Onceapilot The relevance of my military experience escapes me when applied to Tristar APUs. I maintained Tristars from 1981 and ended up operating some of the last in service. I am not a Tristar knocker - as I stated,aircrew loved them ,a comfortable aircraft to fly in but maintenance wise it was a very difficult aircraft to keep serviceable. When I was assigning manpower for routine checks I always required more manpower for a Tristar than a 747. As an example,the early aircraft cargo doors were so much of a problem later aircraft were fitted with what was known as Boeing doors as they were the same as 747. If experience is relevant - how much maintenance experience as opposed to flying them do you have?