Air Tractor 502B accident near Whittemore, Iowa, July 23, 2010
On July 23, 2010 at about 7:00 pm local time, a Air Tractor 502B, registered N4203B, was substantially damaged in an accident during takeoff near Whittemore, Iowa. 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 pilot's failure to abort the takeoff, which resulted in an aerodynamic stall.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- July 23, 2010 · about 7:00 pm local time
- Place
- Whittemore, Iowa · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Air Tractor 502B
- Registration
- N4203B · registry record · serial 502B-2636
- 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 he had made four previous agricultural aerial application runs prior to the accident flight, one of which had the same load as the accident flight. He departed to the north since the windsock was indicating a slight northeast wind. The grass airstrip was about 2,640 feet long and was soft due to recent rains. The weather was about 90 degrees Fahrenheit with high humidity. He reported that he put in 10 degrees of flaps, held the brakes, and ran the engine up to 1,700 lbs of torque. After he released the brakes and started the takeoff roll, the airplane encountered a soft spot in the runway, which reduced his ground speed. Halfway down the runway the tail had still not come up, so the pilot “forced the tail up using the trim tab” and by pushing the stick full forward. The pilot eased the forward stick pressure and the tail went back to the ground. He immediately began to dump the load and he put in full flaps. About 100 yards before the end of the runway, the pilot “pulled the stick all the way back and became airborne, but stalled [the] airplane.” The left wing stalled and impacted the ground. The airplane came to rest in a corn field on the edge of the grass airstrip. The pilot reported that he “should have stopped the ground roll when I encountered the wet spot in the strip.” The airplane sustained substantial damage to the left wing, right wing, and empennage.
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
- Aerodynamic stall/spin during takeoff defining event
- Collision with terrain or object (not controlled flight into terrain) during takeoff
The NTSB's findings
- cause Aircraft › Aircraft oper/perf/capability › Performance/control parameters › Airspeed › Not attained/maintained
- cause Aircraft › Aircraft oper/perf/capability › Performance/control parameters › Angle of attack › Not attained/maintained
- cause Personnel issues › Action/decision › Action › Incorrect action performance › Pilot
Pilot
- Certificate: commercial pilot
- Ratings: single-engine land
- Flight time: 3,468 hours in all; 1,598 in this make and model
- Medical certificate: Class 2
- Injury: no injuries
The aircraft
- Maximum gross weight: 9,400 lb
- Seats: 1
- Landing gear: fixed
- Engine: Pratt & Whitney PT6A-34AG (turboprop); 0 hours total
The flight
- Departed from: Whittemore IA at 7:00 pm
- Destination: Whittemore IA
- Flight plan: none
Weather at the time
- Light: daylight
- Sky: clear
- Temperature: 0°F (-18°C), dew point 0°F (-18°C)
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.