Cat. 2 investigation report: simplified-format report, adapted to the circumstances of the occurrence and the investigation stakes.
On the Saturday morning, in the scope of a weekend organised by their club at the Bretagne-d’Armagnac (Gers) microlight strip, eight gyroplanes and one fixed-wing microlight made a flight over the region.
The flight took place at an altitude of between 1,100 and 1,500 ft with a turning point at the village of Sos. The gyroplanes flew in a V-shaped formation and the fixed-wing microlight outside of the formation. 31LI was at the rear on the left side of the formation.
When passing through the turning point, the gyroplane fell practically vertically and collided with the ground.
During the flight, the main rotor struck the gyroplane’s rudder, causing it to break. This interaction was the result of rotor flapping that may have been caused by rapid actions on the lever along the pitch axis, a localised aerological phenomenon, wake turbulence from one or more of the aircraft ahead, or a combination of several of these phenomena. The investigation was unable to determine the exact origin of this rotor flapping. Given the extent of the damage, it was impossible for the pilot to keep control of the gyroplane and avoid collision with the ground.