Incident Overview
During the final approach phase, the flight crew extended the landing gear and confirmed it was down and locked via the three green indicator lights. This indication was corroborated by the cockpit voice recorder. However, at the moment of touchdown, the left main landing gear either collapsed or retracted. The landing gear actuator rods, rod ends, down lock rollers, and cams were examined and found to be undamaged.
Post-Incident Examination
Following the incident, investigators examined the hydraulic power pack. When operated, it emitted a loud noise and hydraulic pressure fluctuated between 500 and 1,200 psi. Despite these observations, during a subsequent functional test and internal inspection of the hydraulic power pack, no discrepancies were noted. However, the investigating authority determined that procedural errors were made during that testing, which might have invalidated the test results.