What happened
The pilot reported that the airplane experienced a bounce during the initial touchdown phase of landing. Upon the second contact with the runway surface, the left main landing gear collapsed under the load. This structural failure caused the aircraft's weight to shift abruptly forward. As the nose dropped, the nose wheel separated from its strut. The detached nose wheel strut then dug into the sod surface of the airstrip, causing the airplane to rotate forward and come to rest in an inverted position.
The investigation
A thorough inspection of the wreckage revealed that the attachment bolt for the left main landing gear had failed completely. To determine the root cause of this failure, a metallurgical examination was conducted on the fractured portion of the bolt. The analysis identified distinct characteristics in the fracture surface, indicating that the component had undergone both fatigue and overstress separation before final failure.
Findings
The sequence of events began with a bounce during landing, which placed excessive stress on the already compromised left main gear. fatigue in the attachment bolt likely initiated a crack that grew over time. The subsequent bounce caused an overstress event that led to immediate separation. This mechanical failure resulted in the collapse of the landing gear and the eventual nosing over of the aircraft onto the sod airstrip.