Abstract: An apparatus for operating a controlled member on a rotary-wing aircraft is provided with at least one control intended to be subject to the action of a pilot of the rotary-wing aircraft and capable of moving a linkage, a device connected to the linkage for operating the controlled member as a function of movement of the linkage, a ram incorporated into the linkage which is capable of influencing the movement of the linkage as a function of control commands received, a trim device capable of acting on the control and on the linkage as a function of control commands received, a computer determining the control commands which are transmitted to the ram and to the trim device, and at least one sensor which is capable of measuring the values of a parameter that represents an action exerted by a pilot of the rotary-wing aircraft on an auxiliary control.