A control system for a manually-operated control stick and for enabling the control stick to settle to a trim position when zero force is applied to the control stick by an operator, the control system including: a first circuit comprising a summing circuit arranged for a receiving a first signal representative of a force applied to the control stick by an operator and for receiving a second signal representing at least one force feedback signal and arranged to subtract the second signal from the first signal to provide a third signal; a second circuit comprising a first integrator circuit arranged for receiving the third signal and arranged to derive a velocity signal therefrom; a third circuit comprising a second integrator circuit, having an internal stored state, wherein the third circuit is arranged for receiving the velocity signal and arranged to generate a position signal therefrom, wherein the second integrator circuit is also arranged to receive a trim input signal representative of the trim position and is arranged to sum the received trim input signal with its internal stored state to generate the position signal; and a fourth circuit, containing values defining a predetermined force-position mapping characteristic, wherein the fourth circuit is arranged for receiving a position signal from the second integrator and the trim input signal and is arranged to, when no trimming operation is required, extract a force value corresponding to the received position signal from the predetermined force-position mapping characteristic and output a force feedback signal to the first circuit representative of the extracted force value, and when a trimming operation is required, to modify the predetermined force-position mapping characteristic by shifting, the position values in the predetermined force-position mapping characteristic by an amount equal to the trim position represented by the received trim input signal, and select a force value corresponding to a received position signal from the modified force-position mapping characteristic and output a force feedback signal representative of the selected force value to the first circuit, wherein the control system is arranged that the position values defining the predetermined force-position mapping characteristic contained in the fourth circuit are shifted according to trim input signal, and simultaneously with the second integrator summing of the trim input signal with said second integrator circuit internal stored state. a first circuit comprising a summing circuit arranged for a receiving a first signal representative of a force applied to the control stick by an operator and for receiving a second signal representing at least one force feedback signal and arranged to subtract the second signal from the first signal to provide a third signal; a second circuit comprising a first integrator circuit arranged for receiving the third signal and arranged to derive a velocity signal therefrom; a third circuit comprising a second integrator circuit, having an internal stored state, wherein the third circuit is arranged for receiving the velocity signal and arranged to generate a position signal therefrom, wherein the second integrator circuit is also arranged to receive a trim input signal representative of the trim position and is arranged to sum the received trim input signal with its internal stored state to generate the position signal; and a fourth circuit, containing values defining a predetermined force-position mapping characteristic, wherein the fourth circuit is arranged for receiving a position signal from the second integrator and the trim input signal and is arranged to, when no trimming operation is required, extract a force value corresponding to the received position signal from the predetermined force-position mapping characteristic and output a force feedback signal to the first circuit representative of the extracted force value, and when a trimming operation is required, to modify the predetermined force-position mapping characteristic by shifting, the position values in the predetermined force-position mapping characteristic by an amount equal to the trim position represented by the received trim input signal, and select a force value corresponding to a received position signal from the modified force-position mapping characteristic and output a force feedback signal representative of the selected force value to the first circuit, wherein the control system is arranged that the position values defining the predetermined force-position mapping characteristic contained in the fourth circuit are shifted according to trim input signal, and simultaneously with the second integrator summing of the trim input signal with said second integrator circuit internal stored state.