What happened
On 17 April 2021, a LAK1s7 glider, registration F-CJLL, was performing a local flight at Oloron-Herrère aerodrome. During the flight, the pilot was requested by an instructor in another aircraft to perform a short landing on runway 07 to clear the runway for a student training exercise.
While on final approach to runway 07, the pilot perceived the approach path to be too steep. In an attempt to correct the glide path, the pilot intended to deploy the speed brakes; however, the pilot instead operated the flap control. Unaware of this error, the pilot continued the approach, eventually flying over the runway to perform a U-turn to align with runway 25. During the subsequent maneuvers to realign with runway 07, the aircraft's low energy and steep approach led to a loss of control, resulting in a collision with trees near the runway. The glider sustained substantial damage, but the pilot was able to evacuate the aircraft without injury.
The investigation
The BEA examined the flight data, aircraft systems, and pilot statements. The investigation focused on the cockpit ergonomics of the LAK17, specifically the proximity of the speed brake and flap controls. The investigation noted that the speed brake control is a blue handle pointing downwards, while the flap control is a grey handle pointing upwards, both located on the left side of the cabin. The investigators also reviewed the pilot's recent flight history, noting that while the pilot was experienced, he had not flown this specific model in approximately two years and had primarily been flying other glider types recently.
Findings
- The primary cause of the accident was the confusion between the speed brake and flap controls during the approach phase.
- The pilot failed to realize that the flaps had been deployed instead of the speed brakes, which prevented the necessary correction of the approach path.
- The pressure to comply with the instructor's request for a short landing contributed to the pilot's inability to analyze the situation effectively.
- A lack of a pre-flight briefing regarding the specific cockpit ergonomics of the LAK17 contributed to the error.