DHC-6 Twin Otter Accident at Courchevel Altiport

Overview and Flight Details On 10 February 2000, a De Havilland Canada DHC-6-300 Twin Otter, registration F-GUTH, operated by ALP’AZUR, was involved in an accident at the Courchevel altiport in France. The aircraft was conducting a training flight, specifically a familiarization flight, from Courchevel to Lyon. Two pilots were on board: the 51-year-old captain, who had 11,605 total flight hours, and the 45-year-old co-pilot, who had 861 total flight hours. ## Accident Sequence During the takeoff roll on runway 05, the aircraft experienced a sudden, uncontrolled yaw to the left after passing the crest separating the flat section of the runway from the descending section. The captain attempted to correct the deviation using the rudder and tried to lift off, but the aircraft left the runway. The left main landing gear struck a snowdrift, causing the aircraft to pivot and roll onto its back near the runway. The left wing was torn off the fuselage, and the aircraft came to rest heavily damaged. Both pilots were uninjured and evacuated through the left door. ## Investigation Findings The investigation by the French Bureau d’Enquêtes et d’Analyses (BEA) focused on the nose landing gear, which was found broken. The nose wheel had detached with its axle and part of the fork, while the gear strut remained intact. Laboratory examinations of the fuel, engine oil, and engines revealed no anomalies that could have contributed to the accident. The maintenance records showed no prior issues. ## Probable Cause The probable cause of the accident was an untimely lift-off of the nose gear, which led to a static overload fracture of the nose-gear fork when the nose made final contact with the ground. The analysis suggested that at the relatively high speed of 60 knots when the aircraft approached the descending section, insufficient or oscillating control input on the control column may have caused the nose to lift momentarily. The subsequent impact with the ground resulted in the structural failure of the nose-gear fork.