What happened
On 18 April 2021, a Robin DR400-140B, registration F-GNNE, was performing the final leg of a triangular cross-country training flight. The aircraft, operated by Aéroclub Paris.Aero, was carrying an instructor and three student pilots. The flight was part of a program to obtain Private Pilot Licences, traveling between Lognable-Émerainville, Le Touquet-Côte d’Opale, and Beauvais-Tillé.
At approximately 13:20, while flying at roughly 1,400 feet near Plessis-Belleville, the aircraft struck a large bird. The impact caused the aircraft to enter a steep left roll and a nose-down attitude. The aircraft subsequently collided with the ground in a field, resulting in four fatalities (the instructor and three student pilots) and the destruction of the aircraft.
The investigation
The BEA examined the wreckage and recovered the remains of a great cormorant weighing 2.4 kg. Investigation of the left wing revealed that the bird struck the underside of the leading edge near the pitot tube. While the main spar did not break, the impact caused the wing's fabric covering to tear between ribs 6 and 7. This tear, combined with the presence of bird remains, allowed air pressure to inflate the fabric, significantly distorting the wing's profile.
Analysis of onboard video and photos confirmed that the strike likely compromised the pitot tube, as the airspeed indicator showed a reading inconsistent with the aircraft's actual ground speed. The investigation also noted that the aircraft was flying in Class G airspace, constrained by a 1,500-foot ceiling due to the nearby Paris 2 TMA.
Findings
- The high kinetic energy of the impact, caused by the weight of the 2.4 kg great cormorant and the aircraft's cruising speed, was a primary factor in the structural damage.
- The aerodynamic degradation of the left wing, caused by the torn fabric and the resulting wing profile distortion, made the aircraft extremely difficult to control.
- The structural vulnerability of the wing's fabric and wood construction contributed to the severity of the damage.
- An increasing population of great cormorants in the region and the proximity of nesting colonies increased the probability of such a strike.