What happened
A special mission flight departed from Vélizy-Villacoublay Air Base, destined for Orange AFB. The aircraft was transporting a group of personnel, including eight crew members and thirteen passengers consisting of six officers and seven engineers from the CEA (Commissariat à l’Éaunergie Atomique). The purpose of the flight was to perform an inspection of the nuclear facility located at Pierrelatte.
During the flight, Marseille Air Traffic Control provided instructions for the aircraft to descend to 8,000 feet until reaching Montélimar, followed by a further descent to 5,000 feet upon approaching Orange. However, while operating in marginal weather conditions, the crew initiated a descent before the appropriate waypoint was reached. This resulted in the aircraft type striking the slope of Mt Suc de Pradou, which has an elevation of 1,342 meters. The impact occurred approximately 3 km southeast of Mézilhac, with debris located roughly 200 meters below the mountain summit. The accident resulted in 21 fatalities, leaving no survivors among the occupants.
Findings
Investigations into the crash concluded that the crew likely confused the two different altitude clearances provided by controllers. This misunderstanding led to a premature descent into the terrain.