Glider accident while filming commercial in 2011. NTSB Report updated [Archive]

Bill D

June 21st 13, 12:33 AM

On Thursday, June 20, 2013 3:25:18 PM UTC-6, JohnDeRosa wrote:
> Sad event.
>
>
>
> The most telling statement seems to be the very last line of the report.
>
>
>
> "The tow rope broke during the initial takeoff..."
>
>
>
> I take this statement at face value. The rope BROKE. It didn't otherwise inadvertently release such as a back release, the release was mistakenly pulled or failed, etc.
>
>
>
> Never having done an auto or winch tow, is it unrecoverable if the rope would separate from the glider at 200ft when at a "steep nose-high attitude"?
>
>
>
> - John

The answer also depends on airspeed and how quickly the pilot initiates a recovery.

There's an envelope from within which a safe recovery is possible. I call it the "AAA envelope" bounded Altitude, Airspeed and Attitude. With enough airspeed and altitude, you can recover from anything. A steep nose-up attitude at low altitude and airspeed can be unrecoverable.

This can actually be computed using physics simulators like Matlab. For example, from the initiation of recovery, an ASK-21 at 60kts, which is a typical winch airspeed, and 45 degrees nose-up can recover to a normal glide at 1.3xVs with no loss of height assuming a well trained pilot using an aggressive recovery technique. OTOH, an ASK-21 at 50 knots and 50 degrees nose-up will lose 65 - 75 feet so you need to be higher than that. Common sense says you need to add a 100% safety margin on top of this.

Winch launch training involves a lot of these recoveries. A pilot on ground launch should be trained to expect a launch failure on every launch at any altitude and be prepared to deal with it safely.

Continuing the scenario a bit, there's obviously a point defined by height and distance remaining where landing ahead on the runway is no longer possible. If you're too close to the end to land and and too low to circle back, you're in what's been called the "end trap". Auto towing with a short tow rope it's easy to get "end trapped" which I suspect in this accident. With winch launch, you reach a height where a short pattern is possible before the land-ahead option is lost.

Papa3[_2_]

June 21st 13, 12:55 AM

There are a bunch of troubling things in this report. I have a lot of ground launch (auto tow) time, but it's a bit dated, so maybe I've forgotten. IIRC, our target speeds were on the order of 50MPH or 55MPH in zero wind, not 70. This was with a Grob and 2-33, but I can't imagine that 70 is right. The flight profile also sounds odd, as if the pilot was hoping to do an extreme pull-up after building up rather than the usual transition from initial climb to the 45 degrees or so of stage 2 climb. Adding up these two, it seems easy to see how the rope may have been overstressed.

Finally, it's hard to tell, but it sounds like this wasn't a failed recovery from an extreme nose up low altitude rope break. From the text, it appears that it may have been a stall-spin after the initial recovery - maybe trying to perform a full 180 from low altitude? At least, that's how I read it.

Anyone else getting the same picture?

P3

On Thursday, June 20, 2013 7:33:12 PM UTC-4, Bill D wrote:
> On Thursday, June 20, 2013 3:25:18 PM UTC-6, JohnDeRosa wrote:
>
> > Sad event.
>
> >
>
> >
>
> >
>
> > The most telling statement seems to be the very last line of the report..
>
> >
>
> >
>
> >
>
> > "The tow rope broke during the initial takeoff..."
>
> >
>
> >
>
> >
>
> > I take this statement at face value. The rope BROKE. It didn't otherwise inadvertently release such as a back release, the release was mistakenly pulled or failed, etc.
>
> >
>
> >
>
> >
>
> > Never having done an auto or winch tow, is it unrecoverable if the rope would separate from the glider at 200ft when at a "steep nose-high attitude"?
>
> >
>
> >
>
> >
>
> > - John
>
>
>
> The answer also depends on airspeed and how quickly the pilot initiates a recovery.
>
>
>
> There's an envelope from within which a safe recovery is possible. I call it the "AAA envelope" bounded Altitude, Airspeed and Attitude. With enough airspeed and altitude, you can recover from anything. A steep nose-up attitude at low altitude and airspeed can be unrecoverable.
>
>
>
> This can actually be computed using physics simulators like Matlab. For example, from the initiation of recovery, an ASK-21 at 60kts, which is a typical winch airspeed, and 45 degrees nose-up can recover to a normal glide at 1.3xVs with no loss of height assuming a well trained pilot using an aggressive recovery technique. OTOH, an ASK-21 at 50 knots and 50 degrees nose-up will lose 65 - 75 feet so you need to be higher than that. Common sense says you need to add a 100% safety margin on top of this.
>
>
>
> Winch launch training involves a lot of these recoveries. A pilot on ground launch should be trained to expect a launch failure on every launch at any altitude and be prepared to deal with it safely.
>
>
>
> Continuing the scenario a bit, there's obviously a point defined by height and distance remaining where landing ahead on the runway is no longer possible. If you're too close to the end to land and and too low to circle back, you're in what's been called the "end trap". Auto towing with a short tow rope it's easy to get "end trapped" which I suspect in this accident. With winch launch, you reach a height where a short pattern is possible before the land-ahead option is lost.

Bill D

June 21st 13, 01:07 AM

Craig Funston[_2_]

June 21st 13, 01:12 AM

On Thursday, June 20, 2013 4:55:19 PM UTC-7, Papa3 wrote:
> There are a bunch of troubling things in this report. I have a lot of ground launch (auto tow) time, but it's a bit dated, so maybe I've forgotten. IIRC, our target speeds were on the order of 50MPH or 55MPH in zero wind, not 70. This was with a Grob and 2-33, but I can't imagine that 70 is right. The flight profile also sounds odd, as if the pilot was hoping to do an extreme pull-up after building up rather than the usual transition from initial climb to the 45 degrees or so of stage 2 climb. Adding up these two, it seems easy to see how the rope may have been overstressed.
>
>
>
> Finally, it's hard to tell, but it sounds like this wasn't a failed recovery from an extreme nose up low altitude rope break. From the text, it appears that it may have been a stall-spin after the initial recovery - maybe trying to perform a full 180 from low altitude? At least, that's how I read it.
>
>
>
> Anyone else getting the same picture?
>
>
>
> P3
>
>
>
> On Thursday, June 20, 2013 7:33:12 PM UTC-4, Bill D wrote:
>
> > On Thursday, June 20, 2013 3:25:18 PM UTC-6, JohnDeRosa wrote:
>
> >
>
> > > Sad event.
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > > The most telling statement seems to be the very last line of the report.

noel.wade

June 21st 13, 01:16 AM

On Thursday, June 20, 2013 4:55:19 PM UTC-7, Papa3 wrote:
> Finally, it's hard to tell, but it sounds like this wasn't a failed recovery from an extreme nose up low altitude rope break. From the text, it appears that it may have been a stall-spin after the initial recovery - maybe trying to perform a full 180 from low altitude? At least, that's how I read it.
>
> Anyone else getting the same picture?
>

This happened in my area and I was marginally involved in the aftermath (mostly second-hand, so apply some grains of salt as-necessary). Some things to keep in mind, regarding this accident:

1] It was done during the filming of a commercial, NOT a normal launch. There were goals to capture certain maneuvers and angles on-camera.
(You can provide your own conjecture about how that may or may not have affected people's thinking, actions, and/or safety-margins.)

2] The filming location was not chosen for its safety, it was chosen for its aesthetic appeal and/or possibly other factors (that I was not privy to). What I can say for a fact is that several other airports exist in the region that have much longer & wider runways, fewer obstructions, more taxiways, and more "outs" in case of an emergency. (And at least one person told me they suggested one of those other airports to the accident-pilot, sometime in the days or weeks before the accident).

4] Eyewitness reports by fellow pilots (to me) corroborate the NTSB report about the glider returning to "level" after the rope-break, prior to entering a turn/spin. You may speculate about whether the nose-down pitch recovery was done properly; or perhaps whether the pilot recovered properly but then got distracted looking at his emergency landing options. Or perhaps he lost track of the tow-vehicle and was afraid to pitch down and land on the runway area for fear of hitting the car/camera-crew. Or perhaps he had a plan but some combination of low-airspeed and/or cross-wind and/or wind-gradient and/or turbulence from the nearby trees resulted in a loss of lift on one or both wings.

Just remember its speculation. Speculating can be valuable to help us think through potential hazards and guard against them in our own experiences; and I think its worthwhile to play "what if" with accidents with a view towards making ourselves safer. Certainly lessons can be learned. But always keep in mind that we don't _know_ what was going on in that person's mind, or what aggravating factors might have tipped the situation out of "potentially unsafe" territory and into an "accident".

--Noel

Ramy

June 21st 13, 01:38 AM

On Thursday, June 20, 2013 5:16:45 PM UTC-7, noel.wade wrote:
> On Thursday, June 20, 2013 4:55:19 PM UTC-7, Papa3 wrote:
>
> > Finally, it's hard to tell, but it sounds like this wasn't a failed recovery from an extreme nose up low altitude rope break. From the text, it appears that it may have been a stall-spin after the initial recovery - maybe trying to perform a full 180 from low altitude? At least, that's how I read it.
>
> >
>
> > Anyone else getting the same picture?
>
> >
>
>
>
> This happened in my area and I was marginally involved in the aftermath (mostly second-hand, so apply some grains of salt as-necessary). Some things to keep in mind, regarding this accident:
>
>
>
> 1] It was done during the filming of a commercial, NOT a normal launch. There were goals to capture certain maneuvers and angles on-camera.
>
> (You can provide your own conjecture about how that may or may not have affected people's thinking, actions, and/or safety-margins.)
>
>
>
> 2] The filming location was not chosen for its safety, it was chosen for its aesthetic appeal and/or possibly other factors (that I was not privy to). What I can say for a fact is that several other airports exist in the region that have much longer & wider runways, fewer obstructions, more taxiways, and more "outs" in case of an emergency. (And at least one person told me they suggested one of those other airports to the accident-pilot, sometime in the days or weeks before the accident).
>
>
>
> 4] Eyewitness reports by fellow pilots (to me) corroborate the NTSB report about the glider returning to "level" after the rope-break, prior to entering a turn/spin. You may speculate about whether the nose-down pitch recovery was done properly; or perhaps whether the pilot recovered properly but then got distracted looking at his emergency landing options. Or perhaps he lost track of the tow-vehicle and was afraid to pitch down and land on the runway area for fear of hitting the car/camera-crew. Or perhaps he had a plan but some combination of low-airspeed and/or cross-wind and/or wind-gradient and/or turbulence from the nearby trees resulted in a loss of lift on one or both wings.
>
>
>
> Just remember its speculation. Speculating can be valuable to help us think through potential hazards and guard against them in our own experiences; and I think its worthwhile to play "what if" with accidents with a view towards making ourselves safer. Certainly lessons can be learned. But always keep in mind that we don't _know_ what was going on in that person's mind, or what aggravating factors might have tipped the situation out of "potentially unsafe" territory and into an "accident".
>
>
>
> --Noel

Well said Noel.
So much for the "wait for the NTSB report" I keep hearing after every accident. After 2 years the NTSB report didnt tell us anything new. Since there may be new readers on RAS which did not read about this accident, discussing it further can only help.

Ramy

Papa3[_2_]

June 21st 13, 01:53 AM

On Thursday, June 20, 2013 8:07:12 PM UTC-4, Bill D wrote:
> There are a bunch of troubling things in this report. I have a lot of ground launch (auto tow) time, but it's a bit dated, so maybe I've forgotten. IIRC, our target speeds were on the order of 50MPH or 55MPH in zero wind, not 70. This was with a Grob and 2-33, but I can't imagine that 70 is right.
>
>
>
> ---------------------------
>
>
>
> From the DG1000 flight manual:
>
> "Recommended winch launch airspeed 110-130 km/h (60-70 kts.)."
>
>
>
> Theoretically, the best airspeed for winch launch is that which give the angle of attack for best L/D. With the extra wing loading due to the rope pull, it would certainly be in the 60 - 70 knot range.

Right... but IIRC, the vehicle speed is less (significantly?) than the airpseed when the glider is in the aggressive climb portion of the flight profile. If I read the report correctly, it suggests the tow vehicle was briefed for 70. I have to go dig up the diagram, but the airspeed is the additive of some climb vector involving the secant or arc-tangent or some other function on my old Ti-35 that I no longer remember how to use, no? Like I said, it's been 25 years since I was doing 3-5 ground launches per day, so I could easily be off base.

With the increased interest in ground launch, I do think it's useful to revisit some of the old rules of thumb that used to be well known. Sure, we need the SOP and manuals (which are still out there), but it seems to me that it's good to review the underlying physics every now and then.

Dan Marotta

June 21st 13, 01:58 AM

Max ground launch speed for my LAK-17a is 75 kias.

I had many simulated failures during training but only one real break in
service and I climbed away from that.

I'm sure some folks will argue, but my technique is stick full forward NOW
and then recover to controlled flight and decide whether to land (and in
which direction) or climb away. Stick full forward does not result in a
dive if you follow up with proper control inputs.

Oh, yeah... I don't think it's wise to exceed 45 degrees in the climb.

"Bill D" > wrote in message
...

There are a bunch of troubling things in this report. I have a lot of
ground launch (auto tow) time, but it's a bit dated, so maybe I've
forgotten. IIRC, our target speeds were on the order of 50MPH or 55MPH in
zero wind, not 70. This was with a Grob and 2-33, but I can't imagine that
70 is right.

---------------------------

From the DG1000 flight manual:
"Recommended winch launch airspeed 110-130 km/h (60-70 kts.)."

Theoretically, the best airspeed for winch launch is that which give the
angle of attack for best L/D. With the extra wing loading due to the rope
pull, it would certainly be in the 60 - 70 knot range.

Bill D

June 21st 13, 02:05 AM

On Thursday, June 20, 2013 6:38:01 PM UTC-6, Ramy wrote:
> On Thursday, June 20, 2013 5:16:45 PM UTC-7, noel.wade wrote:
>
> > On Thursday, June 20, 2013 4:55:19 PM UTC-7, Papa3 wrote:
>
> >
>
> > > Finally, it's hard to tell, but it sounds like this wasn't a failed recovery from an extreme nose up low altitude rope break. From the text, it appears that it may have been a stall-spin after the initial recovery - maybe trying to perform a full 180 from low altitude? At least, that's how I read it.
>
> >
>
> > >
>
> >
>
> > > Anyone else getting the same picture?
>
> >
>
> > >
>
> >
>
> >
>
> >
>
> > This happened in my area and I was marginally involved in the aftermath (mostly second-hand, so apply some grains of salt as-necessary). Some things to keep in mind, regarding this accident:
>
> >
>
> >
>
> >
>
> > 1] It was done during the filming of a commercial, NOT a normal launch. There were goals to capture certain maneuvers and angles on-camera.
>
> >
>
> > (You can provide your own conjecture about how that may or may not have affected people's thinking, actions, and/or safety-margins.)
>
> >
>
> >
>
> >
>
> > 2] The filming location was not chosen for its safety, it was chosen for its aesthetic appeal and/or possibly other factors (that I was not privy to). What I can say for a fact is that several other airports exist in the region that have much longer & wider runways, fewer obstructions, more taxiways, and more "outs" in case of an emergency. (And at least one person told me they suggested one of those other airports to the accident-pilot, sometime in the days or weeks before the accident).
>
> >
>
> >
>
> >
>
> > 4] Eyewitness reports by fellow pilots (to me) corroborate the NTSB report about the glider returning to "level" after the rope-break, prior to entering a turn/spin. You may speculate about whether the nose-down pitch recovery was done properly; or perhaps whether the pilot recovered properly but then got distracted looking at his emergency landing options. Or perhaps he lost track of the tow-vehicle and was afraid to pitch down and land on the runway area for fear of hitting the car/camera-crew. Or perhaps he had a plan but some combination of low-airspeed and/or cross-wind and/or wind-gradient and/or turbulence from the nearby trees resulted in a loss of lift on one or both wings.
>
> >
>
> >
>
> >
>
> > Just remember its speculation. Speculating can be valuable to help us think through potential hazards and guard against them in our own experiences; and I think its worthwhile to play "what if" with accidents with a view towards making ourselves safer. Certainly lessons can be learned. But always keep in mind that we don't _know_ what was going on in that person's mind, or what aggravating factors might have tipped the situation out of "potentially unsafe" territory and into an "accident".
>
> >
>
> >
>
> >
>
> > --Noel
>
>
>
> Well said Noel.
>
> So much for the "wait for the NTSB report" I keep hearing after every accident. After 2 years the NTSB report didnt tell us anything new. Since there may be new readers on RAS which did not read about this accident, discussing it further can only help.
>
>
>
> Ramy

I thing the NTSB report gives a lot of information and a pretty clear description of what happened.

The proper recovery from a ground launch failure is to pitch over at zero G until the nose is as far below the horizon as it was above at the point of failure then recover from the dive to a normal glide at 1.5xVs. Zero G eliminates induced drag so the glider retains more airspeed. Height loss from a rope break is determined by the minimum airspeed at the top of the ballistic trajectory. This airspeed may be below the 1G level flight stall speed but the glider remains unstalled at 0G.

From the NTSB report:

"Other witnesses located adjacent to the departure runway reported that the first stage of the automobile ground launch appeared normal, and the glider became airborne within the first one-third of the runway. Shortly thereafter, about three-quarters of the way down the runway, the glider pitched to a steep nose-high attitude. As the glider ascended through about 100 – 125 feet above the ground, the rope slackened. The glider continued to ascend, and then leveled off about 200 feet above the end of the runway. Shortly after, the glider entered a steep right bank and descended into the ground.. As it descended, the glider turned approximately 300 degrees from its initial departure heading before it impacted terrain."

If this witness is to be believed, the launch failed at a steep nose-up attitude followed by a continued climb ending level flight attitude. This indicates no attempt at airspeed recovery. A turn was then initiated from what was likely a critically low airspeed resulting in a spin to impact.

waremark

June 21st 13, 02:10 AM

I do lots of winch launching but have never even seen an auto-tow. The report says the rope length was 234 foot. Is that normal or even possible? Using a winch, at my club we get 800 to 1200 foot of launch height from 2,100 feet of winch cable - so launch height is a bit more than one third of the cable length. How on earth could you get to a safe launch height from a 234 foot rope?

Forgive me for teaching granny to suck eggs, but some readers may not have had training or experience in this. As a general comment on ground launch failures, firstly it is vital not to rotate too rapidly and not to be too steep too low. However, once in the full climb at a safe height, if a launch failure occurs, it is vital to lower the nose of the glider rapidly well below a normal glide attitude. If the nose is lowered only to a normal glide attitude after a launch failure in a steep climb, the speed may well have reduced below a safe flying speed, with the potential as here for a stall/spin. It is common to teach a rule of thumb that the nose should be lowered as far below the horizon as it was above the horizon before the launch failure.

Mark Burton, London Gliding Club, UK

On Friday, 21 June 2013 01:53:19 UTC+1, Papa3 wrote:
> On Thursday, June 20, 2013 8:07:12 PM UTC-4, Bill D wrote:
>
> > There are a bunch of troubling things in this report. I have a lot of ground launch (auto tow) time, but it's a bit dated, so maybe I've forgotten. IIRC, our target speeds were on the order of 50MPH or 55MPH in zero wind, not 70. This was with a Grob and 2-33, but I can't imagine that 70 is right.
>
> >
>
> >
>
> >
>
> > ---------------------------
>
> >
>
> >
>
> >
>
> > From the DG1000 flight manual:
>
> >
>
> > "Recommended winch launch airspeed 110-130 km/h (60-70 kts.)."
>
> >
>
> >
>
> >
>
> > Theoretically, the best airspeed for winch launch is that which give the angle of attack for best L/D. With the extra wing loading due to the rope pull, it would certainly be in the 60 - 70 knot range.
>
>
>
> Right... but IIRC, the vehicle speed is less (significantly?) than the airpseed when the glider is in the aggressive climb portion of the flight profile. If I read the report correctly, it suggests the tow vehicle was briefed for 70. I have to go dig up the diagram, but the airspeed is the additive of some climb vector involving the secant or arc-tangent or some other function on my old Ti-35 that I no longer remember how to use, no? Like I said, it's been 25 years since I was doing 3-5 ground launches per day, so I could easily be off base.
>
>
>
> With the increased interest in ground launch, I do think it's useful to revisit some of the old rules of thumb that used to be well known. Sure, we need the SOP and manuals (which are still out there), but it seems to me that it's good to review the underlying physics every now and then.

Bill D

June 21st 13, 02:12 AM

On Thursday, June 20, 2013 6:58:55 PM UTC-6, Dan Marotta wrote:
> Max ground launch speed for my LAK-17a is 75 kias.

Don't confuse max ground launch speed (Vw)with recommended airspeed for winch launch. The DG1000 Vw is 81 knots.

[email protected]

June 21st 13, 02:16 AM

I was supposed to do this commercial.
Instead the company went to the lowest bidder.

I had a much safer script for this and
it would have promoted soaring, but the
car company and the production company
had no interest in any of that. All
they wanted was the low hanging fruit,
which was a glider being jerked into
the sky by a car.

This is very typical in the film biz.

There is a lot I cannot talk about because
of the investigation.

It was a sad event that did not have to happen
and could have easily been avoided.

VI

Bill D

June 21st 13, 02:21 AM

On Thursday, June 20, 2013 7:10:16 PM UTC-6, waremark wrote:
> I do lots of winch launching but have never even seen an auto-tow. The report says the rope length was 234 foot. Is that normal or even possible?

It's not normal or generally advisable but it's possible. With a rope that short, the launch must be planned so the landing is straight ahead or at least with a minimal heading change.

At the end of a day, I've used two aero tow ropes tied together to auto tow to about 300' AGL then glide across the airport infield to land on the ramp.

Papa3[_2_]

June 21st 13, 03:00 AM

Disregard... looks like the whole setup was non-standard, so a lot of the usual rules of thumb go out the door. I hadn't noticed the very short rope for example...

On Thursday, June 20, 2013 8:53:19 PM UTC-4, Papa3 wrote:
> On Thursday, June 20, 2013 8:07:12 PM UTC-4, Bill D wrote:
>
> > There are a bunch of troubling things in this report. I have a lot of ground launch (auto tow) time, but it's a bit dated, so maybe I've forgotten. IIRC, our target speeds were on the order of 50MPH or 55MPH in zero wind, not 70. This was with a Grob and 2-33, but I can't imagine that 70 is right.
>
> >
>
> >
>
> >
>
> > ---------------------------
>
> >
>
> >
>
> >
>
> > From the DG1000 flight manual:
>
> >
>
> > "Recommended winch launch airspeed 110-130 km/h (60-70 kts.)."
>
> >
>
> >
>
> >
>
> > Theoretically, the best airspeed for winch launch is that which give the angle of attack for best L/D. With the extra wing loading due to the rope pull, it would certainly be in the 60 - 70 knot range.
>
>
>
> Right... but IIRC, the vehicle speed is less (significantly?) than the airpseed when the glider is in the aggressive climb portion of the flight profile. If I read the report correctly, it suggests the tow vehicle was briefed for 70. I have to go dig up the diagram, but the airspeed is the additive of some climb vector involving the secant or arc-tangent or some other function on my old Ti-35 that I no longer remember how to use, no? Like I said, it's been 25 years since I was doing 3-5 ground launches per day, so I could easily be off base.
>
>
>
> With the increased interest in ground launch, I do think it's useful to revisit some of the old rules of thumb that used to be well known. Sure, we need the SOP and manuals (which are still out there), but it seems to me that it's good to review the underlying physics every now and then.

Bill D

June 21st 13, 03:15 AM

On Thursday, June 20, 2013 8:00:14 PM UTC-6, Papa3 wrote:
> Disregard... looks like the whole setup was non-standard, so a lot of the usual rules of thumb go out the door. I hadn't noticed the very short rope for example...

> > With the increased interest in ground launch, I do think it's useful to revisit some of the old rules of thumb that used to be well known. Sure, we need the SOP and manuals (which are still out there), but it seems to me that it's good to review the underlying physics every now and then.

I would suggest reading George Moores papers on winch launch. George has taken the whole subject of ground launch into the 21st century with a very deep and detailed mathematical analysis. His fresh view of the subject is very welcome. His papers can be read in the files section of the Yahoo group winchengineer and winchdesign.

If you'd like to take a look at my training materials, they can be downloaded as PDF's.

Winch pilot training guide: https://dl.dropboxusercontent.com/u/79580374/WinchLaunchIllustratedTrainingGuide%20Rev%2017.pdf

Winch training slide show: https://dl.dropboxusercontent.com/u/79580374/Winch%20Training.pdf

Airfield operations: https://dl.dropboxusercontent.com/u/79580374/Winch%20operations.pdf

[email protected]

June 21st 13, 06:30 AM

Le jeudi 20 juin 2013 21:53:31 UTC+2, Steve Leonard a écrit*:
> http://www.ntsb.gov/aviationquery/brief2.aspx?ev_id=20111013X31821&ntsbno=WPR12FA010&akey=1
>
>
>
> Happened to be looking through the NTSB Database and saw that they updated the report about a month ago.

It looks like they tried to more or less duplicate an old commercial by Michelin, where you saw an ASK-21 being auto-towed on a frozen lake. The glider went brutally up on a very short rope and released almost immediately. Then the car came to a braking halt just in front of an obstacle, while the glider was flying away. It was to illustrate the grip of a "Drice" winter tire... I can't find it on the web anymore. Some small stills are visible if you google "Michelin Drice" for images, but the links are dead.

Kevin Neave[_2_]

June 21st 13, 09:04 AM

No mention of the pilot's previous experience with winch / autotow
launching

KN

At 05:30 21 June 2013, wrote:
>Le jeudi 20 juin 2013 21:53:31 UTC+2, Steve Leonard a =E9crit=A0:
>>
>http://www.ntsb.gov/aviationquery/brief2.aspx?ev_id=3D20111013X31821&ntsb=
>no=3DWPR12FA010&akey=3D1
>>=20
>>=20
>>=20
>> Happened to be looking through the NTSB Database and saw that they
>update=
>d the report about a month ago.
>
>It looks like they tried to more or less duplicate an old commercial by
>Mic=
>helin, where you saw an ASK-21 being auto-towed on a frozen lake. The
>glide=
>r went brutally up on a very short rope and released almost immediately.
>Th=
>en the car came to a braking halt just in front of an obstacle, while the
>g=
>lider was flying away. It was to illustrate the grip of a "Drice" winter
>ti=
>re... I can't find it on the web anymore. Some small stills are visible
if
>=
>you google "Michelin Drice" for images, but the links are dead.
>

Sean F (F2)

June 21st 13, 12:20 PM

Sad event and scary stuff.

JohnDeRosa

June 21st 13, 03:16 PM

Can anyone comment if the "steep nose high attitude" was intentional? Were the previous launches straight line low hops which would seem to be safer? Low hops would keep both the glider and the (very important) automobile in the same camera frame. Could something have occurred in the cockpit which forced a dramatic change in pitch attitude?

Which, to me, points back to the length of the rope (234ft) and the tow car driver stating that "The pilot planned to become airborne and then circle back to the airport to land.". Really? Circle back using a 234ft launch rope? He would have only gotten, what, 100feet high? I would seriously doubt that this experienced of a glider pilot (CFIG) would have announced that he could "circle back" even if he thought he would get 200-300 ft sling shot like launch. If not then it flies in the face of what the driver said.

- John "Speculation" D.

WAVEGURU

June 21st 13, 04:02 PM

I wish we could see the videos.

Boggs

Bill D

June 21st 13, 04:05 PM

On Friday, June 21, 2013 8:16:25 AM UTC-6, JohnDeRosa wrote:
> Can anyone comment if the "steep nose high attitude" was intentional? Were the previous launches straight line low hops which would seem to be safer? Low hops would keep both the glider and the (very important) automobile in the same camera frame. Could something have occurred in the cockpit which forced a dramatic change in pitch attitude?
>
>
>
> Which, to me, points back to the length of the rope (234ft) and the tow car driver stating that "The pilot planned to become airborne and then circle back to the airport to land.". Really? Circle back using a 234ft launch rope? He would have only gotten, what, 100feet high? I would seriously doubt that this experienced of a glider pilot (CFIG) would have announced that he could "circle back" even if he thought he would get 200-300 ft sling shot like launch. If not then it flies in the face of what the driver said.
>
>
>
> - John "Speculation" D.

Cle Elum Runway 7/25
Dimensions: 2552 x 40 ft.

With a runway this short, a pilot would have to climb very steeply to get any height at all. I'll guess the Caddy towing a DG1000 would need at least 1000' to reach 70mph and another 500' or so to stop. Add 234' of rope length and that leaves less than 700' of runway for the glider to climb - maybe much less.

OTOH, runways this short are used for winch launch. You could expect at least 1000' AGL launches. But then, the Caddy wouldn't have a leading role.

Dan Marotta

June 21st 13, 04:24 PM

Been doing this a long time. Not confused.

Maybe I need to work on my writing skills.

"Bill D" > wrote in message
...
> On Thursday, June 20, 2013 6:58:55 PM UTC-6, Dan Marotta wrote:
>> Max ground launch speed for my LAK-17a is 75 kias.
>
> Don't confuse max ground launch speed (Vw)with recommended airspeed for
> winch launch. The DG1000 Vw is 81 knots.

Dan Marotta

June 21st 13, 04:49 PM

I just started reviewing your training guide, Bill, and I must say,
"Excellent!" It's time to go fly my glider but I've saved the links and
will review all of your stuff for this evening for the refresher benefit,
though I probably won't be doing another ground launch until next "weekend"
at Roach Dry Lake.

I learned to fly off a winch back in the late 80s at Alice Springs, NT,
Australia (Bond Springs, actually) in a Twin Lark with about a mile of
cable, IIRC. Very exciting stuff and we got away every time!

When Black Forest purchased a winch from the AF Academy, Joe Berger and I
removed the small-block Chevy engine and transmission, extended the frame,
and installed a big-block 454 from a truck donated by Dave Rolley. It was
great fun and we used it during the Women's Soaring Seminar at Westcliffe
back in '92 (I think it was - I'll have to dig out my t-shirt to be
sure...). We also used the winch in the test flying of the first PW-5 to
arrive in those parts. IIRC, the FAA required that all maneuvers intended
to be flown had to be done during the test flying and the owner, being a new
pilot asked Tom Serkowski and I to do the flying. What fun we had!

Unfortunately, there was very little support for the winch and it fell into
disrepair. I recently heard that it had been sold.

"Bill D" > wrote in message
...
On Thursday, June 20, 2013 8:00:14 PM UTC-6, Papa3 wrote:
> Disregard... looks like the whole setup was non-standard, so a lot of the
> usual rules of thumb go out the door. I hadn't noticed the very short
> rope for example...

> > With the increased interest in ground launch, I do think it's useful to
> > revisit some of the old rules of thumb that used to be well known.
> > Sure, we need the SOP and manuals (which are still out there), but it
> > seems to me that it's good to review the underlying physics every now
> > and then.

I would suggest reading George Moores papers on winch launch. George has
taken the whole subject of ground launch into the 21st century with a very
deep and detailed mathematical analysis. His fresh view of the subject is
very welcome. His papers can be read in the files section of the Yahoo
group winchengineer and winchdesign.

If you'd like to take a look at my training materials, they can be
downloaded as PDF's.

Winch pilot training guide:
https://dl.dropboxusercontent.com/u/79580374/WinchLaunchIllustratedTrainingGuide%20Rev%2017.pdf

Winch training slide show:
https://dl.dropboxusercontent.com/u/79580374/Winch%20Training.pdf

Airfield operations:
https://dl.dropboxusercontent.com/u/79580374/Winch%20operations.pdf

Bill D

June 21st 13, 05:20 PM

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

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

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

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

Frank Whiteley

June 21st 13, 06:14 PM

On Thursday, June 20, 2013 1:53:31 PM UTC-6, Steve Leonard wrote:
> http://www.ntsb.gov/aviationquery/brief2.aspx?ev_id=20111013X31821&ntsbno=WPR12FA010&akey=1
>
>
>
> Happened to be looking through the NTSB Database and saw that they updated the report about a month ago.

Some have said there's nothing new in this report. Indeed there remain some missing details, but there is also a new fact that I don't recall from the prior reports and my inquiries, including discussion with the observer in the back of the launch vehicle.

If the facts are correct, anyone involved in ground launching should have zeroed in on the rope. Nylon rope is very elastic compared to premium UHMWPE ropes, that is, nylon has some 16% elongation at 15% of breaking strength.. UHMWPE rope elongation at 30% of breaking strength is under 1%.

Working limits of premium UHMWPE and steel wire ropes are 1/5 to 1/6 of breaking strength. During winch launching we tend to operate beyond these working limits regularly by loading to 1/4 to 1/3 of breaking strength with premium UHMWPE ropes, and presumably as high as 3/5 with the regular UHMWPE and steel wire ropes. For all practical purposes, there is minimal elongation.

noel.wade

June 21st 13, 06:25 PM

On Friday, June 21, 2013 7:16:25 AM UTC-7, JohnDeRosa wrote:
> Can anyone comment if the "steep nose high attitude" was intentional?

I don't think anyone can say exactly what was intentional, other than the deceased pilot.

