What happened
On the evening of September 5, 1997, an Air Création Safari GT BI ultralight departed from the Batzendorf platform for a local flight. While operating near a body of water, the pilot reduced engine power to descend. In an attempt to stabilize the aircraft's altitude at approximately 300 meters above the water, the pilot attempted to increase engine RPM; however, the engine failed to respond to the throttle increase.
Faced with a continuous descent and the surrounding terrain, the pilot elected to perform a forced landing on the Grabi quarry pond. During the final approach, the right wheel struck the water surface, causing the aircraft to pitch forward. The aircraft subsequently sank to a depth of 28 meters. The two occupants successfully evacuated the aircraft before it submerged.
The investigation
The investigation focused on the mechanical performance of the powerplant following the impact. Technical examination of the Rotax 582 engine revealed significant internal issues, specifically noting carbon buildup on the pistons and the seizing of piston rings within their grooves.