The backdrop was Robert McNamara's TFX drive to economize by forcing Navy and Air Force requirements into fewer common aircraft types. The F-111's low-level interdiction design did not provide the maneuverability the Navy wanted, while MiG engagements in Vietnam exposed limitations in the F-4 Phantom II under the conditions then being fought. The Navy combined its fighter-attack requirements with the fleet-defense systems inherited from the F-111B effort. The resulting aircraft was to exceed Mach 2.2, carry an M61 Vulcan, retain a secondary close-air-support role, and mount either six AIM-54 Phoenix missiles or a Sparrow-and-Sidewinder load. The decisive change was a carrier-suitable airframe designed around naval requirements rather than adapted from an Air Force interdictor. VFAX therefore preserved useful weapons development from the failed joint program without preserving its unsuitable airframe assumptions.
Chapter · 19:07-22:17
VFAX requirements create a purpose-built naval fighter
Vietnam-era maneuverability concerns and the failure of the joint F-111B led to a tandem-seat, twin-engine naval fighter built around speed and a heavy missile load.