Air Tractor, Inc. AT-400 N23720 accident near Monango, North Dakota

Probable cause

The pilot did not maintain adequate separation from a tree during the aerial-application flight.

NTSB analysis

The pilot reported that he remembered completing a majority of his spray runs during the aerial-application flight and was finishing along the field's edge when the accident occurred. However, he had no recollection of the airplane colliding with the trees or terrain. Global positioning system data revealed that the airplane had descended from about 300 feet above ground level (agl) to less than 100 feet agl into a sparsely wooded area during the last 15 seconds of the flight. A postaccident examination established that the airplane's right wingtip contacted a tree before the airplane collided with terrain. The examination did not reveal any mechanical malfunctions or failures that would have precluded normal operation of the airplane. The presence of fuel throughout the engine's fuel system and the rotational damage sustained by several engine components was consistent with a sudden stoppage of an operating engine during impact.

Text from the NTSB. Open the NTSB docket for CEN11LA593 for the full record.