Air Tractor AT-401 accident near Knox, Indiana, March 31, 2003
On March 31, 2003 at about 7:40 pm local time, a Air Tractor AT-401, registered N45297, was substantially damaged in an accident near Knox, Indiana (Wheeler airport). It was a flight test under general aviation rules (Part 91). 1 person was seriously injured. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
A loss of engine power due to oil starvation as a result of the failure of the master rod bearing. Contributing factors were the tree line at the edge of the field, and the unsuitable terrain.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- March 31, 2003 · about 7:40 pm local time
- Place
- Knox, Indiana · Wheeler · map
- Type
- Accident
- Injuries
- 1 person was seriously injured.
- Weather
- visual conditions (good weather)
- Aircraft
- Air Tractor AT-401
- Registration
- N45297 · no longer on the register · serial 401-0760
- Damage
- Substantial damage
- Flight
- Flight test · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The aircraft was substantially damaged during a forced landing following an engine failure. The pilot reported that a newly overhauled engine had recently been installed on the aircraft. Several ground test runs had been completed with no problems noted. Immediately prior to the accident flight, the pilot stated that the engine was warmed up and the oil temperature was within takeoff limits. He reported that he departed uneventfully and climbed to 400 feet above ground level. He noted that the oil temperature rose to 180 - 200 degrees before dropping back to 135 degrees, indicating the oil was being circulated through the oil cooler. About five miles south of the departure airport the pilot noted a drop in oil pressure and decided to divert to an intermediate airport. The oil pressure continued to drop and the engine started losing power. The aircraft was not able to maintain altitude at this point. The pilot estimated that he was not going to be able to clear a line of trees adjacent to the intermediate airport. He selected and made a forced landing in a field short of the airport. He stated that he touched down in the field "all right," but to avoid hitting trees at the end of the field, he applied the brakes causing the aircraft to flip over. The aircraft came to rest inverted at the edge of a harvested soybean field. An on-scene inspection revealed that three cylinder heads had failed. The lower fuselage was covered in oil emanating in a fan-shaped pattern from the engine oil breather tube and extending to the tail of the aircraft. An engine teardown was performed. The master rod bearing was deformed and had extruded from the rod. It appeared to have a bluish tint consistent with overheating of the material. The oil pump would not rotate under hand pressure. The drive gear, housing and attachments appeared undamaged. The oil check valve was free to move. Upon disassembly, the oil pump gears appeared undamaged. Scrape marks were observed on the interior of the pump housing. At the oil pump inlet a small piece of rubber hose was recovered. The engine fittings were not capped when the NTSB arrived for the teardown.
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: 10,072 hours in all; 800 in this make and model
- Last flight review: April 16, 2002
- Medical certificate: Class 2 (valid medical--w/ waivers/lim.)
- Seat: sngl
- Injury: serious injuries
The aircraft
- Airframe total time: 3,948 hours
- Last inspection: annual inspection, May 14, 2002; 195 hours since
- Maximum gross weight: 7,400 lb
- Seats: 1
- Landing gear: fixed
- Engine: Pratt & Whitney R-1340 (piston); 0 hours total
- Fire on the ground
The flight
- Departed from: OXI Knox IN at 7:30 pm
- Destination: RWN Winamac IN
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: from 200° at 13 knots
- Visibility: 10 statute miles
- Sky: a few clouds at 7,000 ft
- Temperature: 52°F (11°C), dew point 21°F (-6°C)
- Altimeter: 30.04 inHg
- Observation at 7:53 pm from VPZ, 23 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 N45297 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.