What happened
On May 29, 2003, a Robin DR400/160 aircraft, registered F-GDYS, was conducting a VFR flight from Chavenay, France, toward Lucca Tassignano, Italy. The flight, carrying four occupants, included two pilots and two passengers. During the transit through the Alps, the aircraft encountered deteriorating weather conditions, including the presence of cumulonimbus clouds and towering cumulus.
Radar tracking showed the aircraft climbing through various flight levels, eventually reaching FL135. At approximately 11:05, the aircraft was at FL105, and by 13:06, it was recorded at FL129, showing a significant descent. The aircraft disappeared from radar near the Grand Combin massif. The wreckage was later located on the Mont Durand Glacier at an altitude of approximately 2,950 meters. The impact was high-energy, resulting in the two fatalities of the pilots; the two passengers were also on board, but the report focuses on the deaths of the crew members. The aircraft was destroyed upon impact.
The investigation
Investigators examined the wreckage, the engine, and the flight instruments. Technical analysis of the Robin DR400/160 revealed no mechanical failures; the engine was found to be operating at high RPM at the moment of impact, and the flight controls were intact. The investigation also reviewed radar data, radio communications with Geneva Information, and witness testimony from a person near the site who heard the engine accelerating and a heavy impact.
Medical examinations of the pilots were conducted. Autopsies showed no pre-existing medical conditions or signs of alcohol or drug use. However, the investigation noted that the aircraft was not equipped with any oxygen supply, despite the flight occurring at high altitudes for an extended duration.
Findings
- The primary cause was a collision with terrain following a loss of spatial orientation while attempting to maintain VFR flight in mountainous terrain under adverse weather.
- The presence of heavy cloud cover and the lack of visual contrast between the clouds and the white glacier likely contributed to the pilot's disorientation.
- The crew was subject to physiological stressors, including hypoxia due to the lack of supplemental oxygen at high altitudes, as well as potential hypoglycemia and operational fatigue after more than three hours of flight.
- Frequent course changes observed on radar suggest the pilot was attempting to maneuver around convective weather.