- Date
- July 14, 1990, 09:00 local (17:00 UTC)
- Place
- Farewell, AK
- Injuries
- 5 serious
- Damage
- Substantial damage
- Phase of flight
- Approach
- Aircraft
- N300AHBell 206L-1
- Weather
- Visual (VMC) · Day
- Status
- Completed · report May 10, 1993
- Report
- Approved by Office Director
- NTSB office
- Alaska Regional Office
- FAA report
- 19900714025549A
- Case key
- 5302
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
An internal engine failure due to a thermal fatigue failure of the 1st stage turbine wheel as a result of overtemperature. The high rough/uneven terrain prevented a successful autorotation.
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
While approaching a remote mountaintop site to land, at about 100 ft AGL and 40 mph, the engine lost all power as a result of a contained engine failure, and the helicopter made a hard landing. Engine teardown revealed that the 1st stage turbine wheel had failed due to thermal fatigue which originated on the trailing edge o.d. rim surface. In addition, both the 1st and 2nd stage turbine wheel airfoils exhibited evidence of overtemperature operation. The fuel control was properly set. There was no evidence of an internal engine oil fire. Fast engine shutdowns can also result in overtemperatures if sufficient cool down time at idle power is not allowed before the engine is shutdown. The turbine outlet temperature gauge did not incorporate the 'overtemperature light' feature.
Aircraft
- Registration
- N300AH
- Reported as
- Bell 206L-1
- Category
- Helicopter
- Serial number
- 45519
- Airframe hours
- 6,380
- Engine
- Allison 250-C28B, 500 horsepower, turbo shaft
- Damage
- Substantial damage
- Fire
- On-Ground
- Flight
- Part 135
- Operator
- Alaska Helicopters, Inc.
- Last inspection
- 100 hour · July 7, 1990 · 12 hours before
- Departed
- SVW · Sparrevohn Afs, AK
- Flight plan
- Company VFR
- Airport
- NONE
Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.
Flight crew
As NTSB recorded them. NTSB leaves out names.
- Role
- Pilot
- Age
- 50
- Certificates
- Commercial, Flight instructor
- Medical
- Class 2, Valid Medical--w/ waivers/lim
- Flight hours
- 4,641 total · 330 in this make and model · 4,487 as pilot in command · 36 in the last 90 days · 12 in the last 30 days · 4 in the last 24 hours
Weather
- Conditions
- Visual (VMC) · Day
- Wind
- Calm
- Visibility
- 40 statute miles
- Lowest ceiling
- 6,500 ft overcast
- Temperature
- 52 °F, dew point 48 °F
- Altimeter
- 30.00 inHg
- Observed at
- MCG, 55 nm away
FAA reports on this event · 1
The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.