Designed to participate in Mar 50 US Army fly-off competition to replace WWII Piper L-4 and Stinson L-5. All-metal 305 had new fuselage design, wings of Model 170, and tail assembly of Model 195. With 2 seats in tandem, was designed for low maintenance and good short-field capability from unimproved sites; skis and floats could be interchanged with wheels. Roles for candidates in the competition included reconnaissance, observation, artillery fire direction and control, resupply, aerial telephone wire laying, aerial photography, rescue, and general transportation. One of the most difficult Army specifications was landing over a 50-ft obstacle in 600 ft or less. Accordingly, Cessna provided 60 flaps which caused high sink rate and nose-low approach. Flare-out to 3-point attitude completely stalled aircraft. Such landings required skilled pilot; hard landings resulted unless maneuver was completed smoothly and close to the surface. Won competition 1950, was designated L-19, and remained in service for over 20 yrs. Was also used by 17 other nations. Bird Dog entered combat in Korea 16 Feb 51. More A models produced than any other; by 1954, over 2,500 ordered. Important variant was TL-19D instrument trainer equipped with second instrument panel for rear seat. First ordered 1956, 310 built. Improved E model entered production 1957 with more powerful engine and more modern equipment; 494 built. Navy/Marine version of L-19 designated OE-1. In general reclassification in 1962, aircraft of all services designated O-1. 1963, Army turned over a number of O-1s to Air Force for use as Forward Air Controller (FAC) aircraft in Viet Nam. By 1966, O-1 was being modified at factory for this role. XL-19B became first light aircraft t powered with a gas turbine engine, the Boeing 502-8. Jul 53, set a light aircraft altitude record of 37,036 ft.