What happened
On 18 January 2021, a MAGNI M16 gyroplane, identified as 48BU, departed from the Valloire Bonnenuit mountain airstrip for a local flight. After takeoff, the pilot flew toward Valloire and Valmeinier, eventually heading south toward the Terre Rouge refuge and Mont Thabor. Witnesses observed the aircraft flying at a low altitude along the valley line.
Near the Terre Rouge refuge, the pilot likely initiated a turn to head back north, climbing along the terrain at a low height. During this maneuver, the pilot performed a sudden action on the cyclic stick, possibly in response to immediate danger. This maneuver triggered a significant rotor flapping phenomenon. The resulting movement caused the main rotor blades to strike the aircraft's tailplane and the pusher-propeller, leading to a total loss of control and a fatal collision with the snow-covered ground.
The investigation
The investigation focused on the wreckage found on a snowy plateau and data retrieved from the Rotax engine computer. Investigators identified debris from the vertical and upper sections of the tailplane, as well as propeller fragments, near a former sheep shed. The distribution of this debris suggested a structural separation occurred at a low altitude while flying over the shed.
Analysis of the engine computer showed that the engine was operating normally with no anomalies in oil pressure, temperature, or engine speed prior to the accident. The engine speed was near its maximum at the time of impact. Physical examination of the main rotor blades revealed traces of yellow paint from the tailplane and impact marks from the pusher-propeller. Additionally, the propeller blades showed signs of fracture and damage consistent with the rotor strike.