What happened
On 17 April 2016, a Mooney M20F Executive, registration G-CEJN, was conducting a local flight to verify system serviceability ahead of a scheduled annual inspection. The flight was a private operation returning to Wellesbourne Mountford Airfield in Warwickshire.
During the approach to Runway 18, the pilot maintained a recommended speed of 80 mph. Before touchdown, the pilot confirmed the landing gear position via the cockpit green down light and a physical inspection through a floor window. Following a prompt from the control tower to verify all three gear indicators, the pilot proceeded with the landing.
While the initial touchdown was gentle, the pilot noticed the right wing began to drop as the aircraft decelerated. In response, the pilot applied left aileron and shut down the engine by pulling the mixture control. The aircraft's right flap and tail skid made contact with the runway surface before the plane veered onto the grass and stopped. There were no injuries to the pilot, but the aircraft sustained damage to the right flap, the right aileron tip, and the tail skid.
The investigation
Investigators examined the aircraft's landing gear actuation system, which had been upgraded from the original manual design to an electric system. This system utilizes a single electric motor to operate the rods for the nose and main landing gear.
An engineering examination of the wreckage revealed that the actuating rod for the right main landing gear was bent. This damage suggested that the downlock mechanism had failed to reach its overcentre locked position. Consequently, the rod may have attempted to react to the forces of landing through the retraction rod. The investigation also considered whether a prior event had caused slight distortion to the rod, preventing proper locking.
Findings
- The right main landing gear collapsed during the landing roll.
- The downlock had not overcentred, leaving the gear vulnerable to landing loads.
- The cockpit indicator light and inspection window only confirm the position of the actuating rods, not that the gears are fully locked down.