At 1140 Central time, the airplane was substantially damaged following a loss of control while landing. The Airline Transport pilot, the Commercial pilot acting as first officer and the seven passengers aboard were not inured. Visual conditions prevailed. Tower personnel reported the airplane veered to the left and departed the runway during landing. The pilot reported that during the landing roll and upon nose wheel touchdown, the steering wheel mechanism failed and resulted in an uncommanded turn to the left. Weather observations included calm winds and clear skies.
