What happened
During the landing phase of flight, the right main landing gear experienced a structural failure. Specifically, the shock strut cylinder and piston failed, which resulted in the separation of the axle, wheels, and tires from the aircraft.
The investigation
A metallurgical examination was conducted on the fractured components. The investigation revealed that the fracture surfaces had sustained damage after the initial separation occurred. On the cylinder fracture face, two areas were identified that did not exhibit the angles typically associated with overstress separation. Additionally, ratchet marks were observed, which are features that usually separate initiation sites on offset fracture planes.
In contrast, the fracture surfaces of the piston exhibited features characteristic of overstress separation. Records indicated that the right main landing torque links had failed during a landing 312 flight hours prior to this accident. During the maintenance following that previous failure, the torque links, shimmy damper, and piston were replaced, but the cylinder was not replaced.