What happened
During the approach phase of flight, the pilot initiated the sequence to lower the landing gear. Immediately following this action, a loud thumping noise was audible inside the cockpit. Despite the unusual sound, the pilot did not receive confirmation that all three gear struts were fully extended and locked in place. Visually inspecting the aircraft from the ground or through available indicators, the pilot believed that the main landing gear assembly appeared to be down.
Upon touchdown on the runway surface, the asymmetric configuration of the landing gear became critical. Only the right main gear strut was successfully extended and locked into the down position. The left main gear failed to deploy correctly. Consequently, the aircraft swerved violently off the side of the runway due to the uneven support and drag forces generated by the single functional main gear.
The investigation
Post-accident examination of the airframe revealed significant mechanical failure within the landing gear system. Inspection confirmed that only the right main gear was down and locked. The left main gear remained in an undeployed or partially deployed state, causing the excursion.
Detailed forensic analysis of the retraction mechanism identified the root cause of the failure. The actuator responsible for retracting the right main gear was found to be split open. This structural failure prevented the proper hydraulic or mechanical operation required to cycle the gear correctly, leading to the incomplete deployment during the landing sequence.