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NTSB Report
August 25, 1992 · Bell 206B · N83139
Fairbanks, AK
Overview
Report Status
Probable Cause
Event Type
Accident
Date
August 25, 1992
Injury Outcomes
No injuries (2 uninjured)
Location
Fairbanks, AK
Aircraft
Bell 206B
Tail Number
N83139
Operator
Alaska Public Safety
Injuries
None
Aircraft Damage
Substantial
NTSB Number
ANC92GA155
THE STATE OF ALASKA HELICOPTER EXPERIENCED A FUEL LEAK AND AN UNEVENTFUL PRECAUTIONARY LANDING. THE LEAKING FUEL LINE WAS REPLACED IN FIELD MAINTENANCE WITHOUT MANUFACTURER'S REQUIRED SECURING CLAMPS. A SECOND FUEL LEAK, PRECAUTIONARY LANDING AND FUEL LINE REPLACEMENT WAS EFFECTED, AGAIN WITHOUT CLAMPS. A THIRD FUEL LEAK AT THE SAME REPLACEMENT LINE WAS FOLLOWED BY A FIRE FOLLOWING A PRECUATIONARY LANDING. THE NTSB SUPERVISED MANUFACTURER'S ENGINE EXAMINATION REVEALED VIBRATION IN ROTATING COMPONENTS OF 15 TIMES THE ALLOWED LIMITS, AS WELL AS A FATIGUE CRACK IN THE HOT SECTION. THESE VIBRATIONS AND CRACKS WERE NOT DISCOVERED DURING ENGINE MAINTENANCE AND INSPECTIONS BY COMPANY CONTRACT MAINTENANCE PERSONNEL. THE METALLURGICAL EXAMINATION OF THE FUEL LINES IN EACH EVENT REVEALED FATIGUE PROPAGATION AND THE LACK OF CLAMP MARKS ON THE FUEL LINES FROM EVENTS 2 AND 3.
NTSB Probable Cause
POOR MAINTENANCE AND INSPECTION PROCEDURES BY THE CONTRACT MAINTENANCE PERSONNEL, AS WELL AS IMPROPER MAINTENANCE AND INSTALLATION OF THE FUEL LINE BY THE CONTRACT MAINTENANCE PERSONNEL. FACTORS RELATING TO THE ACCIDENT WERE THE TURBOSHAFT ENGINE VIBRATIONS AND THE CRACKED FUEL LINE(S).
Full Narrative
THE STATE OF ALASKA HELICOPTER EXPERIENCED A FUEL LEAK AND AN UNEVENTFUL PRECAUTIONARY LANDING. THE LEAKING FUEL LINE WAS REPLACED IN FIELD MAINTENANCE WITHOUT MANUFACTURER'S REQUIRED SECURING CLAMPS. A SECOND FUEL LEAK, PRECAUTIONARY LANDING AND FUEL LINE REPLACEMENT WAS EFFECTED, AGAIN WITHOUT CLAMPS. A THIRD FUEL LEAK AT THE SAME REPLACEMENT LINE WAS FOLLOWED BY A FIRE FOLLOWING A PRECUATIONARY LANDING. THE NTSB SUPERVISED MANUFACTURER'S ENGINE EXAMINATION REVEALED VIBRATION IN ROTATING COMPONENTS OF 15 TIMES THE ALLOWED LIMITS, AS WELL AS A FATIGUE CRACK IN THE HOT SECTION. THESE VIBRATIONS AND CRACKS WERE NOT DISCOVERED DURING ENGINE MAINTENANCE AND INSPECTIONS BY COMPANY CONTRACT MAINTENANCE PERSONNEL. THE METALLURGICAL EXAMINATION OF THE FUEL LINES IN EACH EVENT REVEALED FATIGUE PROPAGATION AND THE LACK OF CLAMP MARKS ON THE FUEL LINES FROM EVENTS 2 AND 3.
Flight
Event TypeAccident
Event Time09:43 AKDT
Nearest AirportFairbanks (1nm ESE)
Runway0
Flight Plan FiledCvfr
Aircraft FireBoth
Aircraft ExplosionNo
Aircraft
AircraftBell 206B
Tail NumberN83139
Aircraft CategoryHeli
DamageSubstantial
OperatorAlaska Public Safety
Engines1
Engine TypeTurboshaft
Engine DetailsAllison · 250-C20 · Turboshaft · 317
Seats5
People & Injuries
Injury SummaryNo injuries (2 uninjured)
Fatal0
Serious0
Minor0
Uninjured2
Total2
Crew 1Age 54 · First Class
Conditions
ConditionsVMC
LightDaylight
Wind360° @ 8 kt
CeilingNone
Temperature / Dew Point52 / 39 C
Altimeter29.00 inHg
Observation Time12:43
Weather SourceWFAC