What happened
On 7 October 2022, a Lancair 320, registration G-PJMT, was conducting a private flight when the pilot identified a malfunction during the approach to Little Snoring Airfield. During pre-landing checks, the pilot noted that the right main landing gear failed to indicate as down and locked. After performing a filament test and attempting to cycle the gear, the issue persisted. The pilot even requested a visual confirmation from another aircraft, which confirmed the gear remained retracted.
In an attempt to rectify the situation, the pilot performed several high-energy manoeuvres and engaged the emergency hydraulic pressure release feature, but the gear would not extend. The pilot briefed the passenger on the necessity of landing on only the nose and left main landing gear. During the landing rollout, the pilot used the right aileron to keep the wing elevated and managed directional control via differential braking. However, as the aircraft decelerated, it drifted off the paved runway. The nose gear subsequently collapsed upon hitting a rut at the edge of an adjacent field, resulting in no injuries to the occupants but causing damage to the propeller, the front caster wheel, and the wingtip.
The investigation
Investigators examined the aircraft's hydraulic tricycle landing gear system and discovered that the right main landing gear shock absorber had discharged. This discharge prevented the strut from fully extending once the aircraft's weight was removed from the wheel during takeoff. Consequently, the tyre became caught on the edge of the wheel bay, creating a physical obstruction that the hydraulic actuator lacked the mechanical advantage to overcome.
Findings
- The right main landing gear failed to extend because the tyre was physically impeded by the edge of the wheel well.
- The primary cause of this obstruction was the discharge of the right main landing gear shock absorber.
- The left main landing gear shock absorber was also found to be partially discharged, though to a lesser degree.
- Because both shock absorbers had lost pressure gradually, the resulting difference in wingtip height was negligible during pre-flight inspections and went undetected by the pilot.