CHI03LA095 · Air Tractor AT-401
Air Tractor AT-401 · Accident: total loss of engine power (mechanical failure) en route
From Starke County Airport (OXI) to Arens Field (RWN)
Event
- NTSB case
- CHI03LA095
- Event typeAccident: someone killed or seriously injured, or the aircraft substantially damaged (NTSB definition). Incident: an occurrence that affected or could have affected safety, short of that. Glossary
- Accident
- InvestigationHow far the investigation had got when the record was published: preliminary, ongoing, final or completed. Unknown where the source does not say. Glossary
- Completed
- API-reported fatalities
- 0 · all aircraft and ground
- Ground fatalities
- Unknown
- OperationWhat kind of flying it was, grouped by the rules it flew under: airline (US Part 121), air taxi and commuter (Part 135), general aviation (Part 91 and similar), military or government. Glossary
- General aviation
- WeatherVisual meteorological conditions (VMC): good enough to fly by looking outside. Instrument conditions (IMC): cloud or low visibility, flying by instruments. Glossary
- Visual Meteorological Cond
Air Tractor AT-401
- Aircraft type
- Air Tractor AT-401
- Category
- Airplane
- RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
- N45297
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Starke County Airport (OXI), Knox, INTo Arens Field (RWN), Winamac, IN
- Aircraft age
- Not recorded
- Flight rulesThe regulations the flight operated under: in the US, Part 91 (general aviation), Part 121 (airlines), Part 135 (air taxi and commuter) and others; for flights abroad, the NTSB's coarser commercial or non-commercial code. Glossary
- Part 91: General Aviation
- Phase of flightThe stage of the flight when things started to go wrong: standing, taxi, takeoff, initial climb, en route, maneuvering, approach or landing. Glossary
- En route · cruise
- First occurrenceThe single coded event the NTSB judges best describes what happened (records from 2008 on). Older records name the first occurrence in the sequence instead. Glossary
- Total loss of engine power (mechanical failure)
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Substantial
Cause areas
- Engine assembly, bearing › Failure
- Fluid, oil › Starvation
- Pilot in command › Unsuitable terrain or takeoff/landing/taxi area, encountered
Approximate · Coordinates from the NTSB case API, which marks them as estimated or does not say; no uncertainty radius is established.
NTSB narrative
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.
Probable cause
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.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record CHI03LA095
- Event ID
- 20030414X00504
- Case number
- CHI03LA095
- Dataset
- historical-pre2008
- Source SHA-256
- 89e2df6d848e7ab3b42e7d7c7a03ff403303057a26ca04c95b3ea67201c3ce74
Source notes (4)
- Unreviewed is an editorial label, not an investigation status. API-sourced is not report-checked or human-reviewed. Explicit event totals are used without summing aircraft injury tables; onboard allocation is withheld. Unknown values remain unknown. The operation category is mapped from the NTSB-reported FAR part and has not been reviewed.
- Filled from the NTSB case API where the bulk record had no value: investigation status, coordinates. Values present in the bulk record are kept.
- The date is the local date, which is the same as the UTC date the NTSB stores.
- API snapshot SHA-256: 23f6486c8d1a5dea33012f9856c626eed9764c15a8c8c6dadf5a00dc47bc3343; retrieved 2026-09-21T09:29:43.691Z.