I am going to throw a spanner in the works and say that CASA in fact endorse in their own regulations the on condition operation of engine components where correct condition monitoring has taken place.
It works like this ADs it above all other documents in the CASA hierarchy (therefore an AD overrides contradictory statements from AMM, Engine overhaul and component overhaul manuals.
For private owners AD ENG 4 states:
To ensure the continuing airworthiness of the engine,
and those components necessary for the operation of the engine, in addition to the requirements of Schedule 5 of the Civil Aviation Regulations; carry out the maintenance actions detailed in Appendix A of this Airworthiness Directive (AD).
Requirement A1:
Carry out an engine performance run to determine the engine performance in accordance with approved data. For turbocharged / supercharged engines, the output parameters shall be adjusted in accordance with manufacturer’s data.
Record engine and aircraft details and parameters achieved during the engine run on “Piston Engine Condition Report” (CASA Form 728) or an equivalent form. All completed forms shall be part of the
engine maintenance record.
The above from the AD overrides the manufacturers requirement to do hard life overhaul.
This is also supported by AWB02-1:
Manufacturers Recommended TBO
Aircraft and component manufacturers can make "Hard Time" recommendations (i.e. removal of items from service at a specified period for overhaul or replacement indifferent of the items current performance condition), usually referred to as Time Between Overhaul (TBO), which specify how long they consider their product should remain in service. These recommendations are based on average utilisation and conditions and usually recommend that the item be fully stripped and returned to the original specifications. TBO's do not normally involve a condition check being done during the items life. The ability to escalate these hard time limitations however, comes from effective condition monitoring - the real basis for "
on-condition" maintenance.
CASA Recommendations
C of R holders should utilise the philosophy of "
on-condition" maintenance to detect the onset of failures of such items, particularly when time in-service of these items are in the vicinity of the manufacturer's recommended TBO.
Provided that a component continues to meet the documented standard, at the appropriate frequencies, it is considered satisfactory to remain in service. TBOs that are not included in the manufacturers Airworthiness Limitations or in Airworthiness Directives issued by CASA should still be considered, unless substantiation has been collated to show the outcome of "
on-condition" inspections are still appropriate for the safe operation of the aircraft or equipment.
Where alleviation is permitted beyond the manufacturer's TBO, an example of which would be AD/ENG/4, C of R holders and LAME's must ensure at the completion of the aircraft periodic inspection the "
on-condition" maintenance inspection requirements are included on part 1 of the aircrafts maintenance release as "maintenance required".
The hole point of the private section of AD/ENG 4 was to override hard time overhaul limits: See here
www.casa.gov.au/newrules/parts/039/download/ris9802.pdf