CEN13LA341 · Air Tractor Inc AT-301
Terhune Flying Service Air Tractor Inc AT-301 · Accident: loss of engine power (partial) while maneuvering
From Farnsworth, TX to Farnsworth, TX
Event
- NTSB case
- CEN13LA341
- 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 Inc AT-301
- Aircraft type
- Air Tractor AT-301
- 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
- N4421S
- Operator
- Terhune Flying Service
- Onboard fatalities
- Unknown
- Route
- From Farnsworth, TXTo Farnsworth, TX
- 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 · low-altitude flying
- Defining eventThe 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
- Loss of engine power (partial)
- 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
- Aircraft › Aircraft power plant
- Not determined › Not determined
Approximate · Coordinates from the NTSB case API, which marks them as estimated or does not say; no uncertainty radius is established.
NTSB narrative
The pilot of the agricultural airplane reported that, as he was beginning a spray pass, the airplane sustained a partial loss of engine power. He attempted to dump his chemical load but was unable to maintain altitude and executed a forced landing to a field. He said that the engine continued to run smoothly but at a reduced power setting during the event. Postaccident examination of the engine revealed no anomalies that would explain the partial loss of engine power. The temperature and dew point were within a range of susceptibility for carburetor icing during glide and cruise power settings. However, the sudden reduction of power with the engine continuing to run smoothly described by the pilot was not consistent with the gradual reduction in power and rough running typically associated with carburetor icing.
Probable cause
The partial loss of engine power for reasons that could not be determined because the postaccident engine examination revealed no anomalies.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record CEN13LA341
- Event ID
- 20130611X55452
- Case number
- CEN13LA341
- Dataset
- full-current
- Source SHA-256
- 5cf380f0061817c0331a6b2d8cc7e0ee3a79bea469a1001dc5c10e56f35f5ab3
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: local date, investigation status, coordinates. Values present in the bulk record are kept.
- The date is the local date; the NTSB stores the UTC date 2013-06-09.
- API snapshot SHA-256: 7aa4a80ec0cb0d1751fa9a20ec0160620c9a9e18aaf85e764435d70782046371; retrieved 2026-09-15T21:50:04.724Z.