was
>> a 180 degree turn (teardrop circuit) to land back uphill.
>
>And where's the problem?

The timing. :)


With such a short field it might be necessary to execute this teardrop
circuit at very low altitude because it's not possible anymore to land
straight-on.

Little error margin for finding the right compromise between executing
the turn ionto final at a healthy altitude and not too close to the
airfield.

It's definitely more relaxed to execute this teardrop circuit at
300ft+.


Cheers
Andreas

[Andreas Maurer]

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

[sisu1a]

> 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.


Here are some post 1960 hardware differences: (shooting from the
hip... ;)

1) standardized weak links (Tost system)
2) implementation and standardization of preamble/strop/trace
3) high aspect drums/doing away with level-winds
4) synthetic cables
5) much better control of torque/speed/launch profile
6) electric winch(es)

While procedures may have remained pretty consistent in Germany
(though adapted to accommodate newer hardware setups like strops, and
some some for UHMW...) most everyone else seems to have been quite
behind on the curve and continue to play catch-up; with some groups in
doing it in distinct steps like the GFA writing a manual in 98
http://www.scribd.com/doc/24475893/Winch-Manual and BGA with their
'safe winch launch initiative started in 05 for instance:
http://www.gliding.co.uk/bgainfo/safety/safewinchlaunching.htm , which
have changed SOP in those places as far as I can tell. Also up until
quite recently, a complete mathematical model of the entire launch did
not exist, only partial models. This information is (debatably)
relevant to further hardware and procedural evolution as well, pushing
it even closer towards science and further from it's trial and error
past.

Details aside, the point is if you look at 40-50yrs of winching as a
generic lump sum the picture looks undeservedly bleak compared to
looking at it by what is now commonly being done abroad, with Germany
leading the way with a long record of safety and good procedures.
(which I have a hard time imagining there being *some* changes in the
last 50yrs of German winching though... ;)

-Paul

[bildan]

On Aug 15, 1:21*pm, Andreas Maurer > wrote:
> 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

Actually, I don't disagree. You don't need all new stuff to be safe
but then you can drive a 1960's car and be safe too - as long as
you're careful not to hit anything or get hit. It's a fact that
people driving new cars with air bags and crush zones drive a lot more
aggressively. That's basically what you get from the new winch
designs. Easier, safer launches with greater performance.

Dyneema is an exception. It has been proven safer than steel cable by
every industry that has adopted it - there's lots of industrial safety
data on that. Besides being safer, it's just way nicer to work with.

[bildan]

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.

[Andy[_1_]]

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.

[bildan]

On Aug 15, 11:29*am, Bruce > wrote:

> Interestingly I wonder how much of the relative safety of launches in
> the USA vs Germany / France/ England is the way soaring is administered.
> The US way of licensing and having the proficiency standards and
> examinations mandated and by the FAA is not ideal. Tom Knauf makes a
> strong argument for doing it better.

I've looked at aviation safety for more than half a century and, in
the end, I've decided it comes down to the individual pilot and the
surrounding culture of safety. The regulatory environment has little
to do with it.

If a pilot says, "Yes, this thing I propose to do can be hazardous,
but I intend to manage it by doing everything I possibly can to reduce
the risk." "I will seek training to achieve a far higher level of
skill and knowledge than will be required and rely on it to maintain
the greatest safety margin possible." If he does that, I expect to
see a very long and safe flying career.

Aviation safety is the process of doing something inherently risky in
a way that makes it inherently safe. That requires skill. It also
requires the strength of character to seek that skill and the self-
discipline to use it.

[Andreas Maurer]

On Sun, 15 Aug 2010 19:56:16 -0700 (PDT), bildan >
wrote:



>That's basically what you get from the new winch
>designs. Easier, safer launches with greater performance.
Nope. :)


>Dyneema is an exception. It has been proven safer than steel cable by
>every industry that has adopted it - there's lots of industrial safety
>data on that. Besides being safer, it's just way nicer to work with.

Hmmm... on my airfield (we were the first ones to use Dyneema) we
already had more than only a couple of incidents that were directly
related to the use of Dyneema and wouldn't have happened with steel
cable. We came to the conclusion that -at least on my airfield- steel
cable offers more advantages than disadvatages than Dyneema.

Cheers
Andreas

[bildan]

On Aug 16, 8:19*am, Andreas Maurer > wrote:
> On Sun, 15 Aug 2010 19:56:16 -0700 (PDT), bildan >
> wrote:
>
> >That's basically what you get from the new winch
> >designs. *Easier, safer launches with greater performance.
>
> Nope. :)
>
> >Dyneema is an exception. *It has been proven safer than steel cable by
> >every industry that has adopted it - there's lots of industrial safety
> >data on that. *Besides being safer, it's just way nicer to work with.
>
> Hmmm... on my airfield (we were the first ones to use Dyneema) we
> already had more than only a couple of incidents that were directly
> related to the use of Dyneema and wouldn't have happened with steel
> cable. We came to the conclusion that -at least on my airfield- steel
> cable offers more advantages than disadvatages than Dyneema.
>
> Cheers
> Andreas

I very much doubt yours was the first airfield to use Dyneema since
that would have been in 1998 in Germany and I strongly suspect the
analysis of your incidents was seriously flawed. Dyneema is safer,
period. Airfields have no influence on that.

However, simply replacing steel with Dyneema and attempting to use the
same procedures as with steel will cause problems. Those are
transition issues, not Dyneema issues. The winch must be modified and
the operational rules must be changed to make a successful transition.

[John Smith]

bildan wrote:
> Dyneema is safer, period.

How so? Dyneema isn't elastic, so it doesn't snap back when it breaks,
but that's the only difference safetywise.

> the operational rules must be changed to make a successful transition.

Which operation rules would these be? At our field, we successfully
changed from steel to Dyneema a couple of years ago without changing any
operation rules whatsoever. What did we miss? Of course Dyneema has a
slightly different feel, especially for the winch driver, but that's no
change in operation rules.

[Derek C]

On Aug 16, 4:02*pm, bildan > wrote:
> On Aug 16, 8:19*am, Andreas Maurer > wrote:
>
>
>
>
>
> > On Sun, 15 Aug 2010 19:56:16 -0700 (PDT), bildan >
> > wrote:
>
> > >That's basically what you get from the new winch
> > >designs. *Easier, safer launches with greater performance.
>
> > Nope. :)
>
> > >Dyneema is an exception. *It has been proven safer than steel cable by
> > >every industry that has adopted it - there's lots of industrial safety
> > >data on that. *Besides being safer, it's just way nicer to work with..
>
> > Hmmm... on my airfield (we were the first ones to use Dyneema) we
> > already had more than only a couple of incidents that were directly
> > related to the use of Dyneema and wouldn't have happened with steel
> > cable. We came to the conclusion that -at least on my airfield- steel
> > cable offers more advantages than disadvatages than Dyneema.
>
> > Cheers
> > Andreas
>
> I very much doubt yours was the first airfield to use Dyneema since
> that would have been in 1998 in Germany and I strongly suspect the
> analysis of your incidents was seriously flawed. *Dyneema is safer,
> period. *Airfields have no influence on that.
>
> However, simply replacing steel with Dyneema and attempting to use the
> same procedures as with steel will cause problems. *Those are
> transition issues, not Dyneema issues. *The winch must be modified and
> the operational rules must be changed to make a successful transition.-

Why? We successfully ran a comparative trial with UHWPE cable on one
drum and steel cable on the other drum of a slight modified two drum
Tost winch (mainly to prevent drum crushing, which is a known problem
with UHMWPE synthetic cables). The winch drivers had no difficulty
coping with either type of cable.

Derek C

[Andreas Maurer]

On Mon, 16 Aug 2010 08:02:39 -0700 (PDT), bildan >
wrote:


>I very much doubt yours was the first airfield to use Dyneema since
>that would have been in 1998 in Germany
>and I strongly suspect the
>analysis of your incidents was seriously flawed. Dyneema is safer,
>period. Airfields have no influence on that.

Bill, I really admire your ability to judge a situation from the other
side of the pond.
You neither know about the incidents we had, nor you have the
slightest idea about the enviroment our Dyneema is operated in.

Yet you dare tto " I strongly suspect the analysis of your incidents
was seriously flawed".

Bold, Sir. Very bold.
Unfortunately you simply have no clue.



Andreas

[Andreas Maurer]

On Mon, 16 Aug 2010 17:22:19 +0200, John Smith
> wrote:


>Which operation rules would these be? At our field, we successfully
>changed from steel to Dyneema a couple of years ago without changing any
>operation rules whatsoever. What did we miss? Of course Dyneema has a
>slightly different feel, especially for the winch driver, but that's no
>change in operation rules.

We are having problems with cable breaks in crosswind situations -
Dyneemy tends to float for a long time and gets blown all over the
place even if the wind is weak. We had a couple of close calls until
we learned the hard way that we had to stop the complete operation
(including landings of powered aircraft) on the airfield until the
Dyneemy cable has definitely been moved out of the way (something that
usually takes ten to fifteen minutes). The light Dyneemy rope lies on
the grass and can easily be picked up by the gear of any passing
aircraft.
Combine this with an increased number of cable breaks compared to the
steel cable, and you can imagine that the Dyneemy cable costs us some
headaches... :)


An other problem unique to the Dyneemy cable is a nearby road (1.500
ft away) that already got blocked by a broken Dyneemy cable.

In comparison, our steel cables fall more or less vertically (even in
string winds), causing us no such problems.

We operate two winches on my airfield, one using Dyneema, one steel
cable.


Cheers
Andreas

[John Smith]

Andreas Maurer wrote:
> We are having problems with cable breaks in crosswind situations -
> Dyneemy tends to float for a long time and gets blown all over the
> place

Ah, ok. Depending o your situation this may indeed be a problem. At our
site it's not, luckily.

