NTSB Identification: SEA90LA023.
The docket is stored on NTSB microfiche number 41170.
Accident occurred Wednesday, November 29, 1989 in STAYTON, OR
Probable Cause Approval Date: 06/25/1992
Aircraft: HUGHES 369D, registration: N446TN
Injuries: 1 Uninjured.
NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.
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 National Transportation Safety Board determines the probable cause(s) of this accident to be: 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.
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