These squadrons could use only a limited number of pilots, far fewer than those black cadets qualified for such training. All applicants in excess of requirements were placed on an indefinite waiting list where many became overage or were requisitioned for other military and civilian duties. Yet when the Army Air Forces finally decided to organize a black bomber unit, the 477th Bombardment Group, in late 1943, it encountered a scarcity of black pilots and crewmen. Because of the lack of technical and educational opportunities for Negroes in America, fewer blacks than whites were included in the manpower pool, and Tuskegee, already overburdened with its manifold training functions and lacking the means to train bomber crews, was unable to fill the training gap. Sending black cadets to white training schools was one obvious solution; the Army Air Forces chose instead to postpone the operational date of the 477th until its pilots could be trained at Tuskegee. In the end, the 477th was not declared (p. 030) operational until after the war. Even then some compromise with the Army Air Forces' segregation principles was necessary, since Tuskegee could not accommodate B-25 pilot transition and navigator-bombardier training. In 1944 black officers were therefore temporarily assigned to formerly all-white schools for such training. Tuskegee's position as the sole and separate training center for black pilots remained inviolate until its closing in 1946, however, and its graduates, the "Tuskegee Airmen," continued to serve as a powerful symbol of armed forces segregation.[2-26] [Footnote 2-26: For a detailed discussion of the black training program, see Osur, _Blacks in the Army Air Forces During World War II_, ch. III; Lee, _Employment of Negro Troops_, pp. 461-66; Charles E. Francis, _The Tuskegee Airmen: The Story of the Negro in the U.S. Air Force_ (Boston Bruce Humphries, 1955).]