What happened
The aircraft was operating as an on-demand, nonscheduled domestic cargo flight. After receiving a standard weather briefing and filing an IFR flight plan, the pilot departed at 2228.
At 2320, while descending from 13,000 feet to 11,000 feet, the pilot was cleared to descend further to 9,000 feet due to reports of accumulating ice. At 2329, air traffic control observed that the aircraft had reversed course. When questioned by the controller regarding the change in heading, the pilot stated, "I'm not sure. My instruments are going bad." Shortly after this communication, both radio and radar contact were lost.
The aircraft subsequently struck the ground in a near vertical attitude.
The investigation
The investigation examined the wreckage and found that no avionics, instruments, or vacuum pumps were recovered in an intact state. There was no evidence of any preimpact failure or malfunction related to the airframe, powerplant, propeller, or flight controls.