Air Tractor AT-401 accident near Oconto, Nebraska, May 14, 1993
On May 14, 1993 at about 12:30 pm local time, a Air Tractor AT-401, registered N4503U, was destroyed in an accident near Oconto, Nebraska. It was an aerial application (crop spraying) flight under agricultural flying rules (Part 137). 1 person had minor injuries. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
THE PILOT'S INABILITY TO MAINTAIN ALTITUDE AFTER ENCOUNTERING A DOWNDRAFT.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- May 14, 1993 · about 12:30 pm local time
- Place
- Oconto, Nebraska · map
- Type
- Accident
- Injuries
- 1 person had minor injuries.
- Weather
- visual conditions (good weather)
- Aircraft
- Air Tractor AT-401
- Registration
- N4503U · no longer on the register · serial 401-0748
- Damage
- Destroyed
- Flight
- Aerial application (crop spraying) flight · agricultural flying rules (Part 137)
The NTSB's narrative final · quoted from the NTSB record
THE PILOT WAS OVER FLYING A FIELD IN PREPARATION FOR A SPRAYING RUN WHEN A RAIN SHOWER OCCURRED. THE PILOT STATED A MICROBURST WAS ENCOUNTERED AND HE DUMPED THE CHEMICAL LOAD IN AN ATTEMPT TO MAINTAIN ALTITUDE. THE AIRPLANE DESCENDED FROM AN ALTITUDE OF APPROXIMATELY 400 FEET TO IMPACT WITH THE TERRAIN. A SURFACE WEATHER REPORT ISSUED 25 MINUTES AFTER THE ACCIDENT FROM THE BROKEN BOW AIRPORT, 19 MILES NORTH-NORTHEAST OF THE ACCIDENT SITE, REPORTED VIRGA SOUTH-SOUTHWEST OF THE AIRPORT.
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: 1,848 hours in all; 247 in this make and model; 179 in the last 90 days; 128 in the last 30 days; 1,750 as pilot in command
- Medical certificate: Class 2 (valid medical--no waivers/lim.)
- Seat: ctr
The aircraft
- Airframe total time: 1,159 hours
- Last inspection: annual inspection, March 8, 1993; 140 hours since
- Maximum gross weight: 8,060 lb
- Seats: 1
- Landing gear: fixed
- Engine: P&W R-1340-ANI (piston); 0 hours total
- Operator: Olson Air Service, INC.
The flight
- Departed from: Holdrege NE at 11:30 am
- Flight plan: none
- Runway 0
Weather at the time
- Light: daylight
- Wind: from 200° at 6 knots
- Visibility: 10 statute miles
- Sky: broken clouds at 5,000 ft; not recorded at 5,000 ft
- Temperature: 61°F (16°C), dew point 50°F (10°C)
- Altimeter: 29.00 inHg
- Observation at 12:55 pm from BBW, 19 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.
Other NTSB records under N4503U the same tail number, which may have belonged to a different aircraft at the time
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.