Northland Air Cargo

Witnesses observed the aircraft for approximately 8 minutes in erratic diving, climbing, and steep-turning maneuvers which culminated in a 12° descent to the ground. The sound of the engine was heard throughout the sequence and other evidence indicated engine power at impact. The aircraft struck trees, a farm building, farm equipment, and a vehicle, then burst into flames. The wreckage was strewn along a 320 feet path. No evidence of flight control malfunction was found. The pilot claimed an upset stomach before the flight. The pilot's speech was slurred in radio transmissions. The pilot did not respond to the last radio call from Sioux Falls tower. No emergency or distress calls were received from the pilot. The postmortem examination of the pilot did not identify specific impairment but was limited due to the severity of the impact and fire damage.