Aircraft directors, as their name implies, are responsible for directing all aircraft movement on the hangar and flight decks. They are enlisted Aviation Boatswain's Mates. They are colloquially known as Bears and those that work in the hangar go by the term Hangar Rat. On some carriers, commissioned officers known as flight deck officers also serve as aircraft directors. During flight operations or during a flight deck "re-spot", there are typically about 12-15 yellowshirts on the flight deck, and they report directly to the "handler". Although aircraft directors are often used at airports ashore, their function is particularly crucial in the confined flight deck environment where aircraft are routinely taxied within inches of one another, often with the ship rolling and pitching beneath. Directors wear yellow and use a complex set of hand signals (lighted yellow wands at night) to direct aircraft.