Air Tractor AT-302 accident near Somerton, Arizona, November 16, 1990
On November 16, 1990 at about 3:30 am local time, a Air Tractor AT-302, registered N4441S, was substantially damaged in an accident near Somerton, Arizona. 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 THE NUMBER 3 EXHAUST VALVE WHICH LED TO AN ENGINE FAILURE AND SUBSEQUENT CRASH LANDING.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- November 16, 1990 · about 3:30 am local time
- Place
- Somerton, Arizona · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Air Tractor AT-302
- Registration
- N4441S · no longer on the register · serial 302-0101
- 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 EXPERIENCED A LOSS OF ENGINE POWER AND COLLIDED WITH THE TERRAIN DURING A SWATH RUN. EXAMINATION OF THE ENGINE REVEALED THE NUMBER 3 EXHAUST VALVE WAS CRACKED. THE ENGINE HAD 266 HOURS SINCE OVERHAUL AND HAD 20 HOURS SINCE THE LAST INSPECTION.
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
Pilot
- Certificate: commercial pilot
- Ratings: multi-engine land; single-engine land; single-engine sea; instrument: airplane
- Flight time: 8,300 hours in all; 5,200 in this make and model
- Medical certificate: Class 2 (valid medical--w/ waivers/lim.)
- Seat: frt
The aircraft
- Airframe total time: 4,950 hours
- Last inspection: annual inspection, March 1, 1990; 20 hours since
- Maximum gross weight: 5,000 lb
- Seats: 1
- Landing gear: fixed
- Engine: P&W R-1340 AN1 (piston); 0 hours total
- Fire on the ground
The flight
- Flight plan: none
- Runway 0
Weather at the time
- Light: night, dark
- Sky: clear
- Temperature: 70°F (21°C), dew point 30°F (-1°C)
- Altimeter: 30.00 inHg
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| 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.