What happened
On July 11, 2015, at approximately 19:45 local time, an ELA07 gyroplane, identified as 32-MO, was performing a private flight near the Bézolles ULM airfield. An eyewitness, also a microlight pilot, observed the aircraft approaching on final for runway 27, performing a low pass at an altitude of approximately two to three meters before climbing. The aircraft then entered a left-hand downwind pattern at an altitude of roughly 70 meters.
During the completion of the downwind leg, as the pilot initiated a left turn, the witness observed the rotor blades and heard a distinct "flapping" sound. Immediately following this, the aircraft tilted sharply to the left and fell vertically. The impact resulted in the destruction of the aircraft and a post-crash fire. The pilot, a 63-year-old experienced flyer with over 800 flight hours, was killed in the accident.
The investigation
Investigators examined the wreckage at the accident site but found no evidence of mechanical failure prior to the impact. Components, including the rotor head and a cyclic pitch control rod, were recovered for further analysis. The examination of the rotor head showed no signs of failure preceding the crash, and the broken control rod was determined to have failed due to the forces of the impact with the ground.
While the witness reported hearing a sound associated with rotor blade flapping, investigators found no physical evidence of rotor flapping, a phenomenon characterized by the sudden vertical movement of the advancing and retreating blades. Additionally, although the pilot had previously reported abnormal vibrations to the manufacturer—which had attempted several adjustments without success—the investigation could not establish a link between these vibrations and the accident.
Findings
- The primary cause of the loss of control was likely a decrease in rotor RPM.
- The investigation was unable to identify the specific reason for this loss of rotor speed.