The pilot was using a winch tow to launch the glider. During the launch, the glider became airborne; however, when the pilot increased the angle of attack, the glider entered a stall/spin and subsequently impacted the terrain. Postaccident examination revealed that the automatic transmission on the winch slipped, when tension was applied to the cable.
The National Transportation Safety Board determines the probable cause(s) of this accident as follows.the slippage of the glider launch equipment (winch). Factors were the pilot's encounter with a stall/spin and the lack of possibility for remedial action to avoid impact with the terrain.