What happened
On 23 June 2005, a Piper PA-1im8-150, registration G-SUPA, was taxiing toward a hangar at Headcorn, Kent, following a routine landing. During this taxi phase, the right wing of the aircraft began to descend until it rested on the ground. The pilot immediately shut down the engine, noting that the propeller remained clear of the surface. There were no injuries to the pilot or the passenger on board.
The investigation
An inspection of the aircraft identified a failure in the left side of the V-section support frame, which is responsible for supporting the main undercarriage suspension units. The investigation focused on the point where the frame attaches to the airframe mounting lug.
Upon sectioning the left and right attachment fittings for detailed examination, investigators discovered that the bush on the left fitting was absent. While a securing bolt remained in place, the repair agency confirmed that the bush was not attached to it. Evidence found inside the tube, specifically witness marks, indicated that a bush had previously been present. This suggested the component may have been lost when the frame was previously removed from the aircraft.
Findings
- The landing gear support frame is constructed from two steel tubes welded into a V-shape, with each end featuring a bush held by a shaped plate.
- The missing bush on the left side of the support frame led to the failure of the frame end at its airframe attachment point.
- It is believed the bush was lost during a previous period when the frame was removed from the aircraft.
- Reassembling the V-section frame without replacing the bush meant the securing bolt was in direct contact with the welded plate, causing the plate to fail under overload during normal operations.