Ayres Corporation S2R-T34 and Grumman Acft Eng Cor-Schweizer G-164B mid-air collision near Marysville, California, May 6, 2009
On May 6, 2009, 2 aircraft, Ayres Corporation S2R-T34 (N40208) and Grumman Acft Eng Cor-Schweizer G-164B (N6617K), were involved in a mid-air collision near Marysville, California (Yuba County airport). 1 person was seriously injured; 1 other was unhurt. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The failure of both pilots to see and avoid the other airplane while making their final approach for landing.
The failure of both pilots to see and avoid the other airplane while making their final approach for landing.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- May 6, 2009
- Place
- Marysville, California · Yuba County · map
- Type
- Accident · mid-air collision
- Injuries
- 1 person was seriously injured; 1 other was unhurt.
- Weather
- visual conditions (good weather)
- Aircraft 1
- Ayres Corporation S2R-T34 · all S2R-T34s on the register
- Registration
- N40208 · no longer on the register · serial T34-023
- Damage
- Substantial damage
- Flight
- Aerial application (crop spraying) flight · agricultural flying rules (Part 137)
- Aircraft 2
- Grumman Acft Eng Cor-Schweizer G-164B · all G-164Bs on the register
- Registration
- N6617K · no longer on the register · serial 392B
- Damage
- Substantial damage
- Flight
- Aerial application (crop spraying) flight · agricultural flying rules (Part 137)
The NTSB's narrative for the Ayres Corporation S2R-T34 final · quoted from the NTSB record
An Ayers S2R crop duster entered a left base for the runway at 500-600 feet, then turned left for a 3/4 mile final. At the same time a Grumman G164B entered a long final for the same runway. Neither aircraft had a VHF radio on board and neither pilot had visually acquired the other airplane. As the Grumman crossed the approach end of the runway for landing, the Ayers impacted it from above and behind. Both airplanes crashed entangled onto the runway.
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 NTSB's narrative for the Grumman Acft Eng Cor-Schweizer G-164B final · quoted from the NTSB record
An Ayers S2R crop duster entered a left base for the runway at 500-600 feet, then turned left for a 3/4 mile final. At the same time a Grumman G164B entered a long final for the same runway. Neither aircraft had a VHF radio on board and neither pilot had visually acquired the other airplane. As the Grumman crossed the approach end of the runway for landing, the Ayers impacted it from above and behind. Both airplanes crashed entangled onto the runway.
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 for the Ayres Corporation S2R-T34 from the NTSB's investigation tables, in plain English
What happened, in order
- Midair collision during approach (VFR pattern final) defining event
The NTSB's findings
- cause Personnel issues › Psychological › Attention/monitoring › Monitoring other aircraft › Pilot
- cause Personnel issues › Psychological › Attention/monitoring › Monitoring other aircraft › Pilot of other aircraft
Pilot
- Certificate: flight instructor, commercial pilot
- Ratings: multi-engine land; single-engine land; instructor: airplane multi-engine; instructor: airplane single-engine; instructor: instrument airplane; instrument: airplane
- Flight time: 8,900 hours in all; 3,100 in this make and model; 150 in the last 90 days; 100 in the last 30 days; 8,800 as pilot in command; 1,700 on instruments
- Last flight review: March 20, 2008
- Medical certificate: Class 2 (without waivers/limitations)
- Seat: sngl
- Injury: no injuries
The aircraft
- Airframe total time: 6,508 hours
- Last inspection: 100-hour inspection, April 23, 2009
- Seats: 1
- Landing gear: fixed
- Engine: P&W Canada PT6A-60A (turboprop); 0 hours total
- Operator: G N Dibble Inc
The flight
- Departed from: Nicolas CA
- Destination: KMYV Marysville CA
- Flight plan: none
- Runway 23, 6,006 ft by 150 ft
Weather at the time
- Light: daylight
- Wind: from 210° at 12 knots
- Visibility: 10 statute miles
- Sky: a few clouds at 4,500 ft
- Temperature: 75°F (24°C), dew point 55°F (13°C)
- Altimeter: 30.01 inHg
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 |
The factual record for the Grumman Acft Eng Cor-Schweizer G-164B from the NTSB's investigation tables, in plain English
What happened, in order
- Midair collision during approach (VFR pattern final) defining event
The NTSB's findings
- cause Personnel issues › Psychological › Attention/monitoring › Monitoring other aircraft › Pilot
- cause Personnel issues › Psychological › Attention/monitoring › Monitoring other aircraft › Pilot of other aircraft
Pilot
- Certificate: commercial pilot
- Ratings: multi-engine land; single-engine land
- Flight time: 36,000 hours in all; 33,000 in this make and model; 180 in the last 90 days; 80 in the last 30 days; 36,000 as pilot in command
- Last flight review: February 13, 2009
- Medical certificate: Class 2 (without waivers/limitations)
- Seat: sngl
- Injury: serious injuries
The aircraft
- Airframe total time: 21,133 hours
- Last inspection: annual inspection, April 4, 2009
- Seats: 1
- Landing gear: fixed
- Engine: P&W R1340 SERIES (piston); 0 hours total
The flight
- Departed from: KMYV Marysville CA
- Destination: KMYV Marysville CA
- Flight plan: none
- Runway 23, 6,006 ft by 150 ft
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), has not been read from the NTSB for this case yet; the list appears here once it has. Open the docket at the NTSB.
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.