Air Tractor AT 400 accident near Grand Forks, North Dakota, August 21, 2018
On August 21, 2018 at about 1:50 pm local time, a 1984 Air Tractor AT 400, registered N7300M, was substantially damaged in an accident during maneuvering (low-alt flying) near Grand Forks, North Dakota (J J And T airport). It was an aerial application (crop spraying) flight under agricultural flying rules (Part 137). 1 person was seriously injured. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The loss of engine power while maneuvering due to the failure of the power turbine blade assembly for reasons that could not be determined based on available evidence.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- August 21, 2018 · about 1:50 pm local time
- Place
- Grand Forks, North Dakota · J J And T · map
- Type
- Accident
- Injuries
- 1 person was seriously injured.
- Weather
- visual conditions (good weather)
- Aircraft
- Air Tractor AT 400 Undesignat, built 1984
- Registration
- N7300M · no longer on the register · serial 400-0518
- 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 was maneuvering the airplane during an aerial application over a field. A witness noticed that the airplane’s final turn was different than previous turns. Just before the airplane impacted the ground, the witness noticed a puff of smoke or liquid coming from the airplane. As the witness was a distance away, she was not certain. During the impact, the airplane sustained substantial damage. Examination of the engine revealed circumferential rubbing marks due to contact between the compressor turbine disk assembly and power turbine (PT) disk assembly. Of the 41 PT blades, 18 were recovered, and those blades exhibited fracture surfaces consistent with overstress fracture under elevated temperatures. Impact marks were identified inside the exhaust duct. The fracture of these blades likely occurred at ground impact when the engine was operational. It is likely that one or more of the unrecovered PT blades failed for an undetermined reason during the flight and impacted adjacent PT blades and components, including the exhaust duct. The internal engine damage from the released blades caused the PT disc assembly to fail, resulting in a loss of engine 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 maneuvering (low-alt flying) defining event
The NTSB's findings
- Aircraft › Aircraft power plant › Engine (turbine/turboprop) › Turbine section › Failure
- Not determined › Not determined › (general) › (general) › Unknown/Not determined
Pilot
- Certificate: commercial pilot
- Ratings: single-engine land; instructor: airplane single-engine; instrument: airplane
- Flight time: 1,350 hours in all
- Medical certificate: Class 1 (without waivers/limitations)
- Seat: sngl
- Injury: serious injuries
The aircraft
- Airframe total time: 11,932 hours
- Last inspection: 100-hour inspection, August 14, 2018
- Seats: 1
- Landing gear: fixed
- Engine: Pratt & Whitney PT6A SERIES (turboprop); 21,188 hours total
- Operator: Ross Seed Co Dba
The flight
- Departed from: MN81 East Grand Forks MN
- Destination: MN81 East Grand Forks MN
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: from 350° at 8 knots
- Visibility: 10 statute miles
- Sky: a few clouds at 25,000 ft
- Temperature: 59°F (15°C), dew point 50°F (10°C)
- Altimeter: 30.19 inHg
- Observation at 1:53 pm from KGFK, 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
8 documents, released by the NTSB on June 15, 2022. View them here, or download them; the NTSB redacts some personal details before release, and this site shows the NTSB's own titles rather than its file names.
| # | Document | What it is | |
|---|---|---|---|
| 1 | Materials Laboratory Factual Report | PDF, 22 pages | View Download |
| 2 | FAA Inspector Notes and Witness Statements | PDF, 1 page | View Download |
| 3 | FAA Pilot Interview | PDF, 1 page | View Download |
| 4 | Record of Memorandum | PDF, 1 page | View Download |
| 5 | Logbook Excerpts | PDF, 8 pages | View Download |
| 6 | Pratt & Whitney Canada 18-127 Report | PDF, 45 pages | View Download |
| 7 | Statement of Party Representatives to NTSB Investigation-woodward | PDF, 1 page | View Download |
| 8 | Photo Array-onsite (Courtesy of First Responders) | PDF, 16 pages | View Download |
The same docket at the NTSB · documents without a copy here are fetched from the NTSB when you open them.
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.