Big question is when is CASA retiring Schedule 5?
Two possible answers:
(1) Never, or;
(2) When there are no more FAA certified CAR 3/4 or FAR 23 aircraft on the Australian register and all light aircraft have FAR 25 like MM, see (1).
As has been noted, time and again, Schedule 5 is not some random shopping list (yr rrrr wrong, please note) but is copied from FAR 43, Appendix D, which is, along with supporting "acceptable (not approved) data" the core of the FAA continuing airworthiness requirements for all the relevant US
built aircraft.
Smart Australian workshops also have a statement in their CASA Exposition/name of choice of manual specifying FAA AC43.13A and AC43.13B as the core of how all inspections and rectifications will be carried out.
I have lost count of the number of times, over the years, that CASA have "promised" to align with the rest of the world in using the term "acceptable data", with a suitable definition, instead of "approved" data, but the micro management culture of CASA and its predecessors has guaranteed that these promises have all been broken.
The whole issue is significant, because even relatively recent FAR 23 aircraft do not have comprehensive instructions for continuing airworthiness, because the certification standards assume the use of the FAR requirements, thus the contents Appendix D, and the relevant sections of Parts 91/121/125/135/137 are not repeated in the manufacturer's manuals.
And Cessna etc. are not going to change just for the handful of aircraft sold in Australia.
Bottom line, the proper way of assuring continuing airworthiness for all the aircraft mentioned above ---- the great majority of standard C.of A aircraft in Australia ----- is to use Schedule 5, plus approved data, including the airframe manufacturer's MM, AC43.13A/B and any other necessary sources of data to complete a Schedule 5 inspection and sign off at least annually.
CASA is now so lacking in any "corporate memory" and suitably experienced people in the relevant fields that the result is some of the nonsense that is pumped out, including in CASA training of AWIs.
Before you all start shouting "This is Australia, not the US" I very strongly recommend you acquaint yourselves with CASR 21 in detail, as to how an Australian C. of A is issued, what underlies that C. of A and Type Acceptance Certificate, and what the legal situation becomes if the Type Acceptance Certificate, and hence the Australian issued C.of A is rendered invalid, because the certification standards of the country of original certification are not "maintained".
For those of you who believe CASA can do whatever they like, and bollocks to the FAA/CA/NZ/EASA etc., I refer you to S51 of the Australian Constitution and the long history of relevant litigation in the High Court of Australia, stretching back about 90 years.
Tootle pip!!