What happened
On April 6, 2014, a Jodel D1LL3 aircraft, registration F-PIPE, was performing a private flight from the Bucey-lès-Gy altisurface to Beaune Challanges. After a takeoff roll of approximately 150 meters on runway 22, the aircraft entered its initial climb. Witnesses observed the aircraft enter a left bank of approximately 60 degrees while maintaining a zero pitch attitude, followed by a rapid nose-down movement toward the ground. The aircraft struck trees and impacted the ground on its back, resulting in two fatalities and the destruction of the aircraft.
The investigation
Investigators examined the wreckage and the site, noting that the aircraft's impact trajectory was nearly vertical and headed in a direction almost opposite to its takeoff heading. While the propeller showed evidence of delivering power at the moment of impact, the investigation revealed that the electrical fuel pump and fuel filter block were contaminated with vegetable fibers, which could have restricted fuel flow to the engine.
Regarding flight controls, the left aileron control cable failure was determined to be a result of the impact forces rather than a pre-existing condition. The pilot, a PPL(A) holder with mountain rating qualifications, frequently used this site and was experienced in performing "three-point" takeoffs, a technique used in mountain flying to minimize takeoff distance by allowing the aircraft to lift off at low speed before establishing an acceleration level-off.
Findings
- The loss of control likely resulted from an aerodynamic stall during the initial climb.
- This stall may have been caused by performing the climb at an insufficient airspeed and/or a reduction in engine power due to fuel system contamination from organic matter.
- The low altitude at the time of the stall left the pilot with no opportunity to recover the aircraft's trajectory before colliding with the terrain.