CEN21LA329 · Grumman Acft ENG COR-Schweizer G-164B
Thompson Aero Grumman Acft ENG COR-Schweizer G-164B · Accident: loss of engine power (total) during initial climb
Event
- NTSB case
- CEN21LA329
- 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 Acft ENG COR-Schweizer G-164B
- 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
- N8422K
- Operator
- Thompson Aero
- Onboard fatalities
- Unknown
- Route
- From not recordedTo not recorded
- Aircraft age
- About 45 years (built 1976)
- 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
- Initial climb
- 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
No findings designated as a cause are recorded in the NTSB data yet.
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The pilot of the agricultural airplane reported that the airplane’s engine lost power shortly after takeoff. The airplane settled into the corn field off the departure end of the runway and nosed over. The airplane sustained substantial damage to its left wing and fuselage. All three propeller blades exhibited aft bending, bending opposite rotation, twisting toward low pitch and chordwise/rotational scoring predominately on the camber side which was consistent with impact at low power. Examination of the engine revealed a discontinuity in the drive system consisting of a broken torsion shaft. The broken torsion shaft is indicative of the engine operating at the time of impact. Examination of the fuel control unit and the propeller governor did not reveal any anomalies. No anomalies were found with respect to the engine, propeller, fuel control unit, or propeller governor that would explain the reported loss of engine power. Based on the results of testing and examination, the reason for the reported loss of engine power could not be determined.
Probable cause
The loss of engine power for reasons that could not be determined.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record CEN21LA329
- Event ID
- 20210719103512
- Case number
- CEN21LA329
- 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: 8973920b3d52ccacd90ec1909434102f1fb389742d42c6d4a514cccf005848bd; retrieved 2026-09-16T14:18:21.149Z.