Background
The accident occurred during the pilot's second corporate flight of the day. Prior to departure, the pilot complained to an avionics technician about the autopilot and requested an adjustment. The technician informed him that a flight check would be required for the adjustment. The pilot stated he did not have time for a flight check and instead asked the technician to explain how to perform the adjustment himself.
Flight and Accident Sequence
Radar data indicate that the airplane was stable at 14,100 feet after departure. Subsequently, the aircraft began to deviate from the cruise altitude, with fluctuations ranging from 100 feet above to 200 feet below the assigned altitude. Air traffic control issued a 15-degree course change to avoid traffic, which the pilot acknowledged while the airplane was deviating from its course. Shortly thereafter, radar contact was lost, and no further radio transmissions were received from the pilot.
Witnesses on the ground reported hearing a loud explosion followed by a muffled explosion, and observed the airplane emerging from clouds in a vertical attitude. The outboard six feet of both wings were discovered 1.25 miles from the main crash site. The pilot, who was the sole occupant, sustained fatal injuries.
Probable Cause
The official probable cause was determined to be exceeding the design stress limits of the airplane by the pilot in command.