American pilots (the Flying Tigers whom fought their first combat engagement on 20 December 1941). Throughout the remainder of the war, the ROCAF was involved in attacks on Japanese air and ground forces across the Chinese theatre. From Civil War ROCAF General HQ was established in June 1946. From 1946 to 1948, during the Chinese Civil War, the ROCAF participated in combat against the People's Liberation Army engaging in air-to-air combat on at least eleven occasions in the areas surrounding the Taiwan Strait. The ROCAF reportedly enjoyed a 31:1 kill ratio against the PLA. GHQ was evacuated to Taiwan along with the rest of the ROC Government in April 1949 following the Communist victory in the Chinese Civil War. The ROCAF assisted in halting the PLA advance at the Battle of Kuningtou on Kinmen the same year. The ROCAF regularly patrolled the Taiwan Straits and fought many engagements with its Communist counterpart (the PLAAF). The ROCAF received second hand equipment from the US at that time, such as the F-86, F-100 and F-104. During the Cold War, the ROCAF was involved in combat air patrols over the Taiwan Strait and engaged the PLAAF and PLAN-AF on several occasions. The ROCAF was also the testbed of American technology at this time. The first successful kill scored by an air-to-air missile was accomplished by a ROCAF F-86 Sabre with then experimental AIM-9 Sidewinder. ROCAF pilots also flew U-2 recon overflights of the PRC during this time with assistance from the USAF. Known as the Black Cat Squadron they flew a total of 220 missions, with 102 missions over mainland China, losing 5 aircraft. All five were shot down by SA-2 surface-to-air missiles, the same type of surface-to-air missile that shot down Gary Powers over the USSR in 1960. The 34th "Black Bat Squadron" flew low level missions into China as part of its mapping PRC growing air defense networks, conducting ESM and ECM missions, inserting agents behind enemy lines, and air drop resupply missions. Starting in November 1967, the ROC secretly operated a cargo transport detachment to assist the US and the ROV as part of its participation in the Vietnam War. It was based on existing formation of the 34th squadron of ROC Air force. The unit's strength included two C-123 cargo aircraft, seven flight officers and two mechanics, even though a higher number of military personnel was involved through rotation.