Air Tractor AT-401 accident near Oak Grove, Louisiana, June 6, 2007
On June 6, 2007 at about 4:00 pm local time, a Air Tractor AT-401, registered N92PK, was substantially damaged in an accident near Oak Grove, Louisiana. 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 complete loss of power due to failure of the impeller drive gear train and displacement of the blower spring drive mechanism, which resulted in seizure of the propeller shaft/crankshaft. Also causal was the failure of the phenolic separator bracket of the rear impeller support bearing for undetermined reasons. A factor was the none suitable terrain for the forced landing.
Source: NTSB aviation accident database, copy made October 4, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- June 6, 2007 · about 4:00 pm local time
- Place
- Oak Grove, Louisiana · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Air Tractor AT-401
- Registration
- N92PK · registry record · serial 401-0821
- 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 5,475-hour commercial pilot reported that after performing an aerial application pass in his radial-engine-powered airplane, he initiated a turn to reverse direction to start another pass. At the top of the turn, he heard a loud bang from the radial engine, followed by the sound of the engine winding down. He also noticed white smoke from the exhaust, a loss of power, and a drop in manifold pressure. The pilot made an forced landing to a field, where the airplane rolled about 250 yards before it flipped over. The airplane was released to the owner after the accident, who later sold it to another operator. Due to the damage sustained in the accident, the engine was disassembled and examined before the new owner could return the airplane back to service. The new owner provided an engine disassembly report. According to the report, "undetermined causes resulted in distress to the phenolic separator bracket of the rear impeller support bearing resulted in its separation and fragmentation." The reports adds that "this initiated a chain reaction of events throughout the rest of the engine as clearances, lack of lubrication and subsequent wearing of engine components took place." This damage ultimately resulted in destruction of the blower labyrinth seal and the impeller gear train, which reduced power output. The engine reports concludes that "the destroyed impeller drive gear train and the distress caused by the displaced blower spring drive mechanism, coupled with reduced power output, resulted in seizure of the propeller shaft/crankshaft and complete loss of 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
Pilot
- Certificate: commercial pilot
- Ratings: single-engine land
- Flight time: 5,475 hours in all; 70 in this make and model; 200 in the last 90 days; 110 in the last 30 days; 5,082 as pilot in command
- Last flight review: February 1, 2006
- Medical certificate: Class 2 (without waivers/limitations)
- Seat: sngl
- Injury: no injuries
The aircraft
- Airframe total time: 4,680 hours
- Last inspection: annual inspection, May 1, 2007; 40 hours since
- Maximum gross weight: 6,000 lb
- Seats: 1
- Landing gear: fixed
- Engine: Pratt & Whitney R-1340 ANI (piston); 0 hours total
- Operator: Whittington Air & Ground LLC
The flight
- Departed from: Eudora AR at 3:15 pm
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: from 180° at 10 knots
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 88°F (31°C), dew point 68°F (20°C)
- Altimeter: 29.90 inHg
- Observation at 3:53 pm from KMLU
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.
About this page
Everything above comes from the NTSB's public accident database: the narrative, probable cause and findings are the NTSB's own words, and the coded tables behind its report (pilot, aircraft, flight, weather, injuries, sequence of events) are written out in plain English. Pilots' ages, home towns and medical details are left out on purpose. The documents and photographs are the NTSB's docket, the folder of records gathered during the investigation, shown as the NTSB released them (the NTSB redacts some personal details first) and listed under the NTSB's own titles. This site's own text never names pilots, passengers or anyone else involved. A preliminary report describes what is known soon after the event and can change; the final report, with the probable cause, usually follows one to two years later and this page is refreshed when it does. Case number DFW07LA138.