 In October 1966, the F-100-equipped 612th Tactical Fighter Squadron was activated at Phan Rang, composed of former Colorado Air National Guard aircraft which had deployed to Japan and were sent as additional aircraft to Vietnam when their deployment ended.Logistical difficulties in supporting both F-100 and F-4 aircraft at the same base led to the decision to move the 389th TFS to Da Nang Air Base, where F-4Cs were already stationed, and to make Phan Rang an all F-100 base.As former 366th TFW squadrons were at Da Nang (390th, 480th) already, it was decided to perform a name-only reassignment and move the 366th TFW to Da Nang Air Base as the host unit, and reassign the 35th Tactical Fighter Wing at Da Nang to Phan Rang to become the host unit.