The usual route to AP Art Ed was to start as AP Art Assistant. Notable exceptions are Lisa Nicholls and Lisa Kellett, who left to become Art Eds on other mags, and Sarah Sherley-Price, who left to drop her sprog.
Ostensibly, the difference between Art Ed and Art Assistant was that the assistant handled workaday pages like reviews, leaving the Ed free to concentrate on special things like features. (Incidentally, don't confuse Art Assistants with Deputy Art Editors. Deputy Art Editors have desks.) What actually happened was that everybody did anything that came to hand, as no one had any idea when any writing was supposed to be finished, and Art Assistants tended to turn up randomly to keep us on our toes.
(In - no! But yes! - a cost-cutting move, around about AP35 Future allocated one Art Assistant to at least two mags, so as Art Ed you could expect help maybe two weeks in four and as Art Assistant you could expect to be on deadline all the time for the rest of your life.)
Splendidly, despite their enforced nomadism, AP's Art Assistants never mistook us for one of their other mags, so there were no embarrassing incidents of getting a clutch of pages back and finding them laid out with a clean, white, mature design. For this we are deeply grateful, although we still can't work out exactly why publishers concede you need four people and as many freelancers to write a 132-page issue, but only one-and-a-half art people to lay it out.