What happened
On September 23, 2018, a two-seat DG 500 sailplane, registration HB-3204, departed from Gruyère airfield for a cross-country flight. During the return leg from the Stockhorn region, the pilot encountered strong southwesterly winds at altitude, including a headwind of approximately 65 km/h. Realizing that the glide performance was insufficient to reach the original destination at Gruyère, the pilot diverted toward Ecuvillens airfield, selecting a route with suitable fields for a potential off-field landing.
Upon arriving at Ecuvillens, the pilot performed a short left circuit for runway 27. The approach was complicated by a 35 km/h headwind and sloping terrain near the runway threshold. During the final phase of the flight, the pilot focused heavily on maintaining sufficient altitude to avoid undershooting the runway. Upon touchdown, it was discovered that the landing gear had not been extended. The aircraft slid on its fuselage along the paved runway until coming to a stop. The crew members remained uninjured, though the aircraft sustained light damage to the underside of the fuselage.
The investigation
The investigation examined the pilot's decision-making process, the cockpit environment, and the aircraft's mechanical state. Investigators reviewed the pilot's flight logs and the weather conditions present during the flight. The inquiry also focused on why the pilot failed to notice the landing gear was retracted and why the cockpit warning signal—which activates when spoilers are deployed while the gear is up—was not heard.
Findings
- The pilot's reduced situational awareness was the primary cause of the incident. High levels of stress and a phenomenon known as "target fascination" (focusing excessively on not undershooting the runway) led the pilot to overlook critical tasks.
- The pilot did not perform the final approach checklist due to time constraints, which contributed to the omission of the landing gear extension.
- Although the cockpit warning signal for the landing gear configuration was functional upon inspection the following day, the pilot did not perceive the alert during the approach.
Safety action
- The pilot's failure to use the checklist highlights the necessity of disciplined, habitual use of checklists, even during demanding or time-pressured approaches, to mitigate the risk of manual errors.