- Date
- August 25, 1992, 09:43 local (17:43 UTC)
- Place
- Fairbanks, AK
- Injuries
- 2 uninjured
- Damage
- Substantial damage
- Phase of flight
- Enroute
- Aircraft
- N83139Bell 206B
- Weather
- Visual (VMC) · Day
- Status
- Completed · report August 26, 1993
- Report
- Approved by Office Director
- NTSB office
- Alaska Regional Office
- Case key
- 5654
From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.
On this page
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).
Sequence of events
NTSB’s coding before 2008: each occurrence and phase of flight, and the causes and factors under it. The codes are defined in NTSB’s coding manual.
Analysis
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.
Aircraft
- Registration
- N83139
- Reported as
- Bell 206B
- Category
- Helicopter
- Serial number
- 1018
- Airframe hours
- 11,658
- Engine
- Allison 250-C20, 317 horsepower, turbo shaft
- Damage
- Substantial damage
- Fire
- Both
- Flight
- Public aircraft · Public use
- Operator
- Alaska Public Safety, doing business as Alaska State Troopers
- Registered owner
- State Of Alaska
- Airworthiness certificate
- Standard, Normal
- Last inspection
- 100 hour · June 30, 1992 · 39 hours before
- Departed
- FAI
- Destination
- TKJ · Tok, AK
- Flight plan
- Company VFR
- Airport
- FAI · Fairbanks
Flight crew
As NTSB recorded them. NTSB leaves out names.
- Role
- Pilot
- Age
- 54
- Certificate
- Airline transport
- Airplane ratings
- Single-engine land
- Instrument ratings
- Airplane, Helicopter
- Medical
- Class 1, Valid Medical--no waivers/lim.
- Seat
- Right
- Flight hours
- 8,700 total · 4,500 in this make and model · 8,000 as pilot in command · 100 in the last 90 days · 40 in the last 30 days · 3 in the last 24 hours
Weather
- Conditions
- Visual (VMC) · Day
- Wind
- 360° at 8 knots
- Lowest ceiling
- None
- Temperature
- 52 °F, dew point 39 °F
- Altimeter
- 29.00 inHg
- Observed at
- FAI, 1 nm away