> Combine this with an increased number of cable breaks compared to the
> steel cable,

We do not have more cable breaks with Dyneema than we had with steel. We
did have some breaks at the beginning but quickly learned how to avoid
them by more careful handling. Particularly never cross two cables as
the friction heat when one is pulled over the other will cut them, and
the winch driver must timely cease to pull.

[bildan]

On Aug 16, 1:15*pm, Andreas Maurer > wrote:
> On Mon, 16 Aug 2010 17:22:19 +0200, John Smith
>
> > wrote:
> >Which operation rules would these be? At our field, we successfully
> >changed from steel to Dyneema a couple of years ago without changing any
> >operation rules whatsoever. What did we miss? Of course Dyneema has a
> >slightly different feel, especially for the winch driver, but that's no
> >change in operation rules.
>
> We are having problems with cable breaks in crosswind situations -
> Dyneemy tends to float for a long time and gets blown all over the
> place even if the wind is weak. We had a couple of close calls until
> we learned the hard way that we had to stop the complete operation
> (including landings of powered aircraft) on the airfield until the
> Dyneemy cable has definitely been moved out of the way (something that
> usually takes ten to fifteen minutes). The light Dyneemy rope lies on
> the grass and can easily be picked up by the gear of any passing
> aircraft.
> Combine this with an increased number of cable breaks compared to the
> steel cable, *and you can imagine that the Dyneemy cable costs us some
> headaches... :)
>
> An other problem unique to the Dyneemy cable is a nearby road (1.500
> ft away) that already got blocked by a broken Dyneemy cable.
>
> In comparison, our steel cables fall more or less vertically (even in
> string winds), causing us no such problems.
>
> We operate two winches on my airfield, one using Dyneema, one steel
> cable.
>
> Cheers
> Andreas

Your statements have graphically demonstrated why you have problems
with Dyneema.

Call in an expert like Klaus Fey (www.eqip.de) and he'll show you how
to make it work.

[Derek C]

On Aug 16, 11:06*pm, bildan > wrote:
> On Aug 16, 1:15*pm, Andreas Maurer > wrote:
>
>
>
>
>
> > On Mon, 16 Aug 2010 17:22:19 +0200, John Smith
>
> > > wrote:
> > >Which operation rules would these be? At our field, we successfully
> > >changed from steel to Dyneema a couple of years ago without changing any
> > >operation rules whatsoever. What did we miss? Of course Dyneema has a
> > >slightly different feel, especially for the winch driver, but that's no
> > >change in operation rules.
>
> > We are having problems with cable breaks in crosswind situations -
> > Dyneemy tends to float for a long time and gets blown all over the
> > place even if the wind is weak. We had a couple of close calls until
> > we learned the hard way that we had to stop the complete operation
> > (including landings of powered aircraft) on the airfield until the
> > Dyneemy cable has definitely been moved out of the way (something that
> > usually takes ten to fifteen minutes). The light Dyneemy rope lies on
> > the grass and can easily be picked up by the gear of any passing
> > aircraft.
> > Combine this with an increased number of cable breaks compared to the
> > steel cable, *and you can imagine that the Dyneemy cable costs us some
> > headaches... :)
>
> > An other problem unique to the Dyneemy cable is a nearby road (1.500
> > ft away) that already got blocked by a broken Dyneemy cable.
>
> > In comparison, our steel cables fall more or less vertically (even in
> > string winds), causing us no such problems.
>
> > We operate two winches on my airfield, one using Dyneema, one steel
> > cable.
>
> > Cheers
> > Andreas
>
> Your statements have graphically demonstrated why you have problems
> with Dyneema.
>
> Call in an expert like Klaus Fey (www.eqip.de) and he'll show you how
> to make it work.- Hide quoted text -
>
> - Show quoted text -

I agree with Andreas. Synthetic UHMWPE cable does drop more slowly
than steel and does have a much greater tendency to drift sideways in
a crosswind, especially after a cable break. If the cables get crossed
it is very easy to cut right through synthetic cable, whereas steel
cables are unaffected. The main reason not to use it though is cost.
Dyneema is nearly 6 times more expensive than steel but lasts only
slightly longer, and can be easily wrecked in one incident if it gets
caught around any bit of steelwork during a launch.

Derek C

[Derek C]

On Aug 15, 8:21*pm, Andreas Maurer > wrote:
> 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

I think that one of the most important safety changes we have made in
the UK is the addition of 'Eventualities' to the pre-flight check
list. That is to remind pilots to plan for the possibility of a launch
failure and also applies to aerotows. No fancy computer controlled
winches or other gizmos required.

Derek C

[Derek C]

On Aug 15, 8:21*pm, Andreas Maurer > wrote:
> 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

I think that one of the most important safety changes we have made in
the UK is the addition of 'Eventualities' to the pre-flight check
list. That is to remind pilots to plan for the possibility of a launch
failure and also applies to aerotows. No fancy computer controlled
winches or other gizmos required.

Derek C

[Andreas Maurer]

On Tue, 17 Aug 2010 00:53:51 -0700 (PDT), Derek C
> wrote:


>I think that one of the most important safety changes we have made in
>the UK is the addition of 'Eventualities' to the pre-flight check
>list. That is to remind pilots to plan for the possibility of a launch
>failure and also applies to aerotows. No fancy computer controlled
>winches or other gizmos required.

100% agree.
All the winch launch accidents I had the doubtful pleasure to watch
could have been prevented by a proper pre-flight check, but not with
different winch design.


Andreas

[Derek C]

On Aug 15, 7:51*pm, Andreas Maurer > wrote:
> On Sun, 15 Aug 2010 10:12:03 +0200, John Smith
>
> > wrote:
> >Derek C wrote:
> >> The site in question is a narrow strip 800 metres long, sloping
> >> downhill at about 1 in 10, on top of a hill and totally surrounded by
> >> small unlandable vineyards. They always launched downhill,
> >> irrespective of wind direction. Once above about 200ft, but below
> >> circuit height, the only cable break option to get back onto site was
> >> a 180 degree turn (teardrop circuit) to land back uphill.
>
> >And where's the problem?
>
> The timing. :)
>
> With such a short field it might be necessary to execute this teardrop
> circuit at very low altitude because it's not possible anymore to land
> straight-on.
>
> Little error margin for finding the right compromise between executing
> the turn ionto final at a healthy altitude and not too close to the
> airfield.
>
> It's definitely more relaxed to execute this teardrop circuit at
> 300ft+.
>
> Cheers
> Andreas

Here is a video of a German pilot getting a teardrop circuit wrong
after an 80 metre (about 250ft) cable break:

http://www.youtube.com/watch?v=_xCct8cDtyk&playnext=1&videos=zqLm5HhNvPc

Derek C

[Andreas Maurer]

On Mon, 16 Aug 2010 15:06:12 -0700 (PDT), bildan >
wrote:


>Your statements have graphically demonstrated why you have problems
>with Dyneema.
>
>Call in an expert like Klaus Fey (www.eqip.de) and he'll show you how
>to make it work.

Yeah, he's probably some real good ideas how to get 1.500 ft of
Dyneemy cable out of a wood while the other 1.500 ft are lying all
over the airfield and blocking the traffic.
LOL.


In the last ten years since the introduction of Dyneema we've done
about 40.000 winch launches.
How many have YOU done that you are able to judge a situation from
thousands of miles away without ever having seen the location?

Andreas

[John Smith]

Derek C wrote:
> Here is a video of a German pilot getting a teardrop circuit wrong
> after an 80 metre (about 250ft) cable break:
>
> http://www.youtube.com/watch?v=_xCct8cDtyk&playnext=1&videos=zqLm5HhNvPc

I think we've all known this video for a long time. Apparently the
problem in this film was that the pilot didn't do a proper teardrop but
rather a straight 180 which put him off the runway.

The reason why I don't see any problem is that I happen to fly from a
field with the same "problem": Runway length about 500 meters, winch
placed beyond the runway end and no possibility to land between. There's
a certain altitude range where the only option after a cable break is a
pretty low teardrop return to the runway. But beware of returning too
hastily, because this would put you too high over the threshold of the
short runway, a position particularly uncomfortable if there is some wind.

We've never ever had a problem with that. The "secret" is training,
trainig, training, may I even say drill, and a thorough departure
briefing before every launch.

[Derek C]

On Aug 17, 12:29*pm, John Smith > wrote:
> Derek C wrote:
> > Here is a video of a German pilot getting a teardrop circuit wrong
> > after an 80 metre (about 250ft) cable break:
>
> > *http://www.youtube.com/watch?v=_xCct8cDtyk&playnext=1&videos=zqLm5HhNvPc
>
> I think we've all known this video for a long time. Apparently the
> problem in this film was that the pilot didn't do a proper teardrop but
> rather a straight 180 which put him off the runway.
>
> The reason why I don't see any problem is that I happen to fly from a
> field with the same "problem": Runway length about 500 meters, winch
> placed beyond the runway end and no possibility to land between. There's
> a certain altitude range where the only option after a cable break is a
> pretty low teardrop return to the runway. But beware of returning too
> hastily, because this would put you too high over the threshold of the
> short runway, a position particularly uncomfortable if there is some wind..
>
> We've never ever had a problem with that. The "secret" is training,
> trainig, training, may I even say drill, and a thorough departure
> briefing before every launch.

We don't even teach the teardrop circuit to a downwind landing in the
UK for winch launch cable breaks. It involves a slight turn to one
side followed by a turn reversal though more than 180 degrees to line
up with the runway again, all at very low altitude. Generally you are
almost always low enough to land ahead, or high enough to fly a 360
turn or a limited circuit to an into wind landing after a launch
failure. At worst we aim to fly an S-turn, or a 90 or 270 degree turn
to land across wind if space ahead is limited, or even land more or
less into wind in one of the surrounding fields (one of the options at
Sandhill Farm). The previously mentioned tiny downhill sloping strip
in Germany is the only site I have flown at where I would even
consider a teardrop circuit. The fact that the ground sloped away gave
you a bit more terrain clearance for the necessary low turns and
landing back uphill stopped you pretty quickly, even flying downwind.

