What happened
On 31 May 2010, a Yak-52, registration G-YAKH, was performing a private flight at White Waltham Airfield in Berkshire. Following a series of successful touch-and-go landings on the grass runway 03, the pilot vacated the runway to the right and began taxiing toward the fuel pumps. While the aircraft was moving at approximately walking speed on an upslope, the pilot reduced engine power to 40% and retracted the flaps.
During this maneuver, the aircraft experienced a sudden lurch to the left. The pilot observed the left wing dropping and attempted to verify the position of the landing gear by reaching for the selector. In the process of checking the lever, the pilot believes he may have briefly moved the selector to the up position. Consequently, the left main gear leg retracted, causing the left wing tip to strike the ground. As the pilot attempted to recover, the right main gear leg also retracted. The engine was subsequently shut down, and ground personnel assisted the aircraft.
The investigation
The AAIB examined the pneumatic system responsible for the forward-retracting main landing gear legs. While a strip examination of the actuators identified a small amount of internal corrosion, investigators determined this was not significant enough to cause a mechanical failure of the locking mechanism. Subsequent extension and retraction tests performed by the maintenance organization showed the gear functioned correctly. The investigation also noted that because the nose gear and right main gear remained extended during the initial impact, the propeller did not strike the ground.
Findings
- The primary cause of the gear retraction was the pilot's inadvertent movement of the landing gear selector while attempting to verify the gear's position.
- The aircraft sustained minor damage to the left aileron, left wing tip, and the tail skid.