Incident Overview
The flight crew made several attempts to extend the nose landing gear using both normal and emergency procedures but could not obtain a down-and-locked indication. The nose gear view window was dirty, preventing the crew from visually confirming the gear position. Ground personnel provided conflicting reports on whether the nose gear was down.
During the subsequent landing, the nose gear collapsed. Post-incident examination revealed that a bogus part had been installed in the nose landing gear down lock actuator. This part jammed, preventing full extension of the gear.
Crew Actions
The crew attempted an extension procedure designed for total hydraulic failure. They also reset the selector valve prior to touchdown. When the valve was reset, the pressure on the nose landing gear—which had been achieved using the hand pump—was released.
Maintenance Findings
Investigators noted that the nose landing gear view window was not a scheduled maintenance inspection item. The bogus part in the down lock actuator was the direct cause of the jam.