SEA02LA123 · Grumman-Schweizer G-164B
Grumman-Schweizer G-164B · Accident: total loss of engine power (mechanical failure) while maneuvering
From Weiser Municipal Airport (S87) to an unrecorded destination
Event
- NTSB case
- SEA02LA123
- 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
Grumman-Schweizer G-164B
- Aircraft type
- Grumman Schweizer G-164
- 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
- N8440K
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Weiser Municipal Airport (S87), Weiser, IDTo 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, push rod › Fractured
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 "Agcat" cropduster had just taken off and was making his first spray run over a field when the Pratt & Whitney R-1340 engine began to run rough. He pulled up and executed a right turn away from obstacles crossing the Snake River during which the engine abruptly stopped. The pilot rolled out and executed a forced landing in a beet field during which the aircraft crossed an elevated dirt/gravel roadway bounded on its north and south edges by a shallow ditch, and the aircraft's landing gear separated from the airframe. The aircraft then nosed over and came to a stop. The engine, which had been overhauled and inspected 81 and 31 hours respectively, was examined. The examination revealed that the number 3 cylinder exhaust valve steel pushrod was broken near the rocker arm end of the rod and the rod displayed very slight bending deformation. The separation surfaces of the broken rod end were observed to be mechanically battered. Removal or separation of the exhaust pushrod results in the exhaust valve's inability to open during the exhaust phase cycle for the associated cylinder, and can result in hot exhaust from the cylinder back-flowing out the intake valve when it opens during the intake cycle.
Probable cause
The fracture of the number 3 cylinder exhaust pushrod resulting in the exhaust valve's inability to open during the exhaust cycle and the subsequent engine stoppage. Contributing factors were the ditch and elevated roadway which the aircraft crossed during the gear collapse.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record SEA02LA123
- Event ID
- 20020715X01121
- Case number
- SEA02LA123
- 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: ed210c4d8234fa475671e1d01e092a1937a78407396968e09e9a45f29d731514; retrieved 2026-09-22T10:45:26.828Z.