STAYTON, OR, USA
N446TN
HUGHES 369D
WHILE HOVERING TO PICK UP AN EXTERNAL LOAD, THE PILOT EXPERIENCED LOSS OF ROTOR RPM AND EXECUTED A HOVERING AUTOROTATION. THE ACFT IMPACTED THE GROUND AND WAS SUBSTANTIALLY DAMAGED. EXAMINATION OF THE OVERRUNNING CLUTCH REVEALED FATIGUE FAILURE OF THE OVERRUNNING CLUTCH ASSY. WHEN THE CLUTCH WAS OVERHAULED, THE PREVIOUS TIME WAS LISTED AS UNKNOWN. IT WAS INSTALLED ON THE ACCIDENT ACFT AND OPERATED 175 HOURS PAST MANDATORY REPLACEMENT.
THE MAINTENANCE PERSONNEL FAILED TO RECORD THE PREVIOUS FLIGHT TIME FOR THE OVERRUNNING CLUTCH ON AIRWORTHINESS CERTIFICATION DOCUMENTS WHEN THE ASSEMBLY WAS OVERHAULED. ALSO, CAUSAL TO THE ACCIDENT WAS THE OPERATION OF THE AIRCRAFT BY THE OPERATOR FOR 175 HOURS AFTER MANDATORY RETIREMENT TIME FOR THE SPRAGUE ASSEMBLY.
Source: NTSB Aviation Accident Database
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