for operations in Southeast Asia. Starting in 1972, the short-lived 3542d Operations Squadron conducted Convair T-29 pilot training for the Fifteenth Air Force, a number of T-29s and C-131s having been distributed throughout SAC as utility aircraft for various SAC wings and bases. This was done in conjunction with the 323d Flying Training Wing of the Air Training Command (ATC) at Mather, which also flew the T-29 in support the Undergraduate Navigator Training (UNT) program. The 3542d Operations Squadron was inactivated the following year, in late 1973, concurrent with the retirement of the T-29 from UNT in late 1973 and early 1974 and its replacement with the Boeing 737-200 based T-43 Bobcat. In the early 1980s, the 320th and the 441 BS were equipped to carry, and trained in the employment of, the US Navy's AGM-84 Harpoon missile and various types of anti-ship mines as part of a joint USN-USAF initiative to employ USAF bomber aircraft in maritime operations. The 904th Air Refueling Squadron was inactivated 1 October 1986 and its older KC-135As modified to KC-135E standard and redistributed to other SAC units or sent to AMARC at Davis–Monthan Air Force Base, Arizona for storage. From this point forward, the 441 BS would rely on the Air Force Reserve's tenant 940th Air Refueling Group at Mather for local KC-135 support, or KC-135 and KC-10 support from other units in the western United States. As a result of the START I treaty with the Soviet Union and the associated mandated reductions in strategic bombers on both sides, the 441 BS with its B-52Gs was inactivated at Mather AFB on 30 September 1989. It was the first B-52G squadron to inactivate under the gradual drawdown of the B-52G fleet pursuant to START reductions of the entire USAF strategic bomber force. Along with the 441 BS, the 320th Bombardment Wing was also inactivated on 30 September 1989 as the first B-52 wing to be inactivated in conjunction with the phased retirement of the B-52G fleet and was also made in conjunction with the pending closure of Mather AFB in 1993 due to a 1989 Base Realignment and Closure (BRAC) decision. 320th Air Expeditionary Group (Air Combat Command) In 1998, the 320th was reactivated as the 320th Air Expeditionary Group (320 AEG) at Eskan Village, Riyadh, Kingdom of Saudi Arabia. As an element of U.S. Central Command Air Forces (USCENTAF) / 9th Air Force