What happened
On 12 September 2021, a Guerin G1 microlight, identified as 78XZ, was performing a local flight from the Boissy-sans-Avoir private microlight strip. The pilot, accompanied by a passenger, completed a touch-and-go maneuver on runway 30. During the subsequent initial climb, the aircraft suddenly entered a steep nose-down attitude. The aircraft struck the ground approximately 750 meters from the end of the runway with its wings level, which subsequently triggered a fire. The impact and following fire resulted in two fatalities, involving both the pilot and the passenger.
The investigation
The investigation relied on site observations, wreckage analysis, witness statements, and a live-streamed video captured by a cockpit camera. The video, which was being streamed to a social network at the time, showed the aircraft's descent but did not provide sufficient detail to explain the cause of the pitch change.
Examination of the wreckage revealed that the aircraft's wings were in the flight position and the airframe parachute had not been deployed. The carburetor butterfly valves were found one-third open, indicating the engine was at low power. While the intense fire suggested a significant amount of fuel remained in the wing tanks, investigators found no mechanical anomalies in the wreckage that could be linked to the sudden change in attitude. Additionally, a medical examination of the pilot found no evidence of acute medical issues, such as loss of consciousness, that would explain the maneuver.