 By 1966 the Thud was being phased out of NATO, being replaced by the McDonnell F-4D Phantom II.The tactical nuclear deliver mission, still necessary, was being eclipsed by the ability of ICBMs and the primary mission of the 36th TFW changed to Tactical Air support of NATO ground units in West Germany.By December 1966, all the 36th TFW Thuds had been ferried stateside for combat crew training duties at McConnell Air Force Base, Kansas, or to Southeast Asia after stateside refurbishment.