What happened
On April 23, 1966, a two-seat glider, registration HB-509, was performing a winch-assisted takeoff at a military airfield. During the launch sequence, the pilot lost control of the aircraft. In an attempt to manage the situation, the pilot released the tow line. Following this release, the glider entered an uncontrolled flight path and ultimately struck the ground with considerable force. The impact resulted in substantial damage to the aircraft.
The investigation
The investigation focused on the sequence of events during the winch launch and the subsequent loss of control. The commission examined the flight path following the pilot's decision to unhook from the winch cable and the mechanics of the impact with the terrain.