The executive officer is the billet of the officer who is second-in-command. An XO is assigned to all ships, aviation squadrons, and shore units and installations, and is responsible to the captain for all ship’s work, drills, exercises, personnel organization, and the policing and inspection of the ship. When the ship goes to action stations, the XO confirms that the ship actually is ready for combat and reports this to the captain. The XO's own action station is in a separate part of the ship from that of the captain, so that a single hit will not likely incapacitate both officers. On small ships with no first lieutenant, gunnery officer, or navigator, the executive officer may also be responsible for the duties of those officers. Carrier air wings in the U.S. Navy do not have an XO, but have a deputy commander (DCAG) instead; for shore-based or functional naval air wings headed by a commodore, the equivalent position is the deputy commodore.