You can pretty much (dare I say) guess when something like an orbit is required. There are other ways of avoiding things like incoming heavies or rain showers, most notably the advice given to leave and come back later. You could also extend whichever leg you're on after you've let atc know. I've usually been given a choice namely "G-AB, extend downwind rwy 23, or orbit. Heavy straight in rwy 23 long final". As for an orbit meaning just one 360 degree turn, I've never heard that before, but it makes sense. My instructors always taught me to use my judgement and if it doesn't seem safe to break orbit, call up atc with "G-AB, continuing orbit, base for rwy 23". Also helps in case they've forgotten about you
As for which way to orbit, out from the circuit seems soo much safer to me. Im thinking there's no set definition?
I thought orbitting was mostly done at airfields with different classifications of traffic (jets, helis, GA, business etc) not necessarily at say a busy GA airfield where all types are 'light'
ffw