What happened
On July 21, 2005, a Jodel D 140 C, registration F-PIXX, crashed on the Tsa de Tsan glacier in the municipality of Bionaz, Aosta. The aircraft had departed from Challes-les-Eaux, France, for a recreational flight. The flight crew and three passengers, all French nationals, were killed upon impact. The aircraft was completely destroyed.
While the general weather conditions were clear with good visibility, local atmospheric conditions near the mountain peaks were unstable. Evidence from other pilots operating in the area that day indicated the presence of intense turbulence and strong winds at higher altitudes, specifically involving significant updrafts and downdrag near the ridges.
The investigation
The ANSV investigation, conducted in collaboration with the French BEA, examined the wreckage and analyzed meteorological data. Investigators found that the engine was producing power at the moment of impact and that the aircraft's heading was approximately 240 degrees, suggesting it was moving away from the glacier surface when the accident occurred.
The investigation also reviewed the pilot's credentials and the aircraft's maintenance history. The pilot was highly experienced, with approximately 6,000 total flight hours and significant experience in mountain flying. The aircraft, an amateur-built model, had a valid certificate of airworthiness and had undergone its required 100-hour inspection earlier that year. No mechanical failures or structural issues were identified in the wreckage prior to the impact.
Findings
- The primary cause of the accident was the aircraft encountering severe turbulence and strong downdrafts while flying at a low altitude over the glacier, which led to a loss of control and insufficient terrain separation.
- The pilot was highly proficient and familiar with the local terrain.
- The aircraft was in an airworthy condition with no evidence of in-flight mechanical failure.
- Local meteorological conditions, while appearing favorable in terms of visibility, contained dangerous mountain waves and turbulent currents.