Grumman Acft Eng Cor-Schweizer G-164B accident near Colusa, California, June 4, 2023
On June 4, 2023 at about 4:05 pm local time, a 1978 Grumman Acft Eng Cor-Schweizer G-164B, registered N6750K, was substantially damaged in an accident during takeoff near Colusa, California. 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).
The NTSB's probable cause their words, unchanged
The pilot’s failure to maintain clearance from a power line during a low-level aerial application flight. Contributing to the accident was the pilot’s fatigue.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- June 4, 2023 · about 4:05 pm local time
- Place
- Colusa, California · 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
- N6750K · no longer on the register · serial 449-B
- Damage
- Substantial damage
- Flight
- Aerial application (crop spraying) flight · agricultural flying rules (Part 137)
The NTSB's narrative final · quoted from the NTSB record
The pilot reported this was the eighth aerial application flight of the day spraying rice fields. He had made all takeoff’s flying low under a power line about 3/4 mile from the departure end of the runway. He stated that due to the monotony of the flights combined with fatigue and a bi-plane wing configuration, he lost sight of the power line and struck it. The airplane impacted the ground and cartwheeled sustaining substantial damage to the wings, fuselage, vertical and horizontal stabilizer. The pilot reported no preaccident mechanical malfunctions or failures with the airplane that would have precluded normal operations.
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
- Collision during takeoff/land during takeoff defining event
- Miscellaneous/other during prior to flight
The NTSB's findings
- Personnel issues › Psychological › Mental/emotional state › Boredom › Pilot
- Personnel issues › Physical › Alertness/Fatigue › Fatigue due to work schedule › Pilot
- Environmental issues › Physical environment › Object/animal/substance › Wire › Compliance w/ procedure
- Environmental issues › Physical environment › Object/animal/substance › Wire › Contributed to outcome
Pilot
- Certificate: flight instructor, commercial pilot
- Ratings: multi-engine sea; single-engine land; instructor: airplane multi-engine; instructor: airplane single-engine; instructor: helicopter; instrument: airplane; rotorcraft: helicopter
- Flight time: 28,000 hours in all; 8,000 in this make and model; 225 in the last 90 days; 225 in the last 30 days
- Last flight review: December 31, 2021
- Medical certificate: Class 2 (with waivers/limitations)
- Seat: ctr
- Injury: serious injuries
The aircraft
- Last inspection: annual inspection
- Maximum gross weight: 6,000 lb
- Seats: 1
- Landing gear: fixed
- Engine: Pratt And Whitney R-1340 (piston); 0 hours total
- Operator: Valley Air
The flight
- Departed from: O08 Colusa CA at 4:00 pm
- Flight plan: none
Weather at the time
- Light: daylight
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 75°F (24°C), dew point 54°F (12°C)
- Altimeter: 29.82 inHg
- Observation at 3:53 pm from KMYV, 20 miles away
Weather report (METAR): METAR KMYV 041553Z AUTO 00000KT 10SM CLR 24/12 A2982 RMK AO2 SLP100 T02440117 $=
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 October 20, 2023. 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, 7 pages | View Download |
| 2 | Memorandum for Record A�� Telephone Interview, Pilot | PDF, 1 page | View Download |
| 3 | Photos | PDF, 2 pages | View Download |
The same docket at the NTSB · documents without a copy here are fetched from the NTSB when you open them.
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.