As the intensity of the Viet Nam War increased in 1966, The United States Air Force began to replace its rotational units on temporary duty in Southeast Asia with permanent ones. As a result, the 352d Tactical Fighter Squadron moved to Phan Rang Air Base, South Vietnam on 15 August 1966, where it was assigned to the 366th Tactical Fighter Wing. Two months later Pacific Air Forces moved the 366th Wing to Da Nang Air Base where it became an F-4 Phantom II wing, while the 35th Tactical Fighter Wing took its place at Phan Rang, with F-100 Super Sabre squadrons in a swap of wing headquarters designations.