What happened
On 31 January 2002, a Piper PA-2xy-260 Comanche, registration G-BRXW, was performing a local flight near Coventry Airport. The aircraft, operated for private purposes with two pilots on board, was returning to the airfield circuit to perform a touch-and-go landing on Runway 23.
During the landing roll, the pilot handling the aircraft inadvertently moved the landing gear selector to the 'up' position. This error occurred before the pilot in the right seat could intervene. As a result, the landing gear retracted while the aircraft was still in motion with a groundspeed of roughly 30 kt. The aircraft subsequently settled onto its fuselage and slid along the runway until it came to a stop. There were no injuries to the crew, though the propeller and the underside of the fuselage sustained damage.
The investigation
The AAIB examined the circumstances surrounding the gear retraction and the mechanical state of the aircraft. It was noted that the aircraft had undergone an annual maintenance inspection two weeks prior. During that maintenance, the oleo struts had been inflated to a level slightly higher than prescribed because the aircraft was not carrying a full fuel load at the time.
Investigators found that the oleo extensions were significantly greater than the 2.75 inches recommended by the service manual. While the aircraft was equipped with an anti-retraction switch on the left main gear designed to prevent accidental retraction when the weight is on the wheels, the excessive extension meant the switch was no longer providing adequate protection. The investigation established that the combination of the aircraft's groundspeed, the wind velocity, and the increased oleo extension allowed the gear to retract despite the safety mechanism.
Findings
- The pilot handling the aircraft mistakenly selected the landing gear up during the landing roll.
- The oleo strut extensions were significantly higher than the manufacturer's recommended specifications.
- The excessive oleo extension caused the landing gear to move outside the protection range of the anti-retraction switch.
- The aircraft was traveling at an airspeed of approximately 40 to 45 kt during the event due to the wind and groundspeed.