CEN12LA491 · Grumman G-164A
West Central Ag-Air Grumman G-164A · Accident: loss of engine power (total) while maneuvering
From Wheaton Municipal Airport (ETH) to Dumont, MN
Event
- NTSB case
- CEN12LA491
- 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 G-164A
- Aircraft type
- Grumman 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
- N4638
- Operator
- West Central Ag-Air
- Onboard fatalities
- Unknown
- Route
- From Wheaton Municipal Airport (ETH), Wheaton, MNTo Dumont, MN
- 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 (total)
- 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
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The pilot was spraying a large corn field when he saw a puff of white smoke come from the engine. He turned toward a road, but about half way through the turn, the engine lost all power. The pilot jettisoned the chemical load and landed in the corn field. Examination of the radial engine revealed the No. 2 cylinder head was cracked. A review of the maintenance logbooks revealed that a mandatory Federal Aviation Administration Airworthiness Directive that required a 100-hour visual inspection to prevent cylinder head cracking, had been complied with at the last annual inspection, but no entries were made that any cracks were observed.
Probable cause
A total loss of engine power due to a cracked No. 2 cylinder head.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record CEN12LA491
- Event ID
- 20120730X60857
- Case number
- CEN12LA491
- 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. Values present in the bulk record are kept.
- The date is the local date; the NTSB stores the UTC date 2012-07-20.
- API snapshot SHA-256: 178cedf820a193e43a01770bf8c4b68651b326372761a4cc90953abc1d809e23; retrieved 2026-09-15T19:06:56.762Z.