Accident Sequence
A towplane and a glider were involved in an accident during a glider tow takeoff. An FAA Inspector observed the takeoff and noted that the glider exhibited erratic pitch changes. The glider pilot's canopy was open, and the pilot repeatedly attempted to close it. Each attempt to close the canopy was accompanied by pitch changes and climbs above the towplane.
As the towrope reached a vertical position, the towplane struck the ground, nosed over, and came to rest inverted. The towrope separated, and the glider continued past the towplane, rolled left to an inverted position, and impacted the ground.
Equipment Details
The towrope in use at the time employed a 'Sweitzer Ring' to attach at the towplane and a 'Tost Ring' to attach at the glider. Both rings were attached to their respective airplanes, and both release mechanisms were operational.
Reference Manual
According to the 1998 Soaring Flight Manual sponsored by the Soaring Society of America: 'When the sailplane is too high, it can pull the tail of the towplane up, making it difficult, if not impossible, for the towplane to take off... If corrective action is not taken, the only alternative for the tow pilot is to release the towline...If for any reason, the sailplane pilot loses sight of the towplane, he should release immediately.'