What happened
On August 4, 2012, a private Rolladen-Schneider LS6-18w glider, registration D-2666, was performing a local flight at the Puimoisson airfield. The pilot departed via aero-tow from runway 26. While traversing a thermal area at an altitude of approximately 175 meters, the pilot elected to release from the tow cable. After finding it difficult to utilize the available thermals, the pilot decided to return to the airfield, entering the left-hand downwind leg for runway 26.
During the base leg of the landing pattern, the glider entered an autorotation and struck the ground. The pilot reported that they had misjudged their altitude during the base leg and had deployed air brakes to descend. This maneuver resulted in a sudden, asymmetric stall. An eyewitness noted that the glider appeared to be flying at a low airspeed during the circuit.
The investigation
The investigation focused on the flight path and the aircraft's mechanical condition. Investigators found no structural or mechanical anomalies on the Rolladen-Schneider LS6-18w that could have contributed to the crash. Furthermore, the aircraft's weight and center of gravity were confirmed to be within the manufacturer's specified limits.
Data regarding the pilot's experience showed a highly experienced instructor with 4,325 total flight hours, including 1,944 hours on this specific type. Meteorological conditions at the time were favorable, with CAVOK visibility, a temperature of 32 °C, and winds from 260° at 10 to 15 knots.
Findings
- The pilot made a premature decision to release from the tow cable at a low altitude (approximately 175 meters), whereas the standard release height at Puimoisson is typically around 500 meters.
- This early release led to a late decision to begin the landing approach.
- The resulting lack of an adequate base leg prevented the pilot from maintaining effective control over the approach path and flight parameters, ultimately leading to the asymmetric stall and impact.