What happened
On November 17, 2001, at approximately 16:30, an amateur-built Magny O’Taz’Gire gyroplane, identified as W 973-ES, departed from the Equateur microlight platform for a local flight near Montsinéry. Approximately ten minutes into the flight, witnesses observed the aircraft disintegrating in mid-air before crashing.
The investigation
The investigation focused on the wreckage to determine the sequence of the structural failure. Examination of the debris revealed that one of the two rotor blades had struck and severely damaged the vertical stabilizer. Investigators also examined the configuration of the aircraft prior to departure and the pilot's flight experience.
Findings
Technical analysis determined that the aircraft's longitudinal stability had been compromised. The pilot, who was also the owner of the aircraft, had removed the horizontal stabilizer prior to the flight in an attempt to increase the gyroplane's maneuverability.
In a stabilized flight, any external disturbance can trigger a phenomenon known as "pitching" or "porpoising" (marsouinage), characterized by variations in pitch. Normally, the horizontal stabilizer provides a counter-moment that damps these oscillations and restores the aircraft to its original attitude. Without this component, the aircraft's pitch stability was significantly altered, leading to increased amplitude in the oscillatory movement of the rotor blades. This intensified motion caused a rotor blade to strike the vertical stabilizer, leading to the in-flight breakup and the one fatality.