What happened
During the preflight weather briefing, the pilot was advised to expect rain showers and thunderstorms with intensities reaching Level 6 along the intended route. The pilot departed under instrument flight rules (IFR) in an aircraft equipped with both radar and Stormscope equipment. After establishing radar contact, air traffic control (ATC) cleared the pilot on a direct heading to the destination.
Approximately 21 minutes into the flight, while traveling on a northwesterly track, the aircraft entered a Level 4 thunderstorm cell. The pilot notified ATC that the aircraft had hit a heavy cell, noting surrounding lightning and the accumulation of hard ice. Following a suggestion from the crew of another aircraft that was deviating north to avoid the storm, the pilot indicated an intention to turn north to exit the weather.
As the aircraft began a right turn, radar contact was lost after the aircraft had turned approximately 90 degrees. Six seconds after the final radar position, the pilot transmitted a radio message stating the aircraft was in a tremendous downdraft and losing 6,000 feet of altitude. This served as the final communication from the aircraft.
A search operation was launched following the loss of contact. The wreckage was located approximately 11 1/2 hours later, situated about 1 1/2 miles south of the last known radar position.