Incident Overview
A glider accident occurred during takeoff when the left hook of the winch harness released uncommanded from the center of gravity attachment. The glider yawed to the left toward a ditch on the west side of the runway.
Pilot Actions
The certified flight instructor (CFI) applied right aileron and full right rudder in an attempt to avoid the ditch, but the glider continued into the ditch. The glider came to rest bridging the ditch on a heading of east.
Post-Impact Injuries
During the impact, a broken branch penetrated the left side of the cockpit and impaled itself in the CFI's right calf. The CFI remained hospitalized for five days following the accident.
Pre-Flight and Post-Accident Observations
Members of the glider club reported that they had hooked both the left and right side cables prior to the takeoff. An inspection of the tow winch failed to reveal any mechanical failure or malfunction.