The Yaw Damper on the Q400 is more useless than a screen door on a submarine. AP is INOP if the YD is INOP when in reality that YD switch on the FGC is connected to void. Keeping coordinated flight? HA! At every minuscule change of power, my virtual hand goes automatically to that beloved rudder trim. I always feel bad for the virtual PAX sitting on the back... it must be a fun ride.
I love the Q, even with that "YD".