The 509th was initially phased down for inactivation in late 1965 as a part of the retirement of the B-47, but instead was converted to a B-52D Stratofortress and KC-135 in March 1966. The 509th was taken off nuclear alert as its B-52Ds were designed to carry a large number of conventional bombs (84 500-lb Mk 82 or 42 750 lb M-117s) for service in the Vietnam War as part of Operation Arc Light. The wing deployed KC-135 Stratotanker aircraft and crews, November 1966– December 1975; with B–52 aircraft and crews, November 1966– September 1969, and with B–52 crews, 1970. From 1 April to 1 October 1968 and 26 March to c. 21 March 1968, more than one-half of the wing was deployed to Andersen AFB, Guam to support SAC operations in Southeast Asia.