CEN15LA330 · Grumman G-164A
Precision Aerial Grumman G-164A · Accident: loss of engine power (total) while maneuvering
From Wamego Municipal Airport (69K) to Wamego Municipal Airport (69K)
Event
- NTSB case
- CEN15LA330
- 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
- N963X
- Operator
- Precision Aerial
- Onboard fatalities
- Unknown
- Route
- From Wamego Municipal Airport (69K), Wamego, KSTo Wamego Municipal Airport (69K), Wamego, KS
- Aircraft age
- About 47 years (built 1968)
- 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 handling/service
- Aircraft › Aircraft power plant
- Personnel issues › Task performance
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The commercial pilot was conducting an agricultural application flight. The pilot reported that, while making a spray run, he heard a loud "bang" and saw a puff of smoke emanate from the upper right side of the engine, followed by the propeller seizing. He made a forced landing in a field, and the airplane collided with some bushes and then nosed over.
Examination of the engine revealed several loose cylinder stud nuts and hold-down bolts that appeared to have been pushed up on the cylinder skirt. Several of the studs, particularly the No. 4 cylinder stud, were stretched and looked to be nearly pushed out of the engine crankcase. One cylinder was almost separated from the crankcase.
Examination of the airplane's maintenance logbooks revealed that the engine had received a major overhaul more than 8 years before the accident. The records indicated that, since that time, inspections of the cylinder heads and the cylinder hold-down studs had been conducted in compliance with two Federal Aviation Administration airworthiness directives. The engine was last inspected about 3 months before the accident. During this inspection, maintenance personnel checked the cylinder bases and heads for cracks and loose studs; however, they did not detect that the cylinder nuts and hold-down bolts were not properly secured.
Probable cause
The engine failure due to several loose, damaged cylinder stud nuts and hold-down bolts. Contributing to the accident was maintenance personnel’s failure to detect that the cylinder nuts and hold-down bolts were not properly secured during the engine’s most recent inspection.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record CEN15LA330
- Event ID
- 20150801X23811
- Case number
- CEN15LA330
- 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: 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: f6816509669e7b06ef0536c922f3affa4684347123c1fc41a731c5316d106560; retrieved 2026-09-16T02:36:33.111Z.