What happened
On May 7, 2005, a privately operated Colomban MC 15 « Cri Cri» (amateur-built) was participating in an aircraft gathering at Albertville, France. The pilot departed at 09:15 for a local flight, initially climbing to 9,000 feet before proceeding toward the Grand Pic de la Lauzière at 12,000 feet. While flying near the Mont Blanc massif, the aircraft reached approximately 14,000 feet.
As the pilot began a steep descent through the valley to return to Albertville, the engines lost power. To avoid exceeding the maximum operating speed (VNE), the pilot had reduced power settings, but subsequent attempts to increase power to restart the engines were unsuccessful. Unable to reach a suitable meadow and facing difficult terrain consisting of snowy slopes, the pilot attempted an emergency landing between a stream and a winding road. During the final approach, the aircraft struck a rock, causing the destruction of the aircraft and resulting in one injury to the pilot.
The investigation
The investigation focused on the cause of the engine failure and the pilot's decision-making process. Investigators examined the wreckage and found that the engines were not delivering power at the moment of impact, though no mechanical anomalies were found in the engines themselves.
Crucially, the investigation noted that the two carburetors on this specific MC 15 model are exposed to the air without any heating system. Other pilots at the same gathering reported experiencing similar carburetor icing on that day and had canceled their flights. The investigation also reviewed the pilot's flight preparation, noting that the pilot had not consulted recent meteorological information or sought advice from the event organizers regarding current conditions.
Findings
- Carburetor icing caused the engines to stop in flight.
- The pilot's flight preparation was insufficient, as he failed to account for the specific icing vulnerabilities of the aircraft's engine configuration.
- The pilot did not consult weather reports prior to departure, despite high humidity levels at flight level 100.
- The pilot had limited experience flying this specific aircraft type at high altitudes, having previously only performed short tests at FL 110.
- While the pilot spent approximately 30 minutes above FL 120, which could potentially lead to hypoxia-related impairment, the investigation could not definitively confirm that hypoxia influenced his judgment.