Abstract: A control system of a hydraulic type for a thrust reversal device with which a jet engine nacelle is equipped, and associated with a nozzle variation device, is provided by the present disclosure. The control system includes at least one additional control unit hydraulically connecting actuators together, wherein hydraulic supply lines from the control unit in a nozzle mode and from the control unit in a reverser mode are then able to communicate hydraulically with each other. A plurality of control valves are laid out so that when the unit for driving the actuators in a nozzle mode is active, a corresponding hydraulic signal controls the valves of the control unit in a position such that the hydraulic supply lines of the actuators from the driving unit according to a reverser mode are cut off.