The cockpit and parts of the flight-control systems are protected by of titanium aircraft armor, referred to as a "bathtub". The armor has been tested to withstand strikes from 23 mm cannon fire and some strikes from 57 mm rounds. It is made up of titanium plates with thicknesses varying from determined by a study of likely trajectories and deflection angles. The armor makes up almost six percent of the aircraft's empty weight. Any interior surface of the tub directly exposed to the pilot is covered by a multi-layer nylon spall shield to protect against shell fragmentation. The front windscreen and canopy are resistant to small arms fire.