Abstract: The system for controlling the speed of opening a sliding door for an aircraft including a mechanical braking device for the door including a transmission shaft and a centrifugal absorber including a resistance shaft connected to the transmission shaft, and linking means that are designed to be connected to the sliding door and to cooperate with the transmission shaft so that when the sliding door moves in a predetermined direction, the linking means drive the transmission shaft and the centrifugal absorber applies a resistance torque to the transmission shaft in order to control the speed of movement of the door. The system includes a speed reducer connecting the resistance shaft to the transmission shaft so that the speed of rotation of the resistance shaft is greater than that of the transmission shaft when the sliding door moves in the predetermined direction.