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NTSB Report
November 29, 1989 · Hughes 369D · N446TN
Stayton, OR
Overview
Report Status
Probable Cause
Event Type
Accident
Date
November 29, 1989
Injury Outcomes
No injuries (1 uninjured)
Location
Stayton, OR
Aircraft
Hughes 369D
Tail Number
N446TN
Operator
Associated Helicopter Svcs
Injuries
None
Aircraft Damage
Substantial
NTSB Number
SEA90LA023
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.
NTSB Probable Cause
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.
Full Narrative
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.
Flight
Event TypeAccident
Event Time11:45 PST
Nearest Airport0nm N
Runway0
Runway Length0
Runway Width0
Flight Plan FiledNone
Aircraft FireNo
Aircraft ExplosionNo
Aircraft
AircraftHughes 369D
Tail NumberN446TN
Aircraft CategoryHeli
DamageSubstantial
OperatorAssociated Helicopter Svcs
Operating RulePart 133
Engines1
Engine TypeTurboshaft
Engine DetailsAllison · 250-C20B · Turboshaft · 420
Seats4
People & Injuries
Injury SummaryNo injuries (1 uninjured)
Fatal0
Serious0
Minor0
Uninjured1
Total1
Crew 1Age 43 · Second Class
Conditions
ConditionsIMC
LightDaylight
WindCalm
Visibility1 sm
CeilingOvercast 200 ft
Temperature / Dew Point37 C / 37 C
Altimeter30.00 inHg
Observation Time19:50
Weather SourceWFAC