What happened
Following takeoff, the pilot encountered an issue with the landing gear system. After attempting to retract the gear, he was unable to receive an up-and-locked indication. He subsequently extended the gear and confirmed a safe down-and-locked indication. The pilot then returned to the airport and completed a landing. While taxiing off the runway, the left main gear collapsed.
The investigation
An examination of the aircraft revealed that the left main landing gear was compromised. Specifically, the down lock assembly was found to be defective. This mechanical failure prevented the gear from remaining retracted or functioning properly during the ground phase of the flight.
Findings
The primary factor in this incident was the defective left main landing gear down lock assembly. The defect directly led to the collapse of the gear while the aircraft was on the ground. No other mechanical issues were identified as contributing factors.