What happened
The incident occurred following a local area instructional flight. Upon return, the aircraft's left main landing gear failed to extend. The pilot attempted to deploy the gear multiple times but was unsuccessful in extending and locking it into place. Consequently, the pilot made the decision to perform an intentional wheels-up landing.
The investigation
A post-incident examination of the aircraft revealed that the landing gear pivot assembly had failed. The failure mode was identified as ductile torsional overstress. Forensic analysis found no evidence of fatigue or preexisting cracks in the component, indicating a sudden overload rather than progressive wear.
Findings
The primary factor in this event was the mechanical failure of the landing gear pivot assembly. The failure resulted in the inability to deploy the left main landing gear, necessitating a wheels-up landing to prevent more severe structural damage or loss of control during the approach.