I have heard - secondhand - that during the planning of the commercial they had wanted a shot from in front of the SUV looking back at it, with the glider rising suddenly & dramatically above it. Whether that was part of the final plans or whether they were trying to film that scene at the time of the accident is anyone's guess.

Frank - One thing to remember is that we do not _know_ if the pilot initiated the turn, or if it merely appeared so as the first phase of spin entry (i.e. a wing-drop). It is entirely possible the pilot was intending to land straight ahead but experienced an asymmetric stall (again, could've been the cross-wind, or a gust, or mechanical turbulence, or lack of coordinated controls, or whatever - we just don't know). I also don't think the satellite photo/maps show clearly if there are bushes or a fence between the runway and the large field - it is possible the pilot had better information about that than we do.

--Noel

Frank Whiteley

June 21st 13, 06:40 PM

On Friday, June 21, 2013 11:25:30 AM UTC-6, noel.wade wrote:
> On Friday, June 21, 2013 7:16:25 AM UTC-7, JohnDeRosa wrote:
>
> > Can anyone comment if the "steep nose high attitude" was intentional?
>
>
>
> I don't think anyone can say exactly what was intentional, other than the deceased pilot.
>
>
>
> I have heard - secondhand - that during the planning of the commercial they had wanted a shot from in front of the SUV looking back at it, with the glider rising suddenly & dramatically above it. Whether that was part of the final plans or whether they were trying to film that scene at the time of the accident is anyone's guess.
>
>
>
> Frank - One thing to remember is that we do not _know_ if the pilot initiated the turn, or if it merely appeared so as the first phase of spin entry (i.e. a wing-drop). It is entirely possible the pilot was intending to land straight ahead but experienced an asymmetric stall (again, could've been the cross-wind, or a gust, or mechanical turbulence, or lack of coordinated controls, or whatever - we just don't know). I also don't think the satellite photo/maps show clearly if there are bushes or a fence between the runway and the large field - it is possible the pilot had better information about that than we do.
>
>
>
> --Noel

Google Earth has pretty good images. There is at least a hedge and probably a fence at the airport boundary, which is about 90 yards past the pavement. There do not appear to be wires. The field may be hay production/pasture or something else. Could have been bales as late as October, ruling it out as an option.

I agree, wind may have been a factor, especially with the surrounding hills and mountains. I wouldn't read much into the Ellensburg winds though.

However, the rope break was clearly a contributing factor and might have been eliminated.

Frank Whiteley

Walt Connelly

June 21st 13, 06:54 PM

June 21st 13, 07:46 PM

There are additional documents located in the NTSB Docket including witness statements from the driver, photographs of the broken towrope and a video of the accident scenario.

http://dms.ntsb.gov/pubdms/search/hitlist.cfm?docketID=51899&CFID=27180&CFTOKEN=73517888

On Friday, June 21, 2013 12:14:22 PM UTC-5, Frank Whiteley wrote:
> On Thursday, June 20, 2013 1:53:31 PM UTC-6, Steve Leonard wrote:
>
> > http://www.ntsb.gov/aviationquery/brief2.aspx?ev_id=20111013X31821&ntsbno=WPR12FA010&akey=1
>
> >
>
> >
>
> >
>
> > Happened to be looking through the NTSB Database and saw that they updated the report about a month ago.
>
>
>
> Some have said there's nothing new in this report. Indeed there remain some missing details, but there is also a new fact that I don't recall from the prior reports and my inquiries, including discussion with the observer in the back of the launch vehicle.
>
>
>
> If the facts are correct, anyone involved in ground launching should have zeroed in on the rope. Nylon rope is very elastic compared to premium UHMWPE ropes, that is, nylon has some 16% elongation at 15% of breaking strength. UHMWPE rope elongation at 30% of breaking strength is under 1%.
>
>
>
> Working limits of premium UHMWPE and steel wire ropes are 1/5 to 1/6 of breaking strength. During winch launching we tend to operate beyond these working limits regularly by loading to 1/4 to 1/3 of breaking strength with premium UHMWPE ropes, and presumably as high as 3/5 with the regular UHMWPE and steel wire ropes. For all practical purposes, there is minimal elongation.
>
>
>
> Nylon rope's typical working limit is 1/12 of breaking strength. 5/16" nylon rope, as described in the report is rated from about 1490lbs to 3300lbs breaking strength depending on construction and processing. Most constructions are rated in the 1500lb to 2200lb BS range, which would indicate that a DG1000 could easily reach and exceed 1/1 with most nylon ropes and reach 2/3 with the best ropes assuming a black TOST weak link was used. Repeated [over]load cycles will accelerate fatigue and this rope would have been loaded near breaking strength repeatedly over the course of several launches. One can only imagine the elongation near the breaking point. Perhaps they started with a 200ft rope which was stretched to 234ft when it broke. 17% elongation. Breakage without any signs of appreciable wear would be expected within a very few launches. I'm not aware of any glider operations using nylon rope for ground launching. Steel, poly-types, and dacron, yes, but not nylon.
>
>
>
> There is a large field off the end of runway 7. If the pilot thought he had enough height to attempt to circle to a landing, he definitely had this field as an option. The remainder of the conjecture would seem that he commenced a turn before resuming flying speed after the break.
>
>
>
> Frank Whiteley

Steve Barter

June 21st 13, 08:05 PM

http://www.gliding.co.uk/bgainfo/safety/safewinchlaunching.htm

It's winch launching, not auto towing, but relevant. Some might find it
useful
and interesting.

Bill D

June 21st 13, 08:49 PM

On Friday, June 21, 2013 11:14:22 AM UTC-6, Frank Whiteley wrote:
> On Thursday, June 20, 2013 1:53:31 PM UTC-6, Steve Leonard wrote:
>
> > http://www.ntsb.gov/aviationquery/brief2.aspx?ev_id=20111013X31821&ntsbno=WPR12FA010&akey=1
>
> >
>
> >
>
> >
>
> > Happened to be looking through the NTSB Database and saw that they updated the report about a month ago.
>
>
>
> Some have said there's nothing new in this report. Indeed there remain some missing details, but there is also a new fact that I don't recall from the prior reports and my inquiries, including discussion with the observer in the back of the launch vehicle.
>
>
>
> If the facts are correct, anyone involved in ground launching should have zeroed in on the rope. Nylon rope is very elastic compared to premium UHMWPE ropes, that is, nylon has some 16% elongation at 15% of breaking strength. UHMWPE rope elongation at 30% of breaking strength is under 1%.
>
>
>
> Working limits of premium UHMWPE and steel wire ropes are 1/5 to 1/6 of breaking strength. During winch launching we tend to operate beyond these working limits regularly by loading to 1/4 to 1/3 of breaking strength with premium UHMWPE ropes, and presumably as high as 3/5 with the regular UHMWPE and steel wire ropes. For all practical purposes, there is minimal elongation.
>
>
>
> Nylon rope's typical working limit is 1/12 of breaking strength. 5/16" nylon rope, as described in the report is rated from about 1490lbs to 3300lbs breaking strength depending on construction and processing. Most constructions are rated in the 1500lb to 2200lb BS range, which would indicate that a DG1000 could easily reach and exceed 1/1 with most nylon ropes and reach 2/3 with the best ropes assuming a black TOST weak link was used. Repeated [over]load cycles will accelerate fatigue and this rope would have been loaded near breaking strength repeatedly over the course of several launches. One can only imagine the elongation near the breaking point. Perhaps they started with a 200ft rope which was stretched to 234ft when it broke. 17% elongation. Breakage without any signs of appreciable wear would be expected within a very few launches. I'm not aware of any glider operations using nylon rope for ground launching. Steel, poly-types, and dacron, yes, but not nylon.
>
>
>
> There is a large field off the end of runway 7. If the pilot thought he had enough height to attempt to circle to a landing, he definitely had this field as an option. The remainder of the conjecture would seem that he commenced a turn before resuming flying speed after the break.
>
>
>
> Frank Whiteley

Frank, that's all true but it's in the nature of ropes to break. Good ropes break less often than crappy ropes but they still break - that's just how it is. The trick is to never put oneself in a a position where a rope break causes an accident. Good pilots EXPECT the rope to break on every launch and have a plan to deal with it.

The NTSB supplemental data with the witness video clearly shows the pilot did not lower the nose, made no attempt to recover airspeed and (likely) started a turn leading to a stall and spin to impact. Nor does the video show any evidence the pilot made an attempt to stop the spin departure once it had begun.

Google Earth shows a 1400' plowed field off the departure end of runway 7. If this field was useable, the rope break was survivable provided the pilot promptly lowered the nose, recovered airspeed and landed ahead in the field.

Don Johnstone[_4_]

June 21st 13, 11:21 PM

To people unfamiliar with winch launching or auto tow the climb angle looks
very steep, and certainly is compared to an aero tow.
234 feet is very short for an auto tow rope and you would not expect the
glider to get more than 200 ft from that.
I have completed 10,000 winch launches and of those about 2000 have been
practice launch failures, about 100 for real. I have done about 200 auto
tow launches where the most common cause of lack of power is lifting the
driving wheels of the tow truck off the ground at the top of the launch.
Folowing a launch failure (rope break/loss of power)nearly all pilots take
the initial recovery automatically, moving the stick forward to adopt a
nose down attitude. This will always introduce negative G which in effect
reduces the wing loading on the glider meaning the stall speed is much
lower than is normally the case. If an attempt to turn is made at this
stage, as the effect of the negative G goes away, a stall may occur and if
aileron is applied and there is any bank a spin is most likely. A DG 1000
is one of the GRP gliders that will spin readily. A full recovery from a
spin at 200 ft is not possible.
This is why we teach the recovery as move the stick forward to adopt at
least the approach attitude AND wait until approach speed is gained. Then
make the decision as to whether you are going to land ahead or turn.

[email protected]

June 21st 13, 11:28 PM

the video is heart wrenching. my condolences to friends and family.

I was thinking, the flight is not unlike the second half of a very low pass which has been known to cause another accident in the recent past. Unfortunately done at far too slow of a speed of just 70mph for such a low altitude "pass". Just not enough energy for the pull up and maneuvering back around for landing.

Bill D

June 22nd 13, 01:09 AM

On Friday, June 21, 2013 4:21:55 PM UTC-6, Don Johnstone wrote:

> This is why we teach the recovery as move the stick forward to adopt at
> least the approach attitude AND wait until approach speed is gained. Then make the decision as to whether you are going to land ahead or turn.
________________________
The math says you will do better to push the nose lower than the approach attitude both in recovering airspeed sooner and retaining as much altitude as possible.

Without the benefit of an angle of attack indicator, the greatest safety margin is to push the nose as far below the horizon as it was above at failure and hold it there until at least the "Yellow Triangle" airspeed is in hand. This "rule of thumb" prevents diving the glider into the runway from a low failure and provides a good margin at higher altitudes.

With an AOA indicator, if you chose, you could gently reload the wings at the top of the trajectory using an AOA equivalent to best L/D which results in the least loss of height. Since angle of attack determines whether the wing will stall, the airspeed at the beginning of the reload can safely be below the normal 1G stalling speed.

Speaking of AOA indicators and stick buzzers, does anyone think one might have saved this pilots life?

Bill D

June 22nd 13, 01:10 AM

On Friday, June 21, 2013 4:28:39 PM UTC-6, wrote:
> the video is heart wrenching. my condolences to friends and family.
>
>
>
> I was thinking, the flight is not unlike the second half of a very low pass which has been known to cause another accident in the recent past. Unfortunately done at far too slow of a speed of just 70mph for such a low altitude "pass". Just not enough energy for the pull up and maneuvering back around for landing.

Excellent observation.

Frank Whiteley

June 22nd 13, 01:28 AM

On Friday, June 21, 2013 1:49:25 PM UTC-6, Bill D wrote:
> On Friday, June 21, 2013 11:14:22 AM UTC-6, Frank Whiteley wrote:
>
> > On Thursday, June 20, 2013 1:53:31 PM UTC-6, Steve Leonard wrote:
>
> >
>
> > > http://www.ntsb.gov/aviationquery/brief2.aspx?ev_id=20111013X31821&ntsbno=WPR12FA010&akey=1
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > > Happened to be looking through the NTSB Database and saw that they updated the report about a month ago.
>
> >
>
> >
>
> >
>
> > Some have said there's nothing new in this report. Indeed there remain some missing details, but there is also a new fact that I don't recall from the prior reports and my inquiries, including discussion with the observer in the back of the launch vehicle.
>
> >
>
> >
>
> >
>
> > If the facts are correct, anyone involved in ground launching should have zeroed in on the rope. Nylon rope is very elastic compared to premium UHMWPE ropes, that is, nylon has some 16% elongation at 15% of breaking strength. UHMWPE rope elongation at 30% of breaking strength is under 1%.
>
> >
>
> >
>
> >
>
> > Working limits of premium UHMWPE and steel wire ropes are 1/5 to 1/6 of breaking strength. During winch launching we tend to operate beyond these working limits regularly by loading to 1/4 to 1/3 of breaking strength with premium UHMWPE ropes, and presumably as high as 3/5 with the regular UHMWPE and steel wire ropes. For all practical purposes, there is minimal elongation.
>
> >
>
> >
>
> >
>
> > Nylon rope's typical working limit is 1/12 of breaking strength. 5/16" nylon rope, as described in the report is rated from about 1490lbs to 3300lbs breaking strength depending on construction and processing. Most constructions are rated in the 1500lb to 2200lb BS range, which would indicate that a DG1000 could easily reach and exceed 1/1 with most nylon ropes and reach 2/3 with the best ropes assuming a black TOST weak link was used. Repeated [over]load cycles will accelerate fatigue and this rope would have been loaded near breaking strength repeatedly over the course of several launches. One can only imagine the elongation near the breaking point. Perhaps they started with a 200ft rope which was stretched to 234ft when it broke. 17% elongation. Breakage without any signs of appreciable wear would be expected within a very few launches. I'm not aware of any glider operations using nylon rope for ground launching. Steel, poly-types, and dacron, yes, but not nylon.
>
> >
>
> >
>
> >
>
> > There is a large field off the end of runway 7. If the pilot thought he had enough height to attempt to circle to a landing, he definitely had this field as an option. The remainder of the conjecture would seem that he commenced a turn before resuming flying speed after the break.
>
> >
>
> >
>
> >
>
> > Frank Whiteley
>
>
>
> Frank, that's all true but it's in the nature of ropes to break. Good ropes break less often than crappy ropes but they still break - that's just how it is. The trick is to never put oneself in a a position where a rope break causes an accident. Good pilots EXPECT the rope to break on every launch and have a plan to deal with it.
>
>
>
> The NTSB supplemental data with the witness video clearly shows the pilot did not lower the nose, made no attempt to recover airspeed and (likely) started a turn leading to a stall and spin to impact. Nor does the video show any evidence the pilot made an attempt to stop the spin departure once it had begun.
>
>
>
> Google Earth shows a 1400' plowed field off the departure end of runway 7.. If this field was useable, the rope break was survivable provided the pilot promptly lowered the nose, recovered airspeed and landed ahead in the field.

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

Unfortunately the short out of focus view obscures any chance of seeing control deflections and possible pilot intent.

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

Frank Whiteley

Alan[_6_]

June 22nd 13, 08:41 AM

In article > Bill D > writes:

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

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

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

The Feb 2008 column revisits it with few additional numbers.

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

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

Alan

Don Johnstone[_4_]

June 22nd 13, 11:02 AM

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

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

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

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

Bill D

June 22nd 13, 03:01 PM

On Saturday, June 22, 2013 1:41:41 AM UTC-6, Alan wrote:
> In article > Bill D > writes:
>
>
>
> >I'm positive that if it's done right, winch launch is far safer than aero t=
>
> >ow. Germans suffer one accident on average every 180,000 winch launches wh=
>
> >ile we suffer one every 24,000 aero tows. I know there are cultural differ=
>
> >ences but, presumably, we're pretty good at aero tow and they're at least a=
>
> >s good at winch launch so the comparison is probably valid.
>
>
>
> But, what is the severity of these accidents?

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

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

Vaughn

June 22nd 13, 03:23 PM

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

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

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

See the examination report with pictures here:
http://dms.ntsb.gov/pubdms/search/document.cfm?docID=390740&docketID=51899&mkey=82059

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

Dan Marotta

June 22nd 13, 05:19 PM

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

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

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

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

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

Dan Marotta

June 22nd 13, 05:21 PM

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

"Alan" > wrote in message
...
> In article > Bill D
> > writes:
>
>>I'm positive that if it's done right, winch launch is far safer than aero
>>t=
>>ow. Germans suffer one accident on average every 180,000 winch launches
>>wh=
>>ile we suffer one every 24,000 aero tows. I know there are cultural
>>differ=
>>ences but, presumably, we're pretty good at aero tow and they're at least
>>a=
>>s good at winch launch so the comparison is probably valid.
>
> But, what is the severity of these accidents? An article (referenced
> below)
> lists 18 fatal+36 serious injury out of 380 winch launch accidents (14.2
> percent).
> Aerotow had 1 fatal+2 serious injury out of 103 launch accidents (2.9
> percent).
>
> See http://www.soaringsafety.org/ssf-06/articles.html - the articles
> from
> November 2006 report a higher rate of winch accidents than aerotow, and a
> 7.2
> times ratio of winch fatalities vs aerotow once adjusted for number of
> tows of
> each type.
>
> The Feb 2008 column revisits it with few additional numbers.
>
>>It's natural for familiar things like aero tow to seem safe and unfamiliar
>>=
>>things like winch launch to look unsafe but the numbers tell a different
>>st=
>>ory.
>
> The numbers I found in the November 2006 article appear to favor
> aerotow for safety, both in accidents per launch, and in severity of
> the accident once it has happened.
>
> Alan

Frank Whiteley

June 22nd 13, 09:55 PM

On Saturday, June 22, 2013 4:02:59 AM UTC-6, Don Johnstone wrote:
> At 00:28 22 June 2013, Frank Whiteley wrote:
>
>
>
> >
>
> >Hard to say from the report images whether the rope had any worry marks,
>
> >bu=
>
> >t there are some discolorations in the break area. It appears to be
>
> >reason=
>
> >able quality rope, but nylon just is not the right media and is very low
>
> >wo=
>
> >rking limit for it's breaking strength and diameter. The recoil of the
>
> >rop=
>
> >e in the video is pretty interesting as the bulk of the rope bunches up
>
> in
>
> >=
>
> >a clump only a few fuselage lengths behind the glider. If the rope had
>
> >pre=
>
> >viously recoiled toward the release on the car during earlier launches,
>
> >it'=
>
> >s possible it was compromised by impacting the car or release hardware
>
> >(hen=
>
> >ce the marks). One witness described seeing 6-8 inches of rope remaining
>
> >a=
>
> >t the car end.
>
> >
>
>
>
> >
>
> >Ropes may be expected to break, but choice of rope makes a big
>
> difference.
>
> >
>
> >Frank Whiteley
>
>
>
> We use skyrope, which is nylon rope on our winch and the failure rate is
>
> much less than with wire rope
>
> >

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

Can you point to something more useful about this product?

Frank

Chris Nicholas[_2_]

June 22nd 13, 10:56 PM

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

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

Chris M

Bill D

June 22nd 13, 11:44 PM

On Saturday, June 22, 2013 3:56:46 PM UTC-6, Chris Nicholas wrote:
> Dan M wrote: “Frankly I don't see the problem (I know the physics) - simply fly the glider and who needs the self-righting forces of a nose hook?”
>
>
>
> The small number of pilots who killed a tug pilot by kiting did, and the larger number who nearly have, including some quite recently. We are having a campaign in the UK to try to stop it again, but humans being what they are . . .
>
>
>
>
>
> Chris M

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

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

Chris Nicholas[_2_]

June 23rd 13, 12:50 AM

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

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

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

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

Regards - Chris

B4soaring

June 23rd 13, 01:01 AM

On 22/06/2013 15:01, Bill D wrote:
> On Saturday, June 22, 2013 1:41:41 AM UTC-6, Alan wrote:
>> In article > Bill D >

writes:
>>
>>
>>
>>> I'm positive that if it's done right, winch launch is far safer than aero t=
>>
>>> ow. Germans suffer one accident on average every 180,000 winch launches wh=
>>
>>> ile we suffer one every 24,000 aero tows. I know there are cultural differ=
>>
>>> ences but, presumably, we're pretty good at aero tow and they're at least a=
>>
>>> s good at winch launch so the comparison is probably valid.
>>
>>
>>
>> But, what is the severity of these accidents?
>
> The severity is exactly the same for both aero tow and winch. The German LBU accident statistics are

available on-line just as the NTSB data is. I suggest you verify them
yourself.
>
> I have no idea where the SSF got their numbers but it may have been the UK since no translations

are required. 2011 data shows the UK suffers one accident every 16,000
launches while

Germany suffers one every 180,000. German numbers are roughly
comparable to the rest of continental

Europe. The SSF needs to take another, wider look.
>
Bill makes the classic mistake of the amateur statistician - failing to
understand the different definitions & methods behind the statistics he
quotes.

None of the statistics Bill quotes can be relied upon to be an accurate
comparison.

Ed.

Bill D

June 23rd 13, 01:35 AM

On Saturday, June 22, 2013 5:50:18 PM UTC-6, Chris Nicholas wrote:
> Bill, I entirely agree that it is not the only factor - we have
>
> identified 6 factors as the most notable circumstances, of which
>
> belly hooks are one. It is a fact that the first such UK fatality was
>
> with a belly hook (and also turbulence, and probably
>
> recency/currency, were others in that case).
>
>
>
> Dan’s point AIUI was you only have to fly the glider. My main point
>
> was too many people didn’t, and over here at least are starting not
>
> to again. Another of my points is that by education and supervision,
>
> we are trying to address the re-emergence of the issue.
>
>
>
> Our policy is that you should not have more than two, if that, of the
>
> factors present on any one launch. Had that been known, adopted
>
> and followed, the first such fatality would probably not have
>
> happened.
>
>
>
> By the way, another factor not in the list of 6 is distraction, which
>
> has emerged recently in incident reports.
>
>
>
> Regards - Chris

Maybe this will help.

https://dl.dropboxusercontent.com/u/79580374/Aero%20Tow%20Training%20Guide.pdf

Aero tow is just not an inherently safe procedure and pilots need to understand that. Of course, winch launch isn't inherently safe either but at least they don't kill a tow pilot.

Bill D

June 23rd 13, 01:48 AM

On Saturday, June 22, 2013 6:01:54 PM UTC-6, B4soaring wrote:
> On 22/06/2013 15:01, Bill D wrote:
>
> > On Saturday, June 22, 2013 1:41:41 AM UTC-6, Alan wrote:
>
> >> In article > Bill D >
>
>
>
> writes:
>
> >>
>
> >>
>
> >>
>
> >>> I'm positive that if it's done right, winch launch is far safer than aero t=
>
> >>
>
> >>> ow. Germans suffer one accident on average every 180,000 winch launches wh=
>
> >>
>
> >>> ile we suffer one every 24,000 aero tows. I know there are cultural differ=
>
> >>
>
> >>> ences but, presumably, we're pretty good at aero tow and they're at least a=
>
> >>
>
> >>> s good at winch launch so the comparison is probably valid.
>
> >>
>
> >>
>
> >>
>
> >> But, what is the severity of these accidents?
>
> >
>
> > The severity is exactly the same for both aero tow and winch. The German LBU accident statistics are
>
>
>
> available on-line just as the NTSB data is. I suggest you verify them
>
> yourself.
>
> >
>
> > I have no idea where the SSF got their numbers but it may have been the UK since no translations
>
>
>
> are required. 2011 data shows the UK suffers one accident every 16,000
>
> launches while
>
>
>
> Germany suffers one every 180,000. German numbers are roughly
>
> comparable to the rest of continental
>
>
>
> Europe. The SSF needs to take another, wider look.
>
> >
>
> Bill makes the classic mistake of the amateur statistician - failing to
>
> understand the different definitions & methods behind the statistics he
>
> quotes.
>
>
>
> None of the statistics Bill quotes can be relied upon to be an accurate
>
> comparison.
>
>
>
> Ed.

Bull ****! I've spend years investigating these reports and vetting the analysis with experts. These are not statistics or summaries, they are actual numbers obtained from the respective national aviation safety boards who use the same investigative techniques. They are 100% reliable for comparisons.

There is no way to overcome an order of magnitude difference no matter how you spin the numbers. If you don't believe it, try to make the numbers come out the other way.

Ralph Jones[_3_]

June 23rd 13, 02:18 AM

On Sat, 22 Jun 2013 15:44:22 -0700 (PDT), Bill D >
wrote:
[snip]

>
> something no sane person would approve as an air-show act."

To dramatize that simile, here's an air show act that didn't come off
well today...

www.10tv.com/content/stories/2013/06/22/dayton-airshow-crash.html

B4soaring

June 23rd 13, 02:18 AM

. . .
>>
>> Bill makes the classic mistake of the amateur statistician - failing to
>>
>> understand the different definitions & methods behind the statistics he
>>
>> quotes.
>>
>>
>>
>> None of the statistics Bill quotes can be relied upon to be an accurate
>>
>> comparison.
>>
>>
>>
>> Ed.
>
> Bull ****! I've spend years investigating these reports and vetting the analysis with experts. These are not statistics or summaries,

they are actual numbers obtained from the respective national aviation
safety boards who use the same investigative techniques. They

are 100% reliable for comparisons.
>
> There is no way to overcome an order of magnitude difference no matter how you spin the numbers. If you don't believe it, try to make

the numbers come out the other way.
>

"they are actual numbers obtained from the respective national aviation
safety boards who use the same investigative techniques"

No, they are not. The equivalent of the BFU is the AAIB - if you wish to
make comparisons you should compare the BFU statistics with the AAIB
figures.

Ed.

ps an earlier post of yours refers to the "German LBU"; I'm aware of the
LBA, I know of the BFU but your reference to the "German LBU" is puzzling.

Bill D

June 23rd 13, 03:32 AM

> No, they are not. The equivalent of the BFU is the AAIB - if you wish to make comparisons you should compare the BFU statistics with the AAIB figures.
_____________________

What!!? The AAIB doesn't publish glider accident statistics - they leave that to the BGA. I used the BGA numbers for 2011.

> ps an earlier post of yours refers to the "German LBU"; I'm aware of the LBA, I know of the BFU but your reference to the "German LBU" is puzzling.

The German LBA is their FAA equivalent. The BFU is the NTSB/AAIB equivalent. The "LBU" was a typo.

The numbers I used are available for anybody to read and analyze. The differences are so huge, there's no way to come up with a different result. If you disagree, go read them and do your own analysis.

Ian[_2_]

June 23rd 13, 09:10 AM

On 06/20/2013 09:53 PM, Steve Leonard wrote:

> http://www.ntsb.gov/aviationquery/brief2.aspx?ev_id=20111013X31821&ntsbno=WPR12FA010&akey=1
>
> Happened to be looking through the NTSB Database and saw that they updated the report about a month ago.
>

Firstly let me express my condolences to the friends and family of the
late pilot. There has been a lot of noise on this thread about this
accident. But adding to the above with the additional documents and
video published here:

http://dms.ntsb.gov/pubdms/search/hitlist.cfm?docketID=51899&CFID=27180&CFTOKEN=73517888

I would like to post this in the spirit of learning from past mistakes.
I think this is what probably happened:

- The length of the tow rope was much shorter than the typical minimum
length of 300m used for a conventional auto tow launches. The runway was
also shorter than that which would normally be considered suitable for
auto tow. Thus this operation should be regarded as a stunt contrived
for the benefit of the camera's rather than a conventional soaring launch.

- The video shows the glider being towed horizontally behind the tow
vehicle and then performing a "kite" manoeuvre where the glider pitches
nose up, gains altitude rapidly and accelerates due to the geometry of
changing the relative direction. Intentional "kite" manoeuvres are
conducted in a controlled manner during a conventional ground launch.
They can also occur unintentionally during aerotow where they can cause
tug upset accidents. It is not clear if the kite manoeuvre on the crash
flight was initiated deliberately by the pilot for the purposes of the
camera, or if it happened accidentally.

- In the accident flight the kite manoeuvre caused the rope to break.
The pilot then lowered the nose to return to a normal gliding attitude.
(Even if the rope did not break, the short length of the rope would have
required the manoeuvre to end within a few seconds, eg by a back
release, the pilot releasing or the pilot lowering the nose.)

- As the launch was conducted outside of the parameters of a normal auto
tow, there may have been insufficient runway length available to land
ahead - the conventional recovery procedure for a ground launch failure
at this hight. The tow vehicle also presented an obstacle to landing
ahead, another aspect which differs from a conventional auto tow launch.

- Rather the pilot attempted a 180 degree turn to land downwind on the
runway again, similar to the recovery manoeuvre from an aerotow rope
failure at that altitude. However the pilot lost control, stalled and/or
spun and crashed.

- It is standard procedure when recovering from a ground launch rope
failure to lower the nose and the WAIT UNTIL AIRSPEED RECOVERS BEFORE
TURNING OR USING AIRBRAKES. As the glider experiences lowered or
negative G during the "push over" manoeuvre used to lower the nose after
the cable brake, it can fly normally even if the airspeed drops below
the nominal stalling speed. However after the push over is completed,
the glider experiences 1G and requires airspeed above nominal stall
speed to fly. This may be achieved only after some seconds after the
nose has been lowered. Any attempt to manoeuvre the glider during this
period can easily lead to loss of control. This is clearly illustrated
in this BGA training material:

http://www.gliding.co.uk/bgainfo/safety/winch-video/spin-4.mp4

- I suspect the pilot had insufficient airspeed when he attempted the
180 degree turn.

The pilots options in this situation were compromised due to the non
compliance with the norms for an autotow launch. It is not clear whether
he had sufficient altitude, speed and runway space to complete a safe
landing.

I hope that readers will appreciate that ground launching can be
conducted safely, provided that it is conducted within established
norms. Pilots should have appropriate training and ground launch
operations should be conducted under the supervision of skilled and
current ground launch instructors. However deviating these norms can
rapidly increase the potential hazards.

Ian

Don Johnstone[_4_]

June 23rd 13, 10:35 AM

At 02:32 23 June 2013, Bill D wrote:
>
>> No, they are not. The equivalent of the BFU is the AAIB - if you wish
to
>make comparisons you should compare the BFU statistics with the AAIB
>figures.
>_____________________
>
>What!!? The AAIB doesn't publish glider accident statistics - they leave
>that to the BGA. I used the BGA numbers for 2011.
>
>> ps an earlier post of yours refers to the "German LBU"; I'm aware of the

>LBA, I know of the BFU but your reference to the "German LBU" is
puzzling.
>
>The German LBA is their FAA equivalent. The BFU is the NTSB/AAIB
>equivalent. The "LBU" was a typo.
>
>The numbers I used are available for anybody to read and analyze. The
>differences are so huge, there's no way to come up with a different
result.
>If you disagree, go read them and do your own analysis.
>
Sorry Bill but your statistics are seriously flawed, In the UK the Air
Cadet organisation carry out nearly 50% of the total winch launches in the
UK in any year. The Air Cadets have not had a fatal or serious injury from
a failed winch launch accident since 1963 and probably before that.
The accidents/incidents reported by the BGA far exceed what would normally
be recorded by a national government source.
You will see that minor crime has decreased in the UK over the years if you
look at statistics. What the statistics do not tell you is that people have
stopped reporting minor crime so of course it has reduced. Same thing
applies to AAIB statistics, they do not record all the minor stuff that the
BGA do.

[email protected]

June 23rd 13, 11:20 AM

Le vendredi 21 juin 2013 07:30:21 UTC+2, a écrit*:
> Le jeudi 20 juin 2013 21:53:31 UTC+2, Steve Leonard a écrit*:

> It looks like they tried to more or less duplicate an old commercial by Michelin, where you saw an ASK-21 being auto-towed on a frozen lake. The glider went brutally up on a very short rope and released almost immediately. Then the car came to a braking halt just in front of an obstacle, while the glider was flying away. It was to illustrate the grip of a "Drice" winter tire... I can't find it on the web anymore. Some small stills are visible if you google "Michelin Drice" for images, but the links are dead.

I put a copy of the Michelin ad on YouTube, for comparison purpose: http://youtu.be/Rcc2yKQFW5Q

Bill D

June 23rd 13, 02:21 PM

On Sunday, June 23, 2013 3:35:00 AM UTC-6, Don Johnstone wrote:
> At 02:32 23 June 2013, Bill D wrote:
>
> >
>
> >> No, they are not. The equivalent of the BFU is the AAIB - if you wish
>
> to
>
> >make comparisons you should compare the BFU statistics with the AAIB
>
> >figures.
>
> >_____________________
>
> >
>
> >What!!? The AAIB doesn't publish glider accident statistics - they leave
>
> >that to the BGA. I used the BGA numbers for 2011.
>
> >
>
> >> ps an earlier post of yours refers to the "German LBU"; I'm aware of the
>
>
>
> >LBA, I know of the BFU but your reference to the "German LBU" is
>
> puzzling.
>
> >
>
> >The German LBA is their FAA equivalent. The BFU is the NTSB/AAIB
>
> >equivalent. The "LBU" was a typo.
>
> >
>
> >The numbers I used are available for anybody to read and analyze. The
>
> >differences are so huge, there's no way to come up with a different
>
> result.
>
> >If you disagree, go read them and do your own analysis.
>
> >
>
> Sorry Bill but your statistics are seriously flawed, In the UK the Air
>
> Cadet organisation carry out nearly 50% of the total winch launches in the
>
> UK in any year. The Air Cadets have not had a fatal or serious injury from
>
> a failed winch launch accident since 1963 and probably before that.
>
> The accidents/incidents reported by the BGA far exceed what would normally
>
> be recorded by a national government source.
>
> You will see that minor crime has decreased in the UK over the years if you
>
> look at statistics. What the statistics do not tell you is that people have
>
> stopped reporting minor crime so of course it has reduced. Same thing
>
> applies to AAIB statistics, they do not record all the minor stuff that the
>
> BGA do.

