On 18 September 1966, the 432d Tactical Reconnaissance Wing (TRW) was activated at Udon RTAFB, Thailand as an McDonnell Douglas RF-4C Phantom II wing. At Udon, it became one of the most diversified units of its size in the Air Force.
The mission of the wing was to provide intelligence information about hostile forces through tactical reconnaissance and use its fighter elements to destroy the targets earmarked by the intelligence data provided. The wing had numerous missions in the support area. The 432d TRW accounted for more than 80 percent of all reconnaissance activity over North Vietnam.
In the fall of 1970 the wing was phased down as part of the overall American withdrawal from the Vietnam War; however, in 1972 tactical fighter strength was augmented by deployed Tactical Air Command CONUS-based tactical fighter squadrons being attached to the 432d in response to the North Vietnamese invasion of South Vietnam. In addition, the 421st TFS was reassigned trom Takhli RTAFB. During Operation Linebacker, between May and October 1972, the 432d TRW had seven F-4 tactical fighter squadrons assigned or attached, (13th, 56th, 308th, 414th, 421st, 523d and 555th) making it the largest wing in the USAF. The three Vietnam era Airforce Aces all came from the 432d – two from the 555th and one from the 13th. The CONUS-based squadrons returned to the United States in the fall of 1972.
As a result of the Paris Peace Accords of 1973, the numbers of USAF personnel and aircraft at Udon were reduced. The 421st TFS was inactivated in August and the 555th was reassigned to Luke AFB in 1974. By the spring of 1975, two operational squadrons remained, the 14th TRS (RF-4C) and the 13th TFS (F-4D/E).
Forces from the 432d participated in the SS Mayaguez action in May 1975, sinking two Cambodian Khmer Rouge ships. By 1975, the political climate between Washington and Bangkok had become sour and the Royal Thai Government wanted the USAF out of Thailand by the end of the year. Palace Lightning was the plan under which the USAF would withdraw its aircraft and personnel from Thailand.
The 423nd TFW was inactivated on 23 December 1975. The 13th TFSs F-4E aircraft and some support personnel were reassigned to the 3d TFW at Clark AB, Philippines and the F-4D aircraft and support personnel to the 18th TFW at Kadena Air Base, Okinawa. The 14th TRS was inactivated and the RF-4Cs were sent to Shaw AFB, South Carolina. The last USAF personnel departed Udon RTAFB on 8 January 1976.