Grumman Acft Eng Cor-Schweizer G-164B accident near Durham, California, August 13, 2024
On August 13, 2024 at about 6:00 pm local time, a 1978 Grumman Acft Eng Cor-Schweizer G-164B, registered N6633K, was substantially damaged in an accident during maneuvering (low-alt flying) near Durham, California (Oroville Muni airport). It was an aerial application (crop spraying) flight under agricultural flying rules (Part 137). 1 person was seriously injured. The weather was visual conditions (good weather).
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The NTSB's probable cause their words, unchanged
The pilot’s failure to maintain clearance from powerlines, which resulted in a wire strike.
Source: NTSB aviation accident database, copy made October 4, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- August 13, 2024 · about 6:00 pm local time
- Place
- Durham, California · Oroville Muni · map
- Type
- Accident
- Injuries
- 1 person was seriously injured.
- Weather
- visual conditions (good weather)
- Aircraft
- Grumman Acft Eng Cor-Schweizer G-164B, built 1978 · all G-164Bs on the register
- Registration
- N6633K · no longer on the register · serial 400B
- Damage
- Substantial damage
- Flight
- Aerial application (crop spraying) flight · agricultural flying rules (Part 137)
The NTSB's narrative final · quoted from the NTSB record
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.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record from the NTSB's investigation tables, in plain English
What happened, in order
- Low altitude operation/event during maneuvering (low-alt flying) defining event
The NTSB's findings
- Personnel issues › Psychological › Attention/monitoring › Attention › Pilot
- Environmental issues › Physical environment › Object/animal/substance › Wire › Effect on equipment
Pilot
- Certificate: commercial pilot
- Ratings: multi-engine land; single-engine land; instructor: airplane single-engine; instructor: instrument airplane; instrument: airplane
- Flight time: 23,629 hours in all; 1 in this make and model; 80 in the last 30 days; 23,432 as pilot in command
- Last flight review: August 25, 2023
- Medical certificate: Class 2 (with waivers/limitations)
- Seat: sngl
- Injury: serious injuries
The aircraft
- Airframe total time: 7,536.3 hours
- Last inspection: annual inspection, January 22, 2024
- Maximum gross weight: 7,020 lb
- Seats: 1
- Landing gear: fixed
- Engine: Pratt & Whitney PT6A-15AG (turboprop); 2,508 hours total
Weather at the time
- Light: daylight
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 81°F (27°C), dew point 50°F (10°C)
- Altimeter: 29.96 inHg
- Observation at 11:53 am from KOVE, 3 miles away
Weather report (METAR): KOVE 131853Z AUTO 00000KT 10SM CLR 27/10 A2996 RMK AO2 SLP144 T02720100
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
3 documents, released by the NTSB on March 6, 2025. View them here, or download them; the NTSB redacts some personal details before release, and this site shows the NTSB's own titles rather than its file names.
| # | Document | What it is | |
|---|---|---|---|
| 1 | Pilot/operator Aircraft Accident Report, NTSB Form 6120.1 | PDF, 11 pages | View Download |
| 2 | Photograph | PDF, 2 pages | View Download |
| 3 | Memorandum of Record -pic | PDF, 1 page | View Download |
The same docket at the NTSB · documents without a copy here are fetched from the NTSB when you open them.
Other NTSB records under N6633K the same tail number, which may have belonged to a different aircraft at the time
About this page
Everything above comes from the NTSB's public accident database: the narrative, probable cause and findings are the NTSB's own words, and the coded tables behind its report (pilot, aircraft, flight, weather, injuries, sequence of events) are written out in plain English. Pilots' ages, home towns and medical details are left out on purpose. The documents and photographs are the NTSB's docket, the folder of records gathered during the investigation, shown as the NTSB released them (the NTSB redacts some personal details first) and listed under the NTSB's own titles. This site's own text never names pilots, passengers or anyone else involved. A preliminary report describes what is known soon after the event and can change; the final report, with the probable cause, usually follows one to two years later and this page is refreshed when it does. Case number WPR24LA282.