Air Tractor INC AT-502 accident near Great Bend, North Dakota, August 15, 2023

The NTSB's narrative final · quoted from the NTSB record

The pilot reported that he had completed an aerial application with the airplane and was in a turn when the engine lost power. The pilot said he advanced the power lever to full but there was no engine response. The pilot attempted a forced landing on a nearby county road. The airplane landed hard on the road surface, bounced back in the air and floated some distance before settling back on the road. The airplane then veered off the road, went through a ditch, and came to rest in an adjacent farm field. The airplane sustained substantial damage to the left and right tubular clusters where the main landing gear attach. The pilot later reported that, after reviewing speed and altitude data from one of the airplane’s track logs, his recollection of the event did not match what the data showed. He stated that, “The log shows no loss of airspeed that would indicate a loss of power before the initial impact with the ground.” He went on to state that he was no longer confident that his original recollection that there was a power loss was accurate and that this incident was likely caused by pilot error.  An examination of the airplane’s fuel control unit (FCU) and fuel pump showed black material in the vicinity of the Py orifice inlet. The manufacturer identified the material as soft debris similar to fluorocarbon and most likely from the packing (O-ring) used on the P3 air inlet fitting. The debris’ size and location did not completely obstruct the inlet and would have allowed for air passage into the FCU, hence not hindering its operability. A bench test of the fuel control unit and fuel pump showed the unit and pump performed normally. No other preaccident failures or malfunctions with the airplane were found that would have precluded normal operations.

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.