Don, I used only the BGA numbers. I did not use any AAIB numbers since none are available. I stand by my results until the BGA supplies different numbers. Note carefully that I used the most favorable interpretation for the UK and digging deeper will most likely make things look worse.

For example, the BGA numbers reported were obviously restricted to fatal or serious injury accidents whereas the German BFU and the NTSB reported all of them so the real situation is actually worse for the UK than it appears. I have numbers supporting that contention but I chose not to publish them..

Even giving the UK the benefit of the doubt, the results say the Germans are more than 10 times safer than the Brits on winch launch and the Germans are 7 - 8 times safer on winch launch than US is with aero tow. Play with the numbers if you want, but it's very, very doubtful you can overcome or explain away differences that big.

The solution is fixing the safety problem, not attacking the numbers. I'd start by finding out what the Germans are doing right.

Bill D

June 23rd 13, 02:54 PM

Ian, excellent analysis. I agree.

It was a stunt which brings up the relationship with the video crew.

Directors are known to push stunt people to produce ever more dramatic scenes trusting that, as professionals, they will push back if things get really dangerous. This pilot probably didn't push back and the video folks probably didn't realize he wasn't a professional so things got out of hand.

The real pro's would have gone out to a deserted strip or dry lake with lots of room to recover from mistakes and flown the scripted maneuver over and over approaching the dangerous parts in small steps until all the bugs were worked out before trying it in front of the cameras on a short strip. At the short strip, they would have all the "outs", like the farm field off the departure end, precisely determined and have resolved to use them if something went wrong. It's a hard business, not a game of "dare".

One of the many "take-homes" from this sad affair is never let anyone push you to do something your gut says is dangerous.

On Sunday, June 23, 2013 2:10:17 AM UTC-6, Ian wrote:
> On 06/20/2013 09:53 PM, Steve Leonard wrote:
>
>
>
> > http://www.ntsb.gov/aviationquery/brief2.aspx?ev_id=20111013X31821&ntsbno=WPR12FA010&akey=1
>
> >
>
> > Happened to be looking through the NTSB Database and saw that they updated the report about a month ago.
>
> >
>
>
>
> Firstly let me express my condolences to the friends and family of the
>
> late pilot. There has been a lot of noise on this thread about this
>
> accident. But adding to the above with the additional documents and
>
> video published here:
>
>
>
> http://dms.ntsb.gov/pubdms/search/hitlist.cfm?docketID=51899&CFID=27180&CFTOKEN=73517888
>
>
>
> I would like to post this in the spirit of learning from past mistakes.
>
> I think this is what probably happened:
>
>
>
> - The length of the tow rope was much shorter than the typical minimum
>
> length of 300m used for a conventional auto tow launches. The runway was
>
> also shorter than that which would normally be considered suitable for
>
> auto tow. Thus this operation should be regarded as a stunt contrived
>
> for the benefit of the camera's rather than a conventional soaring launch..
>
>
>
> - The video shows the glider being towed horizontally behind the tow
>
> vehicle and then performing a "kite" manoeuvre where the glider pitches
>
> nose up, gains altitude rapidly and accelerates due to the geometry of
>
> changing the relative direction. Intentional "kite" manoeuvres are
>
> conducted in a controlled manner during a conventional ground launch.
>
> They can also occur unintentionally during aerotow where they can cause
>
> tug upset accidents. It is not clear if the kite manoeuvre on the crash
>
> flight was initiated deliberately by the pilot for the purposes of the
>
> camera, or if it happened accidentally.
>
>
>
> - In the accident flight the kite manoeuvre caused the rope to break.
>
> The pilot then lowered the nose to return to a normal gliding attitude.
>
> (Even if the rope did not break, the short length of the rope would have
>
> required the manoeuvre to end within a few seconds, eg by a back
>
> release, the pilot releasing or the pilot lowering the nose.)
>
>
>
> - As the launch was conducted outside of the parameters of a normal auto
>
> tow, there may have been insufficient runway length available to land
>
> ahead - the conventional recovery procedure for a ground launch failure
>
> at this hight. The tow vehicle also presented an obstacle to landing
>
> ahead, another aspect which differs from a conventional auto tow launch.
>
>
>
> - Rather the pilot attempted a 180 degree turn to land downwind on the
>
> runway again, similar to the recovery manoeuvre from an aerotow rope
>
> failure at that altitude. However the pilot lost control, stalled and/or
>
> spun and crashed.
>
>
>
> - It is standard procedure when recovering from a ground launch rope
>
> failure to lower the nose and the WAIT UNTIL AIRSPEED RECOVERS BEFORE
>
> TURNING OR USING AIRBRAKES. As the glider experiences lowered or
>
> negative G during the "push over" manoeuvre used to lower the nose after
>
> the cable brake, it can fly normally even if the airspeed drops below
>
> the nominal stalling speed. However after the push over is completed,
>
> the glider experiences 1G and requires airspeed above nominal stall
>
> speed to fly. This may be achieved only after some seconds after the
>
> nose has been lowered. Any attempt to manoeuvre the glider during this
>
> period can easily lead to loss of control. This is clearly illustrated
>
> in this BGA training material:
>
>
>
> http://www.gliding.co.uk/bgainfo/safety/winch-video/spin-4.mp4
>
>
>
> - I suspect the pilot had insufficient airspeed when he attempted the
>
> 180 degree turn.
>
>
>
> The pilots options in this situation were compromised due to the non
>
> compliance with the norms for an autotow launch. It is not clear whether
>
> he had sufficient altitude, speed and runway space to complete a safe
>
> landing.
>
>
>
> I hope that readers will appreciate that ground launching can be
>
> conducted safely, provided that it is conducted within established
>
> norms. Pilots should have appropriate training and ground launch
>
> operations should be conducted under the supervision of skilled and
>
> current ground launch instructors. However deviating these norms can
>
> rapidly increase the potential hazards.
>
>
>
>
>
> Ian

B4soaring

June 23rd 13, 05:16 PM

On 23/06/2013 03:32, Bill D wrote:
>
>> No, they are not. The equivalent of the BFU is the AAIB - if you wish to make comparisons you

should compare the BFU statistics with the AAIB figures.
> _____________________
>
> What!!? The AAIB doesn't publish glider accident statistics - they leave that to the BGA.

I used the BGA numbers for 2011.
>
>> ps an earlier post of yours refers to the "German LBU"; I'm aware of the LBA, I know of the

BFU but your reference to the "German LBU" is puzzling.
>
> The German LBA is their FAA equivalent. The BFU is the NTSB/AAIB equivalent. The "LBU" was a typo.
>
> The numbers I used are available for anybody to read and analyze. The differences are so huge,

there's no way to come up with a different result. If you disagree, go
read them and do your own analysis.
>

The AAIB investigate all fatal accidents (including gliding) & publish
their reports.

The BGA, as a regulator, encourages clubs to report anything &
everything - BGA figures will include events too trivial to report to an
official government body.

Ed

B4soaring

June 23rd 13, 05:19 PM

On 23/06/2013 14:21, Bill D wrote:
> On Sunday, June 23, 2013 3:35:00 AM UTC-6, Don Johnstone wrote:
>> At 02:32 23 June 2013, Bill D wrote:
>>
>>>
>>
>>>> No, they are not. The equivalent of the BFU is the AAIB - if you wish
>>
>> to
>>
>>> make comparisons you should compare the BFU statistics with the AAIB
>>
>>> figures.
>>
>>> _____________________
>>
>>>
>>
>>> What!!? The AAIB doesn't publish glider accident statistics - they leave
>>
>>> that to the BGA. I used the BGA numbers for 2011.
>>
>>>
>>
>>>> ps an earlier post of yours refers to the "German LBU"; I'm aware of the
>>
>>
>>
>>> LBA, I know of the BFU but your reference to the "German LBU" is
>>
>> puzzling.
>>
>>>
>>
>>> The German LBA is their FAA equivalent. The BFU is the NTSB/AAIB
>>
>>> equivalent. The "LBU" was a typo.
>>
>>>
>>
>>> The numbers I used are available for anybody to read and analyze. The
>>
>>> differences are so huge, there's no way to come up with a different
>>
>> result.
>>
>>> If you disagree, go read them and do your own analysis.
>>
>>>
>>
>> Sorry Bill but your statistics are seriously flawed, In the UK the Air
>>
>> Cadet organisation carry out nearly 50% of the total winch launches in the
>>
>> UK in any year. The Air Cadets have not had a fatal or serious injury from
>>
>> a failed winch launch accident since 1963 and probably before that.
>>
>> The accidents/incidents reported by the BGA far exceed what would normally
>>
>> be recorded by a national government source.
>>
>> You will see that minor crime has decreased in the UK over the years if you
>>
>> look at statistics. What the statistics do not tell you is that people have
>>
>> stopped reporting minor crime so of course it has reduced. Same thing
>>
>> applies to AAIB statistics, they do not record all the minor stuff that the
>>
>> BGA do.
>
>
> Don, I used only the BGA numbers. I did not use any AAIB numbers since none are available.

I stand by my results until the BGA supplies different numbers. Note
carefully that I used

the most favorable interpretation for the UK and digging deeper will
most likely make things look worse.
>
> For example, the BGA numbers reported were obviously restricted to fatal or serious injury

accidents whereas the German BFU and the NTSB reported all of them so
the real situation is

actually worse for the UK than it appears. I have numbers supporting
that contention but I chose not to publish them.
>
> Even giving the UK the benefit of the doubt, the results say the Germans are more than 10

times safer than the Brits on winch launch and the Germans are 7 - 8
times safer on winch launch

than US is with aero tow. Play with the numbers if you want, but it's
very, very doubtful you

can overcome or explain away differences that big.
>
> The solution is fixing the safety problem, not attacking the numbers. I'd start by finding

out what the Germans are doing right.
>

"the BGA numbers reported were obviously restricted to fatal or serious
injury accidents"

That is simply impossible. There are nowhere near enough fatal or
serious injury accidents across the whole of BGA gliding, never mind
winch operations, to come up with those figures.

Ed

Bill D

June 23rd 13, 06:00 PM

On Sunday, June 23, 2013 10:16:32 AM UTC-6, B4soaring wrote:
> On 23/06/2013 03:32, Bill D wrote:
>
> >
>
> >> No, they are not. The equivalent of the BFU is the AAIB - if you wish to make comparisons you
>
>
>
> should compare the BFU statistics with the AAIB figures.
>
> > _____________________
>
> >
>
> > What!!? The AAIB doesn't publish glider accident statistics - they leave that to the BGA.
>
>
>
> I used the BGA numbers for 2011.
>
> >
>
> >> ps an earlier post of yours refers to the "German LBU"; I'm aware of the LBA, I know of the
>
>
>
> BFU but your reference to the "German LBU" is puzzling.
>
> >
>
> > The German LBA is their FAA equivalent. The BFU is the NTSB/AAIB equivalent. The "LBU" was a typo.
>
> >
>
> > The numbers I used are available for anybody to read and analyze. The differences are so huge,
>
>
>
> there's no way to come up with a different result. If you disagree, go
>
> read them and do your own analysis.
>
> >
>
>
>
>
>
> The AAIB investigate all fatal accidents (including gliding) & publish
>
> their reports.
>
>
>
> The BGA, as a regulator, encourages clubs to report anything &
>
> everything - BGA figures will include events too trivial to report to an
>
> official government body.
>
>
>
> Ed

Yeah? Link me to the AAIB site with the glider accidents.

Bill D

June 23rd 13, 06:13 PM

On Sunday, June 23, 2013 10:19:29 AM UTC-6, B4soaring wrote:

> That is simply impossible. There are nowhere near enough fatal or
>
> serious injury accidents across the whole of BGA gliding, never mind
>
> winch operations, to come up with those figures.
>
>
>
> Ed

Read Sailplane and Gliding.

Mike the Strike

June 23rd 13, 07:04 PM

If we are comparing likely attitudes towards safety and operating procedures affected by cultural differences, it might be useful to look at the traffic accident rates in the three countries. When rated at fatalities per billion kilometers, the Brits come in lowest at 5.7, the Germans second at 7.2 and the USA third at 8.5. Eastern Europe is significantly worse, but the real basket case are in South America.

I have to think that the differences in glider launch accident statistics are so large that there has to be a significant contribution from the way that these are reported.

Mike

Bill D

June 23rd 13, 07:50 PM

On Sunday, June 23, 2013 12:04:42 PM UTC-6, Mike the Strike wrote:
> If we are comparing likely attitudes towards safety and operating procedures affected by cultural differences, it might be useful to look at the traffic accident rates in the three countries. When rated at fatalities per billion kilometers, the Brits come in lowest at 5.7, the Germans second at 7..2 and the USA third at 8.5. Eastern Europe is significantly worse, but the real basket case are in South America.
>
>
>
> I have to think that the differences in glider launch accident statistics are so large that there has to be a significant contribution from the way that these are reported.
>
>
>
> Mike

There could be national differences in reporting but if the problem were under-reporting, then the Germans would have to be the worst offenders by hiding hundreds of serious accidents which would be impossible to do. I trust the German figures much more than those from anyone else. If anyone other than the Germans under-reports, it would actually support the conclusions. OTOH, I can't imagine anyone reporting accidents that didn't happen.

Where distortion is most likely to creep in is due simply to the relative sample sizes. Germany may do over a million winch launches a year making their statistics very meaningful. The UK does only 180,000 launches a year so two or three accidents would skew the ratios. However, when they suffer 12, as the US did with aero tow, that's statistically significant.

BTW, a long list of people have tried to attack my numbers and, so far, they've failed to succeed. I'd be happy for someone to do so but first show me the data. What little new data that has become available actually increases the national differences.

Terry Walsh[_2_]

June 23rd 13, 08:17 PM

Bill,

This 'http://www.gliding.co.uk/bgainfo/documents/safewinchguidance.pdf' is
a link to the BGA web site which breaks down winch accidents from 1974 to
2009, into Fatal/serious and total.

From this I think that you can say that the total number of launches in
that period was 9503000 and there were 110 fatal and serious injury
accidents. That equates to a rate of 1 in 86390.

Since then the UK have campaigned successfully to reduce these numbers and
they are now substantially lower.

Terry Walsh

At 18:50 23 June 2013, Bill D wrote:
>On Sunday, June 23, 2013 12:04:42 PM UTC-6, Mike the Strike wrote:
>> If we are comparing likely attitudes towards safety and operating
>procedu=
>res affected by cultural differences, it might be useful to look at the
>tra=
>ffic accident rates in the three countries. When rated at fatalities per
>b=
>illion kilometers, the Brits come in lowest at 5.7, the Germans second at
>7=
>..2 and the USA third at 8.5. Eastern Europe is significantly worse, but
>th=
>e real basket case are in South America. =20
>>=20
>>=20
>>=20
>> I have to think that the differences in glider launch accident
>statistics=
> are so large that there has to be a significant contribution from the
way
>=
>that these are reported.
>>=20
>>=20
>>=20
>> Mike
>
>There could be national differences in reporting but if the problem were
>un=
>der-reporting, then the Germans would have to be the worst offenders by
>hid=
>ing hundreds of serious accidents which would be impossible to do. I
>trust=
> the German figures much more than those from anyone else. If anyone
>other=
> than the Germans under-reports, it would actually support the
>conclusions.=
> OTOH, I can't imagine anyone reporting accidents that didn't happen.
>
>Where distortion is most likely to creep in is due simply to the relative
>s=
>ample sizes. Germany may do over a million winch launches a year making
>th=
>eir statistics very meaningful. The UK does only 180,000 launches a year
>so=
> two or three accidents would skew the ratios. However, when they suffer
>1=
>2, as the US did with aero tow, that's statistically significant.
>
>BTW, a long list of people have tried to attack my numbers and, so far,
>the=
>y've failed to succeed. I'd be happy for someone to do so but first show
>m=
>e the data. What little new data that has become available actually
>increa=
>ses the national differences.
>
>

Bill D

June 23rd 13, 09:30 PM

On Sunday, June 23, 2013 1:17:17 PM UTC-6, Terry Walsh wrote:
> Bill,
>
>
>
> This 'http://www.gliding.co.uk/bgainfo/documents/safewinchguidance.pdf' is
>
> a link to the BGA web site which breaks down winch accidents from 1974 to
>
> 2009, into Fatal/serious and total.
>
>
>
> From this I think that you can say that the total number of launches in
>
> that period was 9503000 and there were 110 fatal and serious injury
>
> accidents. That equates to a rate of 1 in 86390.
>
>
>
> Since then the UK have campaigned successfully to reduce these numbers and
>
> they are now substantially lower.
>
>
>
> Terry Walsh
>
>
>
>
>
>
>
>
>
>
>
> At 18:50 23 June 2013, Bill D wrote:
>
> >On Sunday, June 23, 2013 12:04:42 PM UTC-6, Mike the Strike wrote:
>
> >> If we are comparing likely attitudes towards safety and operating
>
> >procedu=
>
> >res affected by cultural differences, it might be useful to look at the
>
> >tra=
>
> >ffic accident rates in the three countries. When rated at fatalities per
>
> >b=
>
> >illion kilometers, the Brits come in lowest at 5.7, the Germans second at
>
> >7=
>
> >..2 and the USA third at 8.5. Eastern Europe is significantly worse, but
>
> >th=
>
> >e real basket case are in South America. =20
>
> >>=20
>
> >>=20
>
> >>=20
>
> >> I have to think that the differences in glider launch accident
>
> >statistics=
>
> > are so large that there has to be a significant contribution from the
>
> way
>
> >=
>
> >that these are reported.
>
> >>=20
>
> >>=20
>
> >>=20
>
> >> Mike
>
> >
>
> >There could be national differences in reporting but if the problem were
>
> >un=
>
> >der-reporting, then the Germans would have to be the worst offenders by
>
> >hid=
>
> >ing hundreds of serious accidents which would be impossible to do. I
>
> >trust=
>
> > the German figures much more than those from anyone else. If anyone
>
> >other=
>
> > than the Germans under-reports, it would actually support the
>
> >conclusions.=
>
> > OTOH, I can't imagine anyone reporting accidents that didn't happen.
>
> >
>
> >Where distortion is most likely to creep in is due simply to the relative
>
> >s=
>
> >ample sizes. Germany may do over a million winch launches a year making
>
> >th=
>
> >eir statistics very meaningful. The UK does only 180,000 launches a year
>
> >so=
>
> > two or three accidents would skew the ratios. However, when they suffer
>
> >1=
>
> >2, as the US did with aero tow, that's statistically significant.
>
> >
>
> >BTW, a long list of people have tried to attack my numbers and, so far,
>
> >the=
>
> >y've failed to succeed. I'd be happy for someone to do so but first show
>
> >m=
>
> >e the data. What little new data that has become available actually
>
> >increa=
>
> >ses the national differences.
>
> >
>
> >

Terry, thanks for the link but I've had this document for a long time. It says, quote: "The average frequency of winch accidents [in the UK] is 1 in every 13,000 launches." My figures for 2011 show 1 accident every 16,000 launches so you're doing better but nowhere near as good as the Germans at 1 every 180,000 launches.

What I sincerely hope happens is this will provide an incentive to improve the UK winch safety situation. The really, REALLY good news from the German data is something CAN be done.

waremark

June 24th 13, 01:42 AM

The issue here is whether for the UK you are dealing with all incidents, whereas for Germany you are looking only at more serious ones. So the UK used to have more apples than the Germans had oranges. As it happens the UK recognised the scope for improvement a few years ago and has radically reduced the number of serious winch accidents. The pro-active accident reduction focus here has recently moved on to avoidance of aerotow tug upsets.

John Carlyle

June 24th 13, 01:45 AM

On Sunday, June 23, 2013 4:30:40 PM UTC-4, Bill D wrote:
> On Sunday, June 23, 2013 1:17:17 PM UTC-6, Terry Walsh wrote:[i]
> > Bill,
> >
> > This 'http://www.gliding.co.uk/bgainfo/documents/safewinchguidance.pdf' is
> > a link to the BGA web site which breaks down winch accidents from 1974 to
> > 2009, into Fatal/serious and total.
> >
> > From this I think that you can say that the total number of launches in
> > that period was 9503000 and there were 110 fatal and serious injury
> > accidents. That equates to a rate of 1 in 86390.
> >
> > Since then the UK have campaigned successfully to reduce these numbers and
> > they are now substantially lower.
> >
> > Terry Walsh
>
>
> Terry, thanks for the link but I've had this document for a long time. It says, quote: "The average frequency of winch accidents is 1 in every 13,000 launches." My figures for 2011 show 1 accident every 16,000 launches so you're doing better but nowhere near as good as the Germans at 1 every 180,000 launches.
>
> What I sincerely hope happens is this will provide an incentive to improve the UK winch safety situation. The really, REALLY good news from the German data is something CAN be done.

There's an easy way to settle the dispute between Bill and Terry - look at the insurance rates for comparable gliders in Germany and the UK. If the UK rates are 10x the German rates, Bill is right. If the rates are the same, either Bill is wrong or the Germans are being cheated.

-John, Q3

Mike the Strike

June 24th 13, 02:03 AM

I had always been led to believe that winch launching was about twice as risky as aero-tow and there were reports in the 1980s and 1990s that I think supported this. The recent UK reported winch accident rate is pretty close to double the US aero-tow accident rate, so that gives general support to this premise.

While I am prepared to believe that the Germans are better at it than the rest of the world, an accident rate nearly 15 times lower just doesn't smell right! Maybe someone misplaced a decimal point - it wouldn't be the first time!

Mike

Bill D

June 24th 13, 02:23 AM

On Sunday, June 23, 2013 6:42:19 PM UTC-6, waremark wrote:
> The issue here is whether for the UK you are dealing with all incidents, whereas for Germany you are looking only at more serious ones. So the UK used to have more apples than the Germans had oranges. As it happens the UK recognised the scope for improvement a few years ago and has radically reduced the number of serious winch accidents. The pro-active accident reduction focus here has recently moved on to avoidance of aerotow tug upsets.

Not true. The Germans are very diligent and report MORE accidents. In any event, it wouldn't make much difference if the number of German accidents was doubled or even quadrupled, the numbers would still tell the same story..

Yes, you have improved but you have a ways to go and denial won't help.

Bill D

June 24th 13, 02:47 AM

On Sunday, June 23, 2013 7:03:11 PM UTC-6, Mike the Strike wrote:
> I had always been led to believe that winch launching was about twice as risky as aero-tow and there were reports in the 1980s and 1990s that I think supported this. The recent UK reported winch accident rate is pretty close to double the US aero-tow accident rate, so that gives general support to this premise.
>
>
>
> While I am prepared to believe that the Germans are better at it than the rest of the world, an accident rate nearly 15 times lower just doesn't smell right! Maybe someone misplaced a decimal point - it wouldn't be the first time!
>
>
>
> Mike

Mike, if you or anybody really doubts this, download the data yourself and try to come up with a different story. It's public data.

Yes, you and I were both led to believe winch launch was more dangerous than aero tow but we were seriously misled. The idea came about because the easiest data to get was from the UK and, unfortunately, their winch launch operations really are WAY more dangerous than aero tow. The assumption was then made the UK was typical when it isn't.

German data requires translation so was ignored. Ulrich Newmann helped me find the data on the BFU site and translate it. Just to answer you doubters I had it downloaded and translated by two people. Then, I went on to get similar data from the rest of the Eurozone countries finding the numbers are essentially the same as Germany.

I understand the Brits are angry to be called out on this but numbers are numbers and they don't lie. Hopefully, it will get them to fix the problem.

Uncle Fuzzy[_2_]

June 24th 13, 04:29 AM

I must have missed the subject change. I don't believe this is a winch/auto-tow vs. AERO tow discussion. With 20/20 hindsight, does attempting an auto tow on a short, narrow runway surrounded by trees, in a 20 meter glider, with a 71 meter rope, sound like a scenario likely to generate a happy ending?

B4soaring

June 24th 13, 07:23 AM

On 23/06/2013 18:13, Bill D wrote:
> On Sunday, June 23, 2013 10:19:29 AM UTC-6, B4soaring wrote:
>
>> That is simply impossible. There are nowhere near enough fatal or
>>
>> serious injury accidents across the whole of BGA gliding, never mind
>>
>> winch operations, to come up with those figures.
>>
>>
>>
>> Ed
>
> Read Sailplane and Gliding.
>

Indded.

Count the number of fatal & serious injury accidents & there are nowhere
near enough to give the accident rate that you quote. Not for gliding as
a whole & certainly not for winch operations only.

B4soaring

June 24th 13, 07:28 AM

>>
>> The AAIB investigate all fatal accidents (including gliding) & publish
>>
>> their reports.
>>
>>
>> The BGA, as a regulator, encourages clubs to report anything &
>>
>> everything - BGA figures will include events too trivial to report to an
>>
>> official government body.
>>
>>
>>
>> Ed
>
> Yeah? Link me to the AAIB site with the glider accidents.

?????

AAIB website, go the publications page, enter glider as a keyword & hit
the search button. Really not that difficult.
>

Ramy

June 24th 13, 07:33 AM

On Sunday, June 23, 2013 6:21:56 AM UTC-7, Bill D wrote:
> On Sunday, June 23, 2013 3:35:00 AM UTC-6, Don Johnstone wrote:
>
> > At 02:32 23 June 2013, Bill D wrote:
>
> >
>
> > >
>
> >
>
> > >> No, they are not. The equivalent of the BFU is the AAIB - if you wish
>
> >
>
> > to
>
> >
>
> > >make comparisons you should compare the BFU statistics with the AAIB
>
> >
>
> > >figures.
>
> >
>
> > >_____________________
>
> >
>
> > >
>
> >
>
> > >What!!? The AAIB doesn't publish glider accident statistics - they leave
>
> >
>
> > >that to the BGA. I used the BGA numbers for 2011.
>
> >
>
> > >
>
> >
>
> > >> ps an earlier post of yours refers to the "German LBU"; I'm aware of the
>
> >
>
> >
>
> >
>
> > >LBA, I know of the BFU but your reference to the "German LBU" is
>
> >
>
> > puzzling.
>
> >
>
> > >
>
> >
>
> > >The German LBA is their FAA equivalent. The BFU is the NTSB/AAIB
>
> >
>
> > >equivalent. The "LBU" was a typo.
>
> >
>
> > >
>
> >
>
> > >The numbers I used are available for anybody to read and analyze. The
>
> >
>
> > >differences are so huge, there's no way to come up with a different
>
> >
>
> > result.
>
> >
>
> > >If you disagree, go read them and do your own analysis.
>
> >
>
> > >
>
> >
>
> > Sorry Bill but your statistics are seriously flawed, In the UK the Air
>
> >
>
> > Cadet organisation carry out nearly 50% of the total winch launches in the
>
> >
>
> > UK in any year. The Air Cadets have not had a fatal or serious injury from
>
> >
>
> > a failed winch launch accident since 1963 and probably before that.
>
> >
>
> > The accidents/incidents reported by the BGA far exceed what would normally
>
> >
>
> > be recorded by a national government source.
>
> >
>
> > You will see that minor crime has decreased in the UK over the years if you
>
> >
>
> > look at statistics. What the statistics do not tell you is that people have
>
> >
>
> > stopped reporting minor crime so of course it has reduced. Same thing
>
> >
>
> > applies to AAIB statistics, they do not record all the minor stuff that the
>
> >
>
> > BGA do.
>
>
>
>
>
> Don, I used only the BGA numbers. I did not use any AAIB numbers since none are available. I stand by my results until the BGA supplies different numbers. Note carefully that I used the most favorable interpretation for the UK and digging deeper will most likely make things look worse.
>
>
>
> For example, the BGA numbers reported were obviously restricted to fatal or serious injury accidents whereas the German BFU and the NTSB reported all of them so the real situation is actually worse for the UK than it appears. I have numbers supporting that contention but I chose not to publish them.
>
>
>
> Even giving the UK the benefit of the doubt, the results say the Germans are more than 10 times safer than the Brits on winch launch and the Germans are 7 - 8 times safer on winch launch than US is with aero tow. Play with the numbers if you want, but it's very, very doubtful you can overcome or explain away differences that big.
>
>
>
> The solution is fixing the safety problem, not attacking the numbers. I'd start by finding out what the Germans are doing right.

It is when the differences are so big that it is obvious that the statistics is flawed. Show me that Germans have 10 times less fatal car accidents than UK and maybe I will believe your statistics. Claiming that winch launch is 7-8 times safer than US aerotows is ridiculous. Winch launch is at best almost as safe as aerotows when done with all possible precautions. It is far less forgiving for errors. It's main advantage is with cost and turnaround time, not with safety.

Ramy

Peter F[_2_]

June 24th 13, 10:09 AM

At 06:33 24 June 2013, Ramy wrote:

>Winch launch is at best
>almost as safe as aerotows when done with all possible precautions. It is
>far less forgiving for errors. It's main advantage is with cost and
>turnaround time, not with safety.
>
>Ramy
>

That's simply your opinion.
My opinion is that *with proper training* winch launching is inherently
safer than Aerotow.

If something goes wrong then pilot should have option to land ahead or
safely go around. Is same true of aerotow where you fly.

If pilot puts themself in position where if something goes wrong they don't
have these options *then they haven't been properly trained*

This is why I was interested in how much winching / autotow pilot of DG1000
had done

PF

BruceGreeff

June 24th 13, 10:53 AM

Hi Ramy

That is a controversial position to take.
My understanding and experience is the opposite - winch launch is safer
than aerotow.
I think the safety aspect is partly location, and largely the operating
procedures in either case. Winches are certainly a lot less sensitive to
poor maintenance...

Bruce
--
Bruce Greeff
T59D #1771

BruceGreeff

June 24th 13, 04:09 PM

Numbers, and numbers from which one can draw a conclusion,and whether
the conclusion is supported by the specific set of numbers. These
require careful consideration.

The arithmetic fact that 100<1000, is widely believed to be universally
true. However, context makes fools of us all.

So - for a GIVEN launch method (let's say winch) -
does one accident = one accident.

Not unless the accident reporting behaviour of one group is directly
equivalent to the other, and their equipment and conditions are
equivalent - and even then - disappointingly it is not possible to say
the comparison is valid.

I think there may be some observation bias here.

So, as an example:
I had two events happen to me this year.
One - on an aerotow launch a thermal lifted the wing on a glider.
Despite full opposite control deflection the wingtip touched, and pilot
released. The glider (wings level and slowing down) caught some tall
grass and performed a little 110 degree groundloop.
No damage , no incident report, just normal operations in turbulent
conditions.

The most recent accident was a winch launch that went wrong and resulted
in a ground loop and some damage to a wing. In this instance no ground
contact just slow winch pick up and a strong crosswind, and drifting
towards where the groundsman had missed a patch of grass that was now a
metre high. Same action from same pilot, abandon launch, same result,
low speed groundloop. Very different statistic.
Structural damage - a crack around the D-box, lots of paperwork.

The real reason for the damage to the wing? When we opened it up - there
was a failed glue joint on an earlier repair, that was not in the log
book. (This is a glider that came from Germany)

In both cases the speed, launch phase and pilot was effectively
identical. Same person, airfield, operating procedures. In both cases
the incident and it's outcome was neither caused by, or attributable to
the launch method. Statistically you have one for each method - the
damage reported was significant for one - but not attributable to the
launch method.

One should exercise caution - jumping to conclusions is bad exercise and
numbers are intrinsically not worth a lot unless used in comparable
context.

--
Bruce Greeff
T59D #1771

Bill D

June 24th 13, 04:12 PM

On Monday, June 24, 2013 12:28:07 AM UTC-6, B4soaring wrote:
> >>
>
> >> The AAIB investigate all fatal accidents (including gliding) & publish
>
> >>
>
> >> their reports.
>
> >>
>
> >>
>
> >> The BGA, as a regulator, encourages clubs to report anything &
>
> >>
>
> >> everything - BGA figures will include events too trivial to report to an
>
> >>
>
> >> official government body.
>
> >>
>
> >>
>
> >>
>
> >> Ed
>
> >
>
> > Yeah? Link me to the AAIB site with the glider accidents.
>
>
>
> ?????
>
>
>
> AAIB website, go the publications page, enter glider as a keyword & hit
>
> the search button. Really not that difficult.
>
> >

Been there many times. The AAIB shows no glider accidents for 2011 which does not match the BGA data.

