ARFOR, have a look at the NAS document on my website for the answers - especially the simplified radio procedures in Para 2.5.
From the NAS document on your website:
Procedures
Class D procedures will be aligned to the FAA application.
While VFR aircraft in Class D airspace are subject to an airways clearance (ICAO Annex 11, App. 4), the clearance may be implicit as is current practice at GAAP Zones and in US Class D airspace.
9 On advice of intent to the Tower an implicit clearance is assumed by VFR aircraft unless the Tower directs otherwise. This is consistent with FAA practice.
Interesting point made re: GAAP. You would be aware that the FAA are discontinuing ‘implied clearances’ on the surface areas due the number of Runway Incursions!
Are you aware of the number of Violations of CTA/R in the US and Canada as a result of implied clearances? I must admit that I was not adverse to ‘implied clearances' for VFR in D until I looked at the data. Now I’m not so sure.
Also contained in your NAS document;
SAFETY ANALYSIS
3.1 Methodology
ICAO provides two methodologies for “determining whether the system is acceptably safe:
a. comparison to a reference system, and
b. evaluation of system risks against a threshold.
Comparison with a reference system is a relative method, i.e. all the relative characteristics of the proposed system are compared with the corresponding characteristics of a reference system which has been judged to be safe. Provided that the proposed system can be demonstrated to be the same or better than the reference system in all safety aspects, then it may be assumed also to be safe…”
As the NAS draws on international best practice and the proven ATM system of North America, process a. above is the appropriate methodology.
This goes to the centre of the questions being put to you, which remain unanswered regarding the change, and the use of the US as a reference system. Class D rules, Airspace like for like, traffic mix and most importantly operating infrastructure i.e. Radar approach and departures to Air Carrier Class 1 airports.
The question of course remains, what does the reference system suggest should be in place in Australia? Non-radar D and E?, Class C?, Class B? Becuase the US reference system has quite a divergent application of services in different (but similar to Australian) Air Carrier Airports.
One common non radar tower system has to be better than our present GAAP/Class D "two" systems.
Has to be?? That is the point being repeatedly made, if it is better for all concerned, then it should be easily demonstrated.
Regarding the other thrust/s within this thread. It seems to me that ATC are caught in the middle, the victims if you like. Rather than blaming them, you should be asking your questions of the CASA CEO. After all, he is the author of the direction. Perhaps you need to invite him to another BBQ and ask him directly.