CEN21LA287 · Grumman G164 B
Scott Flying Service Grumman G164 B · Accident: loss of engine power (total) en route
From Fontaine, AR (private airstrip) to an unrecorded destination
Event
- NTSB case
- CEN21LA287
- 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
- Event fatalities
- Unknown
- 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 G164 B
- Aircraft type
- Grumman G164
- 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
- N62375
- Operator
- Scott Flying Service
- Onboard fatalities
- Unknown
- Route
- From Fontaine, AR (private airstrip)To not recorded
- Aircraft age
- About 33 years (built 1988)
- 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
- En route
- 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 conducting an agricultural flight when the airplane had a sudden total loss of engine power. The pilot stated that the sound of the engine went from normal to silent, with no indication of an engine issue before the loss of engine power. The airplane impacted a levee and nosed over in a flooded rice field during the forced landing. The airplane’s empennage, aft fuselage, and engine mounts were substantially damaged during the forced landing.
A postaccident engine examination and disassembly revealed the torque sensor assembly front spur gear was disengaged from the splined shouldered shaft on which it was installed. Additionally, the self-locking nut that secured the front spur gear to the shaft had backed off which allowed the front spur gear to disengage from the shaft.
The examination and testing were unable to determine if the front spur gear self-locking nut was improperly torqued at installation or if it became loose during operation due a loss of retention. However, had the self-locking nut not been seated properly at installation, the disengagement of the front spur gear would likely have occurred well before the accident (2,541.5 hours since the overhauled torque sensor was installed on the engine). Additionally, no anomalies were found with the self-locking nut to suggest why it would have lost retention during operation.
The engine-driven fuel pump and fuel control unit (FCU) are driven through a series of gears in the accessory gearbox, including the front spur gear, and any failure in the gear train that drives the fuel pump and FCU would prevent the fuel pump from delivering fuel to the FCU to sustain engine operation, resulting in an uncommanded engine shutdown.
Probable cause
The total loss of engine power due to the failure and disengagement of the torque sensor assembly front spur gear from its splined shouldered shaft due to a loose self-locking nut.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record CEN21LA287
- Event ID
- 20210622103314
- Case number
- CEN21LA287
- 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, cause areas. 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: 905be5a3f2ab537c97683891648f0a518772909efae07d55af0e3b6a424ccf00; retrieved 2026-09-16T14:12:00.411Z.