Creampuff to give you an example if I was doing SOM for a Piper Warrior

I would strip out seaplane , Ag Plane , aircon , hydraulics ,turbocharger ,anti icing, retractable gear , water injection, ,lavatory,Wood and fabric checks. Slim the bitch right down

Then expand on the general checks to make it more specific to the aircraft . Using the schedule 5 checks as a guide . Schedule 5 is too vague at best and its left for maintainer to use judgement and experience to make good calls. If your aircraft has a SOM ,that you have elected not use or is deemed inadequate, you could draw some information from that instead of Schedule 5.

Then I would focus on known problems of the aircraft like dissimilar metal corrosion in the tail attach , cracking under the wing walk way , stress corrosion in the nose wheel fork, removing the fuel tanks at the MM's scheduled time . In fact those could be put on a calendar system as they don't need to be done annually (Unless an AD mandates otherwise).

You can write yourself a better more comprehensive SOM that is less invasive and more effective if you already know your aircraft. Sure its time consuming but you will get the outcome you want.

You will have to deal with CASA and there will be a bit of back and forth . But is paperwork that scary ??

As I say to people Adapt , Improvise ,Overcome !!

I’d suggest that there’s nothing stopping exactly the same practical outcome being achieved, legally, under Schedule 5 NOW. (Nothing, other than the apparent oversupply of idiots in the weird and whacky world of aviation regulation in Australia.)

I’d go so far as to suggest that it’s the outcome that is required to be achieved in respect of aircraft maintained to Schedule 5 NOW. Bear in mind that Schedule 5 is just that: a Schedule to some regulations. Schedule 5 is just a list of whens and whats. (That's why it's vague and has lots of whats that aren't on many aircraft.) The detailed tech data, which is NOT in Schedule 5, spells out the how.

The regulations contain the obligations with which the maintainer must comply. The regulations have links to Schedule 5 AND the tech data AND what the maintainer sees and knows about the aircraft and aircraft type being inspected. And then there's the common law duty of care ...

It's a very brave maintainer who tries to hide behind Schedule 5 as an excuse for not dealing with something that was a known problem area in a particular aircraft type.

W8
 

If you ever become an owner/builder for your renovations or whatever at home, the local council (the regulator) will require you to do a course. Similarly, it doesn't tell you anything about swinging a hammer, it tells you about insurance and licencing and satisfying the regulator. :ugh:

W8

If that is all your gleaned from doing the course I suggest you need to go back and do it again. Sure there is a fair bit of learning how and why systems of maintenance work, the value in documenting etc, but there is a lot more to it than what you describe above.

Funny how several folk who have been airline guys all their careers attend the course and give it great reviews for how the holistic education process is. Of course beauty is in the eye of the beholder.

First of all, the manufacturers recommendations are not "wild assed guesses" unless you are dealing with a completely new type, in which cases they will be conservative estimates based on testing and design specificatoins. What then happens is that condition vs time in service or cycles or whatever is plotted on a Poisson distribution and the mean and standard deviation is calculated.

We then apply three four or five standard deviations to arrive at a statement about the life of the part with a set confidence limit (often 95% or 99.9%) that gives us the expected life of the part with that level of certainty. This is a "hard time " limit for something that is going to kill us or break the aircraft suddenly with no warning if it fails.

If we design it so that it fails gracefully with plenty of visible warning, we mark it "condition monitored" and check it regularly - the checking interval established so that it can't fail before the next inspection.

If its just a nuisance we mark it "on condition" and fix it when it breaks.

What annoys me is the heavy handed approach ASA applies which requires a LAME to over maintain to protect themselves from criminal prosecution.

Are you able to cite an example of a non-transport category aircraft/component whose Type Certificate holder did the paperwork to revise the periodicities of time-lifed component recommendations, in the light of subsequent service history? (I’m aware of one re engine TBOs, but that’s it.)

Cessna Aircraft Company 310 Service Manual Component Time Limits Schedule requires that the vacuum pump be replaced “every 500 hours or at least once a year”. The Service Manual has said that for around 40 years, despite the millions of hours of vacuum pump operation data to prove that “every 500 hours or at least one a year” was a wild-*ssed guess. Why would Cessna or the component manufacturer have any interest in extending the time limits?

“Conservative estimates” are a primary cause of the Waddington Effect. Remember all those gyro bearings that you told us about?

Spar life on Air Tractor and Thrush would be one example.

fastidious owner/pilots of private aircraft may have a case to argue for "over maintenance"

some crew in the commercial environment will have the opposite opinion

there should never be over maintenance or under maintenance.

there should only ever be appropriate maintenance.

but! we live in a world almost devoid of any real aeronautical engineering understanding, a world replete with "administrative annuals" and a lot of poo to boot.

it is not a good world and one perpetually made worse by CASA.

Hmmm, over maintenance ah?? well perhaps you would like to put on here the call signs of the GA aircraft that have been over maintained, coz quite frankly I aint seen em. I have worked on plenty of GA aeroplanes that have quite obviously been under maintained, but I cant remember too many that I have said to myself, wow this has had way more maintenance than it needs.
It seems to me that what most constitutes over maintenance is the owners saying that the said maintenance costs too much. Not many owners, in my experience, say thanks for finding that defect and rectifying it and I am happy to pay the bill.:ugh:

In many cases Arnold you would be correct.

However the aircraft that has its injectors removed at a 100hrly or annual and reinstalled only to introduce a problem would absolutely be a case of over maintenance.

In fact it is a dumb thing to do IMHO. Especially all those ROP pilots without an EMS. They are at greatest risk of suffering this.

In some other areas I am sure there are cases where a similar thing occurs. But generally speaking you would be right.