Fatal Towplane Accident 5-9-20

Kiting and loss of control of the glider on tow happens more than is known. There are not accurate statistics or data tracked so most of the information is anecdotal or comes after a tragedy.

We are, as a community, extremely challenged by our aversion to checklist, cockpit and single pilot resource management as well as Aeronautical Decision Making. This can be traced partially to poor training, inconsistent procedures and lack of discipline. Attitudes matter.

Look at the shared risk pool, the high and climbing insurance costs, the accidents over the last years, the hazardous attitudes, diminished expectations as well as the sport in decline.

Same types of accidents at very high per-capita rates. Technology solutions may help but until the sport makes a concerted, coherent and consistent full court press the trends will continue. Not hard to predict the future here.

Regards, Tom

Kiting and loss of control of the glider on tow happens more than is known. There are not accurate statistics or data tracked so most of the information is anecdotal or comes after a tragedy.

We are, as a community, extremely challenged by our aversion to checklists, right cockpit discipline and good single pilot resource management as well as incorporating effective Aeronautical Decision Making. This can be traced partially to poor training, inconsistent procedures and lack of discipline. Attitudes matter.

Look at the shared risk pool, the high and climbing insurance costs, the accidents over the last years, the hazardous attitudes, diminished expectations as well as the sport in decline.

Same types of accidents at very high per-capita rates. Technology solutions may help but until the sport makes a concerted, coherent and consistent full court press the trends will continue. Not hard to predict the future here.

Regards, Tom

I believe that full up elevator is what the towpilot will instinctively do in a kite siuation. This device will detect that and hopefully not give any false positives

release logic something like:-
1) GPS groundspeed ~60kmh for for ~5 seconds (so its not an engine test)
2) engine throttle ~80% for ~5 seconds (so its a take-off)
3) full up elevator (for more then ~0.2 second to filter out a knock)

when 1) and 2) are satisfied the system is "armed". A low groundspeed or Landing flaps could disarm it

I have chosen a low groundspeed in 1) to accomodate a strong head wind

GPS groundspeed and full elevator are easy to measure. Throttle a little trickier - maybe one could use flaps instead. tweak as necessary

Manual override, arm and disarm switches in the cockpit of course. some LEDs.

a simple embedded CPU costing 1$ can easily handle this and is very reliable. The BOM could be under 50$. This can be built by a hobbyist.

The tricky bit is
* Mounting the sensors
* triggering the release if its not electical

Peter

Pete, very well said. It is frustrating to hear folks believing that training fix everything and that a trained/experienced/smart pilot will never make a mistake due to distraction or “tunnel vision�. We heard similar arguments against devices like flarm and ADS-B, just look outside.

Ramy

On Saturday, May 16, 2020 at 12:10:01 PM UTC-4, Rhubarb wrote:
I believe that full up elevator is what the towpilot will instinctively do in a kite siuation. This device will detect that and hopefully not give any false positives

release logic something like:-
1) GPS groundspeed ~60kmh for for ~5 seconds (so its not an engine test)
2) engine throttle ~80% for ~5 seconds (so its a take-off)
3) full up elevator (for more then ~0.2 second to filter out a knock)

when 1) and 2) are satisfied the system is "armed". A low groundspeed or Landing flaps could disarm it

I have chosen a low groundspeed in 1) to accomodate a strong head wind

GPS groundspeed and full elevator are easy to measure. Throttle a little trickier - maybe one could use flaps instead. tweak as necessary

Manual override, arm and disarm switches in the cockpit of course. some LEDs.

a simple embedded CPU costing 1$ can easily handle this and is very reliable. The BOM could be under 50$. This can be built by a hobbyist.

The tricky bit is
* Mounting the sensors
* triggering the release if its not electical

Peter

Airspeed is probably better than ground speed.
To sense departure from "normal" measuring line tension and angle are probably the most useful. With those available rate of change of the two would be a very useful indicator of things getting out of hand.
FWIW
UH

Seems to me that the most fool-proof solution is the line tension sensor and a little bit of accumulative logic.

