What happened
During the final minutes of the flight, observers noted the aircraft performing highly irregular movements, including steep turns, sudden climbs, and erratic dives. This sequence of maneuvers lasted roughly eight minutes and ended with the aircraft descending toward the ground at a 12-degree angle. Throughout this period, the engine remained audible, and evidence suggests that power was still being applied to the engine at the moment of impact.
The aircraft collided with several objects, including trees, farm equipment, a vehicle, and a nonresidential farm building. Following the collision, the wreckage spread across a path measuring 320 feet, and the airframe caught fire. No distress signals or emergency declarations were transmitted by the crew prior to the crash, and the pilot failed to respond to the final radio communication from the Sioux Falls tower.
Findings
Investigations into the wreckage revealed no evidence of a malfunction within the flight control systems. While the pilot reported experiencing an upset stomach before departure, and radio communications were noted to be slurred, the postmortem examination could not definitively confirm a specific physical impairment due to the extensive damage caused by the impact and subsequent fire. The investigation concluded that the primary factors involved improper maneuvering and a failure to maintain aircraft control by the pilot in command.