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Originally Posted by
This topic is complex, it probably is appropriate to break it down into the component issues. I'll limit this response to the Schweizer tow release mechanism used on many tow planes.
It is well understood if the glider gets too high during the aerotow, excessive loads on the towplane's Schweizer tow release can make it difficult and even impossible for the tow pilot to operate the release.
This can be safely simulated on the ground by simply connecting a tow rope to the release mechanism, then lifting up on the rope while someone operates the release mechanism from the towpane's cockpit.
The Tost release mechanism is not affected by vertical or horizontal loads imposed by a glider flying in an out of bounds towing position.
The Schweizer tow release, like all other mechanisms require routine maintenance and overhaul. One of the first questions to ask is when was your towplane's release mechanism (regardless of brand) last overhauled? My guess is few, if any towplane release mechanisms are ever overhauled.
Here at Ridge Soaring Gliderport, we faced this problem and contacted our local FAA office. They sent a team of inspectors.
The conversation ended with the FAA saying, "Now let's see what you want to do."
"You want to replace an FAA approved, Schweizer tow release with an approved Tost tow release."
The inspector finished with, "No FAA paperwork needed."
A simple mechanic's logbook entry was all that was necessary
Tom Knauff
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Thank you for a cogent and succinct response, your actions display a proactive approach to the problem. Others would have me believe that it takes an act of Congress and six months of paperwork to change from Schweizer to Tost.
In your article on "Launch Emergencies" you state that the odds are 50/50 of something going bad on each launch. Either it will or it wont. Experiencing something go bad on a launch such as what happened to me will convince any tow pilot of the imperative need to have a positive and unfettered chance to release the glider. As you said, the Tost release mechanism is not affected by vertical or horizontal loads imposed by a glider flying in an out of bounds towing position. Clearly the Scnweizer hook is affected by such conditions rendering it useless.
In a low, severe kiting incident such as mine the tow pilot must react in an instant. Anything that delays that reaction can result in a catastrophy. Relying on the rope to break under such circumstances is not a good alternative to a positive release mechanism. Any commercial operator or club still operating with a Schweizer hook and/or a release handle not conveniently available to the pilot is playing Russian roulette with the life of their tow pilot.
Walt