ZEALOT N61ZT accident near Minneola, Florida

Probable cause

The pilot's failure to maintain adequate airspeed on the base leg for landing, which resulted in an aerodynamic stall and loss of airplane control.

NTSB analysis

The pilot stated that he departed the airport and flew to a training area to conduct flight-testing (the airplane had recently been rebuilt), including some power-on stalls. According to the operating specifications, the glider was supposed to stall at 48 mph with the power on; however, the pilot stated that the glider would stall at 63 mph. However, the airspeed indicator had not been checked for accuracy. He returned to the airport and descended on a left base leg of the traffic pattern for runway 18. The glider was about 100 feet above ground level when the left wing and nose pitched down violently and stalled. There was insufficient altitude to recover and the glider collided with trees and the ground. The pilot stated that the glider did not experience any mechanical problems before the accident, and postcrash examination of the aircraft and engine showed no signs of a mechanical failure or malfunction. Although the pilot stated that the glider was flying at 70 mph at the time of the accident, it is likely that the airspeed indicator was inaccurate and that he was operating at a much lower speed, which resulted in the aerodynamic stall.

Text from the NTSB. Open the NTSB docket for ERA12LA171 for the full record.