On Thursday, November 14, 2013 11:36:01 AM UTC-6, son_of_flubber wrote:

That the probability of a PTT is currently high enough to justify the risk of PTT simulation is part of my motivation. Can the probability of a PTT be lowered to the point that the risk of PTT simulation is no longer justified? How far can better rope material choice and better (practical) inspection go towards eliminating the possibility of PTT?

In over 2500 hours of glider flying, and maybe 700 towing, I've never had a rope break.

As a tow pilot, I inspect the rope at the start of the day, and when there is a break in the action (as part of laying out the rope behind the towplane to get it out of the way).

I've had two (2) PTTs in that time - neither caused by a rope breaking. One was an incorrectly hooked up Schweizer to hook (muddy) that gave me a PTT at about 200' in a loaded 2-32 (quick 180 and rolled back to the doofus who had hooked me up and made him do it again, correctly) and once when the tow pilot ran out of gas and released his end without telling me (but the funny thing was that it happened at exactly 3000' agl and I released at the same time - we never did find that rope!).

And all this at glider fields all over the US.

So I really think our procedures are pretty sound. Can ropes break? Of course. So can tow releases, weak links, etc...

As far as PTT training being dangerous - you can tow with a steel cable and still get a PTT. So yes, it is very important. And really, it's not a Chuck Yeager bit of airmanship, after all...spinning off a PTT is remarkably bad flying - and probably the sign of someone who was scared of stalls or steep banks at low altitude and didn't really know how to fly to the limits of his glider. You want to worry about something, worry about the currency and proficiency of your fellow glider pilots!

Kirk
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