BobW

June 24th 13, 04:32 PM

<Snip>
>>
>> The solution is fixing the safety problem, not attacking the numbers.
>> I'd start by finding out what the Germans are doing right.
>
> It is when the differences are so big that it is obvious that the
> statistics is flawed. Show me that Germans have 10 times less fatal car
> accidents than UK and maybe I will believe your statistics. Claiming that
> winch launch is 7-8 times safer than US aerotows is ridiculous. Winch
> launch is at best almost as safe as aerotows when done with all possible
> precautions. It is far less forgiving for errors. It's main advantage is
> with cost and turnaround time, not with safety.

Seriously interesting discussion...

Coupla thoughts:
1) As an engineer by training/experience, I'm a believer in "If it happens, it
must be possible." Sometimes, the trick is in accurately determining what "it"
was and the reason(s) behind "it."

2) In the USA's intermountain west there are lots of airstrips (including my
home field when launching to the west) I consider "genuinely worrisome" for
aerotowing because of the length of time the glider must spend after liftoff
lacking any safe rope-break landing options. (For example, being at 20-30' agl
over head-high sage brush for miles around is definitely not comfort-inducing;
did that once at a popular glider camp site and never went there again.)

3) With limited winch-launching PIC stick time experience, I quickly concluded
the "worry window" in 2) above was minimal-to-non-existent for intermountain
west winch launching. The rest of the winch launch risk factors were more or
less entirely controllable by the pilot (e.g. training
sought/taken/learned-from, piloting actions, etc.).

Discussion/challenging of statistical information is always worthwhile if it
leads to increased confidence in the stats, increasing personal insight and
ultimately - in this case - improving safety practices (and eventually
statistics). Personally, I don't dismiss out-of-hand the possibility that
there may BE an order of magnitude difference in one country's "safety stats"
vs. another's. In the U.S. it's not uncommon to see similar largish variations
in club-to-club operations, given the widely/thinly spread nature of soaring
in this country, nature's intolerance of "dumb PIC mistakes" and human nature.

Bob W.

Bill D

June 24th 13, 04:32 PM

On Monday, June 24, 2013 9:09:03 AM UTC-6, BruceGreeff wrote:
> Numbers, and numbers from which one can draw a conclusion,and whether
>
> the conclusion is supported by the specific set of numbers. These
>
> require careful consideration.
>
>
>
> The arithmetic fact that 100<1000, is widely believed to be universally
>
> true. However, context makes fools of us all.
>
>
>
> So - for a GIVEN launch method (let's say winch) -
>
> does one accident = one accident.
>
>
>
> Not unless the accident reporting behaviour of one group is directly
>
> equivalent to the other, and their equipment and conditions are
>
> equivalent - and even then - disappointingly it is not possible to say
>
> the comparison is valid.
>
>
>
> I think there may be some observation bias here.
>
>
>
> So, as an example:
>
> I had two events happen to me this year.
>
> One - on an aerotow launch a thermal lifted the wing on a glider.
>
> Despite full opposite control deflection the wingtip touched, and pilot
>
> released. The glider (wings level and slowing down) caught some tall
>
> grass and performed a little 110 degree groundloop.
>
> No damage , no incident report, just normal operations in turbulent
>
> conditions.
>
>
>
> The most recent accident was a winch launch that went wrong and resulted
>
> in a ground loop and some damage to a wing. In this instance no ground
>
> contact just slow winch pick up and a strong crosswind, and drifting
>
> towards where the groundsman had missed a patch of grass that was now a
>
> metre high. Same action from same pilot, abandon launch, same result,
>
> low speed groundloop. Very different statistic.
>
> Structural damage - a crack around the D-box, lots of paperwork.
>
>
>
> The real reason for the damage to the wing? When we opened it up - there
>
> was a failed glue joint on an earlier repair, that was not in the log
>
> book. (This is a glider that came from Germany)
>
>
>
> In both cases the speed, launch phase and pilot was effectively
>
> identical. Same person, airfield, operating procedures. In both cases
>
> the incident and it's outcome was neither caused by, or attributable to
>
> the launch method. Statistically you have one for each method - the
>
> damage reported was significant for one - but not attributable to the
>
> launch method.
>
>
>
> One should exercise caution - jumping to conclusions is bad exercise and
>
> numbers are intrinsically not worth a lot unless used in comparable
>
> context.
>
>
>
> --
>
> Bruce Greeff
>
> T59D #1771

Not sure where you're going with this, Bruce. Of course there are reasons for the differences and that's a a very important discussion to have but it doesn't affect the difference itself.

The raw accident count for the number of launches done is really metadata (To use a currently popular term.) Metadata is very valuable in seeing the big picture but not so much for analyzing the details for why it looks that way. Hopefully, the metadata will provoke that kind of detailed analysis.

Terry Walsh[_3_]

June 24th 13, 04:40 PM

At 15:12 24 June 2013, Bill D wrote:
>On Monday, June 24, 2013 12:28:07 AM UTC-6, B4soaring wrote:
>> >>
>>
>> >> The AAIB investigate all fatal accidents (including gliding) &
publish
>>
>> >>
>>
>> >> their reports.
>>
>> >>
>>
>> >>
>>
>> >> The BGA, as a regulator, encourages clubs to report anything &
>>
>> >>
>>
>> >> everything - BGA figures will include events too trivial to report
to
>an
>>
>> >>
>>
>> >> official government body.
>>
>> >>
>>
>> >>
>>
>> >>
>>
>> >> Ed
>>
>> >
>>
>> > Yeah? Link me to the AAIB site with the glider accidents.
>>
>>
>>
>> ?????
>>
>>
>>
>> AAIB website, go the publications page, enter glider as a keyword & hit

>>
>> the search button. Really not that difficult.
>>
>> >
>
>Been there many times. The AAIB shows no glider accidents for 2011 which
>does not match the BGA data.
>

Posted straight from the BGA web site

"There is some good news to report in that there were no fatal accidents in
2011 and no serious injury accidents from winch launches or instructing
flights. Of the 22 fatal or serious injury gliding accidents from
2008-2011, 10 were associated with field landing. Field landing accidents
with personal injury "

There were 0 fatal accidents and 0 serious injury accidents from winch
launches in 2011. Since the AAIB only gets involved for these categories
then both sites DO agree.

Terry Walsh

Bill D

June 24th 13, 04:49 PM

On Monday, June 24, 2013 9:32:05 AM UTC-6, BobW wrote:
> <Snip>
>
> >>
>
> >> The solution is fixing the safety problem, not attacking the numbers.
>
> >> I'd start by finding out what the Germans are doing right.
>
> >
>
> > It is when the differences are so big that it is obvious that the
>
> > statistics is flawed. Show me that Germans have 10 times less fatal car
>
> > accidents than UK and maybe I will believe your statistics. Claiming that
>
> > winch launch is 7-8 times safer than US aerotows is ridiculous. Winch
>
> > launch is at best almost as safe as aerotows when done with all possible
>
> > precautions. It is far less forgiving for errors. It's main advantage is
>
> > with cost and turnaround time, not with safety.
>
>
>
>
>
> Seriously interesting discussion...
>
>
>
> Coupla thoughts:
>
> 1) As an engineer by training/experience, I'm a believer in "If it happens, it
>
> must be possible." Sometimes, the trick is in accurately determining what "it"
>
> was and the reason(s) behind "it."
>
>
>
> 2) In the USA's intermountain west there are lots of airstrips (including my
>
> home field when launching to the west) I consider "genuinely worrisome" for
>
> aerotowing because of the length of time the glider must spend after liftoff
>
> lacking any safe rope-break landing options. (For example, being at 20-30' agl
>
> over head-high sage brush for miles around is definitely not comfort-inducing;
>
> did that once at a popular glider camp site and never went there again.)
>
>
>
> 3) With limited winch-launching PIC stick time experience, I quickly concluded
>
> the "worry window" in 2) above was minimal-to-non-existent for intermountain
>
> west winch launching. The rest of the winch launch risk factors were more or
>
> less entirely controllable by the pilot (e.g. training
>
> sought/taken/learned-from, piloting actions, etc.).
>
>
>
> Discussion/challenging of statistical information is always worthwhile if it
>
> leads to increased confidence in the stats, increasing personal insight and
>
> ultimately - in this case - improving safety practices (and eventually
>
> statistics). Personally, I don't dismiss out-of-hand the possibility that
>
> there may BE an order of magnitude difference in one country's "safety stats"
>
> vs. another's. In the U.S. it's not uncommon to see similar largish variations
>
> in club-to-club operations, given the widely/thinly spread nature of soaring
>
> in this country, nature's intolerance of "dumb PIC mistakes" and human nature.
>
>
>
> Bob W.

Bob, if we were talking bout two organizations each doing a few hundred launches, a statistical comparison would be suspect simply because the sample size is so small.

In the case of the UK with roughly 180,000 winch launches with 12 accidents a year and Germany with around a 1,000,000 with 5 accidents, those are enormous data sets. I think that's going to make it very hard to attack the conclusion Germany is MUCH safer than the UK and that winch launch in Germany is much safer than aero tow as we practice it in the US.

That conclusion is supported by the BGA whose own data says they suffer 1 accident every 13,000 launches (I used 1:16,000)

The really unfortunate thing for the US is the BGA stats were accepted as globally representative by the SSF leading to articles condemning winch launch as "unsafe". Had the SSF based their conclusion on the German data instead, winch launch would be far more popular in the US than it is.

Mike the Strike

June 24th 13, 06:26 PM

Looking at the German data from 2007, they note that 7 of 62 accidents occurred as a failure of the launch equipment or during launch, however a detailed read of the individual accident reports show that 14 involved a winch. Some of the winch-related accidents are being captured under other categories, such as "heavy landing".

As I suspected, the data are being reported in different ways in different countries and the German rate of failed winch launches is a bit higher than one might at first think. Even so, the German accident rate is impressively low.

Mike

Peter Scholz[_3_]

June 24th 13, 08:25 PM

Am 22.06.2013 18:19, Dan Marotta wrote:
> A few weeks ago a German visitor told me that it's now unlawful in
> Germany to air tow with a CG release. Four of my five gliders have had
> CG hooks only and most of my launches are by air tow. Frankly I don't
> see the problem (I know the physics) - simply fly the glider and who
> needs the self-righting forces of a nose hook?
>
>

This is not true. The only legal requirement for aero tows with CG hook
is that you have to have a minimum of 5 aero tows within the last 6
month. If you don't meet this criteria, you have to make these 5 aero
tows with nose hook before you are allowed to be towed on your CG hook.

Most pilots (including me, having an ASW 24 with CG hook only) do not
believe that this rule added anything towards safety in aero tow. IMHO
it's just a bureaucratic requirement, and I know of quite a few pilots
just ignoring it.
--
Peter Scholz
ASW24 JE

Bill D

June 24th 13, 11:13 PM

On Monday, June 24, 2013 11:26:34 AM UTC-6, Mike the Strike wrote:
> Looking at the German data from 2007, they note that 7 of 62 accidents occurred as a failure of the launch equipment or during launch, however a detailed read of the individual accident reports show that 14 involved a winch.. Some of the winch-related accidents are being captured under other categories, such as "heavy landing".
>
>
>
> As I suspected, the data are being reported in different ways in different countries and the German rate of failed winch launches is a bit higher than one might at first think. Even so, the German accident rate is impressively low.
>
>
>
> Mike

First, a launch failure is part of winch launch just as rope breaks are part of aero tow. You're expected to handle them safely. In both cases pilots are trained extensively in how to cope with failures. The fact that they happen is not remarkable. It is remarkable when one results in an accident.

waremark

June 25th 13, 01:11 AM

I find it exceptionally unlikely that winch launching is an order of magnitude safer in Germany than the UK. Bill, would you be kind enough to write a succinct summary of your evidence with appropriate links in a form which is suitable for referring to the BGA Safety Committee?

Bill D

June 25th 13, 02:45 AM

On Monday, June 24, 2013 6:11:53 PM UTC-6, waremark wrote:
> I find it exceptionally unlikely that winch launching is an order of magnitude safer in Germany than the UK. Bill, would you be kind enough to write a succinct summary of your evidence with appropriate links in a form which is suitable for referring to the BGA Safety Committee?
__________________________________________________ ____

I already have - several times. At this point I'm growing weary of UK denial. Believe what you will. It's your necks your breaking.

This is the last time I'll go through it. The numbers below are just too big to spin no matter how much you attack them. It doesn't' matter if you think it's 10:1 or "merely" 5:1 it's still ugly.

If one simply takes the BGA report supplied earlier in this thread which states there is one accident in the UK every 13,000 launches as true and compare it with the German BFU/DAeC data showing one accident in 180,000 launches you have a ratio of 13.8:1 in favor of Germany - well over an order of magnitude difference.

The German number of launches a year was from the DAeC report showing just under a million launches a year. The BFU shows 5 accidents in 2011. If you choose 900,000 German launches as a conservative number and divide by 5 you get 1 accident in 180,000 launches.

[email protected]

June 25th 13, 11:13 AM

Hi Bill

"Terry, thanks for the link but I've had this document for a long time. It says, quote: "The average frequency of winch accidents [in the UK] is 1 in every 13,000 launches." My figures for 2011 show 1 accident every 16,000 launches so you're doing better but nowhere near as good as the Germans at 1 every 180,000 launches. "

"Yes, you have improved but you have a ways to go and denial won't help."

"At this point I'm growing weary of UK denial. Believe what you will. It's your necks your breaking. "
------------

I think it’s important to recognise how good the improvement has been in the UK – this is actually an example of how a really good piece of (voluntary, BGA led) safety work has saved lives. If only our regulatory authorities could do this.

As you say, you’ve had the document Terry quoted for a long time, and you’re quoting old numbers, which don’t, I think, tell the recent story.

Following an excellent piece of work looking at the stats and analysing the causes of the acccidents, the BGA ran a “Safe winch launching initiative” starting some seven or so years ago. The 2012 stats show a dramatic and statistically significant improvement.

From http://www.gliding.co.uk/bgainfo/documents/accidentreview2012web.pdf
“In the 7 years of the safe winch launch initiative there have been just 2 fatal/serious injury winch accidents involving a stall or spin. The average 7-year total from 1974-2005 was 17. The total in the preceding 7 years from 1999-2005 was also 17. Stall/spin accidents have historically comprised 80% of fatal or serious injury winch accidents. These have declined dramatically. “

That's a big change. I can't think of many other places where we've achieved anything so significant. But I don’t think anyone is in denial or complacent – the document goes on to say:

“But in the last 7 years we have had two fatal and one serious injury accident from a wing drop and cartwheel.”

For that reason, the focus in improvement this year has been on avoiding or dealing with wing drops in the first stage of launch. (This has been supported by a good training materials and delivered through the instructor cadre).

I think that demonstrates that a focused piece of safety work can deliver really good results - also that the long term averages don't reflect the current situation.

What’s interesting is that the results don’t necessarily last (I guess unsurprisingly). A previous programme in the UK was successful in reducing the number of tug upsets – but we can now see them creeping back up, as new pilots come along who don’t have the same memory of the problem.

Paul

[email protected]

June 25th 13, 11:37 AM

Hi Bill

Just to pick up one other point. You said

"If one simply takes the BGA report supplied earlier in this thread which states there is one accident in the UK every 13,000 launches as true and compare it with the German BFU/DAeC data showing one accident in 180,000 launches you have a ratio of 13.8:1 in favor of Germany - well over an order of magnitude difference. "

I don't have all the data, as you clearly have, but others have expressed surprise about an apparent 10:1 difference in accident rates. So a little bit of a back of the envelope calculation to see if the ballpark is right. Whether accidents are reported equally, I don't know, but fatalities probably are.

From here: http://dir.groups.yahoo.com/group/winchdesign/message/9553

"Germany did 712,000 winch launches in 2009.... Only three accidents with 2 pilot fatalities occurred during the actual launch." So that's one fatality per 356,000 launches.

From the BGA stats I quoted in the previous post - UK fatalities 4 in 7 years, with 180K launches per year (from your earlier post). That's one fatality per 315K launches. And that's before we add back in the RAFGSA launches that Don mentioned.

Whilst in no way wishing to be complacent, that doesn't suggest to me that winch launching in Germany is currently an order of magnitude safer than in the UK.

Paul

Bill D

June 25th 13, 02:43 PM

On Tuesday, June 25, 2013 4:13:44 AM UTC-6, wrote:
> Hi Bill
>
>
>
> "Terry, thanks for the link but I've had this document for a long time. It says, quote: "The average frequency of winch accidents [in the UK] is 1 in every 13,000 launches." My figures for 2011 show 1 accident every 16,000 launches so you're doing better but nowhere near as good as the Germans at 1 every 180,000 launches. "
>
>
>
> "Yes, you have improved but you have a ways to go and denial won't help."
>
>
>
> "At this point I'm growing weary of UK denial. Believe what you will. It's your necks your breaking. "
>
> ------------
>
>
>
> I think it’s important to recognise how good the improvement has been in the UK – this is actually an example of how a really good piece of (voluntary, BGA led) safety work has saved lives. If only our regulatory authorities could do this.
>
>
>
> As you say, you’ve had the document Terry quoted for a long time, and you’re quoting old numbers, which don’t, I think, tell the recent story.
>
>
>
> Following an excellent piece of work looking at the stats and analysing the causes of the acccidents, the BGA ran a “Safe winch launching initiative” starting some seven or so years ago. The 2012 stats show a dramatic and statistically significant improvement.
>
>
>
> From http://www.gliding.co.uk/bgainfo/documents/accidentreview2012web.pdf
>
> “In the 7 years of the safe winch launch initiative there have been just 2 fatal/serious injury winch accidents involving a stall or spin. The average 7-year total from 1974-2005 was 17. The total in the preceding 7 years from 1999-2005 was also 17. Stall/spin accidents have historically comprised 80% of fatal or serious injury winch accidents. These have declined dramatically. “
>
>
>
> That's a big change. I can't think of many other places where we've achieved anything so significant. But I don’t think anyone is in denial or complacent – the document goes on to say:
>
>
>
> “But in the last 7 years we have had two fatal and one serious injury accident from a wing drop and cartwheel.”
>
>
>
> For that reason, the focus in improvement this year has been on avoiding or dealing with wing drops in the first stage of launch. (This has been supported by a good training materials and delivered through the instructor cadre).
>
>
>
> I think that demonstrates that a focused piece of safety work can deliver really good results - also that the long term averages don't reflect the current situation.
>
>
>
> What’s interesting is that the results don’t necessarily last (I guess unsurprisingly). A previous programme in the UK was successful in reducing the number of tug upsets – but we can now see them creeping back up, as new pilots come along who don’t have the same memory of the problem.
>
>
>
> Paul

You're shifting the subject from "acidents" to "fatal accidents" to reduce the numbers. Be consistent.

Mike the Strike

June 25th 13, 02:54 PM

On Tuesday, June 25, 2013 6:43:34 AM UTC-7, Bill D wrote:
> On Tuesday, June 25, 2013 4:13:44 AM UTC-6, wrote:
>
> > Hi Bill
>
> >
>
> >
>
> >
>
> > "Terry, thanks for the link but I've had this document for a long time. It says, quote: "The average frequency of winch accidents [in the UK] is 1 in every 13,000 launches." My figures for 2011 show 1 accident every 16,000 launches so you're doing better but nowhere near as good as the Germans at 1 every 180,000 launches. "
>
> >
>
> >
>
> >
>
> > "Yes, you have improved but you have a ways to go and denial won't help.."
>
> >
>
> >
>
> >
>
> > "At this point I'm growing weary of UK denial. Believe what you will. It's your necks your breaking. "
>
> >
>
> > ------------
>
> >
>
> >
>
> >
>
> > I think it’s important to recognise how good the improvement has been in the UK – this is actually an example of how a really good piece of (voluntary, BGA led) safety work has saved lives. If only our regulatory authorities could do this.
>
> >
>
> >
>
> >
>
> > As you say, you’ve had the document Terry quoted for a long time, and you’re quoting old numbers, which don’t, I think, tell the recent story.
>
> >
>
> >
>
> >
>
> > Following an excellent piece of work looking at the stats and analysing the causes of the acccidents, the BGA ran a “Safe winch launching initiative” starting some seven or so years ago. The 2012 stats show a dramatic and statistically significant improvement.
>
> >
>
> >
>
> >
>
> > From http://www.gliding.co.uk/bgainfo/documents/accidentreview2012web.pdf
>
> >
>
> > “In the 7 years of the safe winch launch initiative there have been just 2 fatal/serious injury winch accidents involving a stall or spin. The average 7-year total from 1974-2005 was 17. The total in the preceding 7 years from 1999-2005 was also 17. Stall/spin accidents have historically comprised 80% of fatal or serious injury winch accidents. These have declined dramatically. “
>
> >
>
> >
>
> >
>
> > That's a big change. I can't think of many other places where we've achieved anything so significant. But I don’t think anyone is in denial or complacent – the document goes on to say:
>
> >
>
> >
>
> >
>
> > “But in the last 7 years we have had two fatal and one serious injury accident from a wing drop and cartwheel.”
>
> >
>
> >
>
> >
>
> > For that reason, the focus in improvement this year has been on avoiding or dealing with wing drops in the first stage of launch. (This has been supported by a good training materials and delivered through the instructor cadre).
>
> >
>
> >
>
> >
>
> > I think that demonstrates that a focused piece of safety work can deliver really good results - also that the long term averages don't reflect the current situation.
>
> >
>
> >
>
> >
>
> > What’s interesting is that the results don’t necessarily last (I guess unsurprisingly). A previous programme in the UK was successful in reducing the number of tug upsets – but we can now see them creeping back up, as new pilots come along who don’t have the same memory of the problem.
>
> >
>
> >
>
> >
>
> > Paul
>
>
>
> You're shifting the subject from "acidents" to "fatal accidents" to reduce the numbers. Be consistent.

It is pretty certain that fatal accidents will be accurately recorded in all western countries, so this is definitely a good comparison and very interesting that the British and German numbers are quite similar.

The implication is that, while serious injury accidents occur at about the same rate, accidents that do not cause injury have a ten to fifteen times lower incidence in Germany than the rest of the world. I'm very skeptical of this. Perhaps another explanation is that dealing with the German bureaucracy is so complex and difficult that clubs don't report minor incidents to the national body at all?

From my own observations, there are a lot of minor and sometimes not-so-minor accidents that don't make the US database either.

Mike

[email protected]

June 25th 13, 03:47 PM

Hi Bill

> You're shifting the subject from "acidents" to "fatal accidents" to reduce the numbers. Be consistent.

I am indeed - so that I can be consistent - it seems to me to be a better absolute measure of safety than a poorly defined 'accident'. I think fatal accidents are more likely to get recorded, and won't suffer from differential reporting. (It's also data I could find easily - and note that I only used fatal rather than serious because that was what the German number was.).. If these fatal accident numbers are correct(and I accept I only used one year from Germany, but it was a back of the envelope calculation), they really don't support the contention that winch launching is 10 times as safe in Germany as in the UK. Otherwise we have the proposition that only a 10th as many winch accidents in the UK end up fatal as in Germany - and that seems unlikely. I think different recording is more likely.

It is worth saying that (at least at my club) we're pretty rigorous about recording even relatively minor incidents, and these all end up on the BGA database. We do that, in part I suspect, because the BGA is not seen as a 'regulator' but something that we belong to. And because we've seen the success of initiatives such as the Safe Launching one.

Paul

Terry Walsh[_3_]

June 25th 13, 05:29 PM

At 14:47 25 June 2013, wrote:
>Hi Bill
>
>> You're shifting the subject from "acidents" to "fatal accidents" to
>reduc=
>e the numbers. Be consistent.
>
>I am indeed - so that I can be consistent - it seems to me to be a better
>a=
>bsolute measure of safety than a poorly defined 'accident'. I think
fatal
>=
>accidents are more likely to get recorded, and won't suffer from
>differenti=
>al reporting. (It's also data I could find easily - and note that I only
>u=
>sed fatal rather than serious because that was what the German number
>was.)=
>.. If these fatal accident numbers are correct(and I accept I only used
>one=
> year from Germany, but it was a back of the envelope calculation), they
>re=
>ally don't support the contention that winch launching is 10 times as
safe
>=
>in Germany as in the UK. Otherwise we have the proposition that only a
>10t=
>h as many winch accidents in the UK end up fatal as in Germany - and that
>s=
>eems unlikely. I think different recording is more likely.
>
>It is worth saying that (at least at my club) we're pretty rigorous about
>r=
>ecording even relatively minor incidents, and these all end up on the BGA
>d=
>atabase. We do that, in part I suspect, because the BGA is not seen as a
>'=
>regulator' but something that we belong to. And because we've seen the
>suc=
>cess of initiatives such as the Safe Launching one.
>
>Paul

I believe that if we are really serious about improving safety then all
incidents should be reported if only because an incident was not an
accident due to pure luck in most cases. This then means that it is easier
to analyze what went wrong, simply because we can talk directly to the
pilots. This is obviously not possible following a fatal accident and
difficult after a serious injury one.
Based on this we can then make changes in the way we do things to try to
avoid accidents before they happen. I believe that this is generally the
approach adopted by the BGA.

In short I do not believe that winching, or aero towing for that matter are
inherently dangerous and most incidents and accidents are due to human
error.

Terry Walsh
>

BruceGreeff

June 25th 13, 05:41 PM

From the little I have been able to ascertain.

The German system is very de-centralised - and federated.
If there is an accident or incident it is generally dealt with locally.
Apparently - Only serious events make it up the hierarchy to the LBA/DaEC.

I have seen more than one glider where the log book does not record what
in local terms would have been "Moderate" damage and would definitely
have been reported. But again it is not possible to generalise this to
current practice. These gliders are, in general, decades old. So the
reporting standards were different when this happened. From the
difference in national numbers, one can only deduce that the reporting
methods differ.

Any of our European friends able to comment?

Bruce

--
Bruce Greeff
T59D #1771

Papa3[_2_]

June 25th 13, 07:31 PM

On Tuesday, June 25, 2013 6:13:44 AM UTC-4, Paul Ruskin wrote:
> Hi Bill
>
>
>
> "Terry, thanks for the link but I've had this document for a long time. It says, quote: "The average frequency of winch accidents [in the UK] is 1 in every 13,000 launches." My figures for 2011 show 1 accident every 16,000 launches so you're doing better but nowhere near as good as the Germans at 1 every 180,000 launches. "
>
>
>
> "Yes, you have improved but you have a ways to go and denial won't help."
>
>
>
> "At this point I'm growing weary of UK denial. Believe what you will. It's your necks your breaking. "
>
> ------------
>
>
>
> I think it’s important to recognise how good the improvement has been in the UK – this is actually an example of how a really good piece of (voluntary, BGA led) safety work has saved lives. If only our regulatory authorities could do this.
>
>
>
> As you say, you’ve had the document Terry quoted for a long time, and you’re quoting old numbers, which don’t, I think, tell the recent story.
>
>
>
> Following an excellent piece of work looking at the stats and analysing the causes of the acccidents, the BGA ran a “Safe winch launching initiative” starting some seven or so years ago. The 2012 stats show a dramatic and statistically significant improvement.
>
>
>
> From http://www.gliding.co.uk/bgainfo/documents/accidentreview2012web.pdf
>
> “In the 7 years of the safe winch launch initiative there have been just 2 fatal/serious injury winch accidents involving a stall or spin. The average 7-year total from 1974-2005 was 17. The total in the preceding 7 years from 1999-2005 was also 17. Stall/spin accidents have historically comprised 80% of fatal or serious injury winch accidents. These have declined dramatically. “
>
>
>
> That's a big change. I can't think of many other places where we've achieved anything so significant. But I don’t think anyone is in denial or complacent – the document goes on to say:
>
>
>
> “But in the last 7 years we have had two fatal and one serious injury accident from a wing drop and cartwheel.”
>
>
>
> For that reason, the focus in improvement this year has been on avoiding or dealing with wing drops in the first stage of launch. (This has been supported by a good training materials and delivered through the instructor cadre).
>
>
>
> I think that demonstrates that a focused piece of safety work can deliver really good results - also that the long term averages don't reflect the current situation.
>
>
>
> What’s interesting is that the results don’t necessarily last (I guess unsurprisingly). A previous programme in the UK was successful in reducing the number of tug upsets – but we can now see them creeping back up, as new pilots come along who don’t have the same memory of the problem.
>
>
>
> Paul

Apologies for perhaps contributing to thread drift, but... I have to say I was favorably impressed at the rigor and standardized procedures with which winch operations were run at the UK operations I visited over the last few years. Business had me spending weekends in England, so I would seek out local gliding clubs and volunteered to work the launch point for several hours at a couple of locations. There was an obvious safety culture and a general awareness of the terms/terminology in the BGA Winch procedures manual (don't have it in front of me right now, so I may not be using the right name, but an impressive piece of work). Having also visited several winching ops in Germany and the Netherlands, I was actually struck by the quality of the UK procedures in comparison to those at the clubs on the Continent.

Highly subjective and completely unscientific, but I simply can't fathom an order-of-magnitude difference in outcomes given my very limited sample...

Werner Schmidt

June 25th 13, 08:29 PM

Hello Papa3, you wrote at 06.25.2013 20:31

> Business had me spending weekends in England, so I would seek out
> local gliding clubs and volunteered to work the launch point for
> several hours at a couple of locations. There was an obvious safety
> culture and a general awareness of the terms/terminology in the BGA
> Winch procedures manual (don't have it in front of me right now, so I
> may not be using the right name, but an impressive piece of work).

as highly subjective and completely unscientific as your words and
speaking just for my club here in northern Germany:

For safety reasons no one in our club would let any non-member of the
club volunteer at the launch point in any way.

regards
Werner

Bill D

June 25th 13, 09:24 PM

On Tuesday, June 25, 2013 7:54:17 AM UTC-6, Mike the Strike wrote:
> On Tuesday, June 25, 2013 6:43:34 AM UTC-7, Bill D wrote:
>
> > On Tuesday, June 25, 2013 4:13:44 AM UTC-6, wrote:
>
> >
>
> > > Hi Bill
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > > "Terry, thanks for the link but I've had this document for a long time. It says, quote: "The average frequency of winch accidents [in the UK] is 1 in every 13,000 launches." My figures for 2011 show 1 accident every 16,000 launches so you're doing better but nowhere near as good as the Germans at 1 every 180,000 launches. "
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > > "Yes, you have improved but you have a ways to go and denial won't help."
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > > "At this point I'm growing weary of UK denial. Believe what you will.. It's your necks your breaking. "
>
> >
>
> > >
>
> >
>
> > > ------------
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > > I think it’s important to recognise how good the improvement has been in the UK – this is actually an example of how a really good piece of (voluntary, BGA led) safety work has saved lives. If only our regulatory authorities could do this.
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > > As you say, you’ve had the document Terry quoted for a long time, and you’re quoting old numbers, which don’t, I think, tell the recent story.
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > > Following an excellent piece of work looking at the stats and analysing the causes of the acccidents, the BGA ran a “Safe winch launching initiative” starting some seven or so years ago. The 2012 stats show a dramatic and statistically significant improvement.
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > > From http://www.gliding.co.uk/bgainfo/documents/accidentreview2012web..pdf
>
> >
>
> > >
>
> >
>
> > > “In the 7 years of the safe winch launch initiative there have been just 2 fatal/serious injury winch accidents involving a stall or spin. The average 7-year total from 1974-2005 was 17. The total in the preceding 7 years from 1999-2005 was also 17. Stall/spin accidents have historically comprised 80% of fatal or serious injury winch accidents. These have declined dramatically. “
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > > That's a big change. I can't think of many other places where we've achieved anything so significant. But I don’t think anyone is in denial or complacent – the document goes on to say:
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > > “But in the last 7 years we have had two fatal and one serious injury accident from a wing drop and cartwheel.”
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > > For that reason, the focus in improvement this year has been on avoiding or dealing with wing drops in the first stage of launch. (This has been supported by a good training materials and delivered through the instructor cadre).
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > > I think that demonstrates that a focused piece of safety work can deliver really good results - also that the long term averages don't reflect the current situation.
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > > What’s interesting is that the results don’t necessarily last (I guess unsurprisingly). A previous programme in the UK was successful in reducing the number of tug upsets – but we can now see them creeping back up, as new pilots come along who don’t have the same memory of the problem..
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > > Paul
>
> >
>
> >
>
> >
>
> > You're shifting the subject from "acidents" to "fatal accidents" to reduce the numbers. Be consistent.
>
>
>
> It is pretty certain that fatal accidents will be accurately recorded in all western countries, so this is definitely a good comparison and very interesting that the British and German numbers are quite similar.
>
>
>
> The implication is that, while serious injury accidents occur at about the same rate, accidents that do not cause injury have a ten to fifteen times lower incidence in Germany than the rest of the world. I'm very skeptical of this. Perhaps another explanation is that dealing with the German bureaucracy is so complex and difficult that clubs don't report minor incidents to the national body at all?
>
>
>
> From my own observations, there are a lot of minor and sometimes not-so-minor accidents that don't make the US database either.
>
>
>
> Mike

Lets try different data sets. For consistency, lets use only serious injury or fatal accidents which should be reported in every country.

Go to this site: http://rdd.me/oj4xenk5 and download the BGA "Safe Winching" PDF Look at Figure 2.

