On 2 November 1965, the 505 ACWG was re-activated as the 505th Tactical Control Group (TCG). Replacing the 6250th Tactical Air Support Group that activated three months earlier, 505 TCG called Tan Son Nhut Air Base in South Vietnam home. The 505th was responsible with providing Command and Control (C2), for the Tactical Control System in Southeast Asia (SEA). This mission included the operation of numerous radar sites throughout South Vietnam and Thailand from 1965 to 1973. In addition to the radar sites, the group managed O-1 Bird Dog observation aircraft assigned to five squadrons from late 1965 through 1966. These O-1 units included the 19th, 20th, 21st, 22nd and 23d Tactical Air Support Squadrons, operating from various bases throughout SEA. Forward Air Controllers (FACs) flew the "Bird Dogs" to find and mark enemy activity, direct air strikes and perform battle damage assessment.
