Why is this argument being taken round in circles?
OK so lets all agree that ALL public transport aircraft (and that includes Air Taxi/On Demand and Charter) regardless of seat numbers, size or number of engines should be fitted with TCAS. Social equity demands the same level of safety for ALL.
Whether you set the seat limit at 10 or more is irrelevant when close to if not 100% of these flights are going to a regional/remote/non radar/uncontrolled strips/private mining strips and spend some time during flight in "G".?? If its Public transport its Public transport, see above.
Ergo ALL Public transport aircraft MUST ALSO carry and operate a transponder to be able to see each other.
Given that leaves, oh I dont know, maybe another 9,000 aircraft that MAY or MAY NOT be able to be seen by them. How many of those have serviceable and accurate, or regularly checked, transponders? Dunno, but it only takes one who hasn't or who does and does not have it turned on, or hasn't been in a radar environment requiring it for yonks, to spoil your day. Anecdotal it may be, but in my experience it is probably 60% of the total, and close to 100% of those live and operate in and around the aforementioned regional/remote/non radar/uncontrolled strips/private mining strips and spend close to ALL of the time during flight in "G". This is the unique Australian airspace. It is like no other, anywhere.
Ergo for TCAS to be "fully effective" for ALL Public transport aircraft equipped so, ALL (= every) aircraft must be equipped with serviceable and operating transponder, hard wired to the master switch.
Or do we simply revert to what is merely a modern version of the "old fashioned calling in the blind" technique for Public transport operations .
Unless I'm missing something here TCAS doesn't work with out its mate the transponder also working.
And the thought just occured to me that given universal mandatory equipment of TCAS and transponder in ALL aircraft, for the moment, you could probably give anything not A, C and D airspace back to G. Then we would be "ready" conceptually and in mindset for ADSB, in whatever form it arrives. ????
Cost, well you already know my feelings about that. You are either going to have a seamless safety Public transport safety system or not, you cant have it both ways.
As for the "BIG airlines not wishing to subsidise" GA hogwash, that may well be true but only because they have been persuaded by someone that it is so. IMHO there is a COMPELLING argument why in this country anyway they should revisit this concept and quickly. One may well ask who "sold" or at the least "were not sufficiently competent to be able to defend it" to them in the first place and why. The entry of Tiger and others into the regional marketplaces raises the stakes alarmingly.