One witness interviewed by the NTSB, a pilot driving on a road southwest of the airport, told investigators that he saw the airplane in normal flight at normal altitudes, and that he believed that the approach was not abnormal. The airplane completed a 180-degree turn from the downwind leg of the approach and continued the turn. He then saw the aircraft pitch slightly, before it rolled to the left until the wings were vertical. The airplane then turned nose-down and smashed into the ground. He saw no fire or smoke during the flight and he believed both propellers were rotating.