Accident Description
During the landing rollout, the left main landing gear collapsed and separated from the aircraft. Subsequently, the airplane ground looped and departed the runway to the left, turning 180 degrees and coming to rest on its left side.
Postaccident Examination
Postaccident examination of the aircraft revealed that the left main landing gear u-bolt had failed. The bolt fractured through the bend between the horizontal and vertical leg. The fractured surface displayed ratchet marks and crack arrest positions consistent with fatigue cracking, while features on the remaining surface were typical of an overstress failure.
Cause
The fractured surface at the failure initiation area was damaged following the separation, and the reason for the fatigue initiation could not be determined.