What happened
During the latter part of the landing pattern, the pilot of an L-13 glider encountered a significant loss of lift. While on the final approach leg, the aircraft collided with the airport boundary fence.
The pilot had been checked out in this specific glider type by his flight instructor earlier on the same day. This flight marked the pilot's first solo flight in the L-13.
The investigation
Information provided by the pilot indicated that during the downwind leg of the pattern, he had partially deployed the flaps and partially opened the air brake. The pilot could not recall if the air brake had been closed prior to the loss of lift on final approach. A photograph taken by the flight instructor immediately following the accident showed the air brake in the open position with the flaps deployed.