Piper PA-18-150 accident near Opheim, Montana, July 14, 1999
On July 14, 1999 at about 5:00 pm local time, a Piper PA-18-150, registered N4385Z, was substantially damaged in an accident near Opheim, Montana. It was an aerial application (crop spraying) flight under agricultural flying rules (Part 137). 1 person was killed. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The pilot's failure to maintain an airspeed above stall speed (Vs), resulting in a stall/mush into the terrain during a course reversal at the end of an aerial application run. Factors include hilly terrain and high density altitude.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- July 14, 1999 · about 5:00 pm local time
- Place
- Opheim, Montana · map
- Type
- Accident
- Injuries
- 1 person was killed.
- Weather
- visual conditions (good weather)
- Aircraft
- Piper PA-18-150 · all PA-18-150s on the register
- Registration
- N4385Z · registry record · serial 18-7409044
- Damage
- Substantial damage
- Flight
- Aerial application (crop spraying) flight · agricultural flying rules (Part 137)
The NTSB's narrative final · quoted from the NTSB record
The pilot of the 150 horsepower PA-18 had just returned to an aerial application site after refueling and taking on another load of chemicals. During his refueling/reloading stop he expressed concern about the limited performance of the aircraft at the current temperature (75-80 degrees Fahrenheit) and at the altitude he was flying (about 3,000 feet MSL). He therefore took on a reduced fuel load and mentioned that he was planning on finishing the field by taking on two half-loads of chemical instead of one full one. Although witnesses saw him only partially fill his fuel tanks, no one saw whether he filled his chemical hopper to the top or only took on a partial load. Upon returning to the field, he was seen to make a pass in one direction, but no one saw him return in the other direction. Soon thereafter a column of black smoke was seen rising from the field. When witnesses arrived at the application site, they found the aircraft where it had stall/mushed into rapidly rising terrain at a location where the pilot would be making a course reversal just off the end of the field.
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: single-engine land
- Flight time: 1,600 hours in all; 50 in the last 90 days
- Medical certificate: Class 2 (valid medical--w/ waivers/lim.)
- Seat: rear
The aircraft
- Airframe total time: 3,357 hours
- Last inspection: annual inspection, March 31, 1999
- Maximum gross weight: 1,750 lb
- Seats: 1
- Landing gear: fixed
- Engine: Lycoming O-320-A2A (piston); 0 hours total
- Fire on the ground
The flight
- Departed from: S00 Opheim MT at 4:45 pm
- Flight plan: none
- Runway 0
Weather at the time
- Light: daylight
- Wind: from 360° at 10 knots
- Visibility: 20 statute miles
- Sky: clear
- Temperature: 79°F (26°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.
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.