I like to see folks getting passionate about this stuff
I agree with many of the points made in your first [of three] post above.
G [Oz F] above A100
1. The treatment of IFR/IFR in climb/descent/cruise
above A100 is less of a concern than below A100, due minimal VFR, TXPDR use, and IFR not being in the early departure or late arrival phase of flight. As you suggest quite rightly that the situational awareness may not be as sharp or as comprehensive below A100. [Traffic density, pilot workload]
2. I would argue that IFR/IFR are a lower chance of mid-air intimacy as they know about each other [DTI] from ToD and Taxi throughout [Traffic density, pilot workload]
3. Lower time IFR may be less prepared for complex traffic senarios [traffic density], two or three IFR twins in to somewhere like YSDU might be pushing it, most would have a bit of an idea of the various performance envelopes, is this not part of IFR training? if not, wouldn't you wait a minute or two? pick a different outbound track [granted re-brief involved]? All that aside the regulator should be engaged in regular sampling of traffic density [IFR/IFR data is obviously available] and incident data to watch for hot spots!
I agree, E is technically safer than G - Because of the formalisation of IFR 'separation' by a third party. How much safer for the relatively large cost of establishing an IFR separation service [additional CTA]?
Here is the thing, if ATC have surveillance of G, they issue DTI, they can then monitor the proximities of IFR from IFR, is this so much worse than separating them if it were E? Not if the if delays are lengthy!
If an area of G or CTAF G is showing data that indicates an additional service is necessary, then do the process
with industry
Re: D Again I agree. The key here of course is to provide the right number of ATC positions within the tower to manage the traffic in that particular location. RPT with modest traffic might be single frequency, RPT with moderate to busy might be 2 or three frequencies [Aerod, SMC, CLDel]. It is pointless providing X,Y or Z ATS if it is not set up to manage the environment.
Re your second above - Neither was I, regional 'terrain avoidance services' are not being asked for by industry as far as I am aware. I assumed as it followed Mr Smiths terrain comments you were asking the same. Appologies.
On one hand you argue for using C rather than E because the cost is minimal.
In climb and descent
Approach and Departures areas [C over D up to A100 or; D SFC up to A100] where traffic dictates a tower service below. Little difference between C or D except of course additional flexibility in D for VFR/VFR and VFR/IFR pairs
Yet you don't want to use E rather than G because??? OK there are display, monitoring and staffing issues. In AUS G you (ie ATC) have to assess whether to pass aircraft as traffic - I assume you use the same standards you would use for separation in Class C. Yes it would add some workload to actually separate the aircraft, and it would certainly add delays.
Pretty well my understanding. If IFR need separation to low level [below A050], the delays are minimised by eyes in a tower and tower applicable separation standards. Remote Surveillance ATC must build in the bigger, less well pickable what ifs' - Wx, Missed App's, departure manouvering, procedural until radar identification [if surveillance exists].
Bottom line, if the safety of the facility requires improvement beyond IFR/IFR DTI, then factoring delay costs [remote ATC verses onsite], surveillance cost and availability [might not be any until ADS-B rocks along], the classification that adds most value [safety
and expedition ] for the money is local D not remote E.
Until reaching a need for D [where both IFR and VFR are serviced] what is the point of Class E? as there is in effect little difference with G except the cost!
No argument on ADS-B, the sooner the better