Derek C

[John Smith]

Derek C wrote:
> Generally you are
> almost always low enough to land ahead, or high enough to fly a 360
> turn or a limited circuit to an into wind landing after a launch
> failure.

This may "generally" and "almost always" be true. It isn't at our field.

> At worst we aim to fly an S-turn, or a 90 or 270 degree turn
> to land across wind if space ahead is limited, or even land more or
> less into wind in one of the surrounding fields (one of the options at
> Sandhill Farm).

If there are such options. At our field, there aren't.

[Derek C]

On Aug 17, 1:26*pm, John Smith > wrote:
> Derek C wrote:
> > Generally you are
> > almost always low enough to land ahead, or high enough to fly a 360
> > turn or a limited circuit to an into wind landing after a launch
> > failure.
>
> This may "generally" and "almost always" be true. It isn't at our field.
>
> > At worst we aim to fly an S-turn, or a 90 or 270 degree turn
> > to land across wind if space ahead is limited, or even land more or
> > less into wind in one of the surrounding fields (one of the options at
> > Sandhill Farm).
>
> If there are such options. At our field, there aren't.

Should try to find a bigger site then. The Aussies have some
recommendations on minimum airfield size for safe winch launching.

http://2009.gfa.org.au/Docs/ops/Winchmanual.pdf

Derek C

[John Smith]

Derek C wrote:
> Should try to find a bigger site then. The Aussies have some
> recommendations on minimum airfield size for safe winch launching.

You're right. Despite of not having had any winch related accident in
the last 40 years, we obviously did everything wrong. At the next
meeting I'll propose to shut down the operation.

[Martin Gregorie[_5_]]

On Tue, 17 Aug 2010 03:50:42 -0700, Derek C wrote:

> On Aug 15, 7:51Â*pm, Andreas Maurer > wrote:
>> On Sun, 15 Aug 2010 10:12:03 +0200, John Smith
>>
>> > wrote:
>> >Derek C wrote:
>> >> The site in question is a narrow strip 800 metres long, sloping
>> >> downhill at about 1 in 10, on top of a hill and totally surrounded
>> >> by small unlandable vineyards. They always launched downhill,
>> >> irrespective of wind direction. Once above about 200ft, but below
>> >> circuit height, the only cable break option to get back onto site
>> >> was a 180 degree turn (teardrop circuit) to land back uphill.
>>
>> >And where's the problem?
>>
>> The timing. :)
>>
>> With such a short field it might be necessary to execute this teardrop
>> circuit at very low altitude because it's not possible anymore to land
>> straight-on.
>>
>> Little error margin for finding the right compromise between executing
>> the turn ionto final at a healthy altitude and not too close to the
>> airfield.
>>
>> It's definitely more relaxed to execute this teardrop circuit at
>> 300ft+.
>>
>> Cheers
>> Andreas
>
> Here is a video of a German pilot getting a teardrop circuit wrong after
> an 80 metre (about 250ft) cable break:
>
> http://www.youtube.com/watch?
v=_xCct8cDtyk&playnext=1&videos=zqLm5HhNvPc
>
Oh GAWD! the hysterically stupid PC bunch have struck U-Tube with a
vengeance.

I've seen this video several times in the past, so why should I suddenly
have to say I'm 18 before I can see it now?

Bloody numpties.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

[Derek C]

This particular video probably should have an 18 rating though!

Derek C

Martin Gregorie wrote:
> >
> > Here is a video of a German pilot getting a teardrop circuit wrong after
> > an 80 metre (about 250ft) cable break:
> >
> > http://www.youtube.com/watch?
> v=_xCct8cDtyk&playnext=1&videos=zqLm5HhNvPc
> >
> Oh GAWD! the hysterically stupid PC bunch have struck U-Tube with a
> vengeance.
>
> I've seen this video several times in the past, so why should I suddenly
> have to say I'm 18 before I can see it now?
>
> Bloody numpties.
>
>
> --
> martin@ | Martin Gregorie
> gregorie. | Essex, UK
> org |

[bildan]

On Aug 17, 4:50*am, Derek C > wrote:
> On Aug 15, 7:51*pm, Andreas Maurer > wrote:
>
>
>
> > On Sun, 15 Aug 2010 10:12:03 +0200, John Smith
>
> > > wrote:
> > >Derek C wrote:
> > >> The site in question is a narrow strip 800 metres long, sloping
> > >> downhill at about 1 in 10, on top of a hill and totally surrounded by
> > >> small unlandable vineyards. They always launched downhill,
> > >> irrespective of wind direction. Once above about 200ft, but below
> > >> circuit height, the only cable break option to get back onto site was
> > >> a 180 degree turn (teardrop circuit) to land back uphill.
>
> > >And where's the problem?
>
> > The timing. :)
>
> > With such a short field it might be necessary to execute this teardrop
> > circuit at very low altitude because it's not possible anymore to land
> > straight-on.
>
> > Little error margin for finding the right compromise between executing
> > the turn ionto final at a healthy altitude and not too close to the
> > airfield.
>
> > It's definitely more relaxed to execute this teardrop circuit at
> > 300ft+.
>
> > Cheers
> > Andreas
>
> Here is a video of a German pilot getting a teardrop circuit wrong
> after an 80 metre (about 250ft) cable break:
>
> *http://www.youtube.com/watch?v=_xCct8cDtyk&playnext=1&videos=zqLm5HhNvPc
>
> Derek C

Andreas, Derek, your posts reveal, in great detail and in ways you
obviously don't realize, just how screwed up many UK winch operations
are. The real danger for US operations is if they take your posts as
"normal" operations - they aren't. I hope they will ignore the UK and
study Continental, specifically German operations instead.

Dyneema doesn't just "break", clumsy, incompetent operations break
it. Clearly your Dyneema is being damaged by poor winch design and
rough handling. You don't let Dyneema "fall", you pull it to the
winch.

[bildan]

On Aug 17, 4:50*am, Derek C > wrote:
> On Aug 15, 7:51*pm, Andreas Maurer > wrote:
>
>
>
> > On Sun, 15 Aug 2010 10:12:03 +0200, John Smith
>
> > > wrote:
> > >Derek C wrote:
> > >> The site in question is a narrow strip 800 metres long, sloping
> > >> downhill at about 1 in 10, on top of a hill and totally surrounded by
> > >> small unlandable vineyards. They always launched downhill,
> > >> irrespective of wind direction. Once above about 200ft, but below
> > >> circuit height, the only cable break option to get back onto site was
> > >> a 180 degree turn (teardrop circuit) to land back uphill.
>
> > >And where's the problem?
>
> > The timing. :)
>
> > With such a short field it might be necessary to execute this teardrop
> > circuit at very low altitude because it's not possible anymore to land
> > straight-on.
>
> > Little error margin for finding the right compromise between executing
> > the turn ionto final at a healthy altitude and not too close to the
> > airfield.
>
> > It's definitely more relaxed to execute this teardrop circuit at
> > 300ft+.
>
> > Cheers
> > Andreas
>
> Here is a video of a German pilot getting a teardrop circuit wrong
> after an 80 metre (about 250ft) cable break:
>
> *http://www.youtube.com/watch?v=_xCct8cDtyk&playnext=1&videos=zqLm5HhNvPc
>
> Derek C

Yes, and it's obviously a landing accident, not a winch accident. The
pilot had a perfect opportunity to make a safe landing and failed to
do so.

[Andy[_1_]]

On Aug 17, 10:16*am, bildan > wrote:
> Andreas, Derek, your posts reveal, in great detail and in ways you
> obviously don't realize, just how screwed up many UK winch operations
> are. *The real danger for US operations is if they take your posts as
> "normal" operations - they aren't. *I hope they will ignore the UK and
> study Continental, *specifically German operations instead.

I think I must have lost track of the plot. When did Andreas move to
UK?

Andy

[Andreas Maurer]

On Tue, 17 Aug 2010 10:19:10 -0700 (PDT), bildan >
wrote:

>Yes, and it's obviously a landing accident, not a winch accident. The
>pilot had a perfect opportunity to make a safe landing and failed to
>do so.

Hi Bill,

could you please post the complete clip of the whole flight from the
(supposed) cable break?
Looks like you have more information than this 15-second clip on
YouTube.


Thanks in advance
Andreas

[Martin Gregorie[_5_]]

On Tue, 17 Aug 2010 10:16:48 -0700, bildan wrote:

> Dyneema doesn't just "break", clumsy, incompetent operations break it.
> Clearly your Dyneema is being damaged by poor winch design and rough
> handling. You don't let Dyneema "fall", you pull it to the winch.
>
Its rather difficult to pull the top section in after the rope has broken.

I agree about not crossing the ropes though: good tow-out procedure and
correct choice of which rope to use first should prevent to ropes from
becoming crossed.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

[Martin Gregorie[_5_]]

On Tue, 17 Aug 2010 07:25:42 -0700, Derek C wrote:

> This particular video probably should have an 18 rating though!
>
Why?

It shows the effect of a combination of a strong wind gradient on a low,
slow turn as something to avoid, but there is no obvious blood & guts
such as might turn the stomach of a delicate young person of the under 18
persuasion.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

[Brian Whatcott]

On 8/16/2010 9:19 AM, Andreas Maurer wrote:
> On Sun, 15 Aug 2010 19:56:16 -0700 (PDT), >
> wrote:
>
>
>
>> That's basically what you get from the new winch
>> designs. Easier, safer launches with greater performance.
> Nope. :)
>
>
>> Dyneema is an exception. It has been proven safer than steel cable by
>> every industry that has adopted it - there's lots of industrial safety
>> data on that. Besides being safer, it's just way nicer to work with.
>
> Hmmm... on my airfield (we were the first ones to use Dyneema) we
> already had more than only a couple of incidents that were directly
> related to the use of Dyneema and wouldn't have happened with steel
> cable. We came to the conclusion that -at least on my airfield- steel
> cable offers more advantages than disadvatages than Dyneema.
>
> Cheers
> Andreas
>

is the crucial issue abrasion, or UV degradation?

