On March 23, 1984, a Mitsubishi MU-2B-20 (registration N5HE) was involved in an aviation accident near Charlotte, NC. Investigators recorded the probable cause as: Fatigue cracks in the nose landing gear that propagated to total failure, resulting in the gear shearing off upon landing. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
Aircraft nose landing gear sheared off upon landing after fatigue cracks propagated to total failure, despite the gear being subject to an airworthiness directive.
What happened
Upon landing, the nose landing gear of the aircraft sheared off. The incident occurred during the final phase of flight as the aircraft touched down on the runway.
The investigation
An examination of the nose landing gear assembly revealed that two fatigue cracks had propagated to the point of total failure. The gear was the subject of an airworthiness directive that required inspection of the gear periodically prior to 4000 hrs total time. The accident landing gear had accumulated 2371 hrs total time.
Findings
The structural integrity of the nose landing gear was compromised due to undetected fatigue cracks. The failure occurred despite the gear being within the inspection interval mandated by the airworthiness directive, indicating that the cracks had developed and propagated beyond detectable limits during normal operation.
Probable cause
Fatigue cracks in the nose landing gear that propagated to total failure, resulting in the gear shearing off upon landing.