came under the control of the newly established 33rd Tactical Wing. By midyear, the RVNAF had grown to thirteen squadrons; four fighter, four observation, three helicopter, and two C-47 transport. The RVNAF followed the practice of the U.S. Air Force, organizing the squadrons into wings, with one wing located in each of the four corps tactical zones at Cần Thơ Air Base, Tan Son Nhut AB, Pleiku Air Base and Da Nang Air Base. In May 1965 the Douglas A-1 Skyraider equipped 522nd Fighter Squadron was activated at the base. Command and control center As the headquarters for the RVNAF, Tan Son Nhut was primarily a command base, with most operational units using nearby Biên Hòa Air Base. At Tan Son Nhut, the RVNAF's system of command and control was developed over the years with assistance from the USAF. The system handled the flow of aircraft from take-off to target area, and return to the base it was launched from. This was known as the Tactical Air Control System (TACS), and it assured positive control of all areas where significant combat operations were performed. Without this system, it would not have been possible for the RVNAF to deploy its forces effectively where needed. The TACS was in close proximity to the headquarters of the RVNAF and USAF forces in South Vietnam, and commanders of both Air Forces utilized its facilities. Subordinate to TACS was the Direct Air Support Centers (DASC) assigned to each of corps areas (I DASC – Da Nang AB, DASC Alpha – Nha Trang Air Base, II DASC – Pleiku AB, III DASC – Bien Hoa AB, and IV DASC – Cần Thơ AB). DASCs were responsible for the deployment of aircraft located within their sector in support of ground operations. Operating under each DASC were numerous Tactical Air Control Party (TACPs), manned by one or more RVNAF/USAF personnel posted with the South Vietnamese Army (ARVN) ground forces. A communications network inked these three levels of command and control, giving the TACS overall control of the South Vietnamese air situation at all times. Additional information was provided by a radar network that covered all of South Vietnam and beyond, monitoring all strike aircraft. Another function of Tan Son Nhut Air Base was as an RVNAF recruiting center. Use in coups The base was adjacent to the headquarters of the Joint General Staff of South Vietnam, and was