Cessna A188B accident near Three Forks, Montana, September 2, 1993
On September 2, 1993 at about 10:12 pm local time, a Cessna A188B, registered N21861, was destroyed in an accident near Three Forks, Montana. It was an aerial application (crop spraying) flight under agricultural flying rules (Part 137). 1 person was seriously injured. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
THE PILOT'S FAILURE TO MAINTAIN FLYING SPEED RESULTING IN A STALL/MUSH. THE HIGH DENSITY ALTITUDE AND THE PILOT'S FAILURE TO COMPLETELY JETTISON HIS LOAD WERE FACTORS.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- September 2, 1993 · about 10:12 pm local time
- Place
- Three Forks, Montana · map
- Type
- Accident
- Injuries
- 1 person was seriously injured.
- Weather
- visual conditions (good weather)
- Aircraft
- Cessna A188B · all A188Bs on the register
- Registration
- N21861 · registry record · serial 18801082
- Damage
- Destroyed
- Flight
- Aerial application (crop spraying) flight · agricultural flying rules (Part 137)
The NTSB's narrative final · quoted from the NTSB record
WHILE MANEUVERING IN PREPARATION FOR A SPRAY RUN THE AIRCRAFT BEGAN TO SETTLE. THE PILOT APPLIED FULL POWER BUT JETTISONED ONLY 30 TO 40 OF THE REMAINING 100 TO 110 GALLONS OF HIS CHEMICAL LOAD. A DENSITY ALTITUDE OF APPROXIMATELY 6000 FEET EXISTED AT THE TIME. THE PILOT REPORTED NO MECHANICAL MALFUNCTION WITH THE AIRCRAFT AT THE TIME OF THE EVENT.
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: airline transport pilot, flight instructor
- Ratings: multi-engine land; single-engine land; instructor: airplane multi-engine; instructor: airplane single-engine; instructor: instrument airplane; instrument: airplane; rotorcraft: helicopter
- Flight time: 9,934 hours in all; 3,550 in this make and model; 173 in the last 90 days; 75 in the last 30 days; 9,735 as pilot in command; 689 on instruments
- Medical certificate: Class 2 (valid medical--w/ waivers/lim.)
- Seat: frt
The aircraft
- Airframe total time: 4,056 hours
- Last inspection: 100-hour inspection, July 26, 1993; 84 hours since
- Maximum gross weight: 4,000 lb
- Seats: 1
- Landing gear: fixed
- Engine: Continental IO-520D (piston); 0 hours total
The flight
- Flight plan: none
- Runway 0
Weather at the time
- Light: daylight
- Wind: from 330° at 5 knots
- Visibility: 30 statute miles
- Sky: scat at 7,000 ft
- Temperature: 66°F (19°C), dew point 46°F (8°C)
- Altimeter: 30.00 inHg
- Observation at 8:45 pm from BZN, 11 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.
About this page
Everything above comes from the NTSB's public accident database: the narrative, probable cause and findings are the NTSB's own words, and the coded tables behind its report (pilot, aircraft, flight, weather, injuries, sequence of events) are written out in plain English. Pilots' ages, home towns and medical details are left out on purpose. The documents and photographs are the NTSB's docket, the folder of records gathered during the investigation, shown as the NTSB released them (the NTSB redacts some personal details first) and listed under the NTSB's own titles. This site's own text never names pilots, passengers or anyone else involved. A preliminary report describes what is known soon after the event and can change; the final report, with the probable cause, usually follows one to two years later and this page is refreshed when it does. Case number SEA93LA188.