As stated by others, the newer aircraft have full time yaw dampers which can be turned off if a problem exists. On the B-747 the yaw rate gyros are actually on the front of the yaw computers (upper and lower). Turn coordination with flaps out of the up position is a function of Number 1 INS. If No.1 INS fails and number 3 is selected, turn coordination will not shift. It is lost.