On June 17, 2020, about 1800 central daylight time, an Air Tractor AT-402 airplane, N1532H, was substantially damaged when it was involved in an accident near Pine Bluff, Arkansas. The pilot was seriously injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 137 aerial application flight. The pilot reported that he was spraying applicant over a field and that a partial loss of engine power occurred when he began the first climbing turn to reverse course and make a second pass. The airplane subsequently descended and impacted terrain in a near-vertical attitude. The pilot also reported that the airplane owner had previously told him that the engine could potentially have 15% less power and had a history of engine problems. Maintenance log entries did not show a history of engine problems. Postaccident examination of the engine and its components discovered multiple signatures of rotational scoring and rubbing. The fuel control unit, fuel pump, starting flow control unit, overspeed governor, and propeller governor showed no preimpact anomalies but did show signs of contamination consistent with the presence of agricultural fertilizer. The engine case and components were damaged by impact.