Air Tractor INC AT-502 accident near Lewistown, Montana, June 25, 2011
On June 25, 2011 at about 1:43 am local time, a Air Tractor INC AT-502, registered N1022N, was substantially damaged in an accident during enroute (cruise) near Lewistown, Montana. 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 fatigue fracture and separation of the fuel bypass line, which resulted in a total loss of engine power.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- June 25, 2011 · about 1:43 am local time
- Place
- Lewistown, Montana · 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-502 · all AT-502s on the register
- Registration
- N1022N · registry record · serial 502-0071
- 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 while in cruise flight about 800 feet above ground level, the engine lost power, and he initiated a forced landing to an area of open, uneven terrain. During the landing roll, the left wing struck the ground and the airplane ground looped. Postaccident examination revealed that the fuel bypass line was fractured and had separated from the fuel control unit. Metallurgical analysis revealed that the fuel bypass line fractured near a ferrule at the edge of the braze filler metal fillet. Striations on the fracture surface were consistent with a fatigue crack originating on the outside surface of the tube and propagating toward the inside surface and circumferentially around the tube wall. No maintenance records for the airplane were recovered during the course of the investigation, and, therefore, the amount of time and maintenance history on the line was undetermined.
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 enroute (cruise) defining event
- Off-field or emergency landing during landing
- Collision with terrain or object (not controlled flight into terrain) during landing (landing roll)
The NTSB's findings
- cause Aircraft › Aircraft power plant › Engine fuel and control › (general) › Fatigue/wear/corrosion
Pilot
- Certificate: commercial pilot
- Ratings: single-engine land
- Flight time: 6,200 hours in all
- Medical certificate: Class 2 (without waivers/limitations)
- Seat: ctr
- Injury: no injuries
The aircraft
- Seats: 1
- Landing gear: fixed
- Engine: P&W Canada PT6A-60A (turboprop); 0 hours total
- Operator: Srb Aerial Applicators LLC
The flight
- Departed from: Lewistown MT
- Destination: Lewistown MT
- Flight plan: not recorded
Weather at the time
- Light: daylight
- Wind: from 090° at 7 knots
- Visibility: 10 statute miles
- Sky: scat at 7,000 ft
- Temperature: 64°F (18°C), dew point 45°F (7°C)
- Altimeter: 29.84 inHg
- Observation at 1:54 am from LWT, 10 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.
Other NTSB records under N1022N the same tail number, which may have belonged to a different aircraft at the time
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 WPR11LA288.