A bias gain system for aircraft rudder comprises a pair of connector ends receiving an actuation force from a bias actuator. A rudder bar interface is positioned between the connector ends. The interface rotates about the rudder bar as a function of the actuation forces from the bias actuators. A mechanism comprises links and joints between the connector ends and the rudder bar is actuatable between a contracted configuration, in which first moment arms are defined between the connector ends and the rudder bar interface, and an expanded gain configuration, in which second moment arms have a greater dimension than the first moment arms. An actuator is connected to the mechanism to actuate the mechanism to actuate the mechanism independently from the actuation forces from the bias actuators, to move the mechanism between configurations. An aircraft and a method for controlling a torque on a rudder bar of an aircraft are also provided.