Hello J - the reason we ask pilots to report established on the localiser is because that is the prompt for us then to issue clearance to descend on the ILS.
If that report is not forthcoming because it has not been requested, then unless conditional clearance to descend on the ILS has already been given, the controller would have to ask the pilot if he is established before giving further descent.
I know that you can see the aircraft turn onto the localiser but according to my interpretation of the Pt 1, that is not sufficient.
RTO - this has been debated before. The reason why in the UK we are not permitted to say "cleared ILS" when radar vectoring to an ILS approach is that pilots have taken such a clearance as permission to descend to the altitude at which the approach commences according to the Approach Chart, irrespective of their previously cleared altitude. In the case of Heathrow the ILS/DME approaches commence at 2500ft. An aircraft descending to 2500ft say 15 miles from touchdown on an ILS to 27L/R runs the risk of encountering other aircraft operating up to 3000ft.
