CHI98LA355 · Air Tractor AT-401
Air Tractor AT-401 · Accident: partial loss of engine power (mechanical failure) while maneuvering
From RLA · Northfield, MN to an unrecorded destination
Event
- NTSB case
- CHI98LA355
- 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
- 0
- 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
- N4543F
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From RLA · Northfield, MNTo not recorded
- 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 137: Agricultural
- 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
- Maneuvering · aerial application
- 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
- Partial 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
- Destroyed
Cause areas
- Owner/pilot mechanic › Altitude/clearance, low
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
About 5-minutes after the aerial applicator flight had taken off the pilot said, the airplane's engine experienced a partial power loss. He said the airplane '...did not want to climb and began to settle down.' The pilot ejected his chemical load and was maneuvering for a landing when the right wingtip and landing gear struck the ground. The airplane cartwheeled and rolled over the ground before coming to a stop inverted. The on-scene investigation revealed the airplane s engine had 1 cylinder with no compression. Examination showed the piston rings were badly worn and there was no taper to the cylinder. At the time of the accident the engine was about 70-hours beyond the manufacturer's recommended overhaul time. The airplane had received an annual inspection about 4-months before the accident. The engine logbook showed all compression readings were within the manufacturers recommended range.
Probable cause
A loss of engine power due to a worn piston ring. A related factor was the owner exceeded the manufacturer's recommended engine overhaul.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record CHI98LA355
- Event ID
- 20001211X10823
- Case number
- CHI98LA355
- 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. 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: e17f44e07e2e2d4888426e35f65149c8a5e3907bd2a5ee36363722b536785a91; retrieved 2026-09-22T16:59:22.074Z.