WPR10CA289 · Grumman Acft ENG COR-Schweizer G-164B
Grumman Acft ENG COR-Schweizer G-164B · Accident: low altitude operation/event while maneuvering
From Clarksburg, CA to Clarksburg, CA
Event
- NTSB case
- WPR10CA289
- 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 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
- N6726Q
- Operator
- Walter Avery
- Onboard fatalities
- Unknown
- Route
- From Clarksburg, CATo Clarksburg, CA
- 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
- Low altitude operation/event
- 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 oper/perf/capability
- Environmental issues › Physical environment
- Personnel issues › Psychological
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The pilot reported that during an aerial application flight he was established and stable on an east-to-west spray pass. He recalls checking the pump pressure gauge for an indication of an empty load when he felt and heard a “significant slam” and felt a grinding sensation. The airplane had impacted level terrain and came to rest upside down. The airplane sustained substantial damage to both wings and the tail assembly. The pilot reported that there were no known mechanical malfunctions or failures with the aircraft prior to the accident.
Probable cause
The pilot's failure to maintain clearance from terrain during low-altitude maneuvers.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record WPR10CA289
- Event ID
- 20100613X82552
- Case number
- WPR10CA289
- 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: 6b12c10804ce7accafdd766c04ce5b32390586a90badd584090185cb3838e9f2; retrieved 2026-09-15T14:26:51.399Z.