Brian W

[Andreas Maurer]

On Tue, 17 Aug 2010 16:51:29 -0500, brian whatcott
> wrote:


>is the crucial issue abrasion, or UV degradation?

I guess it's a combination of less-than-perfect winch design, not
completely level airfield and using already damaged cable that results
in shorter than expected lifespan of the Dyneema cable and a
comparably high number of cable breaks.

One problem is that in case of a cable break the latter often falls
into a little wood from which recovery is difficult (pulling the cable
trough the wood usually damages it sufficiently that it needs
replacement).


But our main problem is completely different: As I already wrote in
another posting in this thread, the Dyneema cable gets blown all over
the place in case of a cable break with even a medium crosswind,
forcing us to cease all operation till the cable has definitely been
cleared out of the way.
We've been badly surprised several times about how long the Dyneema
cable stays in the air and how far it can be blown.

Andreas

[Derek C]

On Aug 17, 6:16*pm, bildan > wrote:
> On Aug 17, 4:50*am, Derek C > wrote:
>
>
>
>
>
> > On Aug 15, 7:51*pm, Andreas Maurer > wrote:
>
> > > On Sun, 15 Aug 2010 10:12:03 +0200, John Smith
>
> > > > wrote:
> > > >Derek C wrote:
> > > >> The site in question is a narrow strip 800 metres long, sloping
> > > >> downhill at about 1 in 10, on top of a hill and totally surrounded by
> > > >> small unlandable vineyards. They always launched downhill,
> > > >> irrespective of wind direction. Once above about 200ft, but below
> > > >> circuit height, the only cable break option to get back onto site was
> > > >> a 180 degree turn (teardrop circuit) to land back uphill.
>
> > > >And where's the problem?
>
> > > The timing. :)
>
> > > With such a short field it might be necessary to execute this teardrop
> > > circuit at very low altitude because it's not possible anymore to land
> > > straight-on.
>
> > > Little error margin for finding the right compromise between executing
> > > the turn ionto final at a healthy altitude and not too close to the
> > > airfield.
>
> > > It's definitely more relaxed to execute this teardrop circuit at
> > > 300ft+.
>
> > > Cheers
> > > Andreas
>
> > Here is a video of a German pilot getting a teardrop circuit wrong
> > after an 80 metre (about 250ft) cable break:
>
> > *http://www.youtube.com/watch?v=_xCct8cDtyk&playnext=1&videos=zqLm5HhNvPc
>
> > Derek C
>
> Andreas, Derek, your posts reveal, in great detail and in ways you
> obviously don't realize, just how screwed up many UK winch operations
> are. *The real danger for US operations is if they take your posts as
> "normal" operations - they aren't. *I hope they will ignore the UK and
> study Continental, *specifically German operations instead.
>
> Dyneema doesn't just "break", clumsy, incompetent operations break
> it. *Clearly your Dyneema is being damaged by poor winch design and
> rough handling. *You don't let Dyneema "fall", you pull it to the
> winch.- Hide quoted text -
>
> - Show quoted text -

I note from his profile that Andreas has a German email address, so I
guess that he lives and flies in Germany!

In fact German and UK practices are pretty similar, apart from the
German land line telephone requirement for communication between the
launch point and the winch. The standard European winch used to be the
German Tost, but it is now becoming the British Skylaunch. The French
National Gliding Centre have recently ordered two turbo-diesel engined
Skylaunch 2 winches, with one already delivered and in service.

Derek C

[Derek C]

On Aug 17, 6:16*pm, bildan > wrote:
> On Aug 17, 4:50*am, Derek C > wrote:
>
>
>
>
>
> > On Aug 15, 7:51*pm, Andreas Maurer > wrote:
>
> > > On Sun, 15 Aug 2010 10:12:03 +0200, John Smith
>
> > > > wrote:
> > > >Derek C wrote:
> > > >> The site in question is a narrow strip 800 metres long, sloping
> > > >> downhill at about 1 in 10, on top of a hill and totally surrounded by
> > > >> small unlandable vineyards. They always launched downhill,
> > > >> irrespective of wind direction. Once above about 200ft, but below
> > > >> circuit height, the only cable break option to get back onto site was
> > > >> a 180 degree turn (teardrop circuit) to land back uphill.
>
> > > >And where's the problem?
>
> > > The timing. :)
>
> > > With such a short field it might be necessary to execute this teardrop
> > > circuit at very low altitude because it's not possible anymore to land
> > > straight-on.
>
> > > Little error margin for finding the right compromise between executing
> > > the turn ionto final at a healthy altitude and not too close to the
> > > airfield.
>
> > > It's definitely more relaxed to execute this teardrop circuit at
> > > 300ft+.
>
> > > Cheers
> > > Andreas
>
> > Here is a video of a German pilot getting a teardrop circuit wrong
> > after an 80 metre (about 250ft) cable break:
>
> > *http://www.youtube.com/watch?v=_xCct8cDtyk&playnext=1&videos=zqLm5HhNvPc
>
> > Derek C
>
> Andreas, Derek, your posts reveal, in great detail and in ways you
> obviously don't realize, just how screwed up many UK winch operations
> are. *The real danger for US operations is if they take your posts as
> "normal" operations - they aren't. *I hope they will ignore the UK and
> study Continental, *specifically German operations instead.
>
> Dyneema doesn't just "break", clumsy, incompetent operations break
> it. *Clearly your Dyneema is being damaged by poor winch design and
> rough handling. *You don't let Dyneema "fall", you pull it to the
> winch.- Hide quoted text -
>
> - Show quoted text -

I note from his profile that Andreas has a German email address, so I
guess that he lives and flies in Germany!

In fact German and UK practices are pretty similar, apart from the
German land line telephone requirement for communication between the
launch point and the winch. The standard European winch used to be the
German Tost, but it is now becoming the British Skylaunch. The French
National Gliding Centre have recently ordered two turbo-diesel engined
Skylaunch 2 winches, with one already delivered and in service.

Derek C

[Derek C]

On Aug 17, 6:16*pm, bildan > wrote:
> On Aug 17, 4:50*am, Derek C > wrote:
>
>
>
>
>
> > On Aug 15, 7:51*pm, Andreas Maurer > wrote:
>
> > > On Sun, 15 Aug 2010 10:12:03 +0200, John Smith
>
> > > > wrote:
> > > >Derek C wrote:
> > > >> The site in question is a narrow strip 800 metres long, sloping
> > > >> downhill at about 1 in 10, on top of a hill and totally surrounded by
> > > >> small unlandable vineyards. They always launched downhill,
> > > >> irrespective of wind direction. Once above about 200ft, but below
> > > >> circuit height, the only cable break option to get back onto site was
> > > >> a 180 degree turn (teardrop circuit) to land back uphill.
>
> > > >And where's the problem?
>
> > > The timing. :)
>
> > > With such a short field it might be necessary to execute this teardrop
> > > circuit at very low altitude because it's not possible anymore to land
> > > straight-on.
>
> > > Little error margin for finding the right compromise between executing
> > > the turn ionto final at a healthy altitude and not too close to the
> > > airfield.
>
> > > It's definitely more relaxed to execute this teardrop circuit at
> > > 300ft+.
>
> > > Cheers
> > > Andreas
>
> > Here is a video of a German pilot getting a teardrop circuit wrong
> > after an 80 metre (about 250ft) cable break:
>
> > *http://www.youtube.com/watch?v=_xCct8cDtyk&playnext=1&videos=zqLm5HhNvPc
>
> > Derek C
>
> Andreas, Derek, your posts reveal, in great detail and in ways you
> obviously don't realize, just how screwed up many UK winch operations
> are. *The real danger for US operations is if they take your posts as
> "normal" operations - they aren't. *I hope they will ignore the UK and
> study Continental, *specifically German operations instead.
>
> Dyneema doesn't just "break", clumsy, incompetent operations break
> it. *Clearly your Dyneema is being damaged by poor winch design and
> rough handling. *You don't let Dyneema "fall", you pull it to the
> winch.- Hide quoted text -
>
> - Show quoted text -

I note from his profile that Andreas has a German email address, so I
guess that he lives and flies in Germany!

In fact German and UK practices are pretty similar, apart from the
German land line telephone requirement for communication between the
launch point and the winch. The standard European winch used to be the
German Tost, but it is now becoming the British Skylaunch. The French
National Gliding Centre have recently ordered two turbo-diesel engined
Skylaunch 2 winches, with one already delivered and in service.

