A system that acts on a rudder (L) having its stop parts commanded or moved by an actuator (A) is described. The rudder system comprises a reversible mechanical system with movable stop parts working based on control/command signals, having stop parts (M, M') inside of the field of movement of the actuator (A), interfering in the movement of said actuator; the mentioned control signals are based on informations of the aircraft such as traction of the engines or other signal from each engine (pressure, temperature or axis rotation speed); flight speed ("airspeed"); altitude; skidding angle; aircraft on the ground. The system limits the deflection of the rudder in flight with symmetrical traction, enough for normal maneuvers, and it allows total authority of the rudder (L), allowing a larger movement (larger deflection angle) just when necessary, in other words, when there is a traction asymmetry between the engines and, for aircrafts having wheels mechanically connected to the pedals and rudder, when they are maneuvering on the ground during taxi operations.