Grumman G164 accident near Tracy, California, August 11, 2010
On August 11, 2010 at about 2:15 pm local time, a Grumman G164, registered N6781K, was substantially damaged in an accident during maneuvering near Tracy, California (Private Airstrip airport). It was an aerial application (crop spraying) flight under agricultural flying rules (Part 137). No one was hurt; 1 person was on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
A total loss of engine power while maneuvering due to an internal catastrophic failure to the master rod and piston connecting rod links.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- August 11, 2010 · about 2:15 pm local time
- Place
- Tracy, California · Private Airstrip · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Grumman G164 B · all G164s on the register
- Registration
- N6781K · no longer on the register · serial 472B
- Damage
- Substantial damage
- Flight
- Aerial application (crop spraying) flight · agricultural flying rules (Part 137)
The NTSB's narrative final · quoted from the NTSB record
During an aerial application flight, the pilot heard a loud bang, which was followed by a loss of engine power and shaking. During the forced landing to a wet field, the pilot activated the left brake to intentionally ground-loop the airplane; however, it did not respond. The airplane continued its forward movement until it struck a fence at the end of the field and came to rest inverted. During the postaccident engine examination, it was discovered that the connecting links for all but the No. 7 cylinder were broken and the master rod was sheared. Due to the extent of internal damage, it could not be determined if the master rod or the connecting link had failed first.
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
- Loss of engine power (total) during maneuvering defining event
- Off-field or emergency landing during emergency descent
- Collision with terrain or object (not controlled flight into terrain) during landing (landing roll)
The NTSB's findings
- cause Aircraft › Aircraft power plant › Engine (reciprocating) › Recip eng cyl section › Failure
- Environmental issues › Physical environment › Terrain › Wet/muddy › Contributed to outcome
Pilot
- Certificate: flight instructor, commercial pilot
- Ratings: single-engine land; instructor: airplane single-engine; instructor: instrument airplane; instrument: airplane
- Flight time: 3,280 hours in all; 2,200 in this make and model; 200 in the last 90 days; 100 in the last 30 days
- Last flight review: December 31, 2009
- Medical certificate: Class 2 (with waivers/limitations)
- Seat: ctr
- Injury: no injuries
The aircraft
- Airframe total time: 15,000 hours
- Last inspection: 100-hour inspection, April 23, 2010
- Seats: 1
- Landing gear: fixed
- Engine: Pratt And Whitney R-1340 (piston); 0 hours total
- Operator: Trinkle AG Flying Inc.
The flight
- Departed from: Tracy CA at 1:30 pm
- Destination: Tracy CA
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: from 280° at 10 knots
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 57°F (14°C), dew point 52°F (11°C)
- Altimeter: 29.89 inHg
- Observation at 1:55 pm from SCK, 16 miles away
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.
Other NTSB records under N6781K the same tail number, which may have belonged to a different aircraft at the time
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.