Incident Overview
An aircraft executed a landing with the landing gear retracted following indications that the left main landing gear had not extended fully. The crew had lowered the landing gear for the approach, and while the nose gear and right main gear were confirmed down, the captain's visual inspection from the cockpit reportedly showed the left main gear remained retracted.
Crew Actions
According to the crew, the aircraft's manual was consulted for additional procedures to lower the gear. No fly-by for a tower check was performed, and the MIG light in the wheel well was not used to improve visibility during the nighttime operation. When the remaining fuel reached 100 pounds per side, a decision was made to land with the gear up.
Post-Accident Findings
Subsequent testing of the landing gear extension system found that all operations functioned normally, with the exception of the main gear down-lock indications. A post-accident inspection revealed that the left main gear lock piston was binding, which prevented a down-and-locked indication in the cockpit.
Investigation Outcome
The investigation determined that the binding lock piston was the reason the left main gear did not provide a down-and-lock indication, leading to the gear-up landing. No other anomalies were found in the landing gear system.