galling

If, however, the input crank on the standby rudder actuator is not free to rotate with respect to the actuator housing because of galling between the shaft and bearing, the actuator housing, input crank, and control rod will act as a rigid link between the rudder and the torque tube. The inability to change the length of this link by rotation of the standby rudder actuator input crank within the actuator housing will affect the feedback mechanism between the rudder position and the MPCU input crank. This condition can result in problems ranging from high pilot control force necessary to move the rudder to uncommanded rudder deflections.