What happened
On March 31, 2021, a privately owned Lancair 360, registration HB-YMF, was performing a VFR approach to runway 22 at Emmen Airfield (LSME). The flight originated from St. Gallen-Altenrhein (LSZR). During the final approach, the pilot maintained a stable descent, reducing speed from 100 kt to approximately 87 kt as the aircraft approached the runway.
However, the initial touchdown was hard, with a vertical acceleration of 1.8 g. This impact triggered a sequence of bouncing and subsequent nose-down movements. The aircraft briefly lifted off the ground before striking the runway again with a much harder impact of 3 g. This second impact caused the nose gear to fail; the mounting bolts sheared, and the nose wheel separated from the assembly, striking the underside of the fuselage. A third impact occurred at 2.5 g, after which the aircraft slid along the runway on the nose gear strut, causing the propeller tips to strike the pavement. The pilot escaped the incident without injury, though the aircraft sustained heavy damage.
The investigation
Investigators examined the flight data, which recorded vertical acceleration, altitude, airspeed, and pitch attitude. The data revealed that while the approach was stable, the pilot failed to initiate the flare sufficiently early. The investigation also reviewed the aircraft's technical history, noting it was a homebuilt aircraft in the special category. Maintenance records showed that the landing gear struts had received an oil change approximately nine months prior to the accident.
Findings
- The primary cause of the accident was that the pilot initiated the flare too late, leading to a high sink rate and a hard initial touchdown.
- The subsequent sequence of bounces and nose-down corrections resulted in a pilot-induced oscillation, known as "porpoising."
- The intense forces of the repeated impacts caused the nose gear assembly to break, specifically the failure of the four mounting bolts at the flange.
- The pilot's relatively low amount of recent flight training may have contributed to the inability to recover from the bouncing sequence.
- The aircraft's design characteristics, specifically a natural tendency for the nose to drop in landing configuration without manual elevator input, made the landing more demanding.