thirty USAF pilots temporarily assigned to the RVNAF to serve as C-47 co-pilots. This influx of U.S. personnel quickly returned the 1st Transportation Group to full strength. Unlike the USAF Farm Gate personnel at Bien Hoa Air Base, the C-47 co-pilots actually became part of the RVNAF operational structure – though still under U.S. control. Because of their rather unusual situation, these pilots soon adopted the very unofficial nickname, The Dirty Thirty. In a sense they were the first U.S. airmen actually committed to combat in Vietnam, rather than being assigned as advisors or support personnel. The original Dirty Thirty pilots eventually rotated home during early 1963 and were replaced by a second contingent of American pilots. This detachment remained with the RVNAF until December 1963 when they were withdrawn from Vietnam. 509th Fighter-Interceptor Squadron Starting on 21 March 1962 under Project Water Glass and later remaining under Project Candy Machine, the 509th Fighter-Interceptor Squadron began rotating F-102A Delta Dagger interceptors to Tan Son Nhut Air Base from Clark AB on a rotating basis to provide air defense of the Saigon area in the event of a North Vietnamese air attack. F-102s and TF-102s (two-seat trainer version) were deployed to Tan Son Nhut initially because ground radar sites frequently painted small aircraft penetrating South Vietnamese airspace. The F-102, a supersonic, high altitude fighter interceptor designed to intercept Soviet bombers was given the mission of intercepting, identifying and, if necessary, destroying small aircraft, flying from treetop level to 2000 ft at speeds less than the final approach landing speed of the F-102. The TF-102, employing two pilots with one acting solely as radar intercept operator, was considered to be safer and more efficient as a low altitude interceptor. The T/F-102s would alternate with US Navy AD-5Qs. In May 1963 due to overcrowding at the base and the low-probability of air attack the T/F-102s and AD-5Qs were withdrawn to Clark AB from where they could redeploy to Tan Son Nhut on 12–24 hours' notice. Following the Gulf of Tonkin Incident, 6 F-102s from the 16th Fighter Squadron deployed to the base. Before the rotation ended in July 1970, pilots and F-102 aircraft from other Far East squadrons were used in the deployment. Air rescue In January 1962 5 USAF personnel from the Pacific Air Rescue Center were assigned to the base to establish a Search and Rescue Center, without having any aircraft