What happened
On March 21, 2000, a Stemme S10VT motor glider, registration D-KSVT, was engaged in a ferry flight from Hassfurth, Germany, to Fayence, France, for certification testing purposes. After a five-hour flight, the pilot attempted to land on runway 10 at Fayence aerodrome.
During the approach, the pilot reported being too high and at an excessive speed, having overestimated the crosswind component. The aircraft initially touched down approximately 500 meters before the runway threshold, bounced, and landed again 100 meters further down the runway. While taxiing at approximately 40 km/h, the pilot attempted a left turn but realized the end of the runway was approaching too quickly. This resulted in the collapse of the main landing gear and significant damage to the powerplant.
The investigation
The investigation focused on the flight parameters during the final approach and the mechanical state of the aircraft. The pilot noted that he had attempted to land with 10 degrees of flaps extended, but the locking mechanism likely failed, causing the flaps to retract to 0 degrees. Investigators also examined the engine's power control system, specifically the ROTAX 914 engine, which features an automatic power recall mechanism that can deliver significant power if the throttle lock is not properly secured.
Findings
Several factors contributed to the accident:
- The pilot made the decision to continue the landing attempt despite an unstabilized approach characterized by excessive altitude and airspeed.
- The pilot's fatigue was a contributing factor, as he had completed five hours of flight on the day of the accident and an additional five hours the previous day.
- A failure in the flap locking mechanism caused the flaps to retract during the landing sequence.
- The engine's automatic power recall system may have contributed to unexpected power delivery if the throttle lever was not sufficiently secured.
- The pilot overestimated the crosswind conditions at the aerodrome.