For the 17 years ending in 2004 the UK suffered 18 fatal and 36 serious injury accidents. (379 total accidents or one every 8074 launches) If we assume the current 180,000 launches a year, that is one fatal/serious injury accident every 56,667 launches.

Here are reported German accidents in 2011 in which the DAeC reported 900,000 launches. That's 1:180,000.

3X060--11. A Jeans-Astir got launched into a Remos*ultralight which crossed the pass of the glider from right to left. The two a/c's collided in about 1,200ft and both lost their wings resulting in three fatalities.

3X093-11. Spin-in after normal launch - on YouTube.

3X095-11. A Ka-8 was launched on the winch and when the glider's right wing touched the ground and*veered off to the right, the launch-boss gave the command 'All stop', which was followed by the operator.*The the command to continue the launch was given but the line detached from the glider which then stalled over the right wing and impacted the ground out of about 10m.. The pilot was 65 years old.

3X065-11. The glider was launched on the winch but did not gain sufficient altitude and released in about 40m. Instead of landing straight ahead, the pilot tried to reach a field to the left and then forced the glider into a ground-loop. Pilot suffered broken vertebrae; the passenger only minor injuries.

3X080-11. A LS4 was being launched and after 40-50m of ground roll (!!) the gear collapsed. The glider was dragged for another 23m on the belly and finally lifted off. The launch-boss had given the 'All-stop' command which was followed by the operator. The glider did not have enough speed or altitude to recover and landed very hard. The pilot was 85 years old.

Paul Ruskin[_2_]

June 25th 13, 10:04 PM

On Tuesday, June 25, 2013 9:24:36 PM UTC+1, Bill D wrote:

> Lets try different data sets. For consistency, lets use only serious injury or fatal accidents which should be reported in every country.
>
> Go to this site: http://rdd.me/oj4xenk5 and download the BGA "Safe Winching" PDF Look at Figure 2.
>
> For the 17 years ending in 2004 the UK suffered 18 fatal and 36 serious injury accidents. (379 total accidents or one every 8074 launches) If we assume the current 180,000 launches a year, that is one fatal/serious injury accident every 56,667 launches.

Here are reported German accidents in 2011 in which the DAeC reported 900,000 launches. That's 1:180,000.
>
>
That looks pretty consistent with my first post (about 5 posts ago). You've quoted here the UK experience up to 2004. But my point was that a great piece of safety work reduced the number of winch launched fatality / serious accidents after 2006 by a factor of 4 (and for long enough to be statistically significant). If we include fatals and serious, that's 5 between 2006-2012. At 180K launches per year that's 1:250,000. That puts the UK and German numbers in the same ballpark - actually the UK comes out better, but I don't suppose it's significant given one year's German figures and the uncertainty on the number of launches.

You said something earlier to the effect that the UK should pay attention to the differences and do something about it. I'm pointing out that we did..

Paul

Bill D

June 26th 13, 12:13 AM

On Tuesday, June 25, 2013 3:04:58 PM UTC-6, Paul Ruskin wrote:
> On Tuesday, June 25, 2013 9:24:36 PM UTC+1, Bill D wrote:
>
>
>
> > Lets try different data sets. For consistency, lets use only serious injury or fatal accidents which should be reported in every country.
>
> >
>
> > Go to this site: http://rdd.me/oj4xenk5 and download the BGA "Safe Winching" PDF Look at Figure 2.
>
> >
>
> > For the 17 years ending in 2004 the UK suffered 18 fatal and 36 serious injury accidents. (379 total accidents or one every 8074 launches) If we assume the current 180,000 launches a year, that is one fatal/serious injury accident every 56,667 launches.
>
>
>
> Here are reported German accidents in 2011 in which the DAeC reported 900,000 launches. That's 1:180,000.
>
> >
>
> >
>
> That looks pretty consistent with my first post (about 5 posts ago). You've quoted here the UK experience up to 2004. But my point was that a great piece of safety work reduced the number of winch launched fatality / serious accidents after 2006 by a factor of 4 (and for long enough to be statistically significant). If we include fatals and serious, that's 5 between 2006-2012. At 180K launches per year that's 1:250,000. That puts the UK and German numbers in the same ballpark - actually the UK comes out better, but I don't suppose it's significant given one year's German figures and the uncertainty on the number of launches.
>
>
>
> You said something earlier to the effect that the UK should pay attention to the differences and do something about it. I'm pointing out that we did.
>
>
>
> Paul

Actually, those were all the accidents reported in Germany for 2011 of any type. They were not filtered for serious/fatal.

Andreas Maurer

June 26th 13, 02:40 AM

On Tue, 25 Jun 2013 18:41:36 +0200, BruceGreeff >
wrote:

> From the little I have been able to ascertain.
>
>The German system is very de-centralised - and federated.
>If there is an accident or incident it is generally dealt with locally.
>Apparently - Only serious events make it up the hierarchy to the LBA/DaEC.
>
>I have seen more than one glider where the log book does not record what
>in local terms would have been "Moderate" damage and would definitely
>have been reported. But again it is not possible to generalise this to
>current practice. These gliders are, in general, decades old. So the
>reporting standards were different when this happened. From the
>difference in national numbers, one can only deduce that the reporting
>methods differ.
>
>Any of our European friends able to comment?

<Raises a hand>

The German system is not de-centralized at all concerning aircraft
certification and accident analysis.
All of this is handled centrally by the German equivalent of the FAA,
the "Luftfahrt Bundesamt" (LBA) and the German Federal Bureau of
Aircraft Accident Investigation (BFU).

http://www.bfu-web.de/EN/Home/homepage_node.html;jsessionid=472BAB43CD00E3801A64 341C0F98D1EF.live2051

In Germany *any* incident that causes a severe damage to the glider
(severe damage: a damage that compromises an aircraft's
airworthiness), its pilot or third party property is definitely
reported to the LBA.

Minor incidents without damage but deemed noteworthy are also
reported. This is practiced at least since the early 1980's.

The only accidents that are not reported are minor outlanding damages.

http://www.bfu-web.de/DE/Publikationen/Bulletins/Functions/bulletins2012_table.html?nn=223244

One things needs to be mentioned: There is no relation between a
damage report to the LBA and an entry in the gllider's log book.

For a long time it was accepted practice that a damage report and its
corresponding repair report were not reported in the log book, but
rather in the maintenance history file. Some owners did not feel the
necessity to include these in this file in order to increase the
resale value...

Cheers
Andreas

Bill D

June 26th 13, 04:01 AM

On Tuesday, June 25, 2013 7:40:12 PM UTC-6, Andreas Maurer wrote:
> On Tue, 25 Jun 2013 18:41:36 +0200, BruceGreeff >
>
> wrote:
>
>
>
> > From the little I have been able to ascertain.
>
> >
>
> >The German system is very de-centralised - and federated.
>
> >If there is an accident or incident it is generally dealt with locally.
>
> >Apparently - Only serious events make it up the hierarchy to the LBA/DaEC.
>
> >
>
> >I have seen more than one glider where the log book does not record what
>
> >in local terms would have been "Moderate" damage and would definitely
>
> >have been reported. But again it is not possible to generalise this to
>
> >current practice. These gliders are, in general, decades old. So the
>
> >reporting standards were different when this happened. From the
>
> >difference in national numbers, one can only deduce that the reporting
>
> >methods differ.
>
> >
>
> >Any of our European friends able to comment?
>
>
>
> <Raises a hand>
>
>
>
> The German system is not de-centralized at all concerning aircraft
>
> certification and accident analysis.
>
> All of this is handled centrally by the German equivalent of the FAA,
>
> the "Luftfahrt Bundesamt" (LBA) and the German Federal Bureau of
>
> Aircraft Accident Investigation (BFU).
>
>
>
> http://www.bfu-web.de/EN/Home/homepage_node.html;jsessionid=472BAB43CD00E3801A64 341C0F98D1EF.live2051
>
>
>
>
>
> In Germany *any* incident that causes a severe damage to the glider
>
> (severe damage: a damage that compromises an aircraft's
>
> airworthiness), its pilot or third party property is definitely
>
> reported to the LBA.
>
>
>
> Minor incidents without damage but deemed noteworthy are also
>
> reported. This is practiced at least since the early 1980's.
>
>
>
> The only accidents that are not reported are minor outlanding damages.
>
>
>
> http://www.bfu-web.de/DE/Publikationen/Bulletins/Functions/bulletins2012_table.html?nn=223244
>
>
>
>
>
>
>
> One things needs to be mentioned: There is no relation between a
>
> damage report to the LBA and an entry in the gllider's log book.
>
>
>
> For a long time it was accepted practice that a damage report and its
>
> corresponding repair report were not reported in the log book, but
>
> rather in the maintenance history file. Some owners did not feel the
>
> necessity to include these in this file in order to increase the
>
> resale value...
>
>
>
>
>
>
>
> Cheers
>
> Andreas

So, Andreas verifies the 5 accidents the BFU lists for 2011 was all there was in 900,000 winch launches.

http://rdd.me/dstznowe says the UK suffered 12 for 180,000 launches.

How does that stack up?

UK: 1:15,000
Germany 1:180,000

Seems like Germany has a 12:1 lower accident rate.

It's great that the safer winch launching initiative in the UK has improved things but I think you need to find out what the Germans are doing right. I'd start by watching every "windenstart" video on YouTube. Hint: Time the takeoff rolls.

BruceGreeff

June 26th 13, 06:28 AM

Thanks Andreas

Most informative. The resale value driver is obviously a consideration
when exporting a glider.

It then appears there is a high difference in historical reported
accident rate.
Current rates don't seem to be that different. IT is nice to see that
the BGA safe winching initiative has made such a difference.

Do you know how these numbers compare with the worldwide stats that John
Roake collected?

I am sure there are a number of contributory factors - including the
size/layout of airfield, demographics and composition of fleet which
also contribute.

In South Africa it has been 14 years since we had a fatal winch
accident. No idea how many launches involved.

Bruce

On 2013/06/26 3:40 AM, Andreas Maurer wrote:
> On Tue, 25 Jun 2013 18:41:36 +0200, BruceGreeff >
> wrote:
>
>> From the little I have been able to ascertain.

>

--
Bruce Greeff
T59D #1771

BruceGreeff

June 26th 13, 07:45 AM

Meta data is data describing other data. In this case the metadata is
what is missing.

We don't have enough information for meaningful comparisons.

That is where I where I am going - and in fact gone.

You are using historical data, without enough context to draw
conclusions about current practice.

So the specific example I gave in fact demonstrates that the useful
information is often well hidden. If we use your approach you have a
statistic that supports the contention that winch launch is 100% more
dangerous than aerotow for this set of data.

Lots of problems -
1 the set is too small (the BGA vs LBA sets are statistically significant)
2 the metric and the generator are not linked. Launch method had nothing
to do with either incident. Poor airfield maintenance and pilot decision
on risk is the cause (both involved a groundloop because someone did not
cut the grass properly and the pilot decided to proceed anyway)
3 the outcome is biased by a "hidden" factor - the actual damage that
resulted in the report of damage to an airframe was traced to
progressive failure of a poor repair after an outlanding accident
decades back when the glider was a competitive two seater in Germany. It
was going to break some time soon. This flight just happened to involve
the trigger stress.

Did the launch method have much to do with the damage, not really. If
the poorly repaired wing failed during spin training, would it mean that
our spin training is dangerous?

So - to be very explicit - where I am going with my comment is that I am
concerned that you may be oversimplifying in an attempt to prove your
opinion. Where an hypothesis would be well enough constructed that is
could be proven.

If you said that the historical accident data for the period you
reviewed showed a difference in the relative safety of operations at
German versus British gliding clubs, that might even be an uncontestable
finding (10>2). If you compared the trends in accident rates and found
them to be stable over the period you might even be able to conclude
that this is representative of the current situation. (the numbers are
comparable)
If you had qualified the analysis by using the numbers where the
investigators concluded after careful consideration that the launch
method was the causal factor, then you could even conclude that "Winch
launch operations" are more dangerous in one than in the other.

Since you have too little "metadata" and are making conclusion without
all the painful logical and mathematical rigour that makes Business
Intelligence type metrics such a tedious business, I think it is
dangerous and misleading to make the kind of assertions you are making.

Unless you know the actual cause of every number in the set, you can't
make confident assertions.

(Humour alert) There are 10 kinds of people in the world. Those who
understand binary, and those who don't. (10 in binary = 2 in decimal) ;-)

As Bob says, is it possible? Definitely.
Does a simple integer comparison of two numbers prove the assertion? I
think you would have to question that.

Personally, I find winch launching risk to be more tractable. You can
control risk better.

But again - context is important. Winch launching an open class glass
ship with water ballast would probably be less safe than aerotowing the
same combination, all things being equal.

>> T59D #1771
>
> Not sure where you're going with this, Bruce. Of course there are reasons for the differences and that's a a very important discussion to have but it doesn't affect the difference itself.
>
> The raw accident count for the number of launches done is really metadata (To use a currently popular term.) Metadata is very valuable in seeing the big picture but not so much for analyzing the details for why it looks that way. Hopefully, the metadata will provoke that kind of detailed analysis.
>

--
Bruce Greeff
T59D #1771

Bill D

June 26th 13, 05:58 PM

Bruce, I find your analysis helpful.

Indeed, it is metadata. However, if you have enough of it, a statistically significant picture emerges. But even so, metadata doesn't explain the detailed why and how of the picture it presents. That's the next step. At best it tells you where to look and what to look for.

I contend the 130,000 annual aero tows in the US and the related accidents are statistically significant. It's pretty simple to compare German winch launch to US aero tow for 2011. German winch launch and US aero tow suffered exactly the same number and type of accidents so the relative number of launches tells the story. 900,000 vs 130,000 is 7:1. The two countries can be said to be experts at their respective launch styles so it's a valid comparison. i.e. "Given equal levels of expertise, winch launch is 7 times safer than aero tow." I think both launch styles are equally sensitive to a lack of pilot skill.

Despite the truly excellent German winch safety record, Professor Dr. Richard Eppler at the University of Stuttgart (He of numerical airfoil analysis fame.) thinks it can be improved further and has written a paper on the subject for flight instructors. One of the insights from the paper is the concept of a minimum airspeed for winch launch that should be part of airworthiness documents and listed in flight manuals. DG was apparently listening so the DG1000 manual lists a minimum winch airspeed of 49 knots. So now in addition to Vw-max we have Vw-min. If pilots had simply ensured their airspeed was always above Vw-min, a significant number of accidents would not have happened.

Another not-so-rare accident type starts with a wing tip contacting the ground during the takeoff roll where it digs in and the rapidly accelerating glider "cartwheels". In the worst case, the glider ends up inverted and the result is fatal.

Counter-intuitively, the solution is even more acceleration to give the pilot aileron control before a wing can drop and then get him airborne where the wing can't touch the ground. More acceleration also gets the glider above Vw-min before the pilot can begin rotating into the climb. Vw-min assures enough elevator authority to prevent inertial pitch-up in high-CG, low hook gliders.

YouTube videos show a difference between UK practice and German practice. German ground rolls are pretty consistent at two seconds indicating 1G acceleration. By contrast, I've seen videos of very wobbly UK ground rolls taking as much as 15 seconds but that's an exception - most are 3 - 4 seconds.

On Wednesday, June 26, 2013 12:45:49 AM UTC-6, BruceGreeff wrote:
> Meta data is data describing other data. In this case the metadata is
>
> what is missing.
>
>
>
> We don't have enough information for meaningful comparisons.
>
>
>
> That is where I where I am going - and in fact gone.
>
>
>
> You are using historical data, without enough context to draw
>
> conclusions about current practice.
>
>
>
> So the specific example I gave in fact demonstrates that the useful
>
> information is often well hidden. If we use your approach you have a
>
> statistic that supports the contention that winch launch is 100% more
>
> dangerous than aerotow for this set of data.
>
>
>
> Lots of problems -
>
> 1 the set is too small (the BGA vs LBA sets are statistically significant)
>
> 2 the metric and the generator are not linked. Launch method had nothing
>
> to do with either incident. Poor airfield maintenance and pilot decision
>
> on risk is the cause (both involved a groundloop because someone did not
>
> cut the grass properly and the pilot decided to proceed anyway)
>
> 3 the outcome is biased by a "hidden" factor - the actual damage that
>
> resulted in the report of damage to an airframe was traced to
>
> progressive failure of a poor repair after an outlanding accident
>
> decades back when the glider was a competitive two seater in Germany. It
>
> was going to break some time soon. This flight just happened to involve
>
> the trigger stress.
>
>
>
> Did the launch method have much to do with the damage, not really. If
>
> the poorly repaired wing failed during spin training, would it mean that
>
> our spin training is dangerous?
>
>
>
> So - to be very explicit - where I am going with my comment is that I am
>
> concerned that you may be oversimplifying in an attempt to prove your
>
> opinion. Where an hypothesis would be well enough constructed that is
>
> could be proven.
>
>
>
> If you said that the historical accident data for the period you
>
> reviewed showed a difference in the relative safety of operations at
>
> German versus British gliding clubs, that might even be an uncontestable
>
> finding (10>2). If you compared the trends in accident rates and found
>
> them to be stable over the period you might even be able to conclude
>
> that this is representative of the current situation. (the numbers are
>
> comparable)
>
> If you had qualified the analysis by using the numbers where the
>
> investigators concluded after careful consideration that the launch
>
> method was the causal factor, then you could even conclude that "Winch
>
> launch operations" are more dangerous in one than in the other.
>
>
>
> Since you have too little "metadata" and are making conclusion without
>
> all the painful logical and mathematical rigour that makes Business
>
> Intelligence type metrics such a tedious business, I think it is
>
> dangerous and misleading to make the kind of assertions you are making.
>
>
>
> Unless you know the actual cause of every number in the set, you can't
>
> make confident assertions.
>
>
>
> (Humour alert) There are 10 kinds of people in the world. Those who
>
> understand binary, and those who don't. (10 in binary = 2 in decimal) ;-)
>
>
>
> As Bob says, is it possible? Definitely.
>
> Does a simple integer comparison of two numbers prove the assertion? I
>
> think you would have to question that.
>
>
>
> Personally, I find winch launching risk to be more tractable. You can
>
> control risk better.
>
>
>
> But again - context is important. Winch launching an open class glass
>
> ship with water ballast would probably be less safe than aerotowing the
>
> same combination, all things being equal.
>
>
>
> >> T59D #1771
>
> >
>
> > Not sure where you're going with this, Bruce. Of course there are reasons for the differences and that's a a very important discussion to have but it doesn't affect the difference itself.
>
> >
>
> > The raw accident count for the number of launches done is really metadata (To use a currently popular term.) Metadata is very valuable in seeing the big picture but not so much for analyzing the details for why it looks that way. Hopefully, the metadata will provoke that kind of detailed analysis.
>
> >
>
>
>
> --
>
> Bruce Greeff
>
> T59D #1771

Martin Gregorie[_5_]

June 26th 13, 09:40 PM

On Wed, 26 Jun 2013 09:58:47 -0700, Bill D wrote:

> YouTube videos show a difference between UK practice and German
> practice. German ground rolls are pretty consistent at two seconds
> indicating 1G acceleration. By contrast, I've seen videos of very
> wobbly UK ground rolls taking as much as 15 seconds but that's an
> exception - most are 3 - 4 seconds.
>
In the UK a lot of emphasis is put on having at least 50 kts *and
accelerating* before you rotate into a full climb.

I don't recall any specific comments about acceleration rates, though in
the past I've used a stopwatch and timed consistent launches as taking 5
secs from first movement until the glider started to rotate into full
climb, which I assumed meant the glider was accelerating through 50 kts.
This corresponds to roughly 0.5G on average.

This was on our club's Supacat winch with a 240 hp diesel V8 powering it.
The huge majority of the launches I've had on this winch have been like
that. I've also had a couple of launches on a Skylaunch (350hp+ V8
burning LPG), which provides a noticeably higher initial acceleration
than our V8 Supacat. I'm happy with both.

OTOH, I recently had a few much more sluggish launches with longer ground
rolls and that subjectively seemed to take forever to accelerate past 50
kts. I didn't like these at all and have promised myself that if I get
another I'll be having a discussion with the winch driver.

I'm with you on this Bill: brisk acceleration on the winch is good.

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

Paul Ruskin[_2_]

June 26th 13, 10:38 PM

Hi Bill
> So, Andreas verifies the 5 accidents the BFU lists for 2011 was all there was in 900,000 winch launches.
>
> http://rdd.me/dstznowe says the UK suffered 12 for 180,000 launches.
>
> How does that stack up?
> UK: 1:15,000
> Germany 1:180,000
> Seems like Germany has a 12:1 lower accident rate.
>
Actually, the reference you quote above says that in 2011 there were 12 accidents plus incidents. Not the same as accidents. It's not really credible that the accident rate is 12:1 but the fatality / serious rate roughly the same, as calculated earlier. I think we're going to need to agree to differ on this one though.

>It's great that the safer winch launching initiative in the UK has improved things but I think you need to find out what the Germans are doing right. I'd start by watching every "windenstart" video on YouTube. Hint: Time the takeoff rolls

OK - good thought. So I did. First five UK launches 5,2,2,4,2 seconds (roughly). First five German ones 5,4,3,3,2. Again roughly. Not a lot of difference (caveat - not a large sample and dependent on lots of other things). What was interesting was that the first two UK ones were from the same club, and used their old and new winch respectively. I think this time is largely equipment driven - could be that newer winches tend to be higher power. Don't disagree in principle though - and as I mentioned earlier, avoiding wing drop is a current focus at the moment in the UK.

On your point about minimum winch airspeed, I agree totally. It's standard teaching: (BGA Instructors' manual edition 3 page 16-1). I find it strange that gliders are placarded with maximum airspeed but not minimum.

Paul

Bill D

June 27th 13, 01:17 AM

On Wednesday, June 26, 2013 3:38:21 PM UTC-6, Paul Ruskin wrote:
> Hi Bill
>
> > So, Andreas verifies the 5 accidents the BFU lists for 2011 was all there was in 900,000 winch launches.
>
> >
>
> > http://rdd.me/dstznowe says the UK suffered 12 for 180,000 launches.
>
> >
>
> > How does that stack up?
>
> > UK: 1:15,000
>
> > Germany 1:180,000
>
> > Seems like Germany has a 12:1 lower accident rate.
>
> >
>
> Actually, the reference you quote above says that in 2011 there were 12 accidents plus incidents. Not the same as accidents. It's not really credible that the accident rate is 12:1 but the fatality / serious rate roughly the same, as calculated earlier. I think we're going to need to agree to differ on this one though.
>
>
>
> >It's great that the safer winch launching initiative in the UK has improved things but I think you need to find out what the Germans are doing right. I'd start by watching every "windenstart" video on YouTube. Hint: Time the takeoff rolls
>
>
>
> OK - good thought. So I did. First five UK launches 5,2,2,4,2 seconds (roughly). First five German ones 5,4,3,3,2. Again roughly. Not a lot of difference (caveat - not a large sample and dependent on lots of other things). What was interesting was that the first two UK ones were from the same club, and used their old and new winch respectively. I think this time is largely equipment driven - could be that newer winches tend to be higher power. Don't disagree in principle though - and as I mentioned earlier, avoiding wing drop is a current focus at the moment in the UK.
>
>
>
> On your point about minimum winch airspeed, I agree totally. It's standard teaching: (BGA Instructors' manual edition 3 page 16-1). I find it strange that gliders are placarded with maximum airspeed but not minimum.
>
>
>
> Paul

When timing takeoff rolls, you need to find a way to consistently pick a moment when the acceleration begins. Many of the launches roll for several meters before the winch driver really hits the throttle. I choose the moment a nose wheel/skid glider's tail goes down and for tail wheel gliders when the wing runner lets go to start the clock.

To compensate a bit for this late clock start, I stop the clock when the glider's wheel is .5 - 1m above the ground. It's not perfect but then it's YouTube.

It's also necessary to estimate the wind. If there's a lot of wind noise on the sound track or the trees are obviously bending, I disregard that video. If I can see a wind sock in the background, I can estimate the wind. If there's a good sound track without wind noise, there's probably little wind.

Try that and see if your numbers change.

Dan Marotta

June 27th 13, 03:06 PM

The following short clip is taken from a video made for ESPN back in the 90s
some time. This is how it should have looked:
http://www.youtube.com/watch?v=DHa-tIHrCOQ&feature=youtu.be

"Bill D" > wrote in message
...
On Wednesday, June 26, 2013 3:38:21 PM UTC-6, Paul Ruskin wrote:
> Hi Bill
>
> > So, Andreas verifies the 5 accidents the BFU lists for 2011 was all
> > there was in 900,000 winch launches.
>
> >
>
> > http://rdd.me/dstznowe says the UK suffered 12 for 180,000 launches.
>
> >
>
> > How does that stack up?
>
> > UK: 1:15,000
>
> > Germany 1:180,000
>
> > Seems like Germany has a 12:1 lower accident rate.
>
> >
>
> Actually, the reference you quote above says that in 2011 there were 12
> accidents plus incidents. Not the same as accidents. It's not really
> credible that the accident rate is 12:1 but the fatality / serious rate
> roughly the same, as calculated earlier. I think we're going to need to
> agree to differ on this one though.
>
>
>
> >It's great that the safer winch launching initiative in the UK has
> >improved things but I think you need to find out what the Germans are
> >doing right. I'd start by watching every "windenstart" video on YouTube.
> >Hint: Time the takeoff rolls
>
>
>
> OK - good thought. So I did. First five UK launches 5,2,2,4,2 seconds
> (roughly). First five German ones 5,4,3,3,2. Again roughly. Not a lot
> of difference (caveat - not a large sample and dependent on lots of other
> things). What was interesting was that the first two UK ones were from
> the same club, and used their old and new winch respectively. I think
> this time is largely equipment driven - could be that newer winches tend
> to be higher power. Don't disagree in principle though - and as I
> mentioned earlier, avoiding wing drop is a current focus at the moment in
> the UK.
>
>
>
> On your point about minimum winch airspeed, I agree totally. It's
> standard teaching: (BGA Instructors' manual edition 3 page 16-1). I find
> it strange that gliders are placarded with maximum airspeed but not
> minimum.
>
>
>
> Paul

When timing takeoff rolls, you need to find a way to consistently pick a
moment when the acceleration begins. Many of the launches roll for several
meters before the winch driver really hits the throttle. I choose the
moment a nose wheel/skid glider's tail goes down and for tail wheel gliders
when the wing runner lets go to start the clock.

To compensate a bit for this late clock start, I stop the clock when the
glider's wheel is .5 - 1m above the ground. It's not perfect but then it's
YouTube.

It's also necessary to estimate the wind. If there's a lot of wind noise on
the sound track or the trees are obviously bending, I disregard that video.
If I can see a wind sock in the background, I can estimate the wind. If
there's a good sound track without wind noise, there's probably little wind.

Try that and see if your numbers change.

Bill D

June 27th 13, 04:28 PM

On Wednesday, June 26, 2013 2:40:30 PM UTC-6, Martin Gregorie wrote:

> the past I've used a stopwatch and timed consistent launches as taking 5 secs from first movement until the glider started to rotate into full climb, which I assumed meant the glider was accelerating through 50 kts.
>
> This corresponds to roughly 0.5G on average.

That's about the same result I got from UK videos. The German "windenstart" videos seem to average 1.0G (19kts/sec)acceleration. I've yet to read of an accident that can be unequivocally attributed to excessive acceleration.

BruceGreeff

June 28th 13, 08:56 AM

Indeed.

As an example - the BGA statistics include any accident or incident
reported by a member anywhere in the world. So their numbers include
locations in Spain and South Africa.

The German numbers do not.

I express no opinion on which is a better approach. Merely that the one
is organisational statistics and the other is geographic.

Bruce

On 2013/06/26 11:38 PM, Paul Ruskin wrote:
> Hi Bill
>> So, Andreas verifies the 5 accidents the BFU lists for 2011 was all there was in 900,000 winch launches.
>>
>> http://rdd.me/dstznowe says the UK suffered 12 for 180,000 launches.
>>
>> How does that stack up?
>> UK: 1:15,000
>> Germany 1:180,000
>> Seems like Germany has a 12:1 lower accident rate.
>>
> Actually, the reference you quote above says that in 2011 there were 12 accidents plus incidents. Not the same as accidents. It's not really credible that the accident rate is 12:1 but the fatality / serious rate roughly the same, as calculated earlier. I think we're going to need to agree to differ on this one though.
>
>> It's great that the safer winch launching initiative in the UK has improved things but I think you need to find out what the Germans are doing right. I'd start by watching every "windenstart" video on YouTube. Hint: Time the takeoff rolls
>
> OK - good thought. So I did. First five UK launches 5,2,2,4,2 seconds (roughly). First five German ones 5,4,3,3,2. Again roughly. Not a lot of difference (caveat - not a large sample and dependent on lots of other things). What was interesting was that the first two UK ones were from the same club, and used their old and new winch respectively. I think this time is largely equipment driven - could be that newer winches tend to be higher power. Don't disagree in principle though - and as I mentioned earlier, avoiding wing drop is a current focus at the moment in the UK.
>
> On your point about minimum winch airspeed, I agree totally. It's standard teaching: (BGA Instructors' manual edition 3 page 16-1). I find it strange that gliders are placarded with maximum airspeed but not minimum.
>
> Paul
>

--
Bruce Greeff
T59D #1771

Bill D

June 28th 13, 03:09 PM

On Friday, June 28, 2013 1:56:50 AM UTC-6, BruceGreeff wrote:
> Indeed.
>
>
>
> As an example - the BGA statistics include any accident or incident
>
> reported by a member anywhere in the world. So their numbers include
>
> locations in Spain and South Africa.
>
>
>
> The German numbers do not.
>
>
>
> I express no opinion on which is a better approach. Merely that the one
>
> is organisational statistics and the other is geographic.
>
>
>
> Bruce
>
>
>
> On 2013/06/26 11:38 PM, Paul Ruskin wrote:
>
> > Hi Bill
>
> >> So, Andreas verifies the 5 accidents the BFU lists for 2011 was all there was in 900,000 winch launches.
>
> >>
>
> >> http://rdd.me/dstznowe says the UK suffered 12 for 180,000 launches.
>
> >>
>
> >> How does that stack up?
>
> >> UK: 1:15,000
>
> >> Germany 1:180,000
>
> >> Seems like Germany has a 12:1 lower accident rate.
>
> >>
>
> > Actually, the reference you quote above says that in 2011 there were 12 accidents plus incidents. Not the same as accidents. It's not really credible that the accident rate is 12:1 but the fatality / serious rate roughly the same, as calculated earlier. I think we're going to need to agree to differ on this one though.
>
> >
>
> >> It's great that the safer winch launching initiative in the UK has improved things but I think you need to find out what the Germans are doing right. I'd start by watching every "windenstart" video on YouTube. Hint: Time the takeoff rolls
>
> >
>
> > OK - good thought. So I did. First five UK launches 5,2,2,4,2 seconds (roughly). First five German ones 5,4,3,3,2. Again roughly. Not a lot of difference (caveat - not a large sample and dependent on lots of other things). What was interesting was that the first two UK ones were from the same club, and used their old and new winch respectively. I think this time is largely equipment driven - could be that newer winches tend to be higher power. Don't disagree in principle though - and as I mentioned earlier, avoiding wing drop is a current focus at the moment in the UK.
>
> >
>
> > On your point about minimum winch airspeed, I agree totally. It's standard teaching: (BGA Instructors' manual edition 3 page 16-1). I find it strange that gliders are placarded with maximum airspeed but not minimum.
>
> >
>
> > Paul
>
> >
>
>
>
> --
>
> Bruce Greeff
>
> T59D #1771

Not correct. The Germans do report accidents anywhere in the world.

[email protected]

June 28th 13, 06:50 PM

On Thursday, 27 June 2013 16:28:40 UTC+1, Bill D wrote:
> On Wednesday, June 26, 2013 2:40:30 PM UTC-6, Martin Gregorie wrote:
>
>
>
> > the past I've used a stopwatch and timed consistent launches as taking 5 secs from first movement until the glider started to rotate into full climb, which I assumed meant the glider was accelerating through 50 kts.
>
> >
>
> > This corresponds to roughly 0.5G on average.
>
>
>
> That's about the same result I got from UK videos. The German "windenstart" videos seem to average 1.0G (19kts/sec)acceleration. I've yet to read of an accident that can be unequivocally attributed to excessive acceleration.

================================================== ===========================

Having been winch launching since 1969 I find myself disagreeing that very rapid accelaration at the beginning of the ground run is necessarily a good thing. Being off the ground in 2-3 seconds means (approximately) going from 0-60mph in that time and which gives a rate of increase of energy into the system such that if a wing does drop then and catch then there is little chance of the pilot preventing what should have been a release +/- groundloop turning into a cartwheel/flick tragedy. 1 g acceleration means that the glider is pulled off the ground so fast that it is unlikely to drop a wing but increases the chance of disaster if it does.

