A landing signal officer or landing safety officer (LSO), also informally known as paddles (United States Navy) or batsman (Royal Navy), is a naval aviator specially trained to facilitate the "safe and expeditious recovery" of naval aircraft aboard aircraft carriers. LSOs aboard smaller air capable ships that launch and recover helicopters are informally known as deck. Originally LSOs were responsible for bringing aircraft aboard ship using hand-operated signals. Since the introduction of optical landing systems in the 1950s, LSOs assist pilots by giving information via radio handsets. History In the United States Navy, aircraft carrier operations began with USS Langley (CV-1) in 1922, and it served as a platform to experiment and develop aircraft launch and recovery procedures. The first pilots had no signaling system for assistance from shipboard personnel. Langley'''s first executive officer, Commander Kenneth Whiting, had a hand-cranked movie camera film every landing to aid in evaluation of landing technique. When not flying, Whiting observed all landings from the aft port corner of the flight deck. Whiting's position remained visible to landing pilots in critical touchdown attitudes when the nose of the aircraft might obscure the pilot's view straight ahead. Pilots found Whiting's body language helpful and suggested an experienced pilot be assigned to occupy that position, using agreed signals which evolved with experience. On one occasion when trying to signal an inexperienced pilot who had missed several approaches by coming in too high, Whiting pioneered the use of paddles or flags by grabbing the white hats of two nearby sailors and holding one in each hand to emphasize his hand positions. Hand-operated signals From the 1920s into the 1950s, U.S. Navy and Royal Navy LSOs used a variety of signals to assist pilots landing aboard aircraft carriers. The signals provided information on lineup with the deck, height relative to proper glide slope, angle of attack (fast or slow), and whether the plane's tailhook and wheels were down. The final signal was "the cut" (a slashing motion at the throat) ordering the pilot to reduce power and land the aircraft. In a properly executed landing, the aircraft's tailhook snagged an arresting wire that brought the plane to a halt. A "waveoff" was a mandatory order to abort the landing and go around for another attempt. Sometimes a proper approach drew a waveoff if the deck was "fouled" with aircraft or personnel in the landing area. LSOs faced the