I faced a simular problem with the Majestic Dash8 q400. I am using FSUIPC FSiPanel Saitek Pro Yoke with pedals and throttle quadrant. With the FSiPanel you can do a test and it reported that my SLEW axis were having an issue, If I loaded up the plane with FSiPanel, the plane would just go spinning. I solved the issue by re-calibrating all my attached devices ( Yoke, Pedals and Throttle quadrant). Hope this info helps solving the issue.