Derek C

[Derek C]

On Aug 17, 6:19*pm, bildan > wrote:
> On Aug 17, 4:50*am, Derek C > wrote:
>
> > On Aug 15, 7:51*pm, Andreas Maurer > wrote:
>
> > > On Sun, 15 Aug 2010 10:12:03 +0200, John Smith
>
> > > > wrote:
> > > >Derek C wrote:
> > > >> The site in question is a narrow strip 800 metres long, sloping
> > > >> downhill at about 1 in 10, on top of a hill and totally surrounded by
> > > >> small unlandable vineyards. They always launched downhill,
> > > >> irrespective of wind direction. Once above about 200ft, but below
> > > >> circuit height, the only cable break option to get back onto site was
> > > >> a 180 degree turn (teardrop circuit) to land back uphill.
>
> > > >And where's the problem?
>
> > > The timing. :)
>
> > > With such a short field it might be necessary to execute this teardrop
> > > circuit at very low altitude because it's not possible anymore to land
> > > straight-on.
>
> > > Little error margin for finding the right compromise between executing
> > > the turn ionto final at a healthy altitude and not too close to the
> > > airfield.
>
> > > It's definitely more relaxed to execute this teardrop circuit at
> > > 300ft+.
>
> > > Cheers
> > > Andreas
>
> > Here is a video of a German pilot getting a teardrop circuit wrong
> > after an 80 metre (about 250ft) cable break:
>
> > *http://www.youtube.com/watch?v=_xCct8cDtyk&playnext=1&videos=zqLm5HhNvPc
>
> > Derek C
>
> Yes, and it's obviously a landing accident, not a winch accident. *The
> pilot had a perfect opportunity to make a safe landing and failed to
> do so.- Hide quoted text -
>
> - Show quoted text -

This crash is known to have occured after a cable break at about 80
metres (listen to the commentary) and the pilot attempted to fly a
teardrop circuit to a downwind landing. He looks almost reasonably
high on baseleg, but obviously didn't have enough airspeed, hence the
spin (speed and height being interchangeable). There appear to be
houses and trees in the overshoot field, so landing there might not
have been an option. Does anybody know the runway length at Magdeburg?

Derek C

[John Smith]

Derek C wrote:
> Does anybody know the runway length at Magdeburg?

Plenty. http://eddh.de/info/landeinfo-ergebnisb.php?ueicao=EDBM

[Brian Whatcott]

On 8/17/2010 6:25 PM, Andreas Maurer wrote:
> On Tue, 17 Aug 2010 16:51:29 -0500, brian whatcott
> > wrote:
>
>
>> is the crucial issue abrasion, or UV degradation?
>
> I guess it's a combination of less-than-perfect winch design, not
> completely level airfield and using already damaged cable that results
> in shorter than expected lifespan of the Dyneema cable and a
> comparably high number of cable breaks.
>
> One problem is that in case of a cable break the latter often falls
> into a little wood from which recovery is difficult (pulling the cable
> trough the wood usually damages it sufficiently that it needs
> replacement).
>
>
> But our main problem is completely different: As I already wrote in
> another posting in this thread, the Dyneema cable gets blown all over
> the place in case of a cable break with even a medium crosswind,
> forcing us to cease all operation till the cable has definitely been
> cleared out of the way.
> We've been badly surprised several times about how long the Dyneema
> cable stays in the air and how far it can be blown.
>
> Andreas
>

I see, abrasion and low density blow down. Perhaps a little drogue and
post partum pull back - or is that the way it is?

Brian W

[Andreas Maurer]

On Wed, 18 Aug 2010 06:16:56 -0500, brian whatcott
> wrote:

>I see, abrasion and low density blow down. Perhaps a little drogue and
>post partum pull back - or is that the way it is?

That's the way it is, unfortunately.

Generally we found that Dyneema is simply much less fault-tolerant
than a steel cable - small handling errors (like using a little too
much power to pull it out of the wood) often result in a really
expensive damage.

Andreas

[Martin Gregorie[_5_]]

On Wed, 18 Aug 2010 13:54:38 +0200, Andreas Maurer wrote:

>
> Generally we found that Dyneema is simply much less fault-tolerant than
> a steel cable - small handling errors (like using a little too much
> power to pull it out of the wood) often result in a really expensive
> damage.
>
I'm not altogether surprised. I once tried using a light (5-10Kg) woven
Dyneema line the control tailplane release for VIT and d/t on a small
(F1J) power model, which required it to slide round a 3mm alloy tube that
converted the movement from fore and aft through the fuselage to vertical
travel as the tail surface moved. It was a miserable failure -the mere
act of threading the line into the fuselage caused it to fluff into total
unusability. I threw it away and replaced it with woven Dacron. Problem
solved.

Since then the only Dyneema I've used has been 100 lb kite bridle, which
I used as the towline for an F1A competition model glider. This line has
a core of straight Dyneema fibres inside a woven Dacron sheath and is
excellent: no tangles, nice to handle, abrasion resistant. Its very stiff
too. The total stretch is about 150mm in a 50m length under the nominal
5Kg test tension - and even that stretch is mostly pulling the kinks out.

On this showing I'd be wary of any Dyneema rope that lacks a Dacron outer
casing: the ease with which the naked Dyneema line fluffed up was really
a shock.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

[Derek C]

On Aug 18, 11:47*am, John Smith > wrote:
> Derek C wrote:
> > Does anybody know the runway length at Magdeburg?
>
> Plenty.http://eddh.de/info/landeinfo-ergebnisb.php?ueicao=EDBM

If the runway length is 1000m as claimed, from 80 metres high (260ft)
it should have been possible to just open the airbrakes and land
straight ahead, especially as the windsock in the crash video is
showing a reasonably stiff headwind. In the UK we always encourage
pilots to land ahead as the primary option, if reasonably possible, as
no low turns with a risk of spinning are involved. My club also
charges a much reduced winch launch fee for landing straight ahead as
a futher incentive.

Derek C

[Grider Pirate]

Some translation from Free Flight Duration Model Airplane speak.

> I'm not altogether surprised. I once tried using a light (5-10Kg) woven
> Dyneema line the control tailplane release for VIT -- Variable Incedence Tail
....and d/t -- DE-THERMALIZER (brings the plane down quickly after a
set time) on a small
> (F1J) (.051 Cubic Inch Displacement) power model, which required it to slide round a 3mm alloy tube that
> converted the movement from fore and aft through the fuselage to vertical
> travel as the tail surface moved. It was a miserable failure *-the mere
> act of threading the line into the fuselage caused it to fluff into total
> unusability. I threw it away and replaced it with woven Dacron. Problem
> solved.
>
> Since then the only Dyneema I've used has been 100 lb kite bridle, which
> I used as the towline for an F1A competition model glider. This line has
> a core of straight Dyneema fibres inside a woven Dacron sheath and is
> excellent: no tangles, nice to handle, abrasion resistant. Its very stiff
> too. The total stretch is about 150mm in a 50m length under the nominal
> 5Kg test tension - and even that stretch is mostly pulling the kinks out.
>
> On this showing I'd be wary of any Dyneema rope that lacks a Dacron outer
> casing: the ease with which the naked Dyneema line fluffed up was really
> a shock.
>
> --
> martin@ * | Martin Gregorie
> gregorie. | Essex, UK
> org * * * |

[bildan]

On Aug 18, 5:54*am, Andreas Maurer > wrote:
> On Wed, 18 Aug 2010 06:16:56 -0500, brian whatcott
>
> > wrote:
> >I see, abrasion and low density blow down. Perhaps a little drogue and
> >post partum pull back - or is that the way it is?
>
> That's the way it is, unfortunately.
>
> Generally we found that Dyneema is simply much less fault-tolerant
> than a steel cable - small handling errors (like using a little too
> much power to pull it out of the wood) often result in a really
> expensive damage.
>
> Andreas

And yet there are many user finding Dyneema is far, far more tolerant
than steel. Go to a manufacturer's spec sheet and look at the
numbers. It has 15x the abrasion resistance of steel and absolutely
no tendency to twist or kink. It handles shock loads much better than
steel. It has only three weaknesses - chlorine bleach, heat and sharp
edges.

Users with excellent rope handling winches see no breaks until it
wears out. If it's breaking before it's worn out, it's getting
damaged - most likely by the winch. Undamaged Dyneema just doesn't
suffer random breaks like steel.

Poor fairlead design is the biggest culprit. Allowing the rope to
contact sharp edges somewhere in the rope path runs a close second.
Airfield surfaces, even really rough ones, do little damage.

Fairleads must use sheaves, not rollers. The grooves in the sheaves
must have a very specific cross section called out by the rope
manufacturer. Industrial studies have shown this is critical to long
life. On every winch I've seen without a Dyneema-specific sheave,
I've been able to pull strips of melted Dyneema off the fairlead.

Drums must be boxed. It's not unusual for a loop to form on the drum
for a fraction of a second and whip the rope against a sharp edge on
the winch frame before it gets pulled tight on the drum again. One
winch operator declared this couldn't happen or he would have seen
it. I pointed to bits of torn rope on a frame bracket 8 feet behind
the drum as evidence it was happening.

Dyneema is wonderful stuff and it will last up to 15x steel but it
needs a different rope path design and handling protocol.

