Battle of Lima Site 85

The Battle of Lima Site 85, also called Battle of Phou Pha Thi, was fought as part of a military campaign waged during the Vietnam War and Laotian Civil War by the North Vietnamese People's Army of Vietnam (PAVN) and the Pathet Lao, against airmen of the United States Air Force (USAF)'s 1st Combat Evaluation Group, elements of the Royal Lao Army, Royal Thai Border Patrol Police, and the CIA-led Hmong Clandestine Army. The battle was fought on Phou Pha Thi mountain in Houaphanh Province, Laos, on 10 March 1968, and derives its name from the mountaintop where it was fought or from the designation of a 700-foot (210 m) landing strip in the valley below, and was the largest single ground combat loss of USAF members during the Vietnam War. During the Vietnam War and the Laotian Civil War, Phou Pha Thi mountain was an important strategic outpost which had served both sides at various stages of the conflict. In 1966, the United States Ambassador to Laos William H. Sullivan approved a plan by the USAF to construct a TACAN site atop Phou Pha Thi; at the time they lacked a navigation site with sufficient range to guide U.S. bomber aircraft to their targets in North Vietnam. In 1967 the site was upgraded with the air-transportable all-weather AN/TSQ-81 radar bombing control system. This enabled American aircraft to bomb North Vietnam and Laos at night and in all types of weather, an operation code-named Commando Club. Despite efforts to maintain the secrecy of the installation, which included "sheep-dipping" of the airmen involved, the facility did not escape the attention of the PAVN and Pathet Lao forces. Toward the end of 1967, PAVN units increased the tempo of their operations around Phou Pha Thi, and by 1968 several attacks were launched against Lima Site 85. In the final assault on 10 March 1968, elements of the PAVN 41st Special Forces Battalion attacked the facility, with support from the PAVN 766th Regiment and one Pathet Lao battalion. The Hmong and Thai forces defending the facility were overwhelmed by the combined PAVN and Pathet Lao forces.