A Beechcraft B300 King Air 350, owned by Air Tindi and operating for the Royal Canadian Air Force, sustained substantial damage when it was involved in a runway excursion accident after landing on runway 25 at Thunder Bay Airport (YQT/CYQT), Ontario, Canada. The aircraft was operated on a mission that consisted of a multi-day cross country training and familiarization trip with three military aircrew members onboard. The accident happened on the first segment of the mission. The crew was cleared for the RNAV Z 25 instrument approach into the Thunder Bay Airport. The weather consisted of light winds and good visibility, with a ceiling at 2200 ft AGL. The approach proceeded normally and as the aircraft crossed through 600 ft AGL, the Pilot Flying elected to disconnect the autopilot and continue under manual control. Shortly after the aircraft crossed over the threshold of runway 25, the flying pilot reduced the two power levers to the idle position for landing. The aircraft experienced a yaw to the left and a significant drop of the left wing. The crew initiated an overshoot, however the aircraft continued to descend and the left wing impacted the runway surface. The aircraft progressed off the runway onto the snow-covered infield. After the aircraft came to rest, the crew conducted an emergency shut down and exited the aircraft.