



Two commercial aircraft were selected for testing: the Fairchild Porter and the Helio Stallion. The program, named Credible Chase, was designed to add mobility and firepower to the South Vietnamese Republic of Vietnam Air Force (RVNAF) in a relatively short time. In May 1971 the Aeronautical Systems Division at Wright-Patterson Air Force Base, Ohio, began work on a project to evaluate the potential use of armed light utility short takeoff and landing aircraft in Southeast Asia. All aircraft were later sold to the Royal Thai Air Force. A total of 35 were built under license in the United States by Fairchild Industries, for use during the Vietnam War in the early 1970s. The Fairchild AU-23 Peacemaker is an American armed gunship, counter-insurgency, utility transport version of the Pilatus PC-6 Porter for the United States Air Force.
