Originally Posted by
Fursty Ferret
On a non-precision calling established a tiny bit earlier (ie as the turn starts) just frees up capacity for the whole descent / timing / monitoring stuff.
You are only established when within 5 degrees of the published FAT, - PANS Ops.
UK airspace vertical division between Class D/G requires you to be cleared to descend on the ILSGP by Approach due to the possibility of uncontrolled VFR traffic below the platform altitude and within 10nm from the THR. In Europe the rules are different in Class C airspace where you may be cleared for the approach from the IAF.