Air Tractor INC AT-301 accident near Nekoosa, Wisconsin, August 4, 2011
On August 4, 2011 at about 3:00 pm local time, a Air Tractor INC AT-301, registered N4345S, was substantially damaged in an accident during initial climb near Nekoosa, Wisconsin (Private airport). It was a positioning flight under general aviation rules (Part 91). 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 during initial climb for undetermined reasons.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- August 4, 2011 · about 3:00 pm local time
- Place
- Nekoosa, Wisconsin · Private · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Air Tractor INC AT-301 · all AT-301s on the register
- Registration
- N4345S · no longer on the register · serial 301-0025
- Damage
- Substantial damage
- Flight
- Positioning flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The pilot reported that the engine backfired and lost power during the initial climb after takeoff. The airplane sustained substantial damage to the fuselage and wings during the forced landing. An engine teardown examination revealed a separation of three gear teeth on an intermediate gear located in the accessory section. The gear teeth exhibited signatures of overload failure; no evidence of fatigue failure was observed. Accordingly, separation of the gear teeth likely occurred during the forced landing and not as a result of a preimpact failure. No failures or malfunctions consistent with a preimpact loss of engine power were observed. At the time of the accident, carburetor icing was not probable when the airplane was under takeoff power.
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 initial climb defining event
- Off-field or emergency landing during emergency descent
The NTSB's findings
- cause Not determined › Not determined › (general) › (general) › Unknown/Not determined
Pilot
- Certificate: flight instructor, commercial pilot
- Ratings: single-engine land; instructor: airplane single-engine; instrument: airplane
- Flight time: 885 hours in all; 35 in this make and model; 145 in the last 90 days; 55 in the last 30 days; 820 as pilot in command; 260 on instruments
- Last flight review: March 11, 2011
- Medical certificate: Class 2 (with waivers/limitations)
- Seat: sngl
- Injury: no injuries
The aircraft
- Airframe total time: 7,382 hours
- Last inspection: annual inspection, June 20, 2011; 17 hours since
- Seats: 1
- Landing gear: fixed
- Engine: P&W R-1340-AN-1 (piston); 0 hours total
- Operator: Kafer Stone Applicator Service Inc.
The flight
- Departed from: PVT Nekoosa WI at 3:00 pm
- Destination: PVT Oshkosh WI
- Flight plan: none
- Runway 36, 2,500 ft by 50 ft
Weather at the time
- Light: daylight
- Wind: from 130° at 5 knots
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 77°F (25°C), dew point 64°F (18°C)
- Altimeter: 30.02 inHg
- Observation at 2:54 pm from ISW, 5 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.
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.