In message , Juvat
writes
Please allow me to apologize in advance if you are offended by the
question...but what the heck is AC?

Air Component? (may be too modern, I'm getting regular purple
transfusions at the moment).

Active Component?

--
When you have to kill a man, it costs nothing to be polite.
W S Churchill

Paul J. Adam MainBoxatjrwlynch[dot]demon{dot}co(.)uk