On February 14, 1989, a Cessna 340A (registration N5454X) was involved in an aviation accident near Jacksonville, FL. Investigators recorded the probable cause as: Seizure of the upper downlock top bushing, which allowed the main landing gear to be rigged improperly and not be fully down and locked when the gear down light was illuminated. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
A pilot experienced a collapse of the right main landing gear during taxi. Investigation found the seizure of the upper downlock top bushing allowed improper rigging, preventing full lock despite a down light indication.
Incident Overview
During taxi, the right main landing gear of the aircraft collapsed. The pilot was operating the aircraft on the ground when the gear failure occurred.
Investigation Findings
The subsequent investigation determined that the collapse resulted from the seizure of the upper downlock top bushing within the landing gear mechanism. This seizure allowed the main landing gear to be rigged improperly, preventing it from being fully down and locked even though the gear down light was illuminated.
Maintenance Context
A mechanic involved in the investigation stated that the expanded inspection procedures explicitly require that the landing gear bushing be free. The seized bushing was found to have compromised the gear's ability to lock in the extended position.
Outcome
No further details regarding the aircraft, location, or personnel were provided in the source material. The aircraft sustained damage to the right main landing gear structure as a result of the collapse.
Probable cause
Seizure of the upper downlock top bushing, which allowed the main landing gear to be rigged improperly and not be fully down and locked when the gear down light was illuminated.