We lost the pilot of a Nimbus 3 to a cartwheel accident at our club last year. The accident report not yet published so I am not saying this was a factor there but it is self evident that if a glider pilot can release the cable in time before a wingtip hits the ground then there would be zero chance of a cartwheel accident

Furthermore excessive acceleration can cause some glider types to rotate too fast in that rate of rotation can increse the stall speed at this critical time.

The BGA advice for powerful winches is 3 seconds to the intended maximum intended (not necessarily full) thottle position for the glider and winch type - with the engine rpm following a bit behind that - and that feels right to me.

See the BGA winch operations slide show at:

http://www.gliding.co.uk/bgainfo/safety/documents/winchops.ppsx

John Galloway

Bill D

June 28th 13, 08:04 PM

On Friday, June 28, 2013 11:50:30 AM UTC-6, wrote:
> On Thursday, 27 June 2013 16:28:40 UTC+1, Bill D wrote:
>
> > On Wednesday, June 26, 2013 2:40:30 PM UTC-6, Martin Gregorie wrote:
>
> >
>
> >
>
> >
>
> > > the past I've used a stopwatch and timed consistent launches as taking 5 secs from first movement until the glider started to rotate into full climb, which I assumed meant the glider was accelerating through 50 kts.
>
> >
>
> > >
>
> >
>
> > > This corresponds to roughly 0.5G on average.
>
> >
>
> >
>
> >
>
> > That's about the same result I got from UK videos. The German "windenstart" videos seem to average 1.0G (19kts/sec)acceleration. I've yet to read of an accident that can be unequivocally attributed to excessive acceleration.
>
>
>
> ================================================== ===========================
>
>
>
> Having been winch launching since 1969 I find myself disagreeing that very rapid accelaration at the beginning of the ground run is necessarily a good thing. Being off the ground in 2-3 seconds means (approximately) going from 0-60mph in that time and which gives a rate of increase of energy into the system such that if a wing does drop then and catch then there is little chance of the pilot preventing what should have been a release +/- groundloop turning into a cartwheel/flick tragedy. 1 g acceleration means that the glider is pulled off the ground so fast that it is unlikely to drop a wing but increases the chance of disaster if it does.
>
>
>
> We lost the pilot of a Nimbus 3 to a cartwheel accident at our club last year. The accident report not yet published so I am not saying this was a factor there but it is self evident that if a glider pilot can release the cable in time before a wingtip hits the ground then there would be zero chance of a cartwheel accident
>
>
>
> Furthermore excessive acceleration can cause some glider types to rotate too fast in that rate of rotation can increse the stall speed at this critical time.
>
>
>
> The BGA advice for powerful winches is 3 seconds to the intended maximum intended (not necessarily full) thottle position for the glider and winch type - with the engine rpm following a bit behind that - and that feels right to me.
>
>
>
> See the BGA winch operations slide show at:
>
>
>
> http://www.gliding.co.uk/bgainfo/safety/documents/winchops.ppsx
>
>
>
> John Galloway

You and the BGA are tragically wrong. You need to take another long look at that analysis. Slow acceleration is the most significant cause of the poor UK accident record. Dragging a glider along with the pilot struggling for aileron control is not conducive to winch safety.

The safest possible acceleration would get the glider away from the ground instantly, but a 1G, 2-second ground roll is safe and practical. 1G acceleration winch launches are well proven in Germany to be safer. (It also happens to be the same as that felt when laying on one's back.)

Bill D

June 28th 13, 08:27 PM

On Friday, June 28, 2013 11:50:30 AM UTC-6, wrote:

> Furthermore excessive acceleration can cause some glider types to rotate too fast in that rate of rotation can increse the stall speed at this critical time.

This is waaay over rated. Pick any glider you think is vulnerable and I'm sure there's a video on the Internet of it being launched with less than a 2-second ground roll. Acceleration alone does not cause uncommanded pitch-up.

Is an inertial-couple induced pitch-up real? Yes. But it can't happen with a tailwheel in contact with the runway and the pilot can oppose it with down elevator above the 50 knots Vw-min. That leaves the 40 to 50 knot window lasting 1/2 second at 1G acceleration where a glider's natural rotational inertia about the pitch axis and it's aerodynamic stability will prevent excessive pitch-up.

What CAN go wrong is if the pilot gets impatient with a slow acceleration and pulls up in the window of vulnerability so the inertial couple combines with up elevator to produce an excessive pitch-up. There are dozens of videos showing UK pilots doing exactly that on YouTube. The cure is simple - teach pilot to hold the nose down and wait for Vw-min before allowing the glider to rotate into a climb.

Bill D

June 28th 13, 09:08 PM

On Friday, June 28, 2013 1:04:12 PM UTC-6, Bill D wrote:
> On Friday, June 28, 2013 11:50:30 AM UTC-6, wrote:
>
> > On Thursday, 27 June 2013 16:28:40 UTC+1, Bill D wrote:
>
> >
>
> > > On Wednesday, June 26, 2013 2:40:30 PM UTC-6, Martin Gregorie wrote:
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > > > the past I've used a stopwatch and timed consistent launches as taking 5 secs from first movement until the glider started to rotate into full climb, which I assumed meant the glider was accelerating through 50 kts.
>
> >
>
> > >
>
> >
>
> > > >
>
> >
>
> > >
>
> >
>
> > > > This corresponds to roughly 0.5G on average.
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > > That's about the same result I got from UK videos. The German "windenstart" videos seem to average 1.0G (19kts/sec)acceleration. I've yet to read of an accident that can be unequivocally attributed to excessive acceleration.
>
> >
>
> >
>
> >
>
> > ================================================== ===========================
>
> >
>
> >
>
> >
>
> > Having been winch launching since 1969 I find myself disagreeing that very rapid accelaration at the beginning of the ground run is necessarily a good thing. Being off the ground in 2-3 seconds means (approximately) going from 0-60mph in that time and which gives a rate of increase of energy into the system such that if a wing does drop then and catch then there is little chance of the pilot preventing what should have been a release +/- groundloop turning into a cartwheel/flick tragedy. 1 g acceleration means that the glider is pulled off the ground so fast that it is unlikely to drop a wing but increases the chance of disaster if it does.
>
> >
>
> >
>
> >
>
> > We lost the pilot of a Nimbus 3 to a cartwheel accident at our club last year. The accident report not yet published so I am not saying this was a factor there but it is self evident that if a glider pilot can release the cable in time before a wingtip hits the ground then there would be zero chance of a cartwheel accident
>
> >
>
> >
>
> >
>
> > Furthermore excessive acceleration can cause some glider types to rotate too fast in that rate of rotation can increse the stall speed at this critical time.
>
> >
>
> >
>
> >
>
> > The BGA advice for powerful winches is 3 seconds to the intended maximum intended (not necessarily full) thottle position for the glider and winch type - with the engine rpm following a bit behind that - and that feels right to me.
>
> >
>
> >
>
> >
>
> > See the BGA winch operations slide show at:
>
> >
>
> >
>
> >
>
> > http://www.gliding.co.uk/bgainfo/safety/documents/winchops.ppsx
>
> >
>
> >
>
> >
>
> > John Galloway
>
>
>
> You and the BGA are tragically wrong. You need to take another long look at that analysis. Slow acceleration is the most significant cause of the poor UK accident record. Dragging a glider along with the pilot struggling for aileron control is not conducive to winch safety.
>
This is what I'm talking about:
http://www.youtube.com/watch?v=Ls_VIfxOV8U

Slow acceleration CAUSES accidents.

Andreas Maurer

June 29th 13, 01:23 PM

On Fri, 28 Jun 2013 09:56:50 +0200, BruceGreeff >
wrote:

>Indeed.
>
>As an example - the BGA statistics include any accident or incident
>reported by a member anywhere in the world. So their numbers include
>locations in Spain and South Africa.
>
>The German numbers do not.
>
>I express no opinion on which is a better approach. Merely that the one
>is organisational statistics and the other is geographic.

HI Bruce,

German accident statistics include any accident/incident that happened
on a German airfield, in Germany, or in which a German registered
aircraft was involved, worldwide.

Cheers
Andreas

Nigel Pocock[_2_]

June 29th 13, 03:22 PM

Excessive initial ecceleration can cause problems with certain types. I
have experienced it with 2 types.
PW5 with stick fully forward at the start of the launch. Hard acceleration
caused the glider to rotate from the nose wheel to the tail wheel and
rocket into the air. I only managed to regain control at about 50ft.
The other one is the K8. Light glider, high wing. Similar problem.

If slow acceleration is a safety problem what about the ground run and take
off with aerotow using belly hooks, and autotows?

Bill D

June 29th 13, 03:42 PM

On Saturday, June 29, 2013 8:22:46 AM UTC-6, Nigel Pocock wrote:
> Excessive initial ecceleration can cause problems with certain types. I
>
> have experienced it with 2 types.
>
> PW5 with stick fully forward at the start of the launch. Hard acceleration
>
> caused the glider to rotate from the nose wheel to the tail wheel and
>
> rocket into the air. I only managed to regain control at about 50ft.
>
> The other one is the K8. Light glider, high wing. Similar problem.
>
>
>
> If slow acceleration is a safety problem what about the ground run and take
>
> off with aerotow using belly hooks, and autotows?

K8's and PW-5's, as with all "nose dragger's, are supposed to rotate back onto their tail wheels. What do you mean exactly by "regained control"? You're still with us so, presumably, it worked. With those gliders you should have started the ground roll with the stick full forward.

Aero tow with a CG hook isn't safe as discussed elsewhere on this forum. However a tug can't generate the forces a winch can so a wing drop induced ground loop likely won't be as severe.

Bill D

June 29th 13, 07:32 PM

On Saturday, June 29, 2013 8:22:46 AM UTC-6, Nigel Pocock wrote:
> Excessive initial ecceleration can cause problems with certain types. I
>
> have experienced it with 2 types.
>
> PW5 with stick fully forward at the start of the launch. Hard acceleration
>
> caused the glider to rotate from the nose wheel to the tail wheel and
>
> rocket into the air. I only managed to regain control at about 50ft.
>
> The other one is the K8. Light glider, high wing. Similar problem.
>
>
>
> If slow acceleration is a safety problem what about the ground run and take
>
> off with aerotow using belly hooks, and autotows?

Here's a PW-5 winch launch done right. Note the 1 second ground roll.
http://www.youtube.com/watch?v=IseFvZXK7Dw

Here's a K8 also with a one second ground roll.
http://www.youtube.com/watch?v=ict8W0Q5ZpA

Both of these launches were at accelerations greater than 1G. Neither showed an "uncommanded" pitch up. So, neither the gliders nor the acceleration are a problem.

Andy[_1_]

June 29th 13, 11:16 PM

"Aero tow with a CG hook isn't safe"

bull****!

BruceGreeff

June 30th 13, 07:46 AM

There is a lot of that around.

GC hook is a little more work on aerotow but not intrinsically unsafe.
Possibility of kiting is greater, and the glider is easier to get out of
position laterally. Conversely, the glider is easier to get where you
want it laterally...

Many aerotows later on a CG hook on a Std Cirrus.

On 2013/06/30 12:16 AM, Andy wrote:
> "Aero tow with a CG hook isn't safe"
>
> bull****!
>

--
Bruce Greeff
T59D #1771

BruceGreeff

June 30th 13, 07:49 AM

Thanks for the info Andreas.

Not that the reporting is that diligent in either case when far from home.
And BGA Numbers include any that occurred to a BGA member, anywhere, in
any registration.

Bruce

On 2013/06/29 2:23 PM, Andreas Maurer wrote:
> On Fri, 28 Jun 2013 09:56:50 +0200, BruceGreeff >
> wrote:
>
>> Indeed.
>>
>> As an example - the BGA statistics include any accident or incident
>> reported by a member anywhere in the world. So their numbers include
>> locations in Spain and South Africa.
>>
>> The German numbers do not.
>>
>> I express no opinion on which is a better approach. Merely that the one
>> is organisational statistics and the other is geographic.
>
> HI Bruce,
>
> German accident statistics include any accident/incident that happened
> on a German airfield, in Germany, or in which a German registered
> aircraft was involved, worldwide.
>
>
> Cheers
> Andreas
>

--
Bruce Greeff
T59D #1771

Nigel Pocock[_2_]

July 1st 13, 03:58 PM

If Bill D could be bothered to read my posting before spouting a reply he
wouls see that I had started the launch with full forward stick in both
cases.
Hard acceration with these gliders can cause the tail to hit the ground
hard - not safe. To avoid this the tail of the K8s are usually held down
for the launch. Too hard acceration can cause the glider to shoot into the
air and immediately into a 45 degree climb despite the stick position. If
the rope breaks at this point you have too little height to recover. Hence
the winch driver will give slower initial acceleration with these types.
By regained control I mean the elevator having any effect. Until then you
are just a passenger.
I was always taught with ground launch to keep it straight and level until
the glider lifts off in a shallow climb. When a safe speed had been reached
to rotate steadily into a full climb. At any point in this process you can
still recover and land safely using the correct procedures - as taught be
both the german and british systems.

At 14:42 29 June 2013, Bill D wrote:
>On Saturday, June 29, 2013 8:22:46 AM UTC-6, Nigel Pocock wrote:
>> Excessive initial ecceleration can cause problems with certain types. I
>>=20
>> have experienced it with 2 types.=20
>>=20
>> PW5 with stick fully forward at the start of the launch. Hard
>acceleratio=
>n
>>=20
>> caused the glider to rotate from the nose wheel to the tail wheel and
>>=20
>> rocket into the air. I only managed to regain control at about 50ft.
>>=20
>> The other one is the K8. Light glider, high wing. Similar problem.
>>=20
>>=20
>>=20
>> If slow acceleration is a safety problem what about the ground run and
>ta=
>ke
>>=20
>> off with aerotow using belly hooks, and autotows?
>
>K8's and PW-5's, as with all "nose dragger's, are supposed to rotate back
>o=
>nto their tail wheels. What do you mean exactly by "regained control"?
>Yo=
>u're still with us so, presumably, it worked. With those gliders you
>shoul=
>d have started the ground roll with the stick full forward.
>
>Aero tow with a CG hook isn't safe as discussed elsewhere on this forum.
>H=
>owever a tug can't generate the forces a winch can so a wing drop induced
>g=
>round loop likely won't be as severe.
>

Bill D

July 1st 13, 04:44 PM

Nigel, I read your post and it's mostly an "old wives tale".

Yes, gliders lower their tails which can be an issue on hard surfaces so someone holds them down as seen in the PW-5 video. On turf, it's a non-issue.. However, it has nothing to do with acceleration causing premature uncommanded rotation. The tailwheel on the ground prevents it. Glider's don't "shoot into the air" or do anything else inappropriate under 1G acceleration. It's been thoroughly flight tested.

On Monday, July 1, 2013 8:58:00 AM UTC-6, Nigel Pocock wrote:
> If Bill D could be bothered to read my posting before spouting a reply he
>
> wouls see that I had started the launch with full forward stick in both
>
> cases.
>
> Hard acceration with these gliders can cause the tail to hit the ground
>
> hard - not safe. To avoid this the tail of the K8s are usually held down
>
> for the launch. Too hard acceration can cause the glider to shoot into the
>
> air and immediately into a 45 degree climb despite the stick position. If
>
> the rope breaks at this point you have too little height to recover. Hence
>
> the winch driver will give slower initial acceleration with these types.
>
> By regained control I mean the elevator having any effect. Until then you
>
> are just a passenger.
>
> I was always taught with ground launch to keep it straight and level until
>
> the glider lifts off in a shallow climb. When a safe speed had been reached
>
> to rotate steadily into a full climb. At any point in this process you can
>
> still recover and land safely using the correct procedures - as taught be
>
> both the german and british systems.
>
>
>
>
>
> At 14:42 29 June 2013, Bill D wrote:
>
> >On Saturday, June 29, 2013 8:22:46 AM UTC-6, Nigel Pocock wrote:
>
> >> Excessive initial ecceleration can cause problems with certain types. I
>
> >>=20
>
> >> have experienced it with 2 types.=20
>
> >>=20
>
> >> PW5 with stick fully forward at the start of the launch. Hard
>
> >acceleratio=
>
> >n
>
> >>=20
>
> >> caused the glider to rotate from the nose wheel to the tail wheel and
>
> >>=20
>
> >> rocket into the air. I only managed to regain control at about 50ft.
>
> >>=20
>
> >> The other one is the K8. Light glider, high wing. Similar problem.
>
> >>=20
>
> >>=20
>
> >>=20
>
> >> If slow acceleration is a safety problem what about the ground run and
>
> >ta=
>
> >ke
>
> >>=20
>
> >> off with aerotow using belly hooks, and autotows?
>
> >
>
> >K8's and PW-5's, as with all "nose dragger's, are supposed to rotate back
>
> >o=
>
> >nto their tail wheels. What do you mean exactly by "regained control"?
>
> >Yo=
>
> >u're still with us so, presumably, it worked. With those gliders you
>
> >shoul=
>
> >d have started the ground roll with the stick full forward.
>
> >
>
> >Aero tow with a CG hook isn't safe as discussed elsewhere on this forum.
>
> >H=
>
> >owever a tug can't generate the forces a winch can so a wing drop induced
>
> >g=
>
> >round loop likely won't be as severe.
>
> >

John Galloway[_1_]

July 1st 13, 05:47 PM

Leaving aside the tail hitting the ground aspect, a glider doesn't
necessarily stop accelarating just because it has left the ground
- in fact it is sometimes quite noticeable to me (in a Discus
2cT) that the accelaration is increasing after lift off - especially
with a powerful winch that is capable of acheiving a safe cable
speed of 60+ knots (depending on the type being launched).

Long ago, even with a low powered old winch and far less than
1g acceleration, I remember routinely having to keep the stick
forward in a K8 to prevent over-rotation.

I put my trust in the BGA advice on winch launching which is
based on many decades of experience by dozens of clubs,
thousands of individual pilots and instructors, and with
numerous winch and glider types.

John Galloway

At 15:44 01 July 2013, Bill D wrote:
>Nigel, I read your post and it's mostly an "old wives tale".
>
>Yes, gliders lower their tails which can be an issue on hard
surfaces so
>so=
>meone holds them down as seen in the PW-5 video. On turf,
it's a
>non-issue=
>.. However, it has nothing to do with acceleration causing
premature
>uncomma=
>nded rotation. The tailwheel on the ground prevents it.
Glider's don't
>"s=
>hoot into the air" or do anything else inappropriate under 1G
>acceleration.=
> It's been thoroughly flight tested.
>
>On Monday, July 1, 2013 8:58:00 AM UTC-6, Nigel Pocock
wrote:
>> If Bill D could be bothered to read my posting before
spouting a reply he
>>=20
>> wouls see that I had started the launch with full forward
stick in both
>>=20
>> cases.
>>=20
>> Hard acceration with these gliders can cause the tail to hit
the ground
>>=20
>> hard - not safe. To avoid this the tail of the K8s are usually
held down
>>=20
>> for the launch. Too hard acceration can cause the glider to
shoot into
>th=
>e
>>=20
>> air and immediately into a 45 degree climb despite the stick
position. If
>>=20
>> the rope breaks at this point you have too little height to
recover.
>Henc=
>e
>>=20
>> the winch driver will give slower initial acceleration with
these types.
>>=20
>> By regained control I mean the elevator having any effect.
Until then you
>>=20
>> are just a passenger.
>>=20
>> I was always taught with ground launch to keep it straight
and level
>unti=
>l
>>=20
>> the glider lifts off in a shallow climb. When a safe speed
had been
>reach=
>ed
>>=20
>> to rotate steadily into a full climb. At any point in this
process you
>ca=
>n
>>=20
>> still recover and land safely using the correct procedures -
as taught be
>>=20
>> both the german and british systems.
>>=20
>>=20
>>=20
>>=20
>>=20
>> At 14:42 29 June 2013, Bill D wrote:
>>=20
>> >On Saturday, June 29, 2013 8:22:46 AM UTC-6, Nigel
Pocock wrote:
>>=20
>> >> Excessive initial ecceleration can cause problems with
certain types.
>=
>I
>>=20
>> >>=3D20
>>=20
>> >> have experienced it with 2 types.=3D20
>>=20
>> >>=3D20
>>=20
>> >> PW5 with stick fully forward at the start of the launch.
Hard
>>=20
>> >acceleratio=3D
>>=20
>> >n
>>=20
>> >>=3D20
>>=20
>> >> caused the glider to rotate from the nose wheel to the
tail wheel and
>>=20
>> >>=3D20
>>=20
>> >> rocket into the air. I only managed to regain control at
about 50ft.
>>=20
>> >>=3D20
>>=20
>> >> The other one is the K8. Light glider, high wing. Similar
problem.
>>=20
>> >>=3D20
>>=20
>> >>=3D20
>>=20
>> >>=3D20
>>=20
>> >> If slow acceleration is a safety problem what about the
ground run and
>>=20
>> >ta=3D
>>=20
>> >ke
>>=20
>> >>=3D20
>>=20
>> >> off with aerotow using belly hooks, and autotows?
>>=20
>> >
>>=20
>> >K8's and PW-5's, as with all "nose dragger's, are
supposed to rotate
>bac=
>k
>>=20
>> >o=3D
>>=20
>> >nto their tail wheels. What do you mean exactly by
"regained control"?=
>=20
>>=20
>> >Yo=3D
>>=20
>> >u're still with us so, presumably, it worked. With those
gliders you
>>=20
>> >shoul=3D
>>=20
>> >d have started the ground roll with the stick full forward.
>>=20
>> >
>>=20
>> >Aero tow with a CG hook isn't safe as discussed elsewhere
on this
>forum.=
>=20
>>=20
>> >H=3D
>>=20
>> >owever a tug can't generate the forces a winch can so a
wing drop
>induce=
>d
>>=20
>> >g=3D
>>=20
>> >round loop likely won't be as severe.
>>=20
>> >
>
>

Bill D

July 1st 13, 07:56 PM

On Monday, July 1, 2013 10:47:30 AM UTC-6, John Galloway wrote:
> Leaving aside the tail hitting the ground aspect, a glider doesn't
>
> necessarily stop accelarating just because it has left the ground
>
> - in fact it is sometimes quite noticeable to me (in a Discus
>
> 2cT) that the accelaration is increasing after lift off - especially
>
> with a powerful winch that is capable of acheiving a safe cable
>
> speed of 60+ knots (depending on the type being launched).
>
>
>
> Long ago, even with a low powered old winch and far less than
>
> 1g acceleration, I remember routinely having to keep the stick
>
> forward in a K8 to prevent over-rotation.
>
>
>
> I put my trust in the BGA advice on winch launching which is
>
> based on many decades of experience by dozens of clubs,
>
> thousands of individual pilots and instructors, and with
>
> numerous winch and glider types.
>
>
>
> John Galloway
>

John, your post is too confused to answer. Keep in mind what is considered "normal" in the UK has not resulted in an enviable safety record. Instead of constantly retelling anecdotal stories to each other, maybe you should study the actual physics and what's done in other countries.

[email protected]

July 1st 13, 08:41 PM

On Monday, July 1, 2013 1:56:30 PM UTC-5, Bill D wrote:
> On Monday, July 1, 2013 10:47:30 AM UTC-6, John Galloway wrote:
>
> > Leaving aside the tail hitting the ground aspect, a glider doesn't
>
> >
>
> > necessarily stop accelarating just because it has left the ground
>
> >
>
> > - in fact it is sometimes quite noticeable to me (in a Discus
>
> >
>
> > 2cT) that the accelaration is increasing after lift off - especially
>
> >
>
> > with a powerful winch that is capable of acheiving a safe cable
>
> >
>
> > speed of 60+ knots (depending on the type being launched).
>
> >
>
> >
>
> >
>
> > Long ago, even with a low powered old winch and far less than
>
> >
>
> > 1g acceleration, I remember routinely having to keep the stick
>
> >
>
> > forward in a K8 to prevent over-rotation.
>
> >
>
> >
>
> >
>
> > I put my trust in the BGA advice on winch launching which is
>
> >
>
> > based on many decades of experience by dozens of clubs,
>
> >
>
> > thousands of individual pilots and instructors, and with
>
> >
>
> > numerous winch and glider types.
>
> >
>
> >
>
> >
>
> > John Galloway
>
> >
>
>
>
> John, your post is too confused to answer. Keep in mind what is considered "normal" in the UK has not resulted in an enviable safety record. Instead of constantly retelling anecdotal stories to each other, maybe you should study the actual physics and what's done in other countries.

__________________________________________________ _________________________

I didn't find Johns post confusing nor do I recall him constantly telling anecdotal stories.

John Galloway[_1_]

July 1st 13, 09:56 PM

At 19:41 01 July 2013, wrote:
>On Monday, July 1, 2013 1:56:30 PM UTC-5, Bill D wrote:
>> On Monday, July 1, 2013 10:47:30 AM UTC-6, John
Galloway wrote:
>>=20
>> > Leaving aside the tail hitting the ground aspect, a
glider doesn't=20
>>=20
>> >=20
>>=20
>> > necessarily stop accelarating just because it has left
the ground=20
>>=20
>> >=20
>>=20
>> > - in fact it is sometimes quite noticeable to me (in a
Discus=20
>>=20
>> >=20
>>=20
>> > 2cT) that the accelaration is increasing after lift off -
especially=20
>>=20
>> >=20
>>=20
>> > with a powerful winch that is capable of acheiving a
safe cable=20
>>=20
>> >=20
>>=20
>> > speed of 60+ knots (depending on the type being
launched).
>>=20
>> >=20
>>=20
>> >=20
>>=20
>> >=20
>>=20
>> > Long ago, even with a low powered old winch and far
less than=20
>>=20
>> >=20
>>=20
>> > 1g acceleration, I remember routinely having to keep
the stick=20
>>=20
>> >=20
>>=20
>> > forward in a K8 to prevent over-rotation.
>>=20
>> >=20
>>=20
>> >=20
>>=20
>> >=20
>>=20
>> > I put my trust in the BGA advice on winch launching
which is=20
>>=20
>> >=20
>>=20
>> > based on many decades of experience by dozens of
clubs,=20
>>=20
>> >=20
>>=20
>> > thousands of individual pilots and instructors, and
with=20
>>=20
>> >=20
>>=20
>> > numerous winch and glider types.
>>=20
>> >=20
>>=20
>> >=20
>>=20
>> >=20
>>=20
>> > John Galloway
>>=20
>> >=20
>>=20
>>=20
>>=20
>> John, your post is too confused to answer. Keep in
mind what is
>consider=
>ed "normal" in the UK has not resulted in an enviable
safety record.
>Inst=
>ead of constantly retelling anecdotal stories to each
other, maybe you
>shou=
>ld study the actual physics and what's done in other
countries.
>
>________________________________________________
___________________________
>
>I didn't find Johns post confusing nor do I recall him
constantly telling
>a=
>necdotal stories.

Thank you Scohpilot.

Bill,

http://www.gliding.co.uk/bgainfo/safety/safewinchlaunching
.htm

The BGA safe winch launching program (led by Hugh
Browning), aspects of which include the need to avoid
excessive acceleration on the one hand but for winches to
have sufficient cable speed on the other, has resulted in a
major reduction in winch launch accidents in the UK in the
last few years such that it was awarded a UK CAA safety
award:

http://www.caa.co.uk/application.aspx?
appid=7&mode=detail&nid=2080

It is the size and timescale of the reduction in accidents
that provides evidence of the value of the advice.

I hope that I have not been confusing this time.

John Galloway

Don Johnstone[_4_]

July 1st 13, 11:52 PM

At 13:21 23 June 2013, Bill D wrote:
>> Sorry Bill but your statistics are seriously flawed, In the UK the Air
>>=20
>> Cadet organisation carry out nearly 50% of the total winch launches in
>th=
>e
>>=20
>> UK in any year. The Air Cadets have not had a fatal or serious injury
>fro=
>m
>>=20
>> a failed winch launch accident since 1963 and probably before that.=20
>>=20
>> The accidents/incidents reported by the BGA far exceed what would
>normall=
>y
>>=20
>> be recorded by a national government source.
>>=20
>> You will see that minor crime has decreased in the UK over the years if
>y=
>ou
>>=20
>> look at statistics. What the statistics do not tell you is that people
>ha=
>ve
>>=20
>> stopped reporting minor crime so of course it has reduced. Same thing
>>=20
>> applies to AAIB statistics, they do not record all the minor stuff that
>t=
>he
>>=20
>> BGA do.
>
>
>Don, I used only the BGA numbers. I did not use any AAIB numbers since
>none=
> are available. I stand by my results until the BGA supplies different
>num=
>bers. Note carefully that I used the most favorable interpretation for
>the=
> UK and digging deeper will most likely make things look worse.
>
>For example, the BGA numbers reported were obviously restricted to fatal
>or=
> serious injury accidents whereas the German BFU and the NTSB reported
all
>=
>of them so the real situation is actually worse for the UK than it
>appears.=
> I have numbers supporting that contention but I chose not to publish
>them=
>..
>
>Even giving the UK the benefit of the doubt, the results say the Germans
>ar=
>e more than 10 times safer than the Brits on winch launch and the Germans
>a=
>re 7 - 8 times safer on winch launch than US is with aero tow. Play with
>t=
>he numbers if you want, but it's very, very doubtful you can overcome or
>ex=
>plain away differences that big.
>
>The solution is fixing the safety problem, not attacking the numbers.
I'd
>=
>start by finding out what the Germans are doing right.

You are right of course, the priority is to fix the safety problem, and the
Air Cadets have done that. During my time as a student and instructor with
them (40 years) I was given on average 6 no notice launch failure
simulations every year. As an instructor I gave others about 200 simulated
launch failures per year. It is this level of training that is required to
almost eliminate accidents. I accept that in the real world, where people
have to pay for a launch, even a simulated failed one, we are never ever
going to achieve the Air Cadet level of practice. The answer really is more
simulated failures, everyone would agree that it is a good idea but in
reality will never happen. Safety is fine except no-one wants to pay for
it.
>

Martin Gregorie[_5_]

July 2nd 13, 12:37 AM

On Mon, 01 Jul 2013 08:44:50 -0700, Bill D wrote:

> Nigel, I read your post and it's mostly an "old wives tale".
>
> Yes, gliders lower their tails which can be an issue on hard surfaces so
> someone holds them down as seen in the PW-5 video. On turf, it's a
> non-issue.
>
Er, no!

Most British clubs also hold the tail down if we're launching a DG-50x
regardless of what the surface is. The tail really crashes down with
them, almost regardless of how strong the initial acceleration is.

I haven't winched a PW-5, not a Ka-8 so have no direct experience there.

However its also worth knowing that some types have a tendency to snap
rotate as they leave the ground on a winch launch unless you start the
run with almost full forward stick. I've seen more Ka-8s start like this
than not.

I also know from direct experience that full forward trim and a little
forward pressure beyond that is needed when winching an H.201 Libelle: do
that and you get a smooth lift-off at the ground attitude.

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

Bill D

July 2nd 13, 12:48 AM

On Monday, July 1, 2013 2:56:17 PM UTC-6, John Galloway wrote:
> At 19:41 01 July 2013, wrote:
>
> >On Monday, July 1, 2013 1:56:30 PM UTC-5, Bill D wrote:
>
> >> On Monday, July 1, 2013 10:47:30 AM UTC-6, John
>
> Galloway wrote:
>
> >>=20
>
> >> > Leaving aside the tail hitting the ground aspect, a
>
> glider doesn't=20
>
> >>=20
>
> >> >=20
>
> >>=20
>
> >> > necessarily stop accelarating just because it has left
>
> the ground=20
>
> >>=20
>
> >> >=20
>
> >>=20
>
> >> > - in fact it is sometimes quite noticeable to me (in a
>
> Discus=20
>
> >>=20
>
> >> >=20
>
> >>=20
>
> >> > 2cT) that the accelaration is increasing after lift off -
>
> especially=20
>
> >>=20
>
> >> >=20
>
> >>=20
>
> >> > with a powerful winch that is capable of acheiving a
>
> safe cable=20
>
> >>=20
>
> >> >=20
>
> >>=20
>
> >> > speed of 60+ knots (depending on the type being
>
> launched).
>
> >>=20
>
> >> >=20
>
> >>=20
>
> >> >=20
>
> >>=20
>
> >> >=20
>
> >>=20
>
> >> > Long ago, even with a low powered old winch and far
>
> less than=20
>
> >>=20
>
> >> >=20
>
> >>=20
>
> >> > 1g acceleration, I remember routinely having to keep
>
> the stick=20
>
> >>=20
>
> >> >=20
>
> >>=20
>
> >> > forward in a K8 to prevent over-rotation.
>
> >>=20
>
> >> >=20
>
> >>=20
>
> >> >=20
>
> >>=20
>
> >> >=20
>
> >>=20
>
> >> > I put my trust in the BGA advice on winch launching
>
> which is=20
>
> >>=20
>
> >> >=20
>
> >>=20
>
> >> > based on many decades of experience by dozens of
>
> clubs,=20
>
> >>=20
>
> >> >=20
>
> >>=20
>
> >> > thousands of individual pilots and instructors, and
>
> with=20
>
> >>=20
>
> >> >=20
>
> >>=20
>
> >> > numerous winch and glider types.
>
> >>=20
>
> >> >=20
>
> >>=20
>
> >> >=20
>
> >>=20
>
> >> >=20
>
> >>=20
>
> >> > John Galloway
>
> >>=20
>
> >> >=20
>
> >>=20
>
> >>=20
>
> >>=20
>
> >> John, your post is too confused to answer. Keep in
>
> mind what is
>
> >consider=
>
> >ed "normal" in the UK has not resulted in an enviable
>
> safety record.
>
> >Inst=
>
> >ead of constantly retelling anecdotal stories to each
>
> other, maybe you
>
> >shou=
>
> >ld study the actual physics and what's done in other
>
> countries.
>
> >
>
> >________________________________________________
>
> ___________________________
>
> >
>
> >I didn't find Johns post confusing nor do I recall him
>
> constantly telling
>
> >a=
>
> >necdotal stories.
>
>
>
>
>
>
>
> Thank you Scohpilot.
>
>
>
> Bill,
>
>
>
> http://www.gliding.co.uk/bgainfo/safety/safewinchlaunching
>
> htm
>
>
>
> The BGA safe winch launching program (led by Hugh
>
> Browning), aspects of which include the need to avoid
>
> excessive acceleration on the one hand but for winches to
>
> have sufficient cable speed on the other, has resulted in a
>
> major reduction in winch launch accidents in the UK in the
>
> last few years such that it was awarded a UK CAA safety
>
> award:
>
>
>
> http://www.caa.co.uk/application.aspx?
>
> appid=7&mode=detail&nid=2080
>
>
>
> It is the size and timescale of the reduction in accidents
>
> that provides evidence of the value of the advice.
>
>
>
> I hope that I have not been confusing this time.
>
>
>
> John Galloway

John, I constantly read all the BGA safety material. I'm very aware of the "Safe Winching" program and it's results. I'm also very aware of your actual accident rate. Almost any safety program would have made big improvements from where you were in the '90's.

