Amateur-built PITTS S-1T accident near Shelby, Montana, July 27, 1986
On July 27, 1986 at about 5:45 pm local time, a amateur-built PITTS S-1T, registered N155NK, was destroyed in an accident near Shelby, Montana (Benjamin Ranch airport). It was a personal flight under general aviation rules (Part 91). 1 person was seriously injured. 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 27, 1986 · about 5:45 pm local time
- Place
- Shelby, Montana · Benjamin Ranch · map
- Type
- Accident
- Injuries
- 1 person was seriously injured.
- Weather
- visual conditions (good weather)
- Aircraft
- Amateur-built PITTS S-1T
- Registration
- N155NK · no longer on the register · serial SS-186
- Damage
- Destroyed
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
DURING INITIAL CLIMB AFTER TAKEOFF FROM A PRIVATE RANCH AIRSTRIP, THE ACFT ENGINE QUIT. THE PLT HAD INADVERTENTLY LEFT THE FUEL SELECTOR SWITCH IN THE NO. 2 POSITION WHICH ALLOWED OIL, NORMALLY USED TO PRODUCE SMOKE DURING AERIAL DEMONSTRATIONS, TO ENTER THE ACFT FUEL SYSTEM. THE ACFT STRUCK A TREE AND DESCENDED UNCONTROLLED UNTIL IMPACT WITH THE GROUND 400 FEET FROM THE DEPARTURE END OF THE AIRSTRIP.
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: multi-engine land; single-engine land; rotorcraft: glider
- Flight time: 2,409 hours in all; 1,200 in this make and model; 70 in the last 90 days; 2,347 as pilot in command
- Medical certificate: Class 2 (valid medical--w/ waivers/lim.)
- Seat: unk
The aircraft
- Airframe total time: 50 hours
- Last inspection: inspection type not recorded, July 2, 1986; 50 hours since
- Maximum gross weight: 1,250 lb
- Seats: 1
- Landing gear: fixed
- Engine: Lycoming IO-360-A3A (piston); 0 hours total
The flight
- Departed from: Shelby MT at 4:45 pm
- Destination: CTB Cut Bank MT
- Flight plan: none
- Runway 25, 2,500 ft by 75 ft
Weather at the time
- Light: daylight
- Wind: from 250° at 13 knots
- Visibility: 30 statute miles
- Sky: scat at 6,000 ft
- Temperature: 70°F (21°C), dew point 34°F (1°C)
- Altimeter: 29.00 inHg
- Observation at 5:59 pm from CBT, 20 miles away
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.
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.