We had a discussion on the club group about this and the example used was a 1800lb tow-plane, 700lb glider being towed. Kiting event takes 2 seconds, ends up with the glider gaining 100ft. Starting speed 60mph (glider being a 1-26). After 2 seconds of glider kiting the glider speed is 75 mph, tow-plane speed is 40mph. Average tension on the rope is 900lb and the tow-plane experiences 1/2G deceleration along the longitudal axis. One could just set a longitudal axis g-meter and alert/cut the line at .5G, but that might trip with slack rope etc. Having a rope tension sensor calculate energy loss due to the pull on rope over the last .1, .2 ,.3 seconds would be easy. The hard part would be to decide what the limit should be. One might test this with boxing the wake, tows trough rotor etc. If the event starts fast, the rope angle doesn't really get much above normal (in reference to the tow-plane) since the strong pull on the rope easily lifts the tail. The energy loss for the tow-plane is the bigger problem.

On Saturday, May 16, 2020 at 5:39:46 AM UTC-7, Peter Whitehead wrote:
If we could guarantee the glider pilot would never be stupid, or get distracted (insect bites, battery going bang, medical problem etc etc) there would be no problem to solve.
Giving a miscreant a 'talking to' or a permanent ban may give some satisfaction, but it is retrospective.
Imploring people to have brain in gear and 'be safe',or give more training may make one feel one is addressing the issue but it will fail to stop these occurrences.
I don't regard an engineering solution as particularly complex. The sensors and simple processing power (much less than in your phone) would be easy to source.The mechanics of the rope release would be simple.
Failure to operate would leave us in the same position as now. Inadvertent operation would dump the glider... unlikely to cause death or serious injury.
Certification is a hurdle, but do we not think it would be worth it? The FAA does consider positively any obvious safety enhancements..it may take time but doesn't that mean start as soon as possible?
The costs? Yes it would cost, but development could be in the hands of Universities or manufacturers (eg TOST).
How much would I personally give if only I could bring back my two deceased tug pilot colleagues?
How much would we all give to prevent future tug upset fatalities?
I am considering switching off my auto's airbags, going to 'manual'. It is far too complex. I am sure I would have enough time
during the tyre squeals to press the button.
I'm not being serious, of course.
So an automatic system for me, please.
I shall not post anything further (until the next tug upset fatality). Good luck. Pete

Peter,

I am with you on this one. I envision a self-contained guillotine module that you pass the tow rope through, (works with a static line or reel system). It uses a charge similar to the way a modern table saw can stop a spinning blade before it can scratch a hotdog put in its path. A modular replacement of the charge module could be performed in minutes (at a cost of $500 to the offending glider pilot). Powered by the towplane electrical system, with a light on the dash showing it is operational. Triggered, as you suggest, by the correct profile of deceleration and rotation.

Who wants to design it?

Matt

First time you have a malfunction with one of these contraptions here comes the lawsuit and good by contraption.

With the “technology will fix everything “ mentally, maybe you guys need to design stall/spin proof gliders, cause after all we can’t trust that guys will not be distracted and spin in. Ph we can’t do that, it will impinge on ship performance.you can’t always engineer out “stupid “.

While we’re talking about malfunctions, I was told that the Guillotine used in our winches, will quickly become coated with fir particles from the rope as it is retracted, over and over again, resulting in a jammed Guillotine..............as in, IT WONT CUT THE ROPE! Also, if the rope isn’t under tension, the guillotine may just shove it to one side and WONT CUT THE ROPE!
This from a guy that has installed many winches and tested them on annual inspections!
Recommend you clean guillotine’s weekly and have them tested annually,
JJ

On Saturday, May 16, 2020 at 2:19:41 PM UTC-7, wrote:
First time you have a malfunction with one of these contraptions here comes the lawsuit and good by contraption.

With the “technology will fix everything “ mentally, maybe you guys need to design stall/spin proof gliders, cause after all we can’t trust that guys will not be distracted and spin in. Ph we can’t do that, it will impinge on ship performance.you can’t always engineer out “stupid “.

While the product liability problem can be solved with shell corporations, let's not confuse a stall/spin accident with a tow kiting accident. The former kills the perpetrator, the latter kills innocent bystanders.

If you are confident in the skills and training of everyone you tow, then why have a release on the towplane at all? What could possibly go wrong?