HISTORY OF FLIGHTOn June 15, 2021, at 1632 central daylight time, an Air Tractor AT 502B airplane, N6088K, was destroyed when it was involved in an accident near Paragould, Arkansas. The pilot was fatally injured. The airplane operated as a Title 14 Code of Federal Regulations Part 137 agricultural flight. A witness reported that he observed the airplane about one mile away flying directly toward him. It appeared to be straight and level, about treetop height. Without warning, he observed a small puff of white smoke; the airplane immediately nosed down, impacted the ground and a post-crash fire ensued. The witness did not hear any abnormal noises with the airplane or engine, nor did he observe any wildlife in the area. He stated, “everything appeared normal until it wasn’t." A second pilot reported that, on the day of the accident, he was working with the accident pilot from the same grass strip. Throughout the day they dispersed about 28 loads of fertilizer; during which, the accident pilot did not report any anomalies with the airplane. Shortly before the accident, the accident airplane was loaded with full fuel and fertilizer. The accident pilot was actively spraying a field when the second pilot departed the area to refill fertilizer. When the second pilot returned, he observed the airplane burning on the ground about 0.5 miles east of the field it was spraying. WRECKAGE AND IMPACT INFORMATIONThe airplane came to rest upright on the edge of a field; the dirt was moderately hard and mostly dry. The nose of the airplane was embedded into the dirt at about a 45° angle and only one propeller blade was visible. The forward fuselage, cockpit, inboard right and left wings, and the aft fuselage exhibited extensive thermal damage. The cabin area was destroyed by fire exposing the underlying airframe structure. The instruments and instrument panel were not present. Both wings remained attached at the wing spar. Flight control continuity was established to the control surfaces through multiple fractures and thermal damage. A postaccident examination of the airframe and engine revealed no preimpact mechanical malfunctions or anomalies that would have precluded normal operation.