What happened
On March 7, 2021, a Eurocopter AS350 Écureuil helicopter bearing registration F-GIBM was involved in a fatal accident in Touques, located in the Calvados department of Normandy. The aircraft was operated by Dolijet, an enterprise chaired by the prominent French politician and industrialist Olivier Dassault. At the time of the incident, the airframe had accumulated more than 8,000 flight hours, with its last airworthiness certification issued in July 2020.
The flight was scheduled to depart from a private helipad in Touques and proceed to another private landing site at a property owned by Dassault in Beauvais. The departure location had been selected the previous day and was constrained by surrounding vegetation, with the tallest trees reaching a height of 23 meters. Just two days prior to the crash, on March 5, both the pilot and a mechanic had identified that the artificial horizon indicator was not functioning.
During the takeoff sequence, the helicopter lifted into a hover before climbing vertically alongside the tree line. The main rotor blades struck a tree branch approximately 19 meters above the ground. This collision caused the tail boom to detach from the fuselage, with the majority of the connecting rivets shearing off. The force of the impact also subjected the main rotor hub to excessive torque, resulting in the ejection of the front passenger seats. Following the strike, the aircraft yawed and descended, impacting the ground roughly 50 meters from its point of departure.
Investigation
The Bureau d'enquêtes et d'analyses pour la sécurité de l'aviation civile (BEA) conducted the official inquiry into the crash. The investigation focused on the operational constraints of the chosen landing site and the pilot's decision-making process during the initial climb phase.
Findings
The BEA determined that the selected departure site significantly limited the pilot's ability to execute a safe maneuver. The proximity of tree branches, which were obscured by shadows, created a hazardous environment with minimal safety margins. Investigators concluded that the pilot likely struggled to accurately judge the distance to these branches due to low light contrast and visual shading.
The report highlighted that the pilot may have underestimated the risk posed by the vegetation. Consequently, the BEA issued two safety recommendations aimed at improving training for confined-area operations in this aircraft type and enhancing awareness regarding the aging of the human visual system's ability to perceive depth and distance in low-contrast conditions. Both Olivier Dassault and the pilot perished in the accident.