What happened
On 7 July 2013, a Socata TB20 Trinidad, registration G-TBXX, was completing the final of three local flights of the day at Headcorn Aerodrome, Kent. The flight, which was a private operation, involved one pilot and two passengers. The pilot had performed a pre-flight inspection earlier that day, specifically checking the retractable landing gear, and noted no issues.
The aircraft landed on the grass Runway 10 following a stable approach at 80 kt with full flaps. At the time of landing, the three green indicator lights confirmed the gear was down. The pilot initially allowed the aircraft to decelerate without using the wheel brakes. However, as the pilot retracted the flaps and prepared to apply the brakes, the left wing began to sink. This was caused by the collapse of the left main landing gear leg. The aircraft slid for several metres and veered to the left before coming to a halt on the runway. There were no injuries to the crew or passengers, though the aircraft sustained damage to the left wingtip, the pilot step, and the left landing gear.
The investigation
Investigators examined the aircraft and found that the left landing gear leg had failed approximately 3 inches below its upper attachment point. A subsequent inspection by a maintenance organisation revealed that a crack had developed from the inside of the leg outwards. The engineer noted that the internal surface of the leg was difficult to inspect visually while installed, but they observed evidence of corrosion on the inner surface of the component.