Tow rope strikes ASK 21 wing on slack release during tow-position demo
The right wing of an ASK 21 was marked by the tow rope at Bex Aérodrome (Switzerland) after a slack-rope release during a tow-position demonstration; the instructor and student were uninjured. After a Piper PA-18 aerotow from RWY 33 the instructor demonstrated extreme tow positions to the student on downwind. With the glider offset to the left of the tug, the rope went slack and the instructor released it. The rope whipped up, struck the right wing and broke, and a piece jammed in the partially extended right airbrake. He rejoined RWY 33 by the shortest path and landed in a field at the runway edge, rolling out onto the runway.
- Aerotow r33, extreme-tow demo: On the downwind leg the instructor demonstrated extreme tow positions to the student: first below the tug so the student could feel turbulence, then offset right and above.
- Tug deviates left mid-exercise: The instructor saw the tug deviating left; to avoid a critical position he repositioned the glider on the tug's axis, slightly above, and waited for the path to stabilise.
- Slack rope with glider left of tug: Continuing the exercise the instructor placed the glider to the left of the tug and observed the tow rope going slack. He judged the situation to be becoming critical.
- Instructor releases slack rope: The instructor released the tow rope at the glider end.
- Rope strikes wing, jams airbrake: The released rope whipped up and struck the right wing of the glider. It broke on impact; a piece jammed in the partially extended right airbrake.
- Short return, field landing on r33: The instructor announced intentions by radio and chose the shortest path to the runway; the glider landed in an edge field and rolled onto the runway, with limited damage and no injuries.