What happened
On May 19, 2018, two pilots conducted a training flight at Sion Airport (LSGS) to familiarize a private pilot with the Lancair 320, registration HB-YFR. The session was divided into two segments: the first flight involved the experienced pilot operating from the right seat, and the second flight placed the trainee in the left seat.
Following the second flight, which included simulated maneuvers over Lake Geneva, the aircraft landed on runway 25. As the aircraft exited the active runway via taxiway Foxtrot, the pilot in the right seat intended to retract the flaps. However, the pilot mistakenly toggled the landing gear switch instead. This action caused the nose gear to retract while the aircraft was still on the ground. The resulting nose-down pitch caused the propeller to strike the pavement, leading to the engine stalling and causing extensive damage to the propeller, crankshaft, and engine cowling. One person sustained slight injuries during the incident.
The investigation
The investigation focused on the cockpit ergonomics and the mechanical configuration of the aircraft. It was noted that the pilot is also the owner of another aircraft, a Lancair 360, registration HB-YKB. A critical finding was that the switch layouts between these two aircraft are significantly different. In the HB-YFR, the landing gear switch is located on the upper left of the center console, immediately adjacent to the flap switch. Conversely, in the HB-YKB, the landing gear switch occupies the position where the flap switch sits in the HB-YFR, while the flap control is located further down the console.
Furthermore, the investigation established that the Lancair 320 lacks a mechanical safeguard to prevent the accidental retraction of the landing gear while the aircraft is on the ground or taxiing. While the main landing gear remained extended due to the low taxi speed, the nose gear retracted fully.
Findings
- The primary cause of the incident was the pilot's confusion of the landing gear and flap switches due to differing cockpit ergonomics between the two aircraft operated by the pilot.
- The physical proximity of the switches in the HB-YFR contributed to the error.
- The aircraft design lacks a safety mechanism to prevent inadvertent gear retraction during ground operations.