What happened
On December 3, 2006, an experimental One Design DR-107, registration N107FP, was involved in a fatal accident west of the Langenthal airfield in Switzerland. The pilot, who was the owner and builder of the aircraft, had prepared the plane for flight following the reopening of the airfield's new runway. After refueling the aircraft with 30 liters of AVGAS 100LL, the pilot performed a brief flight for aerobatic training.
During the second takeoff attempt of the day, the engine began to sputter just as the aircraft transitioned from its three-point stance to a level attitude. The engine subsequently failed completely during the initial climb. In an attempt to maneuver, the pilot initiated a left turn at an altitude of approximately 30 to 50 meters AGL. Due to the loss of power and the specific aerodynamic characteristics of the aircraft, the plane stalled and rolled onto its left wing, impacting the ground in an inverted position. The impact resulted in the death of the pilot and the total destruction of the aircraft.
The investigation
Investigators examined the wreckage and the fuel system to determine the cause of the engine failure. The investigation focused on the fuel levels and the functionality of the fuel delivery components. The aircraft's fuel system consisted of two aluminum tanks located in the fuselage. The investigation found no evidence of mechanical malfunctions, leaks, or blockages in the fuel lines, injectors, or filters.
Regarding the fuel quantity, investigators noted that the aircraft's fuel gauges could not provide a reliable reading of the actual fuel remaining in different flight attitudes. While the pilot had added 30 liters of fuel prior to the flight, the amount of fuel present in the tanks before this refueling was unknown. The investigation also reviewed the pilot's medical fitness and found no evidence of health issues or impairment by alcohol or drugs.