Exactly the same scenario I discussed with another instructor today: you are following a STAR maintaining 6000’, (last descend clearance was to 6000’, no “descend via”), STAR terminates at an IAF that has 3000’ minimum altitude (no other alt restrictions on STAR route remain). While still on the STAR, you get cleared for ILS Z (runway), nothing else.. What on Earth allows me to descent to 3000’ immediately? Maintaining 6000’ until IAF was not the answer he was looking.
Where is the written, official reference that would allow such a descend in Europe, U.S. or anywhere else? Because I have yet to see it, and I haven’t seen it in this thread yet, either. I understand if you’re in FAA and on a feeder route on an IAP chart and cleared for the approach, you can descent to the altitude depicted on that route (same rule as descending after IAF). But in this scenario we are still on a STAR, and not yet on the IAP chart. What I’ve seen on AIM though, is that you can descent if you’re cleared for the approach while you’re on a “published route”. The definition of the published route (in the pilot/controller glossary) could cover STAR route as it has altitude depicted, but I’m still skeptical if a clearance for ILS would allow you to descend while still on the STAR. I’ve been wrong before though.