Bell 47-G3B accident near Winston, Montana, October 19, 1997
On October 19, 1997 at about 3:30 am local time, a Bell 47-G3B (helicopter), registered N47AH, was substantially damaged in an accident near Winston, Montana. It was a personal flight under general aviation rules (Part 91). No one was hurt; 2 people were on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
Fuel starvation due to fuel flow restriction from a failed carburetor automatic mixture control device. Factors include night light conditions for the forced landing.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- October 19, 1997 · about 3:30 am local time
- Place
- Winston, Montana · map
- Type
- Accident
- Injuries
- No one was hurt; 2 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Bell 47-G3B · all 47-G3Bs on the register
- Registration
- N47AH · registry record · serial 2645
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
Post accident inspection revealed a loose bellows housing on the MA-6AA carburetor's automatic mixture control. The bellows housing was found loose on the threaded tube, which was still locked to the seat, allowing the bellows to screw down onto the tube, thereby restricting the fuel delivery orifice. The seat and lock nut remained securely bolted to the float. The last recorded carburetor repair was on 7/22/93, with 817 hours since that repair. Records did not reflect the nature of that repair. According to the carburetor manufacturer's engineering drawings, the bellows is bonded to the threaded tube with a permanent type plastic resin.
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: private
- Ratings: rotorcraft: helicopter
- Flight time: 147 hours in all; 143 in this make and model; 52 in the last 90 days; 11 in the last 30 days; 93 as pilot in command
- Medical certificate: Class 3 (valid medical--w/ waivers/lim.)
- Seat: left
The aircraft
- Last inspection: annual inspection, September 30, 1997; 96 hours since
- Maximum gross weight: 2,850 lb
- Seats: 3
- Landing gear: fixed
- Engine: Lycoming TVO-435-A1A (piston); 0 hours total
The flight
- Departed from: 8U8 Townsend MT at 3:17 am
- Destination: HLN Helena MT
- Flight plan: none
- Runway 0
Weather at the time
- Light: night, dark
- Wind: from 310° at 7 knots
- Visibility: 30 statute miles
- Sky: clear
- Temperature: 39°F (4°C), dew point 36°F (2°C)
- Altimeter: 30.00 inHg
- Observation at 3:56 am from HLN
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 1 | |||
| Passengers | 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 N47AH 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.