What happened
On Saturday, June 7, 2003, at 15:50, a Magni Gyro M 14 Scout gyroplane, identified as I-5510, was participating in a gyroplane gathering in Bois-de-la-Pierre, France. The pilot, who had traveled from Italy for the event, took off and headed toward the downwind leg of the airfield. During the flight, the pilot initiated a sudden and steep climb. As the aircraft's translational velocity decreased significantly during this maneuver, witnesses observed the rotor blades flapping and subsequently striking the vertical stabilizer. Following the impact, the aircraft rolled onto its back and entered a three-turn spin, eventually striking the ground in a nearly inverted position. The accident resulted in one fatality and the total destruction of the aircraft.
The investigation
Investigators examined the flight dynamics of the gyroplane during the high-pitch climb. It was established that as the pilot pushed the control stick forward to prevent the aircraft from reaching zero airspeed, the maneuver induced a decrease in rotor RPM. This reduction in rotor speed led to a phenomenon known as rotor flapping. Because the rotor disc had lost most of its translational velocity while the airframe maintained a climbing attitude, the rotor disc began to oscillate or pendulum backward. This movement caused the rotor blades to strike the vertical stabilizer, damaging the tail unit and causing the rotor to lose its lifting capability.
Findings
- The primary cause of the accident was an over-control of the pitch command, which led to the aircraft exiting its safe flight envelope.
- The reduction in rotor RPM during the steep climb caused the blades to flap excessively.
- The loss of translational velocity, combined with the pilot's control inputs, caused the rotor disc to tilt backward into the airframe's vertical stabilizer.
- The impact with the stabilizer destroyed the aerodynamic integrity of the tail and the lift-generating capability of the rotor.