What happened
On November 16, 2014, a Zenair CH601 XL ultralight, registration 59-CYN, departed from Maubeuge-Élesmes airfield for a local flight. The aircraft was carrying a pilot and one passenger. After an initial climb to approximately 7,500 feet, the aircraft flew toward the south of Maubeutig, where the pilot began performing aerobatic maneuvers. At approximately 15:30, the right wing of the aircraft failed, causing the aircraft to plummet and collide with the ground near Ferrière-la-Grande. The accident resulted in two fatalities and the total destruction of the aircraft.
The investigation
The investigation focused on the structural integrity of the aircraft and the flight conditions leading to the failure. Examination of the wreckage revealed that the flight controls and associated surfaces remained attached at the time of the break. GNSS data reconstructed the flight path, showing several sharp turns and a significant pull-up maneuver immediately preceding the loss of altitude.
Investigators also examined the aircraft's configuration and the pilot's history. While the pilot was an experienced flyer who frequently performed aerobatics, the aircraft's flight manual explicitly prohibited such maneuvers, limiting the load factor to +4G and -2G. Additionally, the investigation noted that the aircraft had undergone an undocumented major modification involving the addition of wing tanks. The aircraft also lacked the emergency parachute listed on its identification card.
Findings
- The primary cause of the accident was the application of abnormally high upward bending stress during an aerobatic maneuver, which led to the structural failure of the right wing.
- The aircraft was operating at a takeoff weight exceeding its maximum authorized mass; given the weight of the occupants, the available fuel capacity was extremely limited.
- The pilot performed aerobatic maneuvers in an unauthorized area, violating both the aircraft's flight manual and local regulations regarding aerobatic flight sectors.
- The pilot had consumed alcohol during lunch prior to the flight, which may have contributed to a state of euphoria or disinhibition, leading to increased risk-taking.
- The aircraft featured an undocumented major modification (wing tanks) and was operating without a required emergency parachute.