The Pilatus PC-6 Turbo Porter is a Swiss produced utility aircraft that first flew in 1961. Its superb short take off and landing (STOL) performance lead to it being adopted by many armed forces around the world, and it is a highly successful civilian design.

Fairchild Hillier acquired a production licence from Pilatus for the Turbo Porter in the mid ‘60s to supply aircraft to the local market. In the late ‘60s it developed a COIN variant, powered by a 665-shp Garret turboprop, with provision for one underfuselage and four underwing hardpoints. A total of 36 were built for the USAF, which made use of them in Vietnam.

In June & July 1971, the AU-23A was evaluated in combat conditions in Vietnam under the program PAVE COIN. This program also trialled the Helio AU-24A and North American Mustang derived Piper PA-48 Enforcer.

Despite the airframe reliability and STOL performance, the AU-23A was not found to be suitable for combat. The slow speed and lack of armour protection for the crew were the main problems and the evaluation found that the Peacemaker was vulnerable to even the lightest anti-aircraft fire.
28 were eventually supplied to the Thai Air Force, and 5 to the Thai Police. Although a number have been lost, the survivors still remain in use at present.

Decals are for a white aircraft with blue trim operated by the CIA 'Air America' enterprise; one overall white Thai Police option, and a Thai Air Force camouflaged example.