When the Butterfly program was canceled, it was replaced by the Raven FACs. With the upgrade in personnel to using qualified fighter pilots with their own aircraft to mark targets, it became obvious that support personnel were needed within Laos. Palace Dog was established, containing two components: Raven FACs and Project 404. Project 404 was the program that supplied the support personnel for the fighter pilots who flew under the Raven call sign. Its stated objective was "to maintain the RLAF (Royal Laotian Air Force) Air Operations Center in fighting condition for the defense of Laos".
Beginning unofficially in 1966 at the cessation of the Butterfly program, and officially in October, 1968, United States Air Force Special Operating Force staffed Project 404 by forwarding "sheepdipped" specialists to the United States Embassy in Laos. There they worked for the Air Attaché; he in turn worked directly for the American ambassador in Vientiane, Laos. The specialists escaped the scrutiny of permanent change of station orders by being assigned on 179 day Temporary Duty assignments. Specialties assigned were Air Operations Commander, Line Chief, and Medical and Communications Specialists. There was also a single doctor assigned to the program.
Four Air Operations Centers were established, one at each of the RLAF's airfields, which in turn were located one in each military region of Laos. The AOCs were located and designated respectively at Vientiane's Wattay Field (Lima 08), Pakse (Lima 11), Savannakhet (Lima 39), and Luang Prabang (Lima 54). Approximately June, 1969, a fifth AOC located at Long Tieng (Lima 20A) was added. An advisor to the RLAF AC47 gunship program was added in October, 1970. This latter location supported the Hmong Clandestine Army of General Vang Pao. The Clandestine Army would grow into the largest covert operation in history.
All of these locations except Vientiane were completely surrounded by both the North Vietnamese and Pathet Lao en...