What happened
On August 7, 2017, a Pipistrel Virus 912 SW 100, registration 17-YO, departed from the Saint-Estèphe microlight airfield for a flight to La Rochelle. Shortly after takeoff, the pilot performed a 180-degree turn to return to the airfield to perform a low-altitude pass over the runway, intended as a gesture to greet people on the ground.
During this high-speed maneuver, the aircraft flew at a very low altitude, approximately 10 to 30 meters above the runway. Witnesses observed the aircraft's wings and tail undergoing intense oscillations. The aircraft subsequently entered a steep dive at an angle between 30° and 45°, impacting the runway and catching fire. The impact and subsequent fire resulted in two fatalities (the pilot and one passenger) and the total destruction of the aircraft.
The investigation
The BEA examined the wreckage and the impact site, noting that debris was dispersed over a 130-meter area, indicating high energy at impact. Due to the destruction of the cockpit by the impact and fire, onboard computers could not be recovered.
Investigators analyzed traces left on the runway. The pattern of contact from the wing edges showed asymmetrical flexing, which is consistent with a flutter phenomenon occurring just before impact. Witnesses, including a fighter pilot and another microlight pilot, provided accounts of the aircraft's flight path, describing a sequence of rapid pitch changes and visible structural vibrations (oscillations) in the wings and tail during the low-altitude pass.
Findings
- The pilot's decision to perform a low-altitude, high-speed pass significantly reduced the margin for error and the ability to recover from an upset.
- The aircraft was flying at a very high speed, likely exceeding the maneuvering speed (Va), which increases the risk of structural damage during control inputs.
- The investigation identified a high probability that a flutter phenomenon—a self-sustaining structural vibration—occurred during the maneuver, potentially triggered by high speed and aggressive control inputs.
- The loss of control may have been caused by flutter-induced vibrations, a structural failure resulting from flutter, or a structural failure caused by high G-loads during a recovery attempt (pull-up) at high speed.