Incident Overview
During landing, the left main landing gear strut collapsed, causing the airplane to depart the runway to the left. The pilot had previously heard a "clank" sound while airborne, which he considered unusual. When the landing gear was lowered, an unsafe indication for the left main strut appeared. The pilot decided to return to the airport from which he had departed. After troubleshooting and circling the airport, the pilot made a landing attempt with the gear down.
Post-Accident Examination
Examination of the landing gear strut actuator body revealed numerous fractures and signs consistent with an overload event. The manufacturer had issued a Service Bulletin (SB) directing rework and inspection of the landing gear actuator for cracks at the location of the failures found on the accident actuator. The SB required compliance at 3,000 hours total time and at each 500-hour interval thereafter. The SB advised that failure to comply could result in failure of the actuator.
Maintenance Records
Review of the airplane's maintenance logbooks did not show compliance with the subject Service Bulletin. The airframe had accumulated a total time in service of 7,171 hours.