the war, Tan Son Nhut Air Base was taken over as a base for the Vietnam People's Air Force. Known RVNAF units (June 1974) Tan Son Nhut Air Base was the Headquarters of the RVNAF. It was also the headquarters of the RVNAF 5th Air Division. 33d Tactical Wing 314th Special Air Missions SquadronVC-47, U-17, UH-1, DC-6B 716th Reconnaissance Squadron R/EC-47, U-6A 718th Reconnaissance Squadron EC-47 429th Transport Squadron C-7B 431st Transport Squadron C-7B Det H 259th Helicopter Squadron Bell UH-1H (Medevac) 53d Tactical Wing 819th Combat Squadron AC-119G 821st Combat Squadron AC-119G 435th Transport Squadron C-130A 437th Transport Squadron C-130A Use by the United States During the Vietnam War Tan Son Nhut Air Base was important for both the USAF and the RVNAF. The base served as the focal point for the initial USAF deployment and buildup in South Vietnam in the early 1960s. Tan Son Nhut was initially the main air base for MAC flights to and from South Vietnam, until other bases such as Bien Hoa and Cam Ranh opened in 1966. After 1966, with the establishment of the 7th Air Force as the main USAF command and control headquarters in South Vietnam, Tan Son Nhut functioned as a headquarters, a Tactical Reconnaissance base, and as a Special Operations base. With the drawdown of US forces in South Vietnam after 1971, the base took on a myriad of organizations transferred from deactivated bases across South Vietnam. Between 1968 and 1974, Tan Son Nhut Airport was one of the busiest military airbases in the world. Pan Am schedules from 1973 showed Boeing 747 service was being operated four times a week to San Francisco via Guam and Manila. Continental Airlines operated up to 30 Boeing 707 military charters per week to and from Tan Son Nhut Airport during the 1968–74 period. It was from Tan Son Nhut Air Base that the last U.S. airman left South Vietnam in March 1973. The Air Force Post Office (APO) for Tan Son Nhut Air Base was APO San Francisco, 96307. Military Assistance Advisory Group Davis Station On 13 May 1961 a 92-man unit of the Army Security Agency, operating under cover of the 3rd Radio Research Unit (3rd RRU), arrived at Tan Son Nhut AB and established a communications intelligence facility in disused RVNAF warehouses on the base (). This was the first full deployment of a US Army unit to