SEA95LA161 · Air Tractor AT-301
Air Tractor AT-301 · Accident: total loss of engine power (mechanical failure) while maneuvering
From HVR · UT to an unrecorded destination
Event
- NTSB case
- SEA95LA161
- 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-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
- N3660U
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From HVR · UTTo 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
- 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, cylinder › Fatigue
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
During an aerial application flight, the aircraft experienced a complete loss of engine power. Almost immediately after the loss of power, one of the aircraft's wings caught in the tall barley the pilot was spraying. After catching the wing, the aircraft cartwheeled and came to rest in an inverted position. Examination of the engine revealed that a rocker box had sustained a fatigue fracture at the point where the rocker pivot bolt passes through the box.
Probable cause
the loss of power due to a failure of the cylinder head exhaust valve rocker box. The tall crop encountered during the forced landing is a factor.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record SEA95LA161
- Event ID
- 20001207X04105
- Case number
- SEA95LA161
- 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: 785ed26044deeea694b210171a34a9a56c7f8922fcb8ebef03299e66149d14cf; retrieved 2026-09-22T23:33:46.270Z.