What happened
On May 20, 2017, an APM 20 Lionceau, registration F-HHOT, was conducting a flight instruction session at Chavenay-Villepreux. The flight, operated by Aéroclub Dassault Île-de-France, involved an instructor and a student pilot performing crosswind landing exercises.
During the second landing attempt on runway 28, the aircraft experienced an unstable approach characterized by poorly managed speed and glide path. As the aircraft touched down, it did so with a significant rightward tilt. The instructor took control to rectify the deviation and initiated a go-around. However, the aircraft drifted laterally off the runway, traveling approximately 300 meters through tall grass. During this excursion, the aircraft struck a metal perimeter fence, causing it to pitch forward and eventually land upside down in an adjacent field. Both occupants managed to extricate themselves from the wreckage; the instructor sustained serious injuries, while the student pilot suffered minor injuries.
The investigation
The BEA examined the wreckage and found the aircraft's flaps were set to the takeoff position (12.5°). The investigation focused on the flight sequence, noting that the student pilot was practicing crabbed landing techniques. Air traffic controllers observed the aircraft appearing unstable on all axes and noted the pilot's attempt to climb during the go-around.
The investigation also reviewed the instructor's background and recent workload, noting he had started his professional duties very early that morning. Additionally, the investigators looked into the landing zone parameters and the effectiveness of the go-around procedure under the specific wind conditions (a 9-knot wind from 210°).
Findings
- The primary cause of the accident was the decision to continue the landing attempt despite an unstabilized approach.
- The instructor's takeover of the controls occurred too late to prevent the lateral deviation from the runway.
- The instructor attempted to execute a go-around but failed to realize the aircraft was unable to climb out of the second power regime due to the high grass and a 5-knot tailwind component.
- Potential contributing factors included instructor fatigue, stemming from a workday that began at 05:55.
- A lack of a clearly defined touchdown zone may have hindered the crew's ability to detect the deviation from the nominal landing path earlier.