A method for automatic yaw axis control in aircraft with mechanical controls, said aircraft including a yaw actuator to control orientation of a yaw control surface and deliver a measured value of the torque on the control surface, a yaw trim actuator driving movement of a yaw trim control surface limiting the force applied by the yaw actuator to orient the yaw control surface, and sensors supplying an estimate of a lateral yaw force, includes calculating a setpoint value for the position of the yaw control surface determined by the estimated lateral force, an estimated torque of the yaw actuator determined by the measured value of the torque of the yaw actuator and a measured position of the yaw control surface, the estimated torque calculated having a lower oscillation dynamic range than the measured torque, and a trim command for activating/deactivating the yaw trim actuator determined by the estimated torque.