History of the Flight
At around 18:00, the pilot and a passenger took off from Saint-Rambert-d'Albon aerodrome for a local flight. After returning around 18:35, the microlight lined up on final approach for runway 01. A witness heard a decrease in engine speed while the microlight was in initial climb. The microlight then turned right and stalled during the turn, colliding with the ground approximately 300 m northeast of the northern end of the runway.
Examination of Wreckage
The wreckage was located at the bottom of a basin in a quarry. It was complete and not dispersed. Damage to the fuselage, wings, elevator, and landing gear was consistent with a collision with the ground at a nose-down attitude and a right bank angle. The right wing and front fuselage were compressed. The microlight bounced and leaned on its left wing before stopping. Control linkages were continuous, but the flap position at impact could not be determined.
Engine and Fuel System
The fuel system was continuous from tanks to the engine fuel filter. Both fuel valves were open. The left-wing tank was ripped open; the right-wing tank contained a low amount of fuel, likely due to leakage after the accident. No fuel contamination was detected. The propeller blade failures may indicate the propeller was not rotating at impact. Examination of the engine revealed a pinched seal on the fuel filter, causing a fuel leak. With the pump stopped, leakage was 1.4 to 1.5 l/min; with pumps running, it was 0.2 to 0.3 l/min. According to the injection kit manufacturer, an air leak could cause a rapid loss of power, vibrations, and knocking.
Meteorological Conditions
Conditions at the time included northerly wind of about 10 kt and CAVOK.
Pilot Information
The 76-year-old pilot held a fixed-wing microlight pilot license since 2011 and passenger privileges since 2012. He had logged about 450 flight hours, with 360 hours on the Tecnam P92 since March 2016 and 7 hours in the previous three months. He had not reported abnormal engine operation on previous flights.
Microlight Information
The Tecnam P92 Echo is a high-wing microlight with a Rotax 912 UL engine, modified with a LAD AERO electronic injection kit. It has two wing tanks (30 l each). The fuel filter seal pinching could have been detected during pre-flight inspection if the fuel valves were open. The maintenance manual specifies bleeding the fuel filter daily but does not define an inspection interval for opening the filter.
Investigation Findings
The BEA concluded that a fuel leak during the flight due to incorrect positioning of the fuel strainer seal caused the fuel tanks to drain abnormally. The average engine consumption plus the leak totaled approximately 23 l over the 46-minute flight. In the initial climb, engine power decreased. The pilot turned right, and the microlight stalled. The parachute was not activated.