Bell 206B accident near Kokhanok, Alaska, September 9, 1990
On September 9, 1990 at about 10:00 pm local time, a Bell 206B (helicopter), registered N385EH, was substantially damaged in an accident near Kokhanok, Alaska. It was an other work-use flight under external-load helicopter rules (Part 133). 1 person was seriously injured. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
THE FAILURE OF THE COMPRESSOR END OF THE AIR COMPRESSOR SCROLL TO TEE TUBE ASSEMBLY CAUSING THE ENGINE TO SPOOL DOWN. THE FORCED LANDING IN ENEVEN, UNPREPARED, AND LIGHTLY FORESTED TERRAIN WERE FACTORS.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- September 9, 1990 · about 10:00 pm local time
- Place
- Kokhanok, Alaska · map
- Type
- Accident
- Injuries
- 1 person was seriously injured.
- Weather
- visual conditions (good weather)
- Aircraft
- Bell 206B · all 206Bs on the register
- Registration
- N385EH · no longer on the register · serial 1674
- Damage
- Substantial damage
- Flight
- Other work-use flight · external-load helicopter rules (Part 133)
The NTSB's narrative final · quoted from the NTSB record
THE PILOT EXPERIENCED A SPOOL DOWN ON THE TURBINE ENGINE. EXAMINATION OF THE ENGINE REVEALED THAT THE AIR COMPRESSOR SCROLL TO TEE TUBE ASSEMBLY COMPRESSOR END FITTING HAD BROKEN. METALLURGICAL EXAMINATION OF THE PART SHOWED THAT THERE WERE NO MATERIAL IRREGULARITIES, THAT THE TUBE BEND DEVELOPMENT AND LINEAR MEASUREMENTS VARIED FROM THE ENGINEERING DRAWINGS, AND THAT THE TUBE ASSEMBLY FAILED IN A FATIGUE MODE. THE ORIGIN WAS ON THE TUBE O.D. APPROXIMATELY 0.020 INCH BELOW THE 'B' END FLARE RADIUS.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record from the NTSB's investigation tables, in plain English
Pilot
- Certificate: commercial pilot
- Ratings: instrument: helicopter; rotorcraft: helicopter
- Flight time: 3,570 hours in all; 1,775 in this make and model; 144 in the last 90 days; 85 in the last 30 days; 3,100 as pilot in command
- Medical certificate: Class 1 (valid medical--w/ waivers/lim.)
- Seat: rgt
The aircraft
- Airframe total time: 6,837 hours
- Last inspection: approved inspection programme, August 27, 1990; 865 hours since
- Maximum gross weight: 3,200 lb
- Seats: 5
- Landing gear: fixed
- Engine: Allison 250-C20B (turboshaft); 0 hours total
- Operator: Era Aviation INC.
The flight
- Runway 0
Weather at the time
- Light: daylight
- Wind: from 270° at 15 knots, gusting 20
- Visibility: 15 statute miles
- Sky: broken clouds at 3,000 ft; not recorded
- Temperature: 50°F (10°C), dew point 0°F (-18°C)
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), has not been read from the NTSB for this case yet; the list appears here once it has. Open the docket at the NTSB.
Other NTSB records under N385EH the same tail number, which may have belonged to a different aircraft at the time
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.