What happened
During the ground roll following landing, the pilot noted that the tailwheel began to shimmy. Applying forward pressure on the control yoke temporarily stabilized the movement. However, as the aircraft decelerated and the tail lowered, the shimmy resumed. The aircraft then began to veer toward the right side of the runway. The pilot attempted to correct this by applying left rudder input. Initially, the drift continued to the right despite these efforts. Subsequently, the aircraft rolled sharply to the left, resulting in the left wing striking the ground and the collapse of the left main landing gear.
The investigation
A physical examination of the damaged aircraft revealed significant mechanical failures associated with the landing gear assembly. The retention bolt securing the left landing gear spring assembly was found to be bent. Examination of the bolt showed rotational scoring along its midpoint, indicating excessive stress and twisting forces. Furthermore, forensic analysis confirmed that the threads on both the bolt itself and the corresponding nut had been completely stripped, rendering the fastener ineffective.