HOWABOUT
Thanks for saying that I’m “the acknowledged expert”. I’ll endeavour to answer your questions to the best of my abilities!
The reason we are going to convert GAAP to Class D is that it presently isn’t called Class D. Is that clear?
The reason for the ICAO airspace classifications was so that pilots flying or being trained in different countries would know what service they were likely to get in a particular type of airspace.
When it comes to GAAP, there is no other airspace called that anywhere in the world. If it’s called “D”, who cares if it is ICAO Class D or FAA Class D, they will know what the basic service is.
Do I know which other modern aviation countries use Class D in a similar way to the FAA Class D?
Well, the ones I know are New Zealand, Canada, the USA (of course) and the UK, and most of the countries in Europe. There may be many others – I can’t remember from my flying.
By “most other modern aviation countries” I normally consider the countries with the most traffic density which are, of course, the USA, Canada, the UK and Europe.
I don’t know of any country that has an airspace called “GAAP”. All the countries I know that have Class D airspace comply closely with the airspace classification from ICAO – as does the USA. The USA believes it complies closely with ICAO because ICAO doesn’t actually state the wording for the clearance request. As we all know, the US clearance request is more of a statement – like we have at airports like Bankstown – and the US FAA claims this complies with ICAO. I agree with them.
This is about the best I can do as an “acknowledged expert”.