As I've repeated often, you have to look beyond your island and the BGA to move to the next higher plane. My choice is the German practice given their sterling accident rate.

Andreas Maurer

July 2nd 13, 01:33 AM

Hi Nigel,

On Mon, 01 Jul 2013 14:58:00 +0000, Nigel Pocock >
wrote:

>If Bill D could be bothered to read my posting before spouting a reply he
>wouls see that I had started the launch with full forward stick in both
>cases.

Really bad mistake. Will make you want to change your pants after you
trtied this in a glider with full-flying elevator. NO glider will take
off with the stick full nose-down if the CG is halfways right.

>Hard acceration with these gliders can cause the tail to hit the ground
>hard - not safe.

Safe. Happens all the time, this is what the glider is designed for.

>To avoid this the tail of the K8s are usually held down
>for the launch. Too hard acceration can cause the glider to shoot into the
>air and immediately into a 45 degree climb despite the stick position.

Absolutely not.

> If
>the rope breaks at this point you have too little height to recover. Hence
>the winch driver will give slower initial acceleration with these types.
>By regained control I mean the elevator having any effect. Until then you
>are just a passenger.

Absolutely not.

Really sorry to contradict, but the dangers you are describing are
simply not true (or, rather, caused by bad training).

Even if the tail hits the ground more or less hard (which is easy to
avoid by applying power smoothly), the glider takes off at a speed
where elevator control is always perfectly sufficient to control the
pitch up momentum. If the wing flies fast enough to lift the glider,
the elevator flies fast enough to prevent pitch up - if the elevator
is kept in the correct position.

In case you did not know this: Elevator size of at least any German
designed glider is certified (and verified) that there is always 100%
elevator authority to prevent pitch up.

If the acceleration pushes back the hand that is holding the stick
(or, by using a soft cushion, the whole pilot moves backwards), things
look differerent...

In my club we've been doing winch launches for the last 60 years now,
with about 200.000 winch launches. ***Not one single accident*** due
to the causes you describe. Hundreds of pilots,hundreds of student
pilots, hundreds of winch drivers, dozens of instructors, half a dozen
of different winches from an 120 hp V8 engines to 280 hp turbo
Diesel. Gliders range from Spatz, Ka-6, Ka-8, to ASH-25.

Not one single accident.

And no, we do not push the tails of our Ka-8s down.
I've seen morre winch launches that I care to count where the gound
run was less than 6 ft. (ft - not yards!). Naught to 40 mph in less
than a second.

*Any* too-steep winch launch that I ever saw during the last 30 years
was caused by nose-up elevator at the moment of lift off. Any.

>I was always taught with ground launch to keep it straight and level until
>the glider lifts off in a shallow climb. When a safe speed had been reached
>to rotate steadily into a full climb. At any point in this process you can
>still recover and land safely using the correct procedures - as taught be
>both the german and british systems.

The German system teaches to keep the stick in the recommended
(trimmed) position. If done halfways properly, any glider will launch
itself and rotate into the climb smoothly ***without any elevator
input***.
Works like a charm for absolutely any glider, be it an L--Spatz, a
Ka-8 or a heavy ASH-25.

An absolute no-no is launching with full nose-down elevator as you are
doing it. Makes a smooth transition into the climb really hard and
often leads to over-controlling.

Cheers from Germany
Andreas

p.s.
The only case where the elevator is not able to control a nose-up
rotation of the glider is, if a full-flying elevator is pushed fully
forward, therefore stalling the complete horizontal tail.

B4soaring

July 2nd 13, 12:52 PM

On 02/07/2
>
> John, I constantly read all the BGA safety material. I'm very aware
of the
>"Safe Winching" program and it's results. I'm also very aware of your
actual
>accident rate. Almost any safety program would have made big
improvements from
>where you were in the '90's.
>
> As I've repeated often, you have to look beyond your island and the
BGA to
>move to the next higher plane. My choice is the German practice given
their sterling
>accident rate.
>

The BGA accident rate is rather good, and getting better. Your
assumptions are based on inadequate research.

Edward

Bill D

July 2nd 13, 03:53 PM

Thanks, Andreas. I hope the Brits are reading it.

On Monday, July 1, 2013 6:33:02 PM UTC-6, Andreas Maurer wrote:
> Hi Nigel,
>
>
>
> On Mon, 01 Jul 2013 14:58:00 +0000, Nigel Pocock >
>
> wrote:
>
>
>
> >If Bill D could be bothered to read my posting before spouting a reply he
>
> >wouls see that I had started the launch with full forward stick in both
>
> >cases.
>
>
>
> Really bad mistake. Will make you want to change your pants after you
>
> trtied this in a glider with full-flying elevator. NO glider will take
>
> off with the stick full nose-down if the CG is halfways right.
>
>
>
> >Hard acceration with these gliders can cause the tail to hit the ground
>
> >hard - not safe.
>
>
>
> Safe. Happens all the time, this is what the glider is designed for.
>
>
>
>
>
> >To avoid this the tail of the K8s are usually held down
>
> >for the launch. Too hard acceration can cause the glider to shoot into the
>
> >air and immediately into a 45 degree climb despite the stick position.
>
>
>
> Absolutely not.
>
>
>
> > If
>
> >the rope breaks at this point you have too little height to recover. Hence
>
> >the winch driver will give slower initial acceleration with these types.
>
> >By regained control I mean the elevator having any effect. Until then you
>
> >are just a passenger.
>
>
>
> Absolutely not.
>
>
>
>
>
>
>
> Really sorry to contradict, but the dangers you are describing are
>
> simply not true (or, rather, caused by bad training).
>
>
>
>
>
> Even if the tail hits the ground more or less hard (which is easy to
>
> avoid by applying power smoothly), the glider takes off at a speed
>
> where elevator control is always perfectly sufficient to control the
>
> pitch up momentum. If the wing flies fast enough to lift the glider,
>
> the elevator flies fast enough to prevent pitch up - if the elevator
>
> is kept in the correct position.
>
>
>
> In case you did not know this: Elevator size of at least any German
>
> designed glider is certified (and verified) that there is always 100%
>
> elevator authority to prevent pitch up.
>
>
>
> If the acceleration pushes back the hand that is holding the stick
>
> (or, by using a soft cushion, the whole pilot moves backwards), things
>
> look differerent...
>
>
>
>
>
> In my club we've been doing winch launches for the last 60 years now,
>
> with about 200.000 winch launches. ***Not one single accident*** due
>
> to the causes you describe. Hundreds of pilots,hundreds of student
>
> pilots, hundreds of winch drivers, dozens of instructors, half a dozen
>
> of different winches from an 120 hp V8 engines to 280 hp turbo
>
> Diesel. Gliders range from Spatz, Ka-6, Ka-8, to ASH-25.
>
>
>
> Not one single accident.
>
>
>
> And no, we do not push the tails of our Ka-8s down.
>
> I've seen morre winch launches that I care to count where the gound
>
> run was less than 6 ft. (ft - not yards!). Naught to 40 mph in less
>
> than a second.
>
>
>
>
>
> *Any* too-steep winch launch that I ever saw during the last 30 years
>
> was caused by nose-up elevator at the moment of lift off. Any.
>
>
>
>
>
>
>
>
>
> >I was always taught with ground launch to keep it straight and level until
>
> >the glider lifts off in a shallow climb. When a safe speed had been reached
>
> >to rotate steadily into a full climb. At any point in this process you can
>
> >still recover and land safely using the correct procedures - as taught be
>
> >both the german and british systems.
>
>
>
> The German system teaches to keep the stick in the recommended
>
> (trimmed) position. If done halfways properly, any glider will launch
>
> itself and rotate into the climb smoothly ***without any elevator
>
> input***.
>
> Works like a charm for absolutely any glider, be it an L--Spatz, a
>
> Ka-8 or a heavy ASH-25.
>
>
>
> An absolute no-no is launching with full nose-down elevator as you are
>
> doing it. Makes a smooth transition into the climb really hard and
>
> often leads to over-controlling.
>
>
>
>
>
>
>
> Cheers from Germany
>
> Andreas
>
>
>
>
>
> p.s.
>
> The only case where the elevator is not able to control a nose-up
>
> rotation of the glider is, if a full-flying elevator is pushed fully
>
> forward, therefore stalling the complete horizontal tail.

BruceGreeff

July 2nd 13, 05:55 PM

Bill

With all due respect - how many winch launches do you have in a Ka8?
(Substitute all sorts of very light, early high wing wood and fabric.)

At .5g, and at 1g?

Personally, I would prefer to watch than do, and I would prefer to not
have to watch either.
Have watched the over rotation with full down elevator from over
enthusiastic winch...

Been there - assume I must be an old wife.

Bruce

On 2013/07/01 5:44 PM, Bill D wrote:
> Nigel, I read your post and it's mostly an "old wives tale".
>
> Yes, gliders lower their tails which can be an issue on hard surfaces so someone holds them down as seen in the PW-5 video. On turf, it's a non-issue. However, it has nothing to do with acceleration causing premature uncommanded rotation. The tailwheel on the ground prevents it. Glider's don't "shoot into the air" or do anything else inappropriate under 1G acceleration. It's been thoroughly flight tested.
>
> On Monday, July 1, 2013 8:58:00 AM UTC-6, Nigel Pocock wrote:
>> If Bill D could be bothered to read my posting before spouting a reply he
>>
>> wouls see that I had started the launch with full forward stick in both
>>
>> cases.
>>
>> Hard acceration with these gliders can cause the tail to hit the ground
>>
>> hard - not safe. To avoid this the tail of the K8s are usually held down
>>
>> for the launch. Too hard acceration can cause the glider to shoot into the
>>
>> air and immediately into a 45 degree climb despite the stick position. If
>>
>> the rope breaks at this point you have too little height to recover. Hence
>>
>> the winch driver will give slower initial acceleration with these types.
>>
>> By regained control I mean the elevator having any effect. Until then you
>>
>> are just a passenger.
>>
>> I was always taught with ground launch to keep it straight and level until
>>
>> the glider lifts off in a shallow climb. When a safe speed had been reached
>>
>> to rotate steadily into a full climb. At any point in this process you can
>>
>> still recover and land safely using the correct procedures - as taught be
>>
>> both the german and british systems.
>>
>>
>>
>>
>>
>> At 14:42 29 June 2013, Bill D wrote:
>>
>>> On Saturday, June 29, 2013 8:22:46 AM UTC-6, Nigel Pocock wrote:
>>
>>>> Excessive initial ecceleration can cause problems with certain types. I
>>
>>>> =20
>>
>>>> have experienced it with 2 types.=20
>>
>>>> =20
>>
>>>> PW5 with stick fully forward at the start of the launch. Hard
>>
>>> acceleratio=
>>
>>> n
>>
>>>> =20
>>
>>>> caused the glider to rotate from the nose wheel to the tail wheel and
>>
>>>> =20
>>
>>>> rocket into the air. I only managed to regain control at about 50ft.
>>
>>>> =20
>>
>>>> The other one is the K8. Light glider, high wing. Similar problem.
>>
>>>> =20
>>
>>>> =20
>>
>>>> =20
>>
>>>> If slow acceleration is a safety problem what about the ground run and
>>
>>> ta=
>>
>>> ke
>>
>>>> =20
>>
>>>> off with aerotow using belly hooks, and autotows?
>>
>>>
>>
>>> K8's and PW-5's, as with all "nose dragger's, are supposed to rotate back
>>
>>> o=
>>
>>> nto their tail wheels. What do you mean exactly by "regained control"?
>>
>>> Yo=
>>
>>> u're still with us so, presumably, it worked. With those gliders you
>>
>>> shoul=
>>
>>> d have started the ground roll with the stick full forward.
>>
>>>
>>
>>> Aero tow with a CG hook isn't safe as discussed elsewhere on this forum.
>>
>>> H=
>>
>>> owever a tug can't generate the forces a winch can so a wing drop induced
>>
>>> g=
>>
>>> round loop likely won't be as severe.
>>
>>>
>

--
Bruce Greeff
T59D #1771

BruceGreeff

July 2nd 13, 06:17 PM

Hi Don

Solved that at my club.
Simulated or real launch failures are free.

We make sure everyone gets to practice.

Cheers
Bruce

--
Bruce Greeff
T59D #1771

BruceGreeff

July 2nd 13, 07:25 PM

Hi Andreas

200,000 winch launches without a single incident? Not one cable break,
dropped wing, weak link overload? I would be amazed if this were so.

If you have managed that many launches, with the wide variety of
equipment, and never damaged a glider, that is impressive and laudable.

I have to take issue with you - though it is only a personal opinion.

Glider hitting the tail on the ground on launch - you say no problem
ever. Well anecdotal evidence does not prove a theory. So let me
introduce a "Black Swan" for you. I have repaired a Zugfogel 3 that
returned from a nice cross country, with the rudder base split from end
to end. Pilot was warned that his tail had hit the runway on a snatched
launch, he was confident that it was no problem as it had never caused
damage before, and the strike was "not that hard". He got lucky, there
was still a couple of centimetres of fabric holding it together by the
time he landed.

From an engineering point of view I doubt you would find any designer
who would agree that his glider's tail was designed to strike the runway
firmly hundreds of times. Maybe all German runways are soft deep grass,
but I doubt it.

I am not sure on your assertion that all German designed gliders are
designed to have full elevator authority at all design airspeeds. There
is a fair body of research on kiting on aerotow (at much greater speeds
than initial launch) and I recall it included a wide range of various
manufacturers aircraft. The same happens on winch.

So - if the acceleration is such that the couple caused by the vertical
distance between the hook and the CG exceeds the available controlling
couple that the elevator can generate, the aircraft will rotate
uncontrollably. That is why many gliders drop their tail on the take off
run. If you say you have gliders banging the tail down on launch then
you are saying that you are exceeding the controllable range of the
aircraft.

From a weight and balance point of view - light pilots tend to have
more problem that heavy - if the CG is aft the tendency to over rotate
is greater. From a physics point of view high wing + upright pilot tends
to have a higher rotational couple for any given longitudinal
acceleration.

If the acceleration through this uncontrollable part of the regime
happens entirely on the ground, then the glider reaches sufficient speed
for elevator authority with the ground contact preventing undesirable
rotation. If the launch is (a little slower) close to the limit as the
glider leaves the ground, the reduction in drag as the wheel and cable
lift, can give the little extra acceleration. Then the glider is
climbing strongly, and the tail is rotating downward as the pilot moves
the stick forward. If the tail hits the runway you have stressed the
airframe, and possibly damaged the rudder. If the rate of climb is high
enough that the tail misses the runway, you are at a very high angle of
climb, at relatively low speed at very low height. If your equipment is
less than perfect and something goes wrong the consequences get a lot
more serious if you have too low energy.

Do agree on two points:

You should not have the stick in an extreme position during the launch.

All flying tails will easily stall - when elevators are at big
deflections and low airspeed (as will some other pre JAR22 gliders).
Then some time later when the AoA changes and the control un-stalls you
will get a big unexpected force.
Recipe for trouble. Again, anecdotes do not prove the physics, but I
have watched a light pilot in a Std Cirrus do this and overfly the cable
chute in the ensuing back release. Interestingly he was adamant that
this was the right way to do things despite evidence that it was not the
safest approach.

Perhaps we have to agree to disagree. One thing I am certain of though,
the process and experience has to be predictable and consistent. There
are enough other variables involved.
We prefer a controlled three second acceleration to maximum launch
speed. That gives a reasonably controlled 2s ground run and much lower
initial acceleration - and the correctly trimmed glider does as it is
designed to do, and flies off without pilot input.

--
Bruce Greeff
T59D #1771

Terry Walsh[_2_]

July 2nd 13, 07:42 PM

I have in excess of 4000 winch launches in many types of Glider includung
K8's. I am also current on our clubs K18 which is very much a tail dragger.
I am also not partuculary light. I have ot lost control but on every K18
launch I need to use nearly full forward stick to prevent over rotation
AFTER lift off at uk rates of acceleration.

Terry Walsh

At 14:53 02 July 2013, Bill D wrote:
>Thanks, Andreas. I hope the Brits are reading it.
>
>
>On Monday, July 1, 2013 6:33:02 PM UTC-6, Andreas Maurer wrote:
>> Hi Nigel,
>>
>>
>>
>> On Mon, 01 Jul 2013 14:58:00 +0000, Nigel Pocock
>>
>> wrote:
>>
>>
>>
>> >If Bill D could be bothered to read my posting before spouting a reply
>he
>>
>> >wouls see that I had started the launch with full forward stick in
both
>>
>> >cases.
>>
>>
>>
>> Really bad mistake. Will make you want to change your pants after you
>>
>> trtied this in a glider with full-flying elevator. NO glider will take
>>
>> off with the stick full nose-down if the CG is halfways right.
>>
>>
>>
>> >Hard acceration with these gliders can cause the tail to hit the
ground
>>
>> >hard - not safe.
>>
>>
>>
>> Safe. Happens all the time, this is what the glider is designed for.
>>
>>
>>
>>
>>
>> >To avoid this the tail of the K8s are usually held down
>>
>> >for the launch. Too hard acceration can cause the glider to shoot into
>the
>>
>> >air and immediately into a 45 degree climb despite the stick position.
>>
>>
>>
>> Absolutely not.
>>
>>
>>
>> > If
>>
>> >the rope breaks at this point you have too little height to recover.
>Hence
>>
>> >the winch driver will give slower initial acceleration with these
types.
>>
>> >By regained control I mean the elevator having any effect. Until then
>you
>>
>> >are just a passenger.
>>
>>
>>
>> Absolutely not.
>>
>>
>>
>>
>>
>>
>>
>> Really sorry to contradict, but the dangers you are describing are
>>
>> simply not true (or, rather, caused by bad training).
>>
>>
>>
>>
>>
>> Even if the tail hits the ground more or less hard (which is easy to
>>
>> avoid by applying power smoothly), the glider takes off at a speed
>>
>> where elevator control is always perfectly sufficient to control the
>>
>> pitch up momentum. If the wing flies fast enough to lift the glider,
>>
>> the elevator flies fast enough to prevent pitch up - if the elevator
>>
>> is kept in the correct position.
>>
>>
>>
>> In case you did not know this: Elevator size of at least any German
>>
>> designed glider is certified (and verified) that there is always 100%
>>
>> elevator authority to prevent pitch up.
>>
>>
>>
>> If the acceleration pushes back the hand that is holding the stick
>>
>> (or, by using a soft cushion, the whole pilot moves backwards), things
>>
>> look differerent...
>>
>>
>>
>>
>>
>> In my club we've been doing winch launches for the last 60 years now,
>>
>> with about 200.000 winch launches. ***Not one single accident*** due
>>
>> to the causes you describe. Hundreds of pilots,hundreds of student
>>
>> pilots, hundreds of winch drivers, dozens of instructors, half a dozen
>>
>> of different winches from an 120 hp V8 engines to 280 hp turbo
>>
>> Diesel. Gliders range from Spatz, Ka-6, Ka-8, to ASH-25.
>>
>>
>>
>> Not one single accident.
>>
>>
>>
>> And no, we do not push the tails of our Ka-8s down.
>>
>> I've seen morre winch launches that I care to count where the gound
>>
>> run was less than 6 ft. (ft - not yards!). Naught to 40 mph in less
>>
>> than a second.
>>
>>
>>
>>
>>
>> *Any* too-steep winch launch that I ever saw during the last 30 years
>>
>> was caused by nose-up elevator at the moment of lift off. Any.
>>
>>
>>
>>
>>
>>
>>
>>
>>
>> >I was always taught with ground launch to keep it straight and level
>until
>>
>> >the glider lifts off in a shallow climb. When a safe speed had been
>reached
>>
>> >to rotate steadily into a full climb. At any point in this process you
>can
>>
>> >still recover and land safely using the correct procedures - as taught
>be
>>
>> >both the german and british systems.
>>
>>
>>
>> The German system teaches to keep the stick in the recommended
>>
>> (trimmed) position. If done halfways properly, any glider will launch
>>
>> itself and rotate into the climb smoothly ***without any elevator
>>
>> input***.
>>
>> Works like a charm for absolutely any glider, be it an L--Spatz, a
>>
>> Ka-8 or a heavy ASH-25.
>>
>>
>>
>> An absolute no-no is launching with full nose-down elevator as you are
>>
>> doing it. Makes a smooth transition into the climb really hard and
>>
>> often leads to over-controlling.
>>
>>
>>
>>
>>
>>
>>
>> Cheers from Germany
>>
>> Andreas
>>
>>
>>
>>
>>
>> p.s.
>>
>> The only case where the elevator is not able to control a nose-up
>>
>> rotation of the glider is, if a full-flying elevator is pushed fully
>>
>> forward, therefore stalling the complete horizontal tail.
>
>

Bill D

July 2nd 13, 08:11 PM

On Tuesday, July 2, 2013 10:55:40 AM UTC-6, BruceGreeff wrote:
> Bill

> With all due respect - how many winch launches do you have in a Ka8?
>
> (Substitute all sorts of very light, early high wing wood and fabric.)
> At .5g, and at 1g?

100's maybe 1000's At .5G I'll complain to the winch operator asking for more acceleration since it's unsafe. 1G is much safer.

> Have watched the over rotation with full down elevator from over enthusiastic winch...

I haven't and I don't believe you have either because it doesn't happen. In fact CS-22 (JAR-22) Paragraph CS 22.152(4) expressly forbids forward pressure during winch launch for gliders.

However, people THINK it happens. Google the term "head-up illusion". It says in part, quote:

"Somatogravic illusions are caused by linear accelerations effecting the utricle and the saccule of the vestibular system. The head-up illusion involves a sudden forward linear acceleration during level flight where the pilot perceives the illusion that the nose of the aircraft is pitching up."

This explains 100% of the "uncommanded pitch-up under acceleration" stories..

You guys need to stop telling each other stories and do some basic reading on the subject.

Bill D

July 2nd 13, 08:25 PM

On Tuesday, July 2, 2013 12:42:58 PM UTC-6, Terry Walsh wrote:
> I have in excess of 4000 winch launches in many types of Glider includung
>
> K8's. I am also current on our clubs K18 which is very much a tail dragger.
>
> I am also not partuculary light. I have ot lost control but on every K18
>
> launch I need to use nearly full forward stick to prevent over rotation
>
> AFTER lift off at uk rates of acceleration.
>
>
>
> Terry Walsh
>
>
>
>
>
> At 14:53 02 July 2013, Bill D wrote:
>
> >Thanks, Andreas. I hope the Brits are reading it.
>
> >
>
> >
>
> >On Monday, July 1, 2013 6:33:02 PM UTC-6, Andreas Maurer wrote:
>
> >> Hi Nigel,
>
> >>
>
> >>
>
> >>
>
> >> On Mon, 01 Jul 2013 14:58:00 +0000, Nigel Pocock
>
> >>
>
> >> wrote:
>
> >>
>
> >>
>
> >>
>
> >> >If Bill D could be bothered to read my posting before spouting a reply
>
> >he
>
> >>
>
> >> >wouls see that I had started the launch with full forward stick in
>
> both
>
> >>
>
> >> >cases.
>
> >>
>
> >>
>
> >>
>
> >> Really bad mistake. Will make you want to change your pants after you
>
> >>
>
> >> trtied this in a glider with full-flying elevator. NO glider will take
>
> >>
>
> >> off with the stick full nose-down if the CG is halfways right.
>
> >>
>
> >>
>
> >>
>
> >> >Hard acceration with these gliders can cause the tail to hit the
>
> ground
>
> >>
>
> >> >hard - not safe.
>
> >>
>
> >>
>
> >>
>
> >> Safe. Happens all the time, this is what the glider is designed for.
>
> >>
>
> >>
>
> >>
>
> >>
>
> >>
>
> >> >To avoid this the tail of the K8s are usually held down
>
> >>
>
> >> >for the launch. Too hard acceration can cause the glider to shoot into
>
> >the
>
> >>
>
> >> >air and immediately into a 45 degree climb despite the stick position.
>
> >>
>
> >>
>
> >>
>
> >> Absolutely not.
>
> >>
>
> >>
>
> >>
>
> >> > If
>
> >>
>
> >> >the rope breaks at this point you have too little height to recover.
>
> >Hence
>
> >>
>
> >> >the winch driver will give slower initial acceleration with these
>
> types.
>
> >>
>
> >> >By regained control I mean the elevator having any effect. Until then
>
> >you
>
> >>
>
> >> >are just a passenger.
>
> >>
>
> >>
>
> >>
>
> >> Absolutely not.
>
> >>
>
> >>
>
> >>
>
> >>
>
> >>
>
> >>
>
> >>
>
> >> Really sorry to contradict, but the dangers you are describing are
>
> >>
>
> >> simply not true (or, rather, caused by bad training).
>
> >>
>
> >>
>
> >>
>
> >>
>
> >>
>
> >> Even if the tail hits the ground more or less hard (which is easy to
>
> >>
>
> >> avoid by applying power smoothly), the glider takes off at a speed
>
> >>
>
> >> where elevator control is always perfectly sufficient to control the
>
> >>
>
> >> pitch up momentum. If the wing flies fast enough to lift the glider,
>
> >>
>
> >> the elevator flies fast enough to prevent pitch up - if the elevator
>
> >>
>
> >> is kept in the correct position.
>
> >>
>
> >>
>
> >>
>
> >> In case you did not know this: Elevator size of at least any German
>
> >>
>
> >> designed glider is certified (and verified) that there is always 100%
>
> >>
>
> >> elevator authority to prevent pitch up.
>
> >>
>
> >>
>
> >>
>
> >> If the acceleration pushes back the hand that is holding the stick
>
> >>
>
> >> (or, by using a soft cushion, the whole pilot moves backwards), things
>
> >>
>
> >> look differerent...
>
> >>
>
> >>
>
> >>
>
> >>
>
> >>
>
> >> In my club we've been doing winch launches for the last 60 years now,
>
> >>
>
> >> with about 200.000 winch launches. ***Not one single accident*** due
>
> >>
>
> >> to the causes you describe. Hundreds of pilots,hundreds of student
>
> >>
>
> >> pilots, hundreds of winch drivers, dozens of instructors, half a dozen
>
> >>
>
> >> of different winches from an 120 hp V8 engines to 280 hp turbo
>
> >>
>
> >> Diesel. Gliders range from Spatz, Ka-6, Ka-8, to ASH-25.
>
> >>
>
> >>
>
> >>
>
> >> Not one single accident.
>
> >>
>
> >>
>
> >>
>
> >> And no, we do not push the tails of our Ka-8s down.
>
> >>
>
> >> I've seen morre winch launches that I care to count where the gound
>
> >>
>
> >> run was less than 6 ft. (ft - not yards!). Naught to 40 mph in less
>
> >>
>
> >> than a second.
>
> >>
>
> >>
>
> >>
>
> >>
>
> >>
>
> >> *Any* too-steep winch launch that I ever saw during the last 30 years
>
> >>
>
> >> was caused by nose-up elevator at the moment of lift off. Any.
>
> >>
>
> >>
>
> >>
>
> >>
>
> >>
>
> >>
>
> >>
>
> >>
>
> >>
>
> >> >I was always taught with ground launch to keep it straight and level
>
> >until
>
> >>
>
> >> >the glider lifts off in a shallow climb. When a safe speed had been
>
> >reached
>
> >>
>
> >> >to rotate steadily into a full climb. At any point in this process you
>
> >can
>
> >>
>
> >> >still recover and land safely using the correct procedures - as taught
>
> >be
>
> >>
>
> >> >both the german and british systems.
>
> >>
>
> >>
>
> >>
>
> >> The German system teaches to keep the stick in the recommended
>
> >>
>
> >> (trimmed) position. If done halfways properly, any glider will launch
>
> >>
>
> >> itself and rotate into the climb smoothly ***without any elevator
>
> >>
>
> >> input***.
>
> >>
>
> >> Works like a charm for absolutely any glider, be it an L--Spatz, a
>
> >>
>
> >> Ka-8 or a heavy ASH-25.
>
> >>
>
> >>
>
> >>
>
> >> An absolute no-no is launching with full nose-down elevator as you are
>
> >>
>
> >> doing it. Makes a smooth transition into the climb really hard and
>
> >>
>
> >> often leads to over-controlling.
>
> >>
>
> >>
>
> >>
>
> >>
>
> >>
>
> >>
>
> >>
>
> >> Cheers from Germany
>
> >>
>
> >> Andreas
>
> >>
>
> >>
>
> >>
>
> >>
>
> >>
>
> >> p.s.
>
> >>
>
> >> The only case where the elevator is not able to control a nose-up
>
> >>
>
> >> rotation of the glider is, if a full-flying elevator is pushed fully
>
> >>
>
> >> forward, therefore stalling the complete horizontal tail.
>
> >
>
> >

Why do these stories come exclusively from the UK? No one else seems to have the problem. Maybe the laws of aerodynamics and physics work differently there.

Andreas Maurer

July 2nd 13, 11:00 PM

Hi Bruce,

I think we agree nearly 100%. :)
You describe the physics just as I would do, however, I'd like to add
a couple of comments.

On Tue, 02 Jul 2013 20:25:03 +0200, BruceGreeff >
wrote:

>Hi Andreas
>
>200,000 winch launches without a single incident? Not one cable break,
>dropped wing, weak link overload? I would be amazed if this were so.

200.000 launches without any uncontrolled pitch up caused by
insufficient elevator authority.

Of course plenty of the typical winch-launch incidents, fortunately no
bad crashes so far.

>Glider hitting the tail on the ground on launch - you say no problem
>ever. Well anecdotal evidence does not prove a theory. So let me
>introduce a "Black Swan" for you.

Well... oldtimers are a different case, aren't they?

> From an engineering point of view I doubt you would find any designer
>who would agree that his glider's tail was designed to strike the runway
>firmly hundreds of times. Maybe all German runways are soft deep grass,
>but I doubt it.

I think that grass runways are an important factor here - I'd estimate
that 99.999 of the winch launches in Germany take place on grass
runways. I doubt that anyone who ever heard a Ka-8 tail crash onto a
concrete runway would not try to find a way to prevent that.

Anyway, winch drivers try to provide soft acceleration (we are using
the same standard 3 second 0.5g acceleration as you do), but from time
to time a catapult launch simply happens.

The tail always drops to the ground during initial acceleration, but
in nearly all cases this is relatively soft - definiteloy softer than
any landing.

>I am not sure on your assertion that all German designed gliders are
>designed to have full elevator authority at all design airspeeds. There
>is a fair body of research on kiting on aerotow (at much greater speeds
>than initial launch) and I recall it included a wide range of various
>manufacturers aircraft. The same happens on winch.

They really are. :) Do the maths - even the extremely small tails of
an ASW-27 have plenty of lift to control any pitch-up momentum caused
by the tow rope. At least if the correct weak-link is used.
If the latter is (as it seems to become en vogue these days) much
stronger than certified, the bets are off.

Kiting on aerotow is an entirely different matter.
The problem there was not the inability to get the nose of the glider
down, the problem was the very quick climb that followed a nose-up
input on the stick.
If the pilot reacts halfways quickly, he is always able to arrest the
kiting (as proven by thousands of successful aerotows in belly-hook
only Ka-6s each year).

>So - if the acceleration is such that the couple caused by the vertical
>distance between the hook and the CG exceeds the available controlling
>couple that the elevator can generate, the aircraft will rotate
>uncontrollably. That is why many gliders drop their tail on the take off
>run.

I disagree.
They all drop the tail, don't they?