[Frank Whiteley]

On Aug 12, 4:12*pm, Frank Whiteley > wrote:
> On Aug 12, 3:16*pm, ContestID67 > wrote:
>
>
>
> > I was sent this link from a UK soaring friend of mine about a death
> > when the wings came off of a glider during a winch tow.http://www.dailymail.co.uk/news/article-1302215/Pilot-plunged-death-b...
>
> > Sad story. *A few things;
>
> > - My friend's thought was that the wing pins were left out. *Howerver,
> > this was the second flight of the day. *Both winch launches. *So I
> > would think that the wing pins were installed but the wings failed
> > under a winch load. *Which glider was it? *Older? *Wooden spars?
> > Never having had a winch launch, what happens if you don't release
> > back pressure at the top? *Can you pull your wings off? *Maybe
> > safeties on the pins were missed and the pins wiggled out on the
> > second flight after staying in for the first.
>
> > - I was under the impression that the BGA required parachutes for all
> > pilots. *Wrong? *1000 ft should have been enough to get out in time
> > but who knows what was happening in the cockpit or if she was 1000 MSL
> > or AGL at the time.
>
> > Thanks.
>
> > - John DeRosa
>
> It was aFoka4.
>
> Foka-4was a derivative of theFokalinehttp://en.wikipedia.org/wiki/Foka_%28glider%29
> Cobra was the next to last iteration, with 17m being the last.http://en.wikipedia.org/wiki/SZD-36_Cobra_15
> Note the comments on failures.
>
> I don't know that the4had the same wing join design, but suspect it
> was very similar.
> There was a wing failure on a Cobra in the US and a sobering analysis.http://www.sylacaugasoaring.com/SZD%20COBRA%20WARNING.htm
>
> The SHK has an expanding vertical pin. *There's an anecdotal story of
> someone who used the right-hand to expand the pin, and finished the
> job with left-hand, in the opposite direction. *The wings reportedly
> departed at the top of the launch. *The pilot reportedly pulled the
> tail chute on the way down.
>
> I believe that some German studies found that successful egress and
> parachute deployment below 600m is unlikely, of course there are
> exceptions. *The better emergency chutes are life saving from 100ft
> agl at 100kts horizontal.
>
> Wing failure on a winch launch is very rare. *There was a K-7 at RAF
> Dishforth in the UK a while back, but the investigation determined
> there was prior damage to the spar which was not found following
> another incident. *There was a homebuilt in Colorado that had a wing
> failure due to aileron flutter during a winch launch. *After two weak
> link breaks, the pilot doubled the weak link (unknown to the winch
> crew). *The described flight path was one of climb, level off, climb,
> level off, climb, glider breakup, crash. *The wing inspection hatch
> was found early in the flight path. *What did not appear in the NTSB
> report was that the pilot was refused further tows at the local FBO
> after the glider had suffered significant aileron flutter on aero tow.
>
> I winched at RAF Bicester when it was the RAF/GSA Centre. *Appropriate
> weak links were always used, like any UK club. *It's not a long run,
> but easy enough to climb away on the thermal day.
>
> Steel wire rope used in many places typically has a breaking strength
> of 2800-3500lbs. *The new UHMWPE 12-strand ropes (Spectra, Plasma,
> Dyneema, Amsteel) now in common use are nominally 3500-5400lbs
> breaking strength at similar diameters, thus use of correct weak links
> are essential to avoid damaging a glider as some winches have
> substantial power and there are also gusts and thermals to allow for.
>
> Frank Whiteley

Reading the UK URAS new group today, I see someone posted a link to
this FAA doc
http://www.ntsb.gov/recs/letters/1974/A74_100_101.pdf
which gives another mode of failure specific to the Foka 4.

The AAIB analysis will prove interesting.

Frank Whiteley

[Ventus_a]

On Aug 18, 11:47*am, John Smith wrote:
Derek C wrote:
Does anybody know the runway length at Magdeburg?

Plenty.http://eddh.de/info/landeinfo-ergebnisb.php?ueicao=EDBM

If the runway length is 1000m as claimed, from 80 metres high (260ft)
it should have been possible to just open the airbrakes and land
straight ahead, especially as the windsock in the crash video is
showing a reasonably stiff headwind. In the UK we always encourage
pilots to land ahead as the primary option, if reasonably possible, as
no low turns with a risk of spinning are involved. My club also
charges a much reduced winch launch fee for landing straight ahead as
a futher incentive.

Derek C

At the Auckland Gliding Club, New Zealand, there is no charge levied against a launch failure thereby trying to take a way the temptation of low level heroics that turn out bad. Having said that, poor airmanship is still displayed with some insanely low circuits when a straight ahead landing would have been more appropriate.

It seems that it is just too inconvenient for some people to have to tow their glider back to the launch point!!

Colin

[Derek C]

On Aug 18, 11:32*pm, bildan > wrote:
> On Aug 18, 5:54*am, Andreas Maurer > wrote:
>
> > On Wed, 18 Aug 2010 06:16:56 -0500, brian whatcott
>
> > > wrote:
> > >I see, abrasion and low density blow down. Perhaps a little drogue and
> > >post partum pull back - or is that the way it is?
>
> > That's the way it is, unfortunately.
>
> > Generally we found that Dyneema is simply much less fault-tolerant
> > than a steel cable - small handling errors (like using a little too
> > much power to pull it out of the wood) often result in a really
> > expensive damage.
>
> > Andreas
>
> And yet there are many user finding Dyneema is far, far more tolerant
> than steel. *Go to a manufacturer's spec sheet and look at the
> numbers. *It has 15x the abrasion resistance of steel and absolutely
> no tendency to twist or kink. *It handles shock loads much better than
> steel. *It has only three weaknesses - chlorine bleach, heat and sharp
> edges.
>
> Users with excellent rope handling winches see no breaks until it
> wears out. *If it's breaking before it's worn out, it's getting
> damaged - most likely by the winch. *Undamaged Dyneema just doesn't
> suffer random breaks like steel.
>
> Poor fairlead design is the biggest culprit. *Allowing the rope to
> contact sharp edges somewhere in the rope path runs a close second.
> Airfield surfaces, even really rough ones, do little damage.
>
> Fairleads must use sheaves, not rollers. *The grooves in the sheaves
> must have a very specific cross section called out by the rope
> manufacturer. *Industrial studies have shown this is critical to long
> life. *On every winch I've seen without a Dyneema-specific sheave,
> I've been able to pull strips of melted Dyneema off the fairlead.
>
> Drums must be boxed. *It's not unusual for a loop to form on the drum
> for a fraction of a second and whip the rope against a sharp edge on
> the winch frame before it gets pulled tight on the drum again. *One
> winch operator declared this couldn't happen or he would have seen
> it. *I pointed to bits of torn rope on a frame bracket 8 feet behind
> the drum as evidence it was happening.
>
> Dyneema is wonderful stuff and it will last up to 15x steel but it
> needs a different rope path design and handling protocol.

At our somewhat abrasive airfield at Lasham (UK) we normally get about
1900 launches from a steel cable and the one trial Spectra UHMWPE
cable we tried lasted 2500 launches. The winch we used for this trial
was a modified Tost fitted with what Bill calls sheaves, level wind
paying on gear and specially reinforced drums to prevent drum-
crushing. All the parts that came into contact with the cable had been
highly polished as recommended. According to Bill that cable should
have lasted for 28,500 launches, which is over ten times what was
actually achieved! Other users of UHMWPE (Dyneema or equivalent) cable
have reported similar results to what we found. I wonder how many
launches Bill's 'American Superwinch' has carried out so far?

I believe that Bill has put the cause of winch launching in the US
back by at least 5 years by insisting that only fancy and very
expensive computer controlled diesel hydraulic or electric winches
fitted with Dyneema are capable of giving safe launches. This is in a
country where there are many potential donor vehicles fitted with
suitably large powerful engines and good automatic gearboxes that
could be used as a basis for good and low cost conventional winches.


Derek C

[Derek C]

On Aug 19, 9:23*am, Derek C > wrote:
> On Aug 18, 11:32*pm, bildan > wrote:
>
> > On Aug 18, 5:54*am, Andreas Maurer > wrote:
>
> > > On Wed, 18 Aug 2010 06:16:56 -0500, brian whatcott
>
> > > > wrote:
> > > >I see, abrasion and low density blow down. Perhaps a little drogue and
> > > >post partum pull back - or is that the way it is?
>
> > > That's the way it is, unfortunately.
>
> > > Generally we found that Dyneema is simply much less fault-tolerant
> > > than a steel cable - small handling errors (like using a little too
> > > much power to pull it out of the wood) often result in a really
> > > expensive damage.
>
> > > Andreas
>
> > And yet there are many user finding Dyneema is far, far more tolerant
> > than steel. *Go to a manufacturer's spec sheet and look at the
> > numbers. *It has 15x the abrasion resistance of steel and absolutely
> > no tendency to twist or kink. *It handles shock loads much better than
> > steel. *It has only three weaknesses - chlorine bleach, heat and sharp
> > edges.
>
> > Users with excellent rope handling winches see no breaks until it
> > wears out. *If it's breaking before it's worn out, it's getting
> > damaged - most likely by the winch. *Undamaged Dyneema just doesn't
> > suffer random breaks like steel.
>
> > Poor fairlead design is the biggest culprit. *Allowing the rope to
> > contact sharp edges somewhere in the rope path runs a close second.
> > Airfield surfaces, even really rough ones, do little damage.
>
> > Fairleads must use sheaves, not rollers. *The grooves in the sheaves
> > must have a very specific cross section called out by the rope
> > manufacturer. *Industrial studies have shown this is critical to long
> > life. *On every winch I've seen without a Dyneema-specific sheave,
> > I've been able to pull strips of melted Dyneema off the fairlead.
>
> > Drums must be boxed. *It's not unusual for a loop to form on the drum
> > for a fraction of a second and whip the rope against a sharp edge on
> > the winch frame before it gets pulled tight on the drum again. *One
> > winch operator declared this couldn't happen or he would have seen
> > it. *I pointed to bits of torn rope on a frame bracket 8 feet behind
> > the drum as evidence it was happening.
>
> > Dyneema is wonderful stuff and it will last up to 15x steel but it
> > needs a different rope path design and handling protocol.
>
> At our somewhat abrasive airfield at Lasham (UK) we normally get about
> 1900 launches from a steel cable and the one trial Spectra UHMWPE
> cable we tried lasted 2500 launches. The winch we used for this trial
> was a modified Tost fitted with what Bill calls sheaves, level wind
> paying on gear and specially reinforced drums to prevent drum-
> crushing. All the parts that came into contact with the cable had been
> highly polished as recommended. According to Bill that cable should
> have lasted for 28,500 launches, which is over ten times what was
> actually achieved! Other users of UHMWPE (Dyneema or equivalent) cable
> have reported similar results to what we found. I wonder how many
> launches Bill's 'American Superwinch' has carried out so far?
>
> I believe that Bill has put the cause of winch launching in the US
> back by at least 5 years by insisting that only fancy and very
> expensive computer controlled diesel hydraulic or electric winches
> fitted with Dyneema are capable of giving safe launches. This is in a
> country where there are many potential donor vehicles fitted with
> suitably large powerful engines and good automatic gearboxes that
> could be used as a basis for good and low cost conventional winches.
>
> Derek C- Hide quoted text -
>
> - Show quoted text -

The other thing about Bill Daniels and the Yanks in general, is that
they are trying to re-invent the winch launching wheel and ignore any
advice from the other side of the pond from people who have been winch
launching for years and have a lot of experience in that technique. In
Germany, Holland and the UK about two-thirds of all glider launches
are done by winch.

