Donald H. Sefton

The airplane was departing into instrument meteorological conditions using a standard instrument departure. The takeoff instructions consisted of making a climbing right turn direct to a nondirectional beacon. After departing, the pilot made a radio communication to an air traffic controller asking if he will tell him when to turn. The controller replied that he would not be calling his turn and that the pilot should fly the departure as published making a climbing right turn to overfly the approach end of the runway. The pilot acknowledged the communication, which was his last transmission. The airplane made a 360° turn and descended below the cloud layer. The airplane then climbed back into the cloud layer and made an inverted loop, descending into the ground in a near-vertical attitude. A postaccident examination of the airplane revealed no evidence of preimpact mechanical malfunctions or failures. Recorded audio of the airplane before the accident was consistent with the engines operating. The signatures on both propellers were consistent with one another and consistent with the engines operating at a similar rpm. The pilot was qualified and recently underwent recurrent training. The reasons the pilot became spatially disoriented could not definitely determined. The pilot left the anti-collision lights on while in the clouds, which may have resulted in him having flicker vertigo.