Folks,
Schedule 5 would be the ideal maintenance schedule, if it was allowed to operate as intended.
If you have a knowledge of the design and certification standards of the FAA, including continuing airworthiness requirements, you would know how the US system works, and the Australian system was supposed to, but hasn't worked.
Schedule 5 IS FAR 43, Appendix D, (except for some added AU bullsh1t) an entirely comprehensive Inspection Schedule, it is NOT a system of maintenance, as the Schedule 5 is miss-described.
If you are maintaining virtually any FAR 23 aircraft, operating under Part 91, it is Part 91 that describes the maintenance to be done, Part 43 says how to do it, and (in some cases) Part 145 will tell you where to do it.
If the same aircraft is operating under Part 135 (roughly Charter) there will be additional maintenance requirements, which will be carried out per. Part 43, including the Appendix D.
[As an aside, this is how the Cessna SIDs are not mandatory for Part 91, but are for Part 135 and up, but I am not going to go into the explanation here]
The OEM MM is most certainly not "the best". except for some relatively recent examples, FAR 23 (and earlier CAR 3 equivalents) assume the use of the FAA Annual Inspection Schedule ( Appendix D) will be carried out using acceptable (or authorised) data, which includes but is certainly NOT limited to OEM MM. The OEM MM is required by part 43, Appendix D, but it is only part of the suite of acceptable data.
Indeed, with the Australian misapplication of continuing airworthiness standards for most US built aircraft, the CASA list of deficient OEM MMs is increasing. Mostly they are NOT deficient at all, when they just form part of, but not nearly all the acceptable data needed to complete routine maintenance tasks and all but major repairs.
For may of you, if you are half way smart, you will have at least FAA AC 43.13A/B as CASA approved data in you CAR 30 manuals.
Indeed, in general terms, the OEM MM will only include model specific information, and assumes that all the necessary additional acceptable data to be used will be found in the AC library. Many of your will be familiar with the wealth of detail in FAA AC43.13A and AC 43.13B, and many more FAA publications that cover specific continuing airworthiness issues, that are common to most aircraft.
During the period Bruce Byron was CASA CEO, a instrument was raised, which allowed the whole FAA AC library ( and the equivalent from other NAA ) as CASA approved data, without the need for CASA approval for each CAR 30 workshop.
Needless to say, there was much resistance from bowels of CASA, it eliminated the "data approval industry" at a stroke, the present shower, unsurprisingly, have completely reversed to Byron/Vaughan reform, prohibiting the use of such worldwide acceptable data in Australia, without (expensive and long time delay) CASA approval.
Right now, CASA has no idea where it is going with future GA maintenance rules, but the "iron ring" is pushing Part 42/145 as it stands, a disaster in the making.
Tootle pip!!