What happened
On February 28, 2025, a Jodel D140 (registration F-BMFV) operated by Aéroclub de Megève was conducting a local flight in the Mont Blanc massif. The pilot and a passenger were flying through the Mer de Glace toward the Col du Midi pass. As the aircraft approached the Tacul glacier, the terrain gradient increased significantly, reaching a slope of approximately 20%.
During the climb, the pilot noticed a degradation in performance and interpreted the lack of expected climb as an engine power anomaly. Believing the aircraft could no longer clear the pass, the pilot decided to abort the planned route and attempt an emergency landing on the Vallée Blanche glacier. As the aircraft continued its flight path, the ground speed decreased from 130 km/h to approximately 90 km/h. The aircraft's vertical speed dropped suddenly, and the plane descended roughly 70 meters before striking the glacier surface. The two occupants sustained injuries, and the aircraft was substantially damaged.
The investigation
The BEA examined the wreckage, FLARM flight data, and witness statements. The investigation confirmed that the engine and fuel systems were functioning normally, with no mechanical malfunctions identified. The aircraft was equipped with skis for mountain operations and was within its center of gravity limits. Investigators analyzed the flight path, noting that the aircraft's ground speed and vertical speed indicated a progressive transition into a critical flight regime. The investigation also reviewed the pilot's training and the specific challenges of navigating mountainous terrain without a natural horizon.
Findings
- The primary cause of the accident was the aircraft entering the backside of the power curve during the climb.
- The pilot mistakenly attributed the loss of performance to an engine power loss, leading to an inappropriate flight decision.
- A lack of flight preparation regarding the minimum altitude required to safely clear the pass was a contributing factor.
- The pilot's limited solo experience in mountain flying and the use of a flight path not previously practiced during instruction contributed to the error.
- The increasing pitch attitude, driven by the steepening terrain, increased induced drag and eventually exceeded the available engine power.