Incident Overview
Upon entering the traffic pattern at the destination airport, the pilot extended the landing gear using both normal and alternate methods. The left main landing gear did not extend. The flight departed the traffic pattern and orbited the airport while multiple attempts to extend the left main landing gear were unsuccessful. The flight diverted to an airport with fire rescue services, performed a fly-by, and then climbed to altitude where G-loading maneuvers were performed in an effort to extend the left main landing gear. Despite these efforts, the gear could not be extended. The airplane was landed with the left main landing gear retracted.
Examination and Findings
Post-incident examination of the airplane revealed that the lugs on the cylinder head of the left main landing gear jack were fractured. A metallurgical examination of the fractured lugs showed overstress failure; no evidence of progressive fatigue or stress corrosion cracking was observed. The cylinder head is a 5,000-cycle life-limited component. The failed cylinder head, installed when the airplane was manufactured, had accumulated 4,751 cycles at the time of failure, including the accident landing. The jack attachment and surrounding area, which require inspection every 600 hours, had last been inspected 348 hours and 299 cycles earlier, and no discrepancies were noted.