As long as the glider is slower than liftoff speed, there is of course
insufficient aorodynamic force on the elevator, and of course the
glider drops its tail if there's a halfways decent acceleration. At
liftoff speed it would easily be possible to push the tail up with
forward stick.

I don't think I have ever seen a winch launch in person where the tail
was not on the ground.

>If the acceleration through this uncontrollable part of the regime
>happens entirely on the ground, then the glider reaches sufficient speed
>for elevator authority with the ground contact preventing undesirable
>rotation.

Indeed. This is what ahppens 100% of the time in my opinion.
And once airborne, it is the elevator authority that prevents pitch
up.

> If the launch is (a little slower) close to the limit as the
>glider leaves the ground, the reduction in drag as the wheel and cable
>lift, can give the little extra acceleration. Then the glider is
>climbing strongly, and the tail is rotating downward as the pilot moves
>the stick forward.

Sorry, I cannot imagine the situation you are describing.

What I have seen is this:
- Airspeed too slow
- Winch driver gets notified and immediately increases power
- Increasing winch power causes nose-up rotation
- Pilot's reaction is too slow and too late
- So when he finally reacts, he has to arrest the nose-up rotation
first before he can lower his nose
- Things get interesting

> If the tail hits the runway you have stressed the
>airframe, and possibly damaged the rudder.

I dare to state that a proper held-off landing with the tail first
generates much greater forces in most cases. :)

How are you teaching the winch launch?
Here in Germany it is taught that the correct lift off occurs with
main wheel and tail at the same time.

>All flying tails will easily stall - when elevators are at big
>deflections and low airspeed (as will some other pre JAR22 gliders).

I think these flying tails (early LS-1's and Cirrus are typical
candidates) are the root of most myths of "uncontrolled pitch up
despite stick fully forward".

>Perhaps we have to agree to disagree. One thing I am certain of though,
>the process and experience has to be predictable and consistent. There
>are enough other variables involved.

I absolutely agree.
But I honestly think that winch launching is not as difficult or
angerous as many people try to make it.

>We prefer a controlled three second acceleration to maximum launch
>speed. That gives a reasonably controlled 2s ground run and much lower
>initial acceleration - and the correctly trimmed glider does as it is
>designed to do, and flies off without pilot input.

This is exactly the same way we are doing things.

Cheers
Andreas

Bob Kuykendall

July 3rd 13, 01:03 AM

On Tuesday, July 2, 2013 11:25:03 AM UTC-7, BruceGreeff wrote:

> From an engineering point of view I doubt you would find any designer
> who would agree that his glider's tail was designed to strike the runway
> firmly hundreds of times. Maybe all German runways are soft deep grass,
> but I doubt it.

Bruce, what are we wagering here again?

Thanks, Bob K.
http://www.hpaircraft.com/hp-24

Kevin Neave[_2_]

July 3rd 13, 10:28 AM

Bill,

If you read Andreas' post he's advocating the same 0.5g acceleration that
you seem to think is inadequate

"Anyway, winch drivers try to provide soft acceleration (we are using
the same standard 3 second 0.5g acceleration as you do), but from time
to time a catapult launch simply happens."

Andreas,

Is this typical of German clubs or just yours?
What is typical length of run used for winching in Germany?

(On a separate issue, Isn't the CofG of the Std Cirrus in front of the
CofP?
If so wouldn't a stalled tailplane mean as pitch nose down, not up?

Not trying to start an argument, just trying to understand the
aerodynamics)

KN

At 19:25 02 July 2013, Bill D wrote:

>> At 14:53 02 July 2013, Bill D wrote:
>>
>> >Thanks, Andreas. I hope the Brits are reading it.
>>
>> >
>>
>> >
>>
>> >
>
>Why do these stories come exclusively from the UK? No one else seems to
>have the problem. Maybe the laws of aerodynamics and physics work
>differently there.
>

Paul Ruskin[_2_]

July 3rd 13, 12:00 PM

Hi Bill

None of what follows is to gloss over the need to improve safety, or to say that we can’t learn from others. But, for those of us who have responsibilities in this area, it’s important to distinguish fact from opinion. You seem to be someone who thinks about these things, so here’s a real attempt to engage.

So far as I can tell, your premise is that the UK winch accident rate is very poor – an order of magnitude worse than the Germans, and that the cause of that is insufficient acceleration on launch. I think the facts show that you’re wrong.

Let’s unpack that.

GERMAN VS UK SAFETY
You said “The numbers I used are available for anybody to read and analyze. The differences are so huge, there's no way to come up with a different result. If you disagree, go read them and do your own analysis”. So I did and I have. My conclusion is that safety of winch launches in Germany is similar to that in the UK. I base this on the fact that a German pilot’s chance of being seriously injured or killed on a winch launch is similar to that of a UK pilot. I think the differences you are seeing are reporting and analysis differences.

In the last seven years, there have been 17 accidents with 20 fatalities and serious injuries closely related to winch launching in Germany. I’ve listed them below.

In the same period, there have been five fatal and serious injury accidents relating to winch launching in the UK. (see 2009-2012 accident reports by the BGA) so about a 3.4:1-4:1 ratio depending on whether you count accidents or fatalities. I’ve also listed those.

Given your earlier numbers of 180K launches in the UK, and 900K in Germany (a 5:1 ratio), the chance of someone being injured or killed on a winch launch in Germany looks pretty similar to that in the UK – certainly within statistical significance. I conclude that the safety of the two countries is probably similar (whilst still being very interested in anything we can learn from the way that the Germans go about things). We know we can improve in the UK – but it’s not helpful to suggest that there’s worse than an order of magnitude difference – it leads to looking in the wrong place.

Don Johnstone’s account of the way that the UK Air Cadets go about things Is much more compelling from an evidential point of view (no fatalities, similar numbers of launches to rest of UK, we’re told)

Why are your numbers so different? You seem to be taking the BGA numbers which are all accidents and incidents and comparing them with some fairly filtered results from Germany. The data you previously quoted from 2011, for example, and which you said were not filtered for serious and fatal are all on a table labelled “Reports on completed investigations of accidents and serious incident” from the BFU (http://tinyurl.com/occjw49). I don’t think they get to that list unless they’ve merited an investigation, and it’s notable that in earlier years (up to 2008) there were annual reports published with a lot of incidents that didn’t make it to the main list (see http://tinyurl.com/pxhm4ln).

CAUSE OF ACCIDENTS
If you’re talking about all the accidents and incidents that the BGA records (which is what you generally seem to be looking at), there’s little to support your contention that the speed of acceleration on the winch launch is the prime cause. By far the majority of incidents and accidents can in no way be related to launch acceleration – for example landing accidents following a real or practice cable break.

Even looking at the fatal and serious UK accidents, they appear mostly to be related to other causes.

I don’t think anyone is against the idea that an excessively long ground runs are bad – but it’s not clear that being told that the BGA advises a three second acceleration merits “You and the BGA are tragically wrong. You need to take another long look at that analysis. Slow acceleration is the most significant cause of the poor UK accident record. “ Even Andreas is saying that they use 3s accelerations at his club.

It’s also not persuasive to dismiss first-hand accounts as old wives’ tales. Think of the definition of the latter. At least one of the German accidents I looked at above seems to have been caused by a high acceleration pitch up (09-3X118) (subject to Google translate’s accuracy!). Even if you’re right about that, your correct observation that high accelerations can cause incorrect pitch sensations would seem to me to be quite a good reason to back off the acceleration. I don’t have a strong view or expertise on this, but I note there seems to be a degree of consensus around a 3 second acceleration (and when I looked at youtube videos, as you suggested, there was not a significant difference between UK and German practice – and I know how to time things, thanks).

Bottom line – there’s a useful discussion here, comparing practices in different countries. But it’s not helped by misunderstanding different data sets.

Paul

Here’s the data.

German winch accidents 2006-2012 (serious injury and fatal)

06-3X080: New solo student, cable break at 80m, turned, glider destroyed, serious injury
07-3X127: Steep climb, stall and flick at 40m, glider destroyed, fatal
08-3X041: ASH 26 E, stall and flick at 20-30m, aircraft destroyed, serious injury
08-3X063: Discus 2, water, launch from wing stand, wing drop or low altitude stall, aircraft destroyed, serious injury
08-3X113 : Hornet, roll at about 30m, stall? Aircraft destroyed, fatal
09-3X047: DG300, Low cable break, turned, spun in, glider destroyed, fatal
09-3X118: Cirrus. High acceleration, high angle, flick, aircraft destroyed, fatal
09-3X123: Climb to 10-20m, dropped a wing, crash, injury
09-3X144 : Janus, cable break, heavy landing, one serious injury
10-3X058: SF34, Low cable break, turned, spun in. Aircraft destroyed, two fatalities
10-3X059: ASW19, hit ground from 10-20m. Aircraft destroyed, serious injury
11-3X060. : A Jeans-Astir got launched into a Remos ultralight which crossed the pass of the glider from right to left. The two a/c's collided in about 1,200ft and both lost their wings resulting in three fatalities.
11-3X065: The glider was launched on the winch but did not gain sufficient altitude and released in about 40m. Instead of landing straight ahead, the pilot tried to reach a field to the left and then forced the glider into a ground-loop. Pilot suffered broken vertebrae; the passenger only minor injuries.
11-3X080: A LS4 was being launched and after 40-50m of ground roll (!!) the gear collapsed. The glider was dragged for another 23m on the belly and finally lifted off. The launch-boss had given the 'All-stop' command which was followed by the operator. The glider did not have enough speed or altitude to recover and landed very hard. Minor injuries
11-3X093: Spin-in after normal launch - aircaft destroyed, fatal
11-3X095: A Ka-8 was launched on the winch and when the glider's right wing touched the ground and veered off to the right, the launch-boss gave the command 'All stop', which was followed by the operator. The the command to continue the launch was given but the line detached from the glider which then stalled over the right wing and impacted the ground out of about 10m. The pilot was 65 years old. Serious damage and injury
12-3X034: Wing drop, serious injury, aircraft destroyed

I missed out a couple that were on a winch but were, for example, controls not connected.

UK winch accidents 2006-2012 (serious injury and fatal)

2006-2008: 2 fatal or serious injury accidents connected with winch launching (BGA Glider Accidents in 2008)
2009: Cable break at 300 ft, instructor lowered nose, turned, stalled. Serious injury
2009: Stall and flick during rotation. Fatal
2012: Cartwheel after wing drop. Fatal

Bill D

July 3rd 13, 03:12 PM

Going back 20 years comparing data the roughly 10x difference in accident rate holds true year over year. The German data is not filtered in any way. This is a settled issue and you can't change it by spinning the numbers to make the Germans look worse or yourselves look better. End the denial before you are the laughing stick of the world. Then, when you can show one accident of any type in 180,000 launches, we'll have this discussion again. Meanwhile, stop trying to push your solutions on the world - we're not buying it.

..5G acceleration is not common in Germany - in fact, try to find a "windenstart" video showing a .5G launch. You'll find a fairly consistent 1.0G. German launches consistently use a far higher acceleration than the UK. This higher acceleration contributes directly to their better safety record - particularly as related to the UK's current problem with "cartwheeling" accidents.

On Wednesday, July 3, 2013 5:00:05 AM UTC-6, Paul Ruskin wrote:
> Hi Bill
>
>
>
> None of what follows is to gloss over the need to improve safety, or to say that we can’t learn from others. But, for those of us who have responsibilities in this area, it’s important to distinguish fact from opinion. You seem to be someone who thinks about these things, so here’s a real attempt to engage.
>
>
>
> So far as I can tell, your premise is that the UK winch accident rate is very poor – an order of magnitude worse than the Germans, and that the cause of that is insufficient acceleration on launch. I think the facts show that you’re wrong.
>
>
>
> Let’s unpack that.
>
>
>
> GERMAN VS UK SAFETY
>
> You said “The numbers I used are available for anybody to read and analyze. The differences are so huge, there's no way to come up with a different result. If you disagree, go read them and do your own analysis”. So I did and I have. My conclusion is that safety of winch launches in Germany is similar to that in the UK. I base this on the fact that a German pilot’s chance of being seriously injured or killed on a winch launch is similar to that of a UK pilot. I think the differences you are seeing are reporting and analysis differences.
>
>
>
> In the last seven years, there have been 17 accidents with 20 fatalities and serious injuries closely related to winch launching in Germany. I’ve listed them below.
>
>
>
> In the same period, there have been five fatal and serious injury accidents relating to winch launching in the UK. (see 2009-2012 accident reports by the BGA) so about a 3.4:1-4:1 ratio depending on whether you count accidents or fatalities. I’ve also listed those.
>
>
>
> Given your earlier numbers of 180K launches in the UK, and 900K in Germany (a 5:1 ratio), the chance of someone being injured or killed on a winch launch in Germany looks pretty similar to that in the UK – certainly within statistical significance. I conclude that the safety of the two countries is probably similar (whilst still being very interested in anything we can learn from the way that the Germans go about things). We know we can improve in the UK – but it’s not helpful to suggest that there’s worse than an order of magnitude difference – it leads to looking in the wrong place.
>
>
>
> Don Johnstone’s account of the way that the UK Air Cadets go about things Is much more compelling from an evidential point of view (no fatalities, similar numbers of launches to rest of UK, we’re told)
>
>
>
> Why are your numbers so different? You seem to be taking the BGA numbers which are all accidents and incidents and comparing them with some fairly filtered results from Germany. The data you previously quoted from 2011, for example, and which you said were not filtered for serious and fatal are all on a table labelled “Reports on completed investigations of accidents and serious incident” from the BFU (http://tinyurl.com/occjw49). I don’t think they get to that list unless they’ve merited an investigation, and it’s notable that in earlier years (up to 2008) there were annual reports published with a lot of incidents that didn’t make it to the main list (see http://tinyurl.com/pxhm4ln).
>
>
>
>
>
> CAUSE OF ACCIDENTS
>
> If you’re talking about all the accidents and incidents that the BGA records (which is what you generally seem to be looking at), there’s little to support your contention that the speed of acceleration on the winch launch is the prime cause. By far the majority of incidents and accidents can in no way be related to launch acceleration – for example landing accidents following a real or practice cable break.
>
>
>
> Even looking at the fatal and serious UK accidents, they appear mostly to be related to other causes.
>
>
>
> I don’t think anyone is against the idea that an excessively long ground runs are bad – but it’s not clear that being told that the BGA advises a three second acceleration merits “You and the BGA are tragically wrong. You need to take another long look at that analysis. Slow acceleration is the most significant cause of the poor UK accident record. “ Even Andreas is saying that they use 3s accelerations at his club.
>
>
>
> It’s also not persuasive to dismiss first-hand accounts as old wives’ tales. Think of the definition of the latter. At least one of the German accidents I looked at above seems to have been caused by a high acceleration pitch up (09-3X118) (subject to Google translate’s accuracy!). Even if you’re right about that, your correct observation that high accelerations can cause incorrect pitch sensations would seem to me to be quite a good reason to back off the acceleration. I don’t have a strong view or expertise on this, but I note there seems to be a degree of consensus around a 3 second acceleration (and when I looked at youtube videos, as you suggested, there was not a significant difference between UK and German practice – and I know how to time things, thanks).
>
>
>
>
>
>
>
> Bottom line – there’s a useful discussion here, comparing practices in different countries. But it’s not helped by misunderstanding different data sets.
>
>
>
> Paul
>
>
>
> Here’s the data.
>
>
>
> German winch accidents 2006-2012 (serious injury and fatal)
>
>
>
> 06-3X080: New solo student, cable break at 80m, turned, glider destroyed, serious injury
>
> 07-3X127: Steep climb, stall and flick at 40m, glider destroyed, fatal
>
> 08-3X041: ASH 26 E, stall and flick at 20-30m, aircraft destroyed, serious injury
>
> 08-3X063: Discus 2, water, launch from wing stand, wing drop or low altitude stall, aircraft destroyed, serious injury
>
> 08-3X113 : Hornet, roll at about 30m, stall? Aircraft destroyed, fatal
>
> 09-3X047: DG300, Low cable break, turned, spun in, glider destroyed, fatal
>
> 09-3X118: Cirrus. High acceleration, high angle, flick, aircraft destroyed, fatal
>
> 09-3X123: Climb to 10-20m, dropped a wing, crash, injury
>
> 09-3X144 : Janus, cable break, heavy landing, one serious injury
>
> 10-3X058: SF34, Low cable break, turned, spun in. Aircraft destroyed, two fatalities
>
> 10-3X059: ASW19, hit ground from 10-20m. Aircraft destroyed, serious injury
>
> 11-3X060. : A Jeans-Astir got launched into a Remos ultralight which crossed the pass of the glider from right to left. The two a/c's collided in about 1,200ft and both lost their wings resulting in three fatalities.
>
> 11-3X065: The glider was launched on the winch but did not gain sufficient altitude and released in about 40m. Instead of landing straight ahead, the pilot tried to reach a field to the left and then forced the glider into a ground-loop. Pilot suffered broken vertebrae; the passenger only minor injuries.
>
> 11-3X080: A LS4 was being launched and after 40-50m of ground roll (!!) the gear collapsed. The glider was dragged for another 23m on the belly and finally lifted off. The launch-boss had given the 'All-stop' command which was followed by the operator. The glider did not have enough speed or altitude to recover and landed very hard. Minor injuries
>
> 11-3X093: Spin-in after normal launch - aircaft destroyed, fatal
>
> 11-3X095: A Ka-8 was launched on the winch and when the glider's right wing touched the ground and veered off to the right, the launch-boss gave the command 'All stop', which was followed by the operator. The the command to continue the launch was given but the line detached from the glider which then stalled over the right wing and impacted the ground out of about 10m. The pilot was 65 years old. Serious damage and injury
>
> 12-3X034: Wing drop, serious injury, aircraft destroyed
>
>
>
> I missed out a couple that were on a winch but were, for example, controls not connected.
>
>
>
> UK winch accidents 2006-2012 (serious injury and fatal)
>
>
>
> 2006-2008: 2 fatal or serious injury accidents connected with winch launching (BGA Glider Accidents in 2008)
>
> 2009: Cable break at 300 ft, instructor lowered nose, turned, stalled. Serious injury
>
> 2009: Stall and flick during rotation. Fatal
>
> 2012: Cartwheel after wing drop. Fatal

Paul Ruskin[_2_]

July 3rd 13, 03:39 PM

On Wednesday, July 3, 2013 3:12:58 PM UTC+1, Bill D wrote:
> Going back 20 years comparing data the roughly 10x difference in accident rate holds true year over year. The German data is not filtered in any way. This is a settled issue and you can't change it by spinning the numbers to make the Germans look worse or yourselves look better. End the denial before you are the laughing stick of the world. Then, when you can show one accident of any type in 180,000 launches, we'll have this discussion again. Meanwhile, stop trying to push your solutions on the world - we're not buying it.
>

Let's take the last seven years. I accept that the UK winch accident rate was higher before that (though not that high) - and I'm interested in now, not history.

If you believe that the UK winch accident rate is still 10* or more than the German one, then what explains the roughly common rate of fatalities / serious injuries? Either we're having much safer accidents than they are, or it's something else. I think it's comparing apples and oranges.

As it stands, you've got us in a catch 22. The better our incident reporting, the less safe you think we are!

Paul

Andreas Maurer

July 3rd 13, 11:54 PM

On Wed, 03 Jul 2013 09:28:16 +0000, Kevin Neave
> wrote:

>Is this typical of German clubs or just yours?

It's typical.

>What is typical length of run used for winching in Germany?

usually about 3.300 to 3.500 ft.

>(On a separate issue, Isn't the CofG of the Std Cirrus in front of the
>CofP?
>If so wouldn't a stalled tailplane mean as pitch nose down, not up?
>
>Not trying to start an argument, just trying to understand the
>aerodynamics)

Aerodynamics don't play a role here - the mechanical forces are a lot
stronger than pitch momentums of the wing.

The tow cable pulls below the CG, therefore rotating the glider
nose-up.
There is not only a horizontal position of the CG (this is the one we
are used to), but also a vertical one. The CG is usualy located at the
lower boarder of the main spar where the latter crosses the fuselage.

Cheers
Andreas

Andreas Maurer

July 4th 13, 12:16 AM

On Wed, 3 Jul 2013 07:12:58 -0700 (PDT), Bill D >
wrote:

>.5G acceleration is not common in Germany - in fact, try to find a "windenstart" video showing a .5G launch.
>You'll find a fairly consistent 1.0G. German launches consistently use a far higher acceleration than the UK.
> This higher acceleration contributes directly to their better safety record - particularly as related to the UK's current problem with "cartwheeling" accidents.

Hi Bill, here are a few 0.5g winch launches (the first two are
shameless promotion for my own humble videos, I have to admit):

http://www.youtube.com/watch?v=AjSHjfEdwLs
http://www.youtube.com/watch?v=WVpKhAnTKRk
http://www.youtube.com/watch?v=JHDRvjkpl5c
http://www.youtube.com/watch?v=PQNSnpfImHg
http://www.youtube.com/watch?v=zPKnHc9kC4M

All kinds of (German) gliders, but in all cases pretty precisely 3
seconds till liftoff.

http://www.youtube.com/watch?v=C6pf4MzArEY
(ok - no winch launch in this one, but I want the clicks....)

Related search on Youtube:
http://www.youtube.com/results?search_query=windenstart&oq=windenstart&gs_l=youtube.3..0l6.3024.6418.0.7721.11.8.0.3.3.0. 346.1589.2j2j1j3.8.0...0.0...1ac.1.11.youtube.Psiq ThFeeUc

Cheers
Andreas

Bill D

July 4th 13, 02:14 PM

On Wednesday, July 3, 2013 5:16:07 PM UTC-6, Andreas Maurer wrote:
> On Wed, 3 Jul 2013 07:12:58 -0700 (PDT), Bill D >
>
> wrote:
>
>
>
>
>
> >.5G acceleration is not common in Germany - in fact, try to find a "windenstart" video showing a .5G launch.
>
> >You'll find a fairly consistent 1.0G. German launches consistently use a far higher acceleration than the UK.
>
> > This higher acceleration contributes directly to their better safety record - particularly as related to the UK's current problem with "cartwheeling" accidents.
>
>
>
>
>
> Hi Bill, here are a few 0.5g winch launches (the first two are
>
> shameless promotion for my own humble videos, I have to admit):
>
>
>
> http://www.youtube.com/watch?v=AjSHjfEdwLs
>
> http://www.youtube.com/watch?v=WVpKhAnTKRk
>
> http://www.youtube.com/watch?v=JHDRvjkpl5c
>
> http://www.youtube.com/watch?v=PQNSnpfImHg
>
> http://www.youtube.com/watch?v=zPKnHc9kC4M
>
>
>
> All kinds of (German) gliders, but in all cases pretty precisely 3
>
> seconds till liftoff.
>
>
>
>
>
> http://www.youtube.com/watch?v=C6pf4MzArEY
>
> (ok - no winch launch in this one, but I want the clicks....)
>
>
>
>
>
> Related search on Youtube:
>
> http://www.youtube.com/results?search_query=windenstart&oq=windenstart&gs_l=youtube.3..0l6.3024.6418.0.7721.11.8.0.3.3.0. 346.1589.2j2j1j3.8.0...0.0...1ac.1.11.youtube.Psiq ThFeeUc
>
>
>
>
>
> Cheers
>
> Andreas

Andreas, you're starting the clock too soon. The early roll is just the glider creeping forward. You can tell when the acceleration really starts because the nose wheel/skid comes off the ground. I get two second acceleration on all your videos.

Bill D

July 4th 13, 02:19 PM

On Wednesday, July 3, 2013 8:39:49 AM UTC-6, Paul Ruskin wrote:
> On Wednesday, July 3, 2013 3:12:58 PM UTC+1, Bill D wrote:
>
> > Going back 20 years comparing data the roughly 10x difference in accident rate holds true year over year. The German data is not filtered in any way. This is a settled issue and you can't change it by spinning the numbers to make the Germans look worse or yourselves look better. End the denial before you are the laughing stick of the world. Then, when you can show one accident of any type in 180,000 launches, we'll have this discussion again. Meanwhile, stop trying to push your solutions on the world - we're not buying it.
>
> >
>
>
>
> Let's take the last seven years. I accept that the UK winch accident rate was higher before that (though not that high) - and I'm interested in now, not history.
>
>
>
> If you believe that the UK winch accident rate is still 10* or more than the German one, then what explains the roughly common rate of fatalities / serious injuries? Either we're having much safer accidents than they are, or it's something else. I think it's comparing apples and oranges.
>
>
>
> As it stands, you've got us in a catch 22. The better our incident reporting, the less safe you think we are!
>
>
>
> Paul

You don't look bad because you're reporting accidents, it's because your having accidents.

Terry Walsh[_2_]

July 4th 13, 02:37 PM

Bill,

With respect you are talking utter nonsense. You even bend the times given
to you by Andreas to suite your own agenda.

Terry Walsh

At 13:14 04 July 2013, Bill D wrote:
>On Wednesday, July 3, 2013 5:16:07 PM UTC-6, Andreas Maurer wrote:
>> On Wed, 3 Jul 2013 07:12:58 -0700 (PDT), Bill D
>>
>> wrote:
>>
>>
>>
>>
>>
>> >.5G acceleration is not common in Germany - in fact, try to find a
>"windenstart" video showing a .5G launch.
>>
>> >You'll find a fairly consistent 1.0G. German launches consistently
use
>a far higher acceleration than the UK.
>>
>> > This higher acceleration contributes directly to their better safety
>record - particularly as related to the UK's current problem with
>"cartwheeling" accidents.
>>
>>
>>
>>
>>
>> Hi Bill, here are a few 0.5g winch launches (the first two are
>>
>> shameless promotion for my own humble videos, I have to admit):
>>
>>
>>
>> http://www.youtube.com/watch?v=AjSHjfEdwLs
>>
>> http://www.youtube.com/watch?v=WVpKhAnTKRk
>>
>> http://www.youtube.com/watch?v=JHDRvjkpl5c
>>
>> http://www.youtube.com/watch?v=PQNSnpfImHg
>>
>> http://www.youtube.com/watch?v=zPKnHc9kC4M
>>
>>
>>
>> All kinds of (German) gliders, but in all cases pretty precisely 3
>>
>> seconds till liftoff.
>>
>>
>>
>>
>>
>> http://www.youtube.com/watch?v=C6pf4MzArEY
>>
>> (ok - no winch launch in this one, but I want the clicks....)
>>
>>
>>
>>
>>
>> Related search on Youtube:
>>
>>
>http://www.youtube.com/results?search_query=windenstart&oq=windenstart&gs_l=youtube.3..0l6.3024.6418.0.7721.11.8.0.3.3.0. 346.1589.2j2j1j3.8.0...0.0...1ac.1.11.youtube.Psiq ThFeeUc
>>
>>
>>
>>
>>
>> Cheers
>>
>> Andreas
>
>Andreas, you're starting the clock too soon. The early roll is just the
>glider creeping forward. You can tell when the acceleration really
starts
>because the nose wheel/skid comes off the ground. I get two second
>acceleration on all your videos.
>

Bill D

July 5th 13, 12:15 AM

On Thursday, July 4, 2013 7:37:19 AM UTC-6, Terry Walsh wrote:
> Bill,
>
>
>
> With respect you are talking utter nonsense. You even bend the times given
>
> to you by Andreas to suite your own agenda.
>

I have no agenda. It's your necks at risk, not mine.

I stand by what my eyes tell me. You have to pick a time when the acceleration starts and that's not when the glider starts creeping forward it's when the tail goes down. That's just experienced observation.

Peter F[_2_]

July 5th 13, 09:28 AM

Having beaten the UK vs Germany accident stats to death, we're obviously
not going to convince either side that they're wrong.

Going back to the original post on this thread...

Does *anyone* out there think the pilot of the DG did *anything* right in
the whole sorry incident. Starting with agreeing to do the shoot in the
first place.

Would anyone with any significant amount experience with of winch or
autotow launching have agreed to do this?

PF

brianDG303[_2_]

July 7th 13, 12:10 AM

Peter,
I can't answer your question, but can perhaps add to the discussion. There is no question in my mind what happened and why things went wrong. I knew the pilot very well, he was my CFIG and I flew with him in that glider a hundred times, soloed in that glider, my first ever glider flight was in that glider with that pilot. He was safety minded enough that once when the wing dolly fell against the ship and punched a tiny hole in the fuselage you could barely get a pencil point through he called off the day. His point was that you don't fly a damaged ship no matter how slight the damage. The damaged wing in the NTSB images tells a different story. It's my understanding that the damage happened on the first day of filming and clearly he was willing to slap on that tape and keep on going. That is so unlike him, as is so much of what he did during this event, it's my opinion that he simply lost the ability to make reasonable judgements in the presence of the social pressure presented by being the star performer to an audience consisting of a helicopter pilot, a film director, stunt driver, actress, etc. knowing that he would be letting everyone down if he didn't come through. Perhaps there were financial penalties as well. In the past I've been confronted with such challenges and have failed to pass the test, I think it takes a lot to imagine the pressure he was under to perform, I suspect he knew he was in over his head and just could not back away.

The key missing element was the presence of a dedicated safety officer whose roll would be to evaluate the situation and stop the process if nessasary.. At least two people were available with those skills and the mojo to kill the deal were close friends of Lynn's.

Because of social pressures people commit suicide, take all kinds of stupid chances, come to any number of bad ends. This is such a sad and dreary end to really good guy.

Frank Whiteley

July 8th 13, 08:51 PM

On Saturday, July 6, 2013 5:10:27 PM UTC-6, brianDG303 wrote:
> Peter,
>
> I can't answer your question, but can perhaps add to the discussion. There is no question in my mind what happened and why things went wrong. I knew the pilot very well, he was my CFIG and I flew with him in that glider a hundred times, soloed in that glider, my first ever glider flight was in that glider with that pilot. He was safety minded enough that once when the wing dolly fell against the ship and punched a tiny hole in the fuselage you could barely get a pencil point through he called off the day. His point was that you don't fly a damaged ship no matter how slight the damage. The damaged wing in the NTSB images tells a different story. It's my understanding that the damage happened on the first day of filming and clearly he was willing to slap on that tape and keep on going. That is so unlike him, as is so much of what he did during this event, it's my opinion that he simply lost the ability to make reasonable judgements in the presence of the social pressure presented by being the star performer to an audience consisting of a helicopter pilot, a film director, stunt driver, actress, etc. knowing that he would be letting everyone down if he didn't come through. Perhaps there were financial penalties as well. In the past I've been confronted with such challenges and have failed to pass the test, I think it takes a lot to imagine the pressure he was under to perform, I suspect he knew he was in over his head and just could not back away.
>
>
>
> The key missing element was the presence of a dedicated safety officer whose roll would be to evaluate the situation and stop the process if nessasary. At least two people were available with those skills and the mojo to kill the deal were close friends of Lynn's.
>
>
>
> Because of social pressures people commit suicide, take all kinds of stupid chances, come to any number of bad ends. This is such a sad and dreary end to really good guy.

Here come the lawyers
http://www.courthousenews.com/2013/07/08/59159.htm

Brad[_2_]

July 9th 13, 02:49 AM

This will probably settle out of court, or get booted before it even gets there. Lot of inside information available that might not be favorable for the plaintiff if it goes too far.

I didn't know Lynn was married at the time of the accident. Reminds me of another lawsuit several years ago.

Brad

Bob Kuykendall

July 9th 13, 06:14 AM

Brian, thanks for pointing out the duct tape repair. It adds an entirely new dimension to this accident. I sure wish I could see what was under the tape.

Bob K.

Papa3[_2_]

July 9th 13, 02:38 PM

Brian,

Thanks for a really thoughtful, compassionate post. Peer and social pressure make people do strange things.

P3

On Saturday, July 6, 2013 7:10:27 PM UTC-4, brianDG303 wrote:
> Peter,
>
I can't answer your question, but can perhaps add to the discussion. There is no question in my mind what happened and why things went wrong. I knew the pilot very well, he was my CFIG and I flew with him in that glider a hundred times, soloed in that glider, my first ever glider flight was in that glider with that pilot. He was safety minded enough that once when the wing dolly fell against the ship and punched a tiny hole in the fuselage you could barely get a pencil point through he called off the day. His point was that you don't fly a damaged ship no matter how slight the damage. The damaged wing in the NTSB images tells a different story. It's my understanding that the damage happened on the first day of filming and clearly he was willing to slap on that tape and keep on going. That is so unlike him, as is so much of what he did during this event, it's my opinion that he simply lost the ability to make reasonable judgements in the presence of the social pressure presented by being the star performer to an audience consisting of a helicopter pilot, a film director, stunt driver, actress, etc. knowing that he would be letting everyone down if he didn't come through. Perhaps there were financial penalties as well. In the past I've been confronted with such challenges and have failed to pass the test, I think it takes a lot to imagine the pressure he was under to perform, I suspect he knew he was in over his head and just could not back away.
>
>
>
> The key missing element was the presence of a dedicated safety officer whose roll would be to evaluate the situation and stop the process if nessasary. At least two people were available with those skills and the mojo to kill the deal were close friends of Lynn's.
>
>
>
> Because of social pressures people commit suicide, take all kinds of stupid chances, come to any number of bad ends. This is such a sad and dreary end to really good guy.