In February 1964 SAC deployed a detachment of four U-2s of the 4080th SRW to Bien Hoa to fly high-altitude reconnaissance flights over Southeast Asia. The U-2 had been one of the USA’s best kept secrets of the Cold War until the shooting down of Gary Powers over Russia on 1 May 1960. Although complex to operate and still shrouded in secrecy, its ability to collect intelligence made the U-2 an invaluable asset in Southeast Asia. On 5 April 1965 a U-2 took photographs of SA-2 missile sites under construction near Hanoi and Haiphong. The detachment, initially known as Lucky Dragon then Trojan Horse and then Giant Dragon, was operated by the 4028th SRS but on 11 February 1966 the Wing was redesignated as the 100th SRW and the Bien Hoa detachment later came under the 349th SRS. The aircraft that crashed on 8 October 1966 was the only U-2 lost in connection with the wars in Southeast Asia. On 11 July 1970 the U-2 detachment moved to U-Tapao and the detachment was upgraded to become the 99th SRS. The last U-2 did not finally leave Thailand until March 1976.