The USAF bought 76 production FB-111As to fill a gap in the strategic bomber force as Boeing B-52C and F models and Convair B-58As were being phased out from the late 1960's into the early 1970's, while the AMSA project that eventually produced the Rockwell International B-1A was still in its early phases and a new bomber remained more than a decade away. Modifying the F-111A into a strategic bomber offered a relatively quick and inexpensive way to provide a supersonic bomber capability. The prototype FB-111A was converted on the assembly line from the last F-111A, serial number 63-9783, and the aircraft had a larger wing, stronger landing gear, and the ability to carry up to six AGM-69A Short Range Attack Missiles, with two in the enlarged internal bomb bay and four on wing pylons. General Dynamics also proposed an enlarged FB-111H with a 15-foot fuselage extension, more powerful engines, and greater weapons capacity, but it never advanced beyond the design stage. This FB-111 was the last supersonic bomber flown by 8th Air Force and the last medium bomber in Strategic Air Command. It last served with the 380th Bomb Wing at Plattsburg, New York, and when the FB-111s were retired, this bomber flew to Barksdale AFB on July 10, 1991. It is marked with the insignia and colors it carried circa 1984.