What happened
On 5 July 1998, a Piper PA-28R-180, registration G-AVWU, departed Wycombe Air Park for Le Touquet on a private flight. Shortly after takeoff, the pilot attempted to retract the landing gear, but the gear failed to move into the up position. In an effort to rectify the issue, the pilot cycled the gear selector and utilized the emergency override lever, but the cockpit indicators failed to show the gear was down and locked.
Seeking clarification, the pilot performed a low pass over the control tower. Tower personnel observed the gear to be in the down position. Following a second circuit, the pilot landed on Runway 25. During the ground roll, the left main landing gear collapsed, causing the aircraft to swing 90 degrees to the left. The aircraft eventually came to rest on the grass after the left wing made contact with the ground. There were no injuries to the two occupants, though the aircraft sustained damage to the left wing, the left flap, and the main landing gear.
The investigation
Investigators examined the aircraft's retractable tricycle landing gear system, which relies on an electrically powered reversible pump. The inspection revealed that the pump motor had been contaminated with hydraulic fluid because of a leaking seal. This contamination had been present for an extended period and eventually caused the motor to fail. Because the override function still required the pump to operate, the pilot was unable to achieve a locked gear position using the standard or override settings.
Further testing at a maintenance facility demonstrated that the emergency free-fall procedure—using the emergency down selection—was capable of achieving a down and locked condition, suggesting the failure was specifically tied to the pump's inability to move the fluid.
Additionally, the investigation noted that the instructional placard regarding the override system was a typewritten paper label. This label had become soiled and curled, making it difficult for a pilot to read clearly from the cockpit seat.