What happened
On September 23, 2022, at approximately 17:00, a BRAKOGYRO 914 UL gyroplane, identified by the registration 65QX, attempted a takeoff from the Geville microlight strip. During the takeoff roll on runway 17, the aircraft failed to lift off and instead overran the end of the grass runway. The aircraft traveled approximately 270 meters beyond the runway threshold before coming to a stop on its right side. The accident resulted in one fatality (the pilot) and substantial damage to the aircraft.
The investigation
Investigators examined the wreckage and the site, noting that the aircraft was largely intact but heavily damaged. Impact marks on the ground, extending 100 meters behind the main wreckage, indicated that the engine was producing power and the pre-rotator was active at the time of the accident. One of the main rotor blades had broken into several pieces, with some fragments found over 100 meters from the main wreckage.
Technical analysis of the aircraft's Flybox computer revealed that the maximum rotor speed reached during the flight was only 51 rpm. This is significantly below the manufacturer's recommended operating range of 200 to 390 rpm. The investigation also reviewed the pilot's experience and maintenance history, noting that the pilot had performed maintenance on the aircraft the previous day and had completed two flights in the aircraft on the day of the accident.
Findings
- The primary cause of the accident was insufficient rotor speed during the takeoff run.
- The low rotor speed likely caused the rotor blades to flap and bend, a phenomenon that occurs when centrifugal force is insufficient to maintain blade rigidity.
- The pilot likely initiated the takeoff roll before the rotor had reached a sufficient rotation speed to prevent blade flapping.
- The investigation could not determine the specific reason why the takeoff was attempted with such low rotor RPM.