AC ? I ordered plugs for connection to an aircraft 28 V DC outlet !?!#¤%#"
From whom?
Its a non-standard use. Here in the USA, it could get you into some trouble (plugging into the wrong supply). That use might be permitted elsewhere, but due to the international nature of aircraft, one of those plugs is bound to show up in the wrong place. Not something I'd expect a competent aircraft manufacturer to let slip by.
Its possible that someone at an electrical supply house figured the 'AC' stood for 'aircraft' and pulled the wrong part off the shelf. Just guessing here.