Derek C

[Derek C]

On Aug 17, 6:16*pm, bildan > wrote:
>
> Andreas, Derek, your posts reveal, in great detail and in ways you
> obviously don't realize, just how screwed up many UK winch operations
> are. *The real danger for US operations is if they take your posts as
> "normal" operations - they aren't. *I hope they will ignore the UK and
> study Continental, *specifically German operations instead.
>

For the record I have found out that Andreas Maurer flies at Landau,
which is situated about 100 kilometres south of Frankfurt in GERMANY,
yet we seem to agree on most issues related to winch launching,
despite me being a Brit! There is quite a lot of interchange of
information between the European countries that practice winch
launching. A link to his club is:

http://www.djk-landau.de/

It's in German but Google will translate it into English if you need
it.

Derek C

[Derek C]

On Aug 12, 10:16*pm, ContestID67 > wrote:
> I was sent this link from a UK soaring friend of mine about a death
> when the wings came off of a glider during a winch tow.http://www.dailymail.co.uk/news/article-1302215/Pilot-plunged-death-b...
>
> Sad story. *A few things;
>
> - My friend's thought was that the wing pins were left out. *Howerver,
> this was the second flight of the day. *Both winch launches. *So I
> would think that the wing pins were installed but the wings failed
> under a winch load. *Which glider was it? *Older? *Wooden spars?
> Never having had a winch launch, what happens if you don't release
> back pressure at the top? *Can you pull your wings off? *Maybe
> safeties on the pins were missed and the pins wiggled out on the
> second flight after staying in for the first.
>
> - I was under the impression that the BGA required parachutes for all
> pilots. *Wrong? *1000 ft should have been enough to get out in time
> but who knows what was happening in the cockpit or if she was 1000 MSL
> or AGL at the time.
>
> Thanks.
>
> - John DeRosa

Getting back to the original subject, many Polish gliders have a
rigging system which consists of vertical tapered mainpins that expand
outwards on a screw to engage with the wing root fittings. This is
basically a good system because the pins stay as part of the
structure, so there is no separate mainpin that can be lost, and if
correctly assembled gives a positive, secure and play free joint. I
understand that the problem comes when the bushing that keeps the
expanding pins central becomes worn. Then it is possible that one half
of the pin may not fully engage in one the wing root fitting, even if
the jack screw is fully tightened. I have a share in an elderly Polish
two-seater glider with two such taper mainpins. We are always careful
to check that these are fully and equally engaged in the wing root
fittings when rigging it, but it is easier to see this than in the
single seaters with a single pin. See:
http://www.sylacaugasoaring.com/SZD%20COBRA%20WARNING.htm

On the subject of bailing out, it is not compulsory to wear parachutes
in gliders in the UK, but it is normal practice to do so if the design
of the glider permits. We don't know exactly at what height the wings
fell off the crash glider (but probably less than 1000ft) and the
fuselage would have dropped like a stone without them. I doubt if the
pilot could have got out in time.

Derek C

[Derek C]

On Aug 12, 10:16*pm, ContestID67 > wrote:
> I was sent this link from a UK soaring friend of mine about a death
> when the wings came off of a glider during a winch tow.http://www.dailymail.co.uk/news/article-1302215/Pilot-plunged-death-b...
>
> Sad story. *A few things;
>
> - My friend's thought was that the wing pins were left out. *Howerver,
> this was the second flight of the day. *Both winch launches. *So I
> would think that the wing pins were installed but the wings failed
> under a winch load. *Which glider was it? *Older? *Wooden spars?
> Never having had a winch launch, what happens if you don't release
> back pressure at the top? *Can you pull your wings off? *Maybe
> safeties on the pins were missed and the pins wiggled out on the
> second flight after staying in for the first.
>
> - I was under the impression that the BGA required parachutes for all
> pilots. *Wrong? *1000 ft should have been enough to get out in time
> but who knows what was happening in the cockpit or if she was 1000 MSL
> or AGL at the time.
>
> Thanks.
>
> - John DeRosa

Getting back to the original subject, many Polish gliders have a
rigging system which consists of vertical tapered mainpins that expand
outwards on a screw to engage with the wing root fittings. This is
basically a good system because the pins stay as part of the
structure, so there is no separate mainpin that can be lost, and if
correctly assembled gives a positive, secure and play free joint. I
understand that the problem comes when the bushing that keeps the
expanding pins central becomes worn. Then it is possible that one half
of the pin may not fully engage in one of the wing root fitting, even
if the jack screw is fully tightened. I have a share in an elderly
Polish two-seater glider with two such taper mainpins. We are always
careful to check that these are fully and equally engaged in the wing
root fittings when rigging it, but it is easier to see this than in
the single seaters with a single pin. See:
http://www.sylacaugasoaring.com/SZD%20COBRA%20WARNING.htm

On the subject of bailing out, it is not compulsory to wear parachutes
in gliders in the UK, but it is normal practice to do so if the design
of the glider permits. We don't know exactly at what height the wings
fell off the crash glider (but probably less than 1000ft) and the
fuselage would have dropped like a stone without them. I doubt if the
pilot could have got out in time.

Derek C

[Derek C]

On Aug 12, 10:16*pm, ContestID67 > wrote:
> I was sent this link from a UK soaring friend of mine about a death
> when the wings came off of a glider during a winch tow.http://www.dailymail.co.uk/news/article-1302215/Pilot-plunged-death-b...
>
> Sad story. *A few things;
>
> - My friend's thought was that the wing pins were left out. *Howerver,
> this was the second flight of the day. *Both winch launches. *So I
> would think that the wing pins were installed but the wings failed
> under a winch load. *Which glider was it? *Older? *Wooden spars?
> Never having had a winch launch, what happens if you don't release
> back pressure at the top? *Can you pull your wings off? *Maybe
> safeties on the pins were missed and the pins wiggled out on the
> second flight after staying in for the first.
>
> - I was under the impression that the BGA required parachutes for all
> pilots. *Wrong? *1000 ft should have been enough to get out in time
> but who knows what was happening in the cockpit or if she was 1000 MSL
> or AGL at the time.
>
> Thanks.
>
> - John DeRosa

Getting back to the original subject, many Polish gliders have a
rigging system which consists of vertical tapered mainpins that expand
outwards on a screw to engage with the wing root fittings. This is
basically a good system because the pins stay as part of the
structure, so there is no separate mainpin that can be lost, and if
correctly assembled gives a positive, secure and play free joint. I
understand that the problem comes when the bushing that keeps the
expanding pins central becomes worn. Then it is possible that one half
of the pin may not fully engage in one of the wing root fitting, even
if the jack screw is fully tightened. I have a share in an elderly
Polish two-seater glider with two such taper mainpins. We are always
careful to check that these are fully and equally engaged in the wing
root fittings when rigging it, but it is easier to see this than in
the single seaters with a single pin. See:
http://www.sylacaugasoaring.com/SZD%20COBRA%20WARNING.htm

On the subject of bailing out, it is not compulsory to wear parachutes
in gliders in the UK, but it is normal practice to do so if the design
of the glider permits. We don't know exactly at what height the wings
fell off the crash glider (but probably less than 1000ft) and the
fuselage would have dropped like a stone without them. I doubt if the
pilot could have got out in time.

Derek C

[Chris Nicholas[_2_]]

We had a Foka 4 at my club in the 1970s, with this sort of expanding
bolt.

My recollection is that the owners used to count the number of turns
to get the full expansion. If the number of turns was correct, and the
top bolt was visible in the right place, then the invisible lower one
must also have fully engaged with the lower lugs.

Might be a useful check in the absence of a visible sign.

(I'm not saying that this had anything to do with the recent accident
- the latter may have been caused by something different.)

Chris N

[bildan]

