What happened
Shortly after departing from runway 04 at Nice Airport, an four-engine aircraft entered its initial climb phase. Approximately forty-five seconds into the flight, the aircraft experienced a sudden left bank and overturned. The plane subsequently crashed near the Saint-Augustin station, located north of the airfield, resulting in a massive explosion.
The impact caused the aircraft to disintegrate. While one female passenger was initially discovered alive, she succumbed to her injuries four days after the accident. The crash resulted in all fatalities among those on board, including members of the crew and several notable passengers.
Findings
Investigations into the accident determined that the flight path became irregular immediately following takeoff because the left ailerons were obstructed at an angle of roughly 10 degrees. Technical analysis revealed that a link cheek in the upper rear chain of the co-pilot's control column had become unclamped. This caused the chain to slip from its sprocket and jam against the internal boss of the pin responsible for locking the ailerons in neutral.
The investigation also highlighted significant maintenance challenges related to the aircraft's design. Specifically, it was noted that inspecting and adjusting the chains within the dual control columns is difficult. This design flaw could lead to chains becoming unfastened due to torsion during routine service or maintenance procedures.