The Iroquois ('Huey') helicopters used by the SAS patrols in this movie are those of 9 Squadron, Royal Australian Air Force, on kind loan from the Australian Defence Force. This squadron - and indeed, the very helicopters seen in the film - actually served in combat during the Vietnam War.
Controversy arose in Western Australia when this movie was selected to screen at a Western Australian Royal Gala Premiere Screening in Perth for King Charles III (then Prince of Wales) as part of his 1979 Royal Visit to Western Australia for its Sesquicentenary (150th) Anniversary Birthday celebrations. Then state premier Sir Charles Court canceled the event due to grave concerns over the film's use of offensive language (too many four-letter words) and nudity. In the Western Australian parliament, the then leader of the opposition said that Western Australia had been made a laughing-stock due to a 67 year-old politician [Court] stopping a 30 year old prince from watching a film that was classification approved for old audiences 15 years old and above.
This film's producer Sue Milliken has said of this movie: '[The novel] was written by a wild Vietnam veteran called Bill Nagle [William L. Nagle] whom we assumed had been in the SAS but eventually it turned out he had been an army cook. Nevertheless, a cook with an ear for the vernacular. The story was told from the soldiers' point of view and was sardonically anti-war. We made this film in 1978, which was only four years after the end of the war, so feelings were still very strong. The book said everything you needed to know about the misery and alienation of fighting a war which should never have been fought in the first place. It was also acerbic and funny, and it was this aspect of the piece, which we emphasized to wary investors as making the story accessible to an audience. After months of perseverance, we got the cooperation of the army, although the army hierarchy was very nervous about anything to do with Vietnam. The soldiers, on the other hand, couldn't have been more helpful. We shot for six weeks at the Land Warfare Centre at Canungra, in the hills behind the Gold Coast. The film is recognized by soldiers in all sorts of places around the world as one of the best films ever made about how a war is fought."
The Australian Army and the Royal Australian Air Force (RAAF) acted as technical consultants to the production and provided equipment and vehicles such as aircraft and helicopters which are seen in the film. The production reimbursed the military outfits for their services.
The film featured two songs not composed by the film's composer, Michael Carlos. They were "Who Cares, Anyway" sung by Normie Rowe which was written especially for this movie and John Denver's 1967 "Leaving on a Jet Plane" performed by an uncredited Peter Paul & Mary. The latter song had been a well-known Vietnam War anthem for Australian soldiers.