Incident Overview
During the approach to Topeka, the flight crew encountered difficulty extending the left landing gear. Unable to resolve the issue, they diverted to Kansas City, where after numerous unsuccessful attempts to lower the left gear, they elected to land with the gear retracted (wheels-up).
Aircraft and Maintenance History
Following the landing, it was discovered that the left main gear was jammed into the gear doors. The cause was identified as a missing aft hinge bolt from the left inboard gear door. The absence of this bolt allowed the gear door to shift slightly, jamming the gear as it began to extend.
Seventeen days prior to the incident, the loose aft hinge was noted during a preflight inspection. Company maintenance personnel were unable to retorque the bolt because the nutplate attachment rivets were stripped. This item was being tracked as a delayed discrepancy.
Maintenance Challenges
The affected assembly is noted to be nearly impossible to inspect, remove, lubricate, install, torque, and safety. Lubrication can only be performed before installation. Replacement of the nutplate is considered a major undertaking.
Manufacturer Guidance
The aircraft manufacturer stated that "short cycling" the gear—cycling it up to 18 times—would eventually break open the gear doors. This emergency method of extending the gear had not been disseminated to all operators.