Thanks HPP,
It's a hypothetical question (of probably no practical use) but IF you had JUST the landing RWY(plus may be CF) in your FMGC FPLN(with NO IAP selected), and say you are on visual downwind leg of that runway, and had APPROACH PHASE activated, what vertical path would the "doughnut VDEV" (or the "yo yo") be following?
My training organisation (quite reputable) is officially teaching this method to guide you vertically from the start of base turn in a circling approach, and if i was to follow it I want to know what exactly I'm following. So far no one has given me any definitive answer with a reference.