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WPR18LA234 · Air Tractor AT 400 Undesignat

21 Aug 2018 · Grand Forks, ND, United States

Ross Seed Co Dba Air Tractor AT 400 Undesignat · Accident: loss of engine power (total) while maneuvering

From J J and T Airport (MN81) to J J and T Airport (MN81)

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Event

NTSB case
WPR18LA234
Event typeAccident: someone killed or seriously injured, or the aircraft substantially damaged (NTSB definition). Incident: an occurrence that affected or could have affected safety, short of that. Glossary
Accident
InvestigationHow far the investigation had got when the record was published: preliminary, ongoing, final or completed. Unknown where the source does not say. Glossary
Completed
API-reported fatalities
0 · all aircraft and ground
Ground fatalities
Unknown
OperationWhat kind of flying it was, grouped by the rules it flew under: airline (US Part 121), air taxi and commuter (Part 135), general aviation (Part 91 and similar), military or government. Glossary
General aviation
WeatherVisual meteorological conditions (VMC): good enough to fly by looking outside. Instrument conditions (IMC): cloud or low visibility, flying by instruments. Glossary
Visual Meteorological Cond

Air Tractor AT 400 Undesignat

Aircraft type
Air Tractor AT-400
Category
Airplane
RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
N7300M
Onboard fatalities
Unknown
Route
From J J and T Airport (MN81), East Grand Forks, MNTo J J and T Airport (MN81), East Grand Forks, MN
Aircraft age
About 34 years (built 1984)
Flight rulesThe regulations the flight operated under: in the US, Part 91 (general aviation), Part 121 (airlines), Part 135 (air taxi and commuter) and others; for flights abroad, the NTSB's coarser commercial or non-commercial code. Glossary
Part 137: Agricultural
Phase of flightThe stage of the flight when things started to go wrong: standing, taxi, takeoff, initial climb, en route, maneuvering, approach or landing. Glossary
Maneuvering · low-altitude flying
Defining eventThe single coded event the NTSB judges best describes what happened (records from 2008 on). Older records name the first occurrence in the sequence instead. Glossary
Loss of engine power (total)
DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
Substantial

Cause areas

  • Aircraft › Aircraft power plant
  • Not determined › Not determined

Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.

NTSB narrative

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.

Probable cause

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.

Verbatim NTSB analysis and probable cause from the NTSB dataset

Sources

NTSB record WPR18LA234
Event ID
20180821X62540
Case number
WPR18LA234
Dataset
full-current
Source SHA-256
5cf380f0061817c0331a6b2d8cc7e0ee3a79bea469a1001dc5c10e56f35f5ab3
Source notes (4)
  • Unreviewed is an editorial label, not an investigation status. API-sourced is not report-checked or human-reviewed. Explicit event totals are used without summing aircraft injury tables; onboard allocation is withheld. Unknown values remain unknown. The operation category is mapped from the NTSB-reported FAR part and has not been reviewed.
  • Filled from the NTSB case API where the bulk record had no value: investigation status, cause areas. Values present in the bulk record are kept.
  • The date is the local date, which is the same as the UTC date the NTSB stores.
  • API snapshot SHA-256: a6f3cd23ad4a991f051d380341fc1640d8cc61e14301d983e1af8b80b4f1164c; retrieved 2026-09-16T08:07:59.174Z.