Air Tractor AT-402B accident near Mount Vernon, South Dakota, June 3, 2001
On June 3, 2001 at about 1:32 pm local time, a Air Tractor AT-402B, registered N484WB, was destroyed in an accident near Mount Vernon, South Dakota. 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 not maintaining aircraft control while maneuvering close to the ground.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- June 3, 2001 · about 1:32 pm local time
- Place
- Mount Vernon, South Dakota · map
- Type
- Accident
- Injuries
- 1 person was killed.
- Weather
- visual conditions (good weather)
- Aircraft
- Air Tractor AT-402B
- Registration
- N484WB · registry record · serial 402B-1098
- Damage
- Destroyed
- Flight
- Aerial application (crop spraying) flight · agricultural flying rules (Part 137)
The NTSB's narrative final · quoted from the NTSB record
An Air Tractor 201 impacted the terrain 4.5 miles northeast of Mount Vernon, South Dakota. A witness said he was outside in his farmyard working when he heard an airplane working east of his farm. The witness said he saw the airplane a couple of times as it was making turns. The witness said he could hear the airplane's engine. He then heard a loud crash noise and didn't hear the airplane's engine anymore. An examination of the airplane revealed no anomalies. FAA toxicology testing of specimens from the pilot showed trace levels of QUININE in blood. Quinine is found in tonic water and is used to treat malaria. It is also commonly used to reduce the frequency of nocturnal leg cramps - a condition which may cause painful leg muscle spasm at night, and was available over-the-counter for this purpose until 1995. The side effects of quinine can include disturbances of vision, hearing, and balance. According to the pilot's brother, tonic water was the pilot's favorite beverage. The night prior to the accident, the pilot was observed drinking tonic water with his dinner.
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; instrument: airplane
- Flight time: 6,984 hours in all; 291 in this make and model; 6,877 as pilot in command
- Last flight review: September 23, 2000
- Medical certificate: Class 2
- Seat: ctr
- Injury: fatal
The aircraft
- Airframe total time: 619 hours
- Last inspection: annual inspection, January 1, 2001; 90 hours since
- Maximum gross weight: 7,800 lb
- Seats: 1
- Landing gear: fixed
- Engine: P&W Canada PT6A-15AG (turboprop); 0 hours total
The flight
- Departed from: MHE Mitchell SD at 12:38 pm
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: from 100° at 10 knots
- Visibility: 10 statute miles
- Sky: a few clouds at 12,000 ft
- Temperature: 59°F (15°C), dew point 48°F (9°C)
- Altimeter: 29.84 inHg
- Observation at 12:59 pm from MHE, 7 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.