Air Tractor AT-502 accident near Dinuba, California, December 16, 2008
On December 16, 2008 at about 6:08 pm local time, a Air Tractor AT-502, registered N1035F, was substantially damaged in an accident during maneuvering (low-alt flying) near Dinuba, California. 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
The failure of maintenance personnel to properly install the engine's Py line correctly, which resulted in the total loss of engine power and subsequent force landing. Contributing to the accident was the lack of suitable terrain.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- December 16, 2008 · about 6:08 pm local time
- Place
- Dinuba, California · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Air Tractor AT-502
- Registration
- N1035F · no longer on the register · serial 502-0081
- 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 that about halfway through the first spray pass he experienced a complete loss of engine power. The pilot stated that he pulled up out of the field, dumped the load, and chose to land straight ahead in an adjoining field. The pilot reported that after touching down and holding the stick back the tail started lifting. Before it stopped, the airplane nosed over and came to rest inverted. A Federal Aviation Administration (FAA) airworthiness aviation safety inspector conducted a post accident examination of the airplane. The airplane's most recent annual inspection had been completed the day prior to the accident. The FAA inspector found the engine's Py line had not been secured properly, which would have prevented proper fuel scheduling to the engine's fuel control unit. The inspector also reported that the outboard leading edge of the left wing tip had sustained substantial damage, which would have adversely affected the flight characteristics of the airplane.
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
- Aircraft maintenance event during prior to flight
- Loss of engine power (total) during maneuvering (low-alt flying) defining event
- Off-field or emergency landing during emergency descent
- Nose over/nose down during landing (flare/touchdown)
The NTSB's findings
- cause Aircraft › Aircraft power plant › Engine (turbine/turboprop) › (general) › Incorrect service/maintenance
- cause Personnel issues › Task performance › Maintenance › Installation › Maintenance personnel
- factor Environmental issues › Physical environment › Terrain › Rough terrain › Ability to respond/compensate
Pilot
- Certificate: commercial pilot
- Ratings: single-engine land
- Flight time: 1,752 hours in all; 434 in this make and model; 66 in the last 90 days; 1,642 as pilot in command
- Last flight review: November 21, 2008
- Medical certificate: Class 2 (without waivers/limitations)
- Seat: sngl
- Injury: no injuries
The aircraft
- Airframe total time: 9,990.2 hours
- Last inspection: annual inspection, December 15, 2008; 0.3 hours since
- Maximum gross weight: 8,000 lb
- Seats: 1
- Landing gear: fixed
- Engine: Pratt & Whitney PT6A-34 (turboprop); 0 hours total
- Operator: Gilbert Aviation Industries INC
The flight
- Departed from: D86 Visalia CA at 6:05 pm
- Destination: D86 Visalia CA
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: from 090° at 9 knots
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 41°F (5°C), dew point 36°F (2°C)
- Altimeter: 30.01 inHg
- Observation at 5:53 pm from VIS
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.