What happened
On 17 July 2011, a Piper PA-24-250 Comanche, registration G-BYTI, was performing a private flight between Sherburn-in-Elmet Airfield and Gamston Airport. After completing several circuits at Gamston, the pilot attempted to return to the airfield. During the climb to 2,000 ft, the pilot noticed that the amber indication light for the landing gear did not illuminate, suggesting the gear had not locked in the up position.
Subsequent attempts to cycle the landing gear selector switch and use the emergency extension system were unsuccessful. After notifying air traffic control and performing fly-pasts, the pilot elected to land in a rapeseed field adjacent to Runway 21 at Gamston Airport. During the landing, the propeller and the lower fuselage skin sustained damage. There were no injuries to the two crew members on board.
The investigation
Investigators examined the aircraft's landing gear retraction mechanism and the airframe. They found that a clevis pin, which connects the nose landing gear push-pull rod to the torque tube assembly, had become lodged against the edge of an access hole in a structural longitudinal beam. This interference prevented the gear from being lowered via the standard or emergency methods.
Further inspection of the aircraft's structure revealed a small dent on the right wing lower skin, which was consistent with the torque link contacting the edge of the wheel well. The investigation also looked into the status of the right landing gear oleo, which was found to be fully compressed at the time of the accident.
Findings
- The right landing gear oleo had deflated during the takeoff run from Sherburn-in-Elmet.
- This deflation caused the landing gear to fail to retract fully.
- A clevis pin in the landing gear mechanism had fouled against the edge of an access hole in a structural beam, which jammed the system and prevented both normal and emergency extension.
- The forces from the motor attempting to overcome the jam likely caused enough misalignment in the transmission assembly to allow the interference to occur.