The 4134th Airborne Missile Maintenance Squadron was activated in November to maintain these missiles In 1962, in order to retain the lineage of its MAJCOM 4-digit combat units and to perpetuate the lineage of many currently inactive bombardment units with illustrious World War II records, Headquarters SAC received authority from Headquarters USAF to discontinue its Major Command controlled (MAJCON) strategic wings that were equipped with combat aircraft and to activate Air Force controlled (AFCON units), most of which were inactive at the time which could carry a lineage and history. 320th Bombardment Wing As a result, the 4134th SW was replaced by the 320th Bombardment Wing, Heavy, which assumed its mission, personnel, and equipment on 1 February 1963. In the same way the 441st Bombardment Squadron, one of the unit's World War II historical bomb squadrons, replaced the 341st BS. The 49th Munitions Maintenance Squadron and the 904th Air Refueling Squadron were reassigned to the 320th. Component support units were replaced by units with numerical designation of the newly established wing. Under the Dual Deputate organization, all flying and maintenance squadrons were directly assigned to the wing, so no operational group element was activated. Each of the new units assumed the personnel, equipment, and mission of its predecessor. At Mather, the wing performed global bombardment training and air refueling operations to meet SAC commitments, February 1963 – 1965 and later. In 1964 and 1965, the wing's B-52Fs were selected for modification under programs South Bay and Sun Bath. These modifications enabled the wing's bombers to double their bomb load from 24 to 48 750 lb bombs by the installation of external bomb racks. With these modifications, the wing's planes, along with those of the 7th Bombardment Wing were the first to deploy to Andersen Air Force Base, Guam and the first to fly Arc Light bombing missions. The modified B-52Fs were the only SAC bombers to deploy for Arc Light missions until 1966, when the B-52Fs were replaced by B-52Ds with the Big Belly modification than enabled them to carry a larger and more varied bomb load. The entire wing was drastically reduced from February to July 1965, from December 1965 to March 1966, and from June 1972 to October 1973, when all aircraft, crews, and most support personnel were loaned to other SAC units based at Andersen AFB Guam, U-Tapao Royal Thai Navy Airfield, Thailand and Kadena AB, Okinawa