Unsure what AER stands for but the switch above the left hand stick on G2 on my controller is my idle up 1 & 2 switch. It clicks two times. Normal mode is for taking off, landing and hovering etc but flicking the switch up one or two clicks put it into Idle up which is what you use when flying 3D i.e inverted etc etc. You will notice that in idle up mode the the engine revs dont change much when the throttle stick is moved. The engine stays reving fast but the pitch of you blades changes from full negitive at bottem stick (so you can fly inverted) to full postive at top stick.