The Cessna L-19/O-1 Bird Dog is a liaison and observation aircraft. It was the first all metal fixed wing aircraft ordered for and by the United States Army, since the U.S. Army Air Force separated from the army in 1947, becoming its own branch of service, U.S. Air Force. The Bird Dog had a lengthy career in the U.S. military as well as in other countries.
The U.S. Army was searching for an aircraft that could adjust artillery fire, as well as perform liaison duties, and preferably be constructed of all metal, as the canvas covered Liaison airplanes used during World war II (primarily Stinson and Piper products) had a short service life. The US Army issued the specification for a two-seat liaison and observation monoplane and the Cessna Aircraft Company submitted the Cessna Model 305A a development of the Cessna 170. The Cessna 305A was a single-engined light-weight strut-braced high-wing monoplane with a tailwheel landing gear. The greatest difference from the Cessna 170 was that the 305A only had two seats, in tandem configuration (the only tandem-seat plane that Cessna ever produced), with angled side windows to improve ground observation. Other differences included a re-designed rear fuselage, providing a view directly to the rear (a feature later dubbed "Omni-View" and carried to Cessna single-engine planes after 1964), and transparent panels in the wings' center-section (similar to those found on the Cessna 140 and the later Cessna 150 Aerobat model), which allowed the pilot to look directly overhead. A wider door was fitted to allow a stretcher to be loaded.
The U.S. Army awarded a contract to Cessna for 418 aircraft which was designated the L-19A Bird Dog. The prototype Cessna 305 (registration N41694) first flew on 14 December 1949. Deliveries began in December 1950 and the aircraft was soon in use fighting its first war in Korea from 1950 through 1953. An instrument trainer variant was developed in 1953, later versions had constant-speed propellers and the final version the L-19E had a larger gross weight. Cessna produced 3,431 aircraft which was also built under license by Fuji in Japan.
The L-19 received the name Bird Dog as a result of a contest held with Cessna employees to name the aircraft. The winning entry, submitted by Jack A. Swayze, an industrial photographer, was selected by a U.S. Army board. The name was chosen because the role of the army's new airplane was to find the enemy and orbit overhead until artillery (or attack aircraft) could be brought to bear on the enemy. While flying low and close to the battlefield, the pilot would observe the exploding shells and adjust the fire via his radios, in the manner of a bird dog (Gun dog) used by game hunters.
The Defense Department ordered 3,200 L-19s that were built between 1950 and 1959. The planes were used in various utility roles such as artillery spotting, front line communications, medevac and training. In 1962 the Army L-19 was redesignated the O-1 (Observation) Bird Dog and entered its second war in Vietnam. During the early 1960s the Bird Dog was flown by South Vietnamese airmen (ARVN-Army Republic Vietnam/SVAF South Vietnamese Air Force), US Army aviators, and clandestine (Ravens) aircrews. In 1964 the Department of Defense (DOD) issued a memorandum directing that the U.S. Army turn over its "Fixed Wing" O-1 Bird Dogs to the US Air Force, while the army began its transition to a "rotor-wing" force (helicopters).
The U.S. Army was allowed to retain some O-1 Bird Dogs for artillery observation (spotting/forward air control) until the new army helicopters entered service. All previous operators mentioned above, including the US Army, continued using the O-1 Bird Dog throughout the war, however the bulk of the O-1s were operated by the U.S. Air Force from 1964 until the end of the war in 1975 (flown primarily by South Vietnamese airmen in 1975). During the Vietnam War, the planes were used for reconnaissance and forward air control (FAC). Supplementing the O-1, then gradually replacing it, was the USAF O-2 Skymaster, a faster, twin-engine aircraft which entered Vietnam in the mid 1960s. The last U.S. Army O-1 Bird Dog was officially retired in 1974.
During the course of the Vietnam War, 469 O-1 Bird Dogs were lost to all causes. The USAF lost 178, the USMC lost seven, and 284 were lost from the US Army, South Vietnamese Forces, and clandestine operators. Three Bird Dogs were lost to enemy surface-to-air missiles (SAMs).
As USAF phased out the O-1 in favor of the O-2, many O-1s in the United States were sold as surplus. During the 1970s and 80s, Ector Aircraft remanufactured many as the Ector Mountaineer with their original powerplants, and as the Ector Super Mountaineer with the Lycoming O-540-A4B5.
Many O-1s were turned over to the Civil Air Patrol for such duties as aerial search. Many of these were damaged in groundloops and other accidents, and eventually all were replaced by tricycle-gear Cessnas. The only O-1 remaining in CAP inventory is a static display on a post in front of CAP headquarters at Maxwell Air Force Base.
In Canada, the Royal Canadian Air Cadets use L-19 aircraft equipped with a towing rig to tow their Schweizer 2-33 gliders for the Air Cadet gliding program. These particular L-19 variants are used in the Atlantic Region, Eastern Region and Pacific regions. They have been modified for noise reduction by the use of a smaller-diameter, 4-blade Hoffman composite propeller and exhaust modification. The fuel delivery system has also been modified from the original design, placing the fuel selector valve closer to the pilot. As with most aircraft used for glider towing, the aircraft has also been outfitted with mirrors mounted to the struts.