On Aug 19, 2:23*am, Derek C > wrote:
> On Aug 18, 11:32*pm, bildan > wrote:
>
>
>
> > On Aug 18, 5:54*am, Andreas Maurer > wrote:
>
> > > On Wed, 18 Aug 2010 06:16:56 -0500, brian whatcott
>
> > > > wrote:
> > > >I see, abrasion and low density blow down. Perhaps a little drogue and
> > > >post partum pull back - or is that the way it is?
>
> > > That's the way it is, unfortunately.
>
> > > Generally we found that Dyneema is simply much less fault-tolerant
> > > than a steel cable - small handling errors (like using a little too
> > > much power to pull it out of the wood) often result in a really
> > > expensive damage.
>
> > > Andreas
>
> > And yet there are many user finding Dyneema is far, far more tolerant
> > than steel. *Go to a manufacturer's spec sheet and look at the
> > numbers. *It has 15x the abrasion resistance of steel and absolutely
> > no tendency to twist or kink. *It handles shock loads much better than
> > steel. *It has only three weaknesses - chlorine bleach, heat and sharp
> > edges.
>
> > Users with excellent rope handling winches see no breaks until it
> > wears out. *If it's breaking before it's worn out, it's getting
> > damaged - most likely by the winch. *Undamaged Dyneema just doesn't
> > suffer random breaks like steel.
>
> > Poor fairlead design is the biggest culprit. *Allowing the rope to
> > contact sharp edges somewhere in the rope path runs a close second.
> > Airfield surfaces, even really rough ones, do little damage.
>
> > Fairleads must use sheaves, not rollers. *The grooves in the sheaves
> > must have a very specific cross section called out by the rope
> > manufacturer. *Industrial studies have shown this is critical to long
> > life. *On every winch I've seen without a Dyneema-specific sheave,
> > I've been able to pull strips of melted Dyneema off the fairlead.
>
> > Drums must be boxed. *It's not unusual for a loop to form on the drum
> > for a fraction of a second and whip the rope against a sharp edge on
> > the winch frame before it gets pulled tight on the drum again. *One
> > winch operator declared this couldn't happen or he would have seen
> > it. *I pointed to bits of torn rope on a frame bracket 8 feet behind
> > the drum as evidence it was happening.
>
> > Dyneema is wonderful stuff and it will last up to 15x steel but it
> > needs a different rope path design and handling protocol.
>
> At our somewhat abrasive airfield at Lasham (UK) we normally get about
> 1900 launches from a steel cable and the one trial Spectra UHMWPE
> cable we tried lasted 2500 launches. The winch we used for this trial
> was a modified Tost fitted with what Bill calls sheaves, level wind
> paying on gear and specially reinforced drums to prevent drum-
> crushing. All the parts that came into contact with the cable had been
> highly polished as recommended. According to Bill that cable should
> have lasted for 28,500 launches, which is over ten times what was
> actually achieved! Other users of UHMWPE (Dyneema or equivalent) cable
> have reported similar results to what we found. I wonder how many
> launches Bill's 'American Superwinch' has carried out so far?
>
> I believe that Bill has put the cause of winch launching in the US
> back by at least 5 years by insisting that only fancy and very
> expensive computer controlled diesel hydraulic or electric winches
> fitted with Dyneema are capable of giving safe launches. This is in a
> country where there are many potential donor vehicles fitted with
> suitably large powerful engines and good automatic gearboxes that
> could be used as a basis for good and low cost conventional winches.
>
> Derek C

This is yet another in a long list of your gross fabrications and
lies. Can you point to any source where i wrote 28,500 launches on
one rope?

The only "re-invention" is your adoption of our 50 year old technology
using big V8's and automatic transmissions and claiming it as your
idea. We knew it was a bad idea long before you even heard of it.

Yes, I emphatically do not want the US to adopt UK methods or winch
designs. They are extremely uninformed and dangerous - as your
accident record proves. Geez, you guys still use steel cable!

[Derek C]

On Aug 23, 2:28*am, bildan > wrote:
> On Aug 19, 2:23*am, Derek C > wrote:

>
> > > Dyneema is wonderful stuff and it will last up to 15x steel but it
> > > needs a different rope path design and handling protocol.
>
> > At our somewhat abrasive airfield at Lasham (UK) we normally get about
> > 1900 launches from a steel cable and the one trial Spectra UHMWPE
> > cable we tried lasted 2500 launches. The winch we used for this trial
> > was a modified Tost fitted with what Bill calls sheaves, level wind
> > paying on gear and specially reinforced drums to prevent drum-
> > crushing. All the parts that came into contact with the cable had been
> > highly polished as recommended. According to Bill that cable should
> > have lasted for 28,500 launches, which is over ten times what was
> > actually achieved! Other users of UHMWPE (Dyneema or equivalent) cable
> > have reported similar results to what we found. I wonder how many
> > launches Bill's 'American Superwinch' has carried out so far?
>
> > I believe that Bill has put the cause of winch launching in the US
> > back by at least 5 years by insisting that only fancy and very
> > expensive computer controlled diesel hydraulic or electric winches
> > fitted with Dyneema are capable of giving safe launches. This is in a
> > country where there are many potential donor vehicles fitted with
> > suitably large powerful engines and good automatic gearboxes that
> > could be used as a basis for good and low cost conventional winches.
>
> > Derek C
>
> This is yet another in a long list of your gross fabrications and
> lies. *Can you point to any source where i wrote 28,500 launches on
> one rope?

To quote your posting on 18th August at 11.32:

"Dyneema is wonderful stuff and it will last up to 15x steel but it
needs a different rope path design and handling protocol."

Our steel cables last about 1900 launches on an airfield where you
always have to run over two 50 yard wide concrete or asphalt runways,
so I multiplied 1900 x 15 which makes 28,500.
>
> The only "re-invention" is your adoption of our 50 year old technology
> using big V8's and automatic transmissions and claiming it as your
> idea. *We knew it was a bad idea long before you even heard of it.

Well you need a big powerful engine to power a winch and big gas or
turbo-diesel V8s are ideal for this. We are using modern engines and
gearboxes, not 50 year old ones.
>
> Yes, I emphatically do not want the US to adopt UK methods or winch
> designs. *They are extremely uninformed and dangerous - as your
> accident record proves. *Geez, you guys still use steel cable!- Hide quoted text -
>
Strange therefore that German winches are generally very similar in
design to UK winches, and indeed quite a few British Skylaunch winches
have been sold to German and French gliding clubs. The trend at the
moment is to use polyrope cable, which is stronger and lighter than
steel, and costs slightly less. We have nothing against Dyneema apart
from the fact it costs 6 times more than steel cable (but doesn't last
6 times longer) and can cause handling difficulties, as described by
Andreas Maurer from the Laudau club in Germany. The UK winch
launching safety record has recently been very good, although we had
one fatality last year when a pilot rotated too quickly. I seem to
remember that you were recommending very rapid ground run
accelerations and rotations at one time, which are dangerous for a
number of reasons. The Germans call these 'Kavalierstarts' and have
stopped doing them after a number of fatal flick spin accidents.

Derek C

[Cats]

On Aug 22, 9:09*am, Chris Nicholas > wrote:
> We had a Foka 4 at my club in the 1970s, with this sort of expanding
> bolt.
>
> My recollection is that the owners used to count the number of turns
> to get the full expansion. If the number of turns was correct, and the
> top bolt was visible in the right place, then the invisible lower one
> must also have fully engaged with the lower lugs.
>
> Might be a useful check in the absence of a visible sign.
>
> (I'm not saying that this had anything to do with the recent accident
> - the latter may have been caused by something different.)
>

It's an assumption that if the correct number of turns have been done
and the top bolt is seen to be correctly expanded that the lower bolt
has also correctly expanded. I gather that in the US Cobra accident
there was some sort of fault in the bolt such that the top part
expanded correctly but the bottom didn't, and it is very hard to see.

Personally I am so glad I fly a relatively modern glass glider with
two horizontal main pins where the only mechanism is me pushing them
home and then crossing and latching their 'handles'.

[Derek C]

On Aug 23, 9:52*am, Cats > wrote:
> On Aug 22, 9:09*am, Chris Nicholas > wrote:
>
> > We had a Foka 4 at my club in the 1970s, with this sort of expanding
> > bolt.
>
> > My recollection is that the owners used to count the number of turns
> > to get the full expansion. If the number of turns was correct, and the
> > top bolt was visible in the right place, then the invisible lower one
> > must also have fully engaged with the lower lugs.
>
> > Might be a useful check in the absence of a visible sign.
>
> > (I'm not saying that this had anything to do with the recent accident
> > - the latter may have been caused by something different.)
>
> It's an assumption that if the correct number of turns have been done
> and the top bolt is seen to be correctly expanded that the lower bolt
> has also correctly expanded. *I gather that in the US Cobra accident
> there was some sort of fault in the bolt such that the top part
> expanded correctly but the bottom didn't, and it is very hard to see.
>
> Personally I am so glad I fly a relatively modern glass glider with
> two horizontal main pins where the only mechanism is me pushing them
> home and then crossing and latching their 'handles'.

In the US Cobra accident the taper bolt mainpin expanded correctly,
but wasn't centred due to wear in the central locating bush. Hence it
didn't fully engage in the bottom wing root fitting. This failure
could have been prevented by a visual inspection, but apparently it is
difficult to see the bottom fitting in this type of glider. I will
repeat that there is nothing intrinsically wrong with this rigging
system, as long as it is properly maintained and a visual check is
made after rigging.

Derek C

[Derek C]

Following the recent break up of a Foka 4 glider during a winch
launch, the British Gliding Association has issued the following
safety alert. Please note that it also applies to a number of other
glider types fitting with expanding taper mainpins.

http://www.gliding.co.uk/bgainfo/safety/documents/safetyalert020910.pdf

Derek C


On Aug 23, 10:19*am, Derek C > wrote:
> On Aug 23, 9:52*am, Cats > wrote:
>

> > On Aug 22, 9:09*am, Chris Nicholas > wrote:
>
> > > We had a Foka 4 at my club in the 1970s, with this sort of expanding
> > > bolt.
>
> > > My recollection is that the owners used to count the number of turns
> > > to get the full expansion. If the number of turns was correct, and the
> > > top bolt was visible in the right place, then the invisible lower one
> > > must also have fully engaged with the lower lugs.
>
> > > Might be a useful check in the absence of a visible sign.
>
> > > (I'm not saying that this had anything to do with the recent accident
> > > - the latter may have been caused by something different.)
>
> > It's an assumption that if the correct number of turns have been done
> > and the top bolt is seen to be correctly expanded that the lower bolt
> > has also correctly expanded. *I gather that in the US Cobra accident
> > there was some sort of fault in the bolt such that the top part
> > expanded correctly but the bottom didn't, and it is very hard to see.
>
> > Personally I am so glad I fly a relatively modern glass glider with
> > two horizontal main pins where the only mechanism is me pushing them
> > home and then crossing and latching their 'handles'.
>
> In the US Cobra accident the taper bolt mainpin expanded correctly,
> but wasn't centred due to wear in the central locating bush. Hence it
> didn't fully engage in the bottom wing root fitting. This failure
> could have been prevented by a visual inspection, but apparently it is
> difficult to see the bottom fitting in this type of glider. I will
> repeat that there is nothing intrinsically wrong with this rigging
> system, as long as it is properly maintained and a visual check is
> made after rigging.
>
> Derek C- Hide quoted text -
>
> - Show quoted text -