HISTORY OF FLIGHTOn September 17, 2021, about 0800 central daylight time, a Boeing A75 airplane, N19BB, was substantially damaged when it was involved in an accident near Delta, Colorado. The pilot sustained fatal injuries. The flight was operated under the provisions of Title 14 Federal Code of Regulations Part 91 as a personal flight. The airplane took off from runway 3 at Blake Field Airport (AJZ), Delta, Colorado. Two witnesses observed the airplane climb out and begin aerobatic maneuvers about 5 miles to the northeast of AJZ. Both witnesses reported that the airplane began a loop maneuver, and at the top of the loop while inverted, the airplane entered a flat spin. They observed the airplane recover from that spin. The airplane then gained altitude and they observed the airplane begin another loop maneuver. At the top of that loop, while inverted, the airplane entered another flat spin, but this time the pilot did not recover. The airplane impacted rugged, sloped terrain about 5 miles to the northeast of AJZ. First responders located the airplane wreckage and notified authorities. There were no radio or distress calls heard from the pilot. The witnesses reported that the engine could be heard running during the descent to the point of impact. AIRCRAFT INFORMATIONAccording to an acquaintance of the pilot, who also witnessed the accident, he and the pilot flew the airplane to AJZ a few days before the accident flight. The acquaintance stated that the airplane operated normally. AIRPORT INFORMATIONAccording to an acquaintance of the pilot, who also witnessed the accident, he and the pilot flew the airplane to AJZ a few days before the accident flight. The acquaintance stated that the airplane operated normally. WRECKAGE AND IMPACT INFORMATIONThe wreckage was found resting inverted on a 45-degree sloped hill. The fuselage was oriented downslope and crushed inward from impact forces. The engine was partially separated from its mounts. The empennage section was bent rearward, the upper wings were bent upward, and lower wings were separated from their respective mounting braces, consistent with a flat impact. One blade of the two-bladed propeller had no damage while the other blade was bent aft 45o with no twisting. Flight control continuity was confirmed from the cockpit to all flight control surfaces. The engine throttle control was found in the idle position. Engine rotation continuity (compression resistance) was confirmed. The smell of fuel was present. The airplane was not equipped with inverted fuel or oil supply systems. MEDICAL AND PATHOLOGICAL INFORMATIONThe Pathology Group, P.C., Grand Junction, Colorado, performed the pilot’ s autopsy as authorized by the Delta County Coroner’s Office, Delta, Colorado. According to the pilot’s autopsy report, his cause of death was multiple blunt force injuries, and his manner of death was accident. The autopsy did not identify significant natural disease. The Federal Aviation Administration Forensic Sciences laboratory performed toxicology testing of postmortem specimens from the pilot. Diphenhydramine, famotidine, desloratadine, and pseudoephedrine were detected in cavity blood and urine.