Swearingen SA227-AC incident near Williston, North Dakota, December 14, 2012
On December 14, 2012 at about 3:18 pm local time, a Swearingen SA227-AC, registered N3108B, was involved in an incident during takeoff near Williston, North Dakota (Sloulin International airport). It was a positioning 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 snowplow driver’s failure to ensure that the runway was clear before driving onto it, which resulted in a runway incursion with a departing airplane.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- December 14, 2012 · about 3:18 pm local time
- Place
- Williston, North Dakota · Sloulin International · map
- Type
- Incident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- instrument conditions (cloud, fog or low visibility)
- Aircraft
- Swearingen SA227-AC · all SA227-ACs on the register
- Registration
- N3108B · registry record · serial AC509
- Damage
- Not recorded
- Flight
- Positioning flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The pilot reported that he made several radio calls announcing his intention to take off and that he did not hear any radio calls from other aircraft or vehicles. At the end of the ground roll, he heard a "garbled" transmission stating something about the departure runway. He stated that, as the airplane lifted off, he saw a snowplow on the runway heading in the opposite direction. He continued the takeoff and flew over the snowplow. The snowplow driver stated that he did not hear any radios transmissions from the airplane until after it was airborne and that he had been plowing for about 30 minutes and had made radio calls every 2 to 3 minutes announcing his position. Another pilot who landed about 30 minutes after the incident reported that he also saw a snowplow operating on the airport and that he did not hear any radio calls from the snowplow even after it had crossed a runway. A postincident check of the snowplow and airplane radios revealed that they were functioning properly. The reason why the pilot and snowplow driver were not aware of each other's presence could not be determined due to the lack of recorded radio transmissions and because the airplane and snowplow radios were functioning properly. However, Federal Aviation Administration guidelines to ground vehicle operators state that they need to yield right-of-way to moving aircraft and that they need to ensure that no potential conflict with a moving aircraft exists.
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
What happened, in order
- Runway incursion veh/AC/person during takeoff defining event
The NTSB's findings
- cause Personnel issues › Psychological › Attention/monitoring › Task monitoring/vigilance › Airport personnel
Pilot
- Certificate: airline transport pilot
- Ratings: multi-engine land; single-engine land; instrument: airplane
- Flight time: 5,025 hours in all
- Last flight review: October 31, 2012
- Medical certificate: Class 1 (without waivers/limitations)
- Seat: left
- Injury: no injuries
The aircraft
- Airframe total time: 34,538 hours
- Last inspection: approved inspection programme, November 27, 2012
- Maximum gross weight: 11,152 lb
- Seats: 3
- Landing gear: retractable
- Engine 1: Garrett TPE331-11U (turboprop); 0 hours total
- Engine 2: (turboprop); 0 hours total
- Operator: Business Aviation Courier
The flight
- Departed from: ISN Williston ND at 3:18 pm
- Destination: FSD Sioux Falls SD
- Flight plan: IFR
- Runway 29, 6,650 ft by 100 ft
Weather at the time
- Light: daylight
- Wind: from 170° at 5 knots
- Visibility: 1 statute miles
- Sky: overcast at 100 ft
- Temperature: 21°F (-6°C), dew point 21°F (-6°C)
- Altimeter: 29.72 inHg
- Observation at 3:15 pm from ISN
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight 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.