Piper PA-18-150 accident near Williston, North Dakota, October 11, 1997
On October 11, 1997 at about 3:30 pm local time, a Piper PA-18-150, registered N9691P, was substantially damaged in an accident near Williston, North Dakota. It was a ferry flight under general aviation rules (Part 91). No one was hurt; 1 person was on board or involved. The weather was instrument conditions (cloud, fog or low visibility).
The NTSB's probable cause their words, unchanged
the pilot's inadequate preflight planning/preparation, and his selection of an unsuitable area for landing. The adverse weather condition (low ceiling) and submerged object were related factors.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- October 11, 1997 · about 3:30 pm local time
- Place
- Williston, North Dakota · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- instrument conditions (cloud, fog or low visibility)
- Aircraft
- Piper PA-18-150 · all PA-18-150s on the register
- Registration
- N9691P · registry record · serial 18-7709040
- Damage
- Substantial damage
- Flight
- Ferry flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The pilot decided to land before reaching his original destination due to deteriorating weather conditions. During a landing on the Missouri River, the airplane's floats contacted an unknown object in the water. The airplane subsequently rolled over and sank in the river. The pilot reported he did not obtain a weather briefing before the flight.
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: flight instructor, commercial pilot
- Ratings: multi-engine land; single-engine land; single-engine sea; instructor: airplane single-engine; instrument: airplane
- Flight time: 9,000 hours in all; 1,400 in this make and model; 70 in the last 90 days; 35 in the last 30 days; 9,000 as pilot in command; 1,500 on instruments
- Medical certificate: Class 2 (valid medical--w/ waivers/lim.)
- Seat: frt
The aircraft
- Airframe total time: 1,517 hours
- Last inspection: 100-hour inspection, September 23, 1997; 61 hours since
- Maximum gross weight: 1,750 lb
- Seats: 2
- Landing gear: fixed
- Engine: Lycoming O-320-A2B (piston); 0 hours total
The flight
- Departed from: Poplar MT at 1:30 pm
- Destination: Bismark ND
- Flight plan: none
- Runway 0
Weather at the time
- Light: daylight
- Wind: from 060° at 4 knots
- Visibility: 4 statute miles
- Sky: overcast at 300 ft; not recorded
- Temperature: 50°F (10°C), dew point 50°F (10°C)
- Altimeter: 29.00 inHg
- Observation at 2:54 pm from ISN, 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.