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