Cessna 170B accident near Swan Lake, Montana, July 6, 1985
On July 6, 1985, a Cessna 170B, registered N2432D, was substantially damaged in an accident near Swan Lake, 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
The NTSB has not yet published a probable cause for this accident. Investigations usually take one to two years; this page updates when the final report is released.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- July 6, 1985
- Place
- Swan Lake, Montana · map
- Type
- Accident
- Injuries
- No one was hurt; 2 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Cessna 170B · all 170Bs on the register
- Registration
- N2432D · no longer on the register · serial 20584
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
THE PLT SAID THAT PRIOR TO DEPARTURE THERE WAS AN ESTIMATED 14 GALS OF FUEL ON BOARD. AFTER APRX 30 MINUTES OF FLIGHT THE ENG LOST ALL PWR AND A FORCED LANDING WAS ACCOMPLISHED IN A MOUNTAINOUS CREEK BED. DURING THE LANDING ROLL THE ACFT STRUCK A FEELED TREE AND OVERTURNED. POST-CRASH EXAM OF THE ACFT REVEALED ONLY TRACE AMOUNTS OF FUEL IN THE FUEL TANKS, LINES, CARBURETOR BOWL, AND ACCELERATOR PUMP. NO FUEL WAS FOUND IN THE GASCOLATOR. THE ENG WAS LATER TEST RUN AND OPERATED SATISFACTORILY. THE FUEL LINE BETWEEN THE FIREWALL AND CARBURETOR WAS SAID TO BE A RUBBER VACUUM LINE AND AN UNAPPROVED INSTALLATION. THE LINE WAS SO DETERIORATED AND BRITTLE THAT IT BROKE INTO SEVERAL PIECES WHILE BEING REMOVED FOR EXAMINATION. THE PLT REPORTED HE USED A STOPWATCH TO KEEP TRACK OF THE FUEL SUPPLY BECAUSE THE FUEL GAGES WERE INACCURATE.
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: single-engine land
- Flight time: 104 hours in all; 48 in this make and model; 48 in the last 90 days; 76 as pilot in command
- Medical certificate: Class 3 (valid medical--w/ waivers/lim.)
- Seat: left
The aircraft
- Airframe total time: 2,980 hours
- Last inspection: annual inspection, March 28, 1985; 50 hours since
- Maximum gross weight: 2,200 lb
- Seats: 4
- Landing gear: fixed
- Engine: Franklin O-300 (piston); 0 hours total
The flight
- Departed from: 8U4 Spotted Bear MT at 11:30 pm
- Flight plan: none
- Runway 0
- A second pilot was aboard
Weather at the time
- Light: daylight
- Wind: from 260° at 11 knots
- Visibility: 40 statute miles
- Sky: scat at 25,000 ft
- Temperature: 86°F (30°C), dew point 41°F (5°C)
- Altimeter: 30.00 inHg
- Observation at 10:55 pm from FCA, 40 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 2 |
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.
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.