# NTSB WPR24LA282: Grumman Acft ENG Cor-Schweizer G-164B, N6633K, Durham, CA, August 13, 2024

- Type: NTSB accident investigation
- Classification: Accident · Serious injuries · Class 4 · Limited · Final report
- Date: August 13, 2024, 11:00 local (18:00 UTC)
- Place: Durham, CA
- Coordinates: 39.543815, -121.65765
- Nearby events: https://openairdocs.org/map.md?lat=39.5438&lon=-121.6577&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Defining event: [Maneuvering-low-alt flying: Low altitude operation/event](https://openairdocs.org/ntsb-events/220)
- Highest injury: Serious injuries
- Injuries: 1 serious
- Status: Completed
- Report: Approved by Office Director
- Investigation class: Class 4 - Basic report with no Prelim publish
- NTSB office: Western Pacific Region
- Parties: FAA
- NTSB case key (mKey): 194957
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR24LA282
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/194957/pdf
- NTSB docket: https://data.ntsb.gov/Docket?ProjectID=194957
- Page: https://openairdocs.org/ntsb/WPR24LA282

## Probable cause

The pilot’s failure to maintain clearance from powerlines, which resulted in a wire strike.

## Findings

NTSB's coded findings; those marked are part of the probable cause.

- [Attention/monitoring: attention](https://openairdocs.org/ntsb-findings/02021510): Personnel issues › Psychological · Pilot (probable cause); cases with it: [Grumman Acft ENG Cor-Schweizer G-164B, 1 case](https://openairdocs.org/ntsb-findings/02021510/cases.md?model=3952802), [All aircraft, 226 cases](https://openairdocs.org/ntsb-findings/02021510/cases.md)
- [Object/animal/substance: wire](https://openairdocs.org/ntsb-findings/03022032): Environmental issues › Physical environment · Effect on equipment (probable cause); cases with it: [Grumman Acft ENG Cor-Schweizer G-164B, 8 cases](https://openairdocs.org/ntsb-findings/03022032/cases.md?model=3952802), [All aircraft, 588 cases](https://openairdocs.org/ntsb-findings/03022032/cases.md)

## Sequence of events

The events NTSB coded, in order, by phase of flight. The defining event best describes what happened.

- [Maneuvering-low-alt flying: Low altitude operation/event](https://openairdocs.org/ntsb-events/220) (defining event); cases with it: [Grumman Acft ENG Cor-Schweizer G-164B, 10 cases](https://openairdocs.org/ntsb-events/220/sequence.md?model=3952802), [All aircraft, 780 cases](https://openairdocs.org/ntsb-events/220/sequence.md)

## Analysis

According to the operator, the pilot was flying near high tension powerline wires during an aerial application flight. During the application of a rice field while flying north, the airplane’s right wing struck one of the powerlines. The airplane subsequently impacted the ground north of the powerline wires and sustained substantial damage to all four wings the empennage and the fuselage. The pilot exited the airplane, called the operator and reported that the accident was caused by pilot error. The Investigator-in-charge made several attempts to contact the pilot in command (PIC) via email and cell phone, but an email reply was not received from the PIC and the voicemail box was full. The pilot reported there were no preaccident mechanical malfunctions or failures with the airplane that would have precluded normal operation.

## Aircraft

- Registration: [N6633K](https://openairdocs.org/deregistered/N6633K-2025-04-30), registration cancelled 2025-04-30, S/N 400B (OpenAirDocs)
- Reported make and model: GRUMMAN ACFT ENG COR-SCHWEIZER G-164B
- Registry model: [Grumman Acft ENG Cor-Schweizer G-164B](https://openairdocs.org/model/grumman-acft-eng-cor-schweizer-g-164b) (registry code 3952802) (OpenAirDocs)
- Registry engine: [Pratt & Whitney R1340 series](https://openairdocs.org/engine/pratt-whitney-r1340-series) (registry code 52016, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: 400B
- Year built: 1978
- Airframe hours: 7536.3
- Engines: Pratt & Whitney PT6A-15AG 680 horsepower turbo prop
- Damage: Substantial damage
- Flight: Aerial application, Part 137
- Airworthiness certificate: Special, Restricted (Special)
- Last inspection: Annual, January 22, 2024
- Flight plan: Company VFR
- Airport: OVE, Oroville Muni
- Equipment: Satellite tracking device, ADS-B

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 74; injuries: serious; commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; last flight review August 25, 2023; seat: single; restraint: 3-point; flight hours: 23,629 total, 1 in this make and model, 23,432 as pilot in command, 80 in the last 30 days, 6 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: calm
- Visibility: 10 statute miles
- Lowest ceiling: none
- Temperature: 81 °F, dew point 50 °F
- Altimeter: 29.96 inHg
- Observed at: KOVE, 3 nm away
- METAR: KOVE 131853Z AUTO 00000KT 10SM CLR 27/10 A2996 RMK AO2 SLP144 T02720100

## FAA reports on this event (1)

The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs).

- [Accident 20240813017999A](https://openairdocs.org/incident/20240813017999A), Aug 13, 2024: Grumman Acft Eng Cor-Schweizer G-164B, Durham, CA, Substantial damage. The pilot reported that while maneuvering under a power line he started to bank the aircraft before he was clear of the line which seperated most of the…

## Other investigations on N6633K (3)

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

- [NTSB CHI99LA215](https://openairdocs.org/ntsb/CHI99LA215), Jul 3, 1999: Grumman-Schweizer G-164B (N6633K), Page, ND, substantial damage. Probable cause: the pilot's failure to compensate for the wind conditions. Factors were the sudden windshift and the crops.
- [NTSB CHI97LA204](https://openairdocs.org/ntsb/CHI97LA204), Jul 7, 1997: Grumman-Schweizer G-164B (N6633K), Donnelly, MN, substantial damage. Probable cause: undetermined event resulting in the broken connecting rod and cylinder.
- [NTSB LAX91LA301](https://openairdocs.org/ntsb/LAX91LA301), Jul 9, 1991: Grumman G-164B (N6633K), Eloy, AZ, substantial damage. Probable cause: THE FAILURE OF THE PILOT TO MAINTAIN THE TERRAIN CLEARANCE OF THE AIRCRAFT WHILE MANEUVERING FOR A POTENTIAL EMERGENCY LANDING ON A MOONLESS DARK NIGHT.

## Docket (3 files)

The files NTSB released with the investigation on March 6, 2025, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=194957. 4.0 MB in all.

- Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 11 pages, 3.4 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17762170&FileExtension=pdf&FileName=6120_1_Redacted-Rel.pdf
- Photograph (item 2, PDF, 2 pages, 571 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17761597&FileExtension=pdf&FileName=Photograph-Rel.pdf
- Memorandum of record -PIC (item 3, PDF, 1 page, 66 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=18354910&FileExtension=pdf&FileName=Memorandum%20of%20Record%20-PIC-Rel.pdf

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

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