The disclosure provides in one embodiment a wing tip device for a wing of an air vehicle. The device comprises a tip tail element, a boom element attaching the tip tail element to a wing tip, a hinge element connecting the tip tail element to the boom element, and an actuator element connected to the hinge element. One or more wing load sensors sense wing loads, and a flight control system controls the actuator element. A load alleviation method and system for an air vehicle are also provided.