A method and control system for an aircraft engine comprising a gas turbine driving a fan propeller with a mechanical gear-train and a dedicated pitch change mechanism for the fan propeller includes a fuel flow signal input; a pitch change mechanism signal input; a controlled plant for relating a pitch change mechanism pitch angle (BetaP) and a fuel flow (Wf) to at least two controlled outputs and a set of constraints. A decoupling control decoupling the controlled plant and/or the constraints into two separate single-input single-output (SISO) control loops for the first and second controlled outputs and a decoupling control decoupling the constraints from the decoupled controlled outputs and the constraints from one another provide gas turbine and fan propeller coordinate control while coordinately controlling constraints and outputs. A feedforward control can compensate the load change effect on engine speed and fan propeller rotor speed control.