Over Maintenance

[Old Akro]

This is a very interesting article on a study done in the second world war indicating that the availability of aircraft was increased if less maintenance was performed.

The Waddington Effect « Opinion Leaders (http://blog.aopa.org/opinionleaders/2014/01/14/the-waddington-effect/)

I have often wondered if part of our "aging aircraft" issue has in fact been caused by imposed over maintenance and cumulative sloppy workmanship.

[Andy_RR]

It probably has its parallels in over regulation...

[VH-XXX]

I'm sure many of us have spent the next 10 hours after a 100 hourly going back and forth to the LAME shop getting them to fix all the things that broke during the "inspection" !

[nitpicker330]

Military requirements in a War zone in WW2 are hardly relevant to today in civil aviation.

Less spanner time would equal more flying time initially. They weren't really looking at a long airframe lifespan were they!!

[RatsoreA]

I'm sure many of us have spent the next 10 hours after a 100 hourly going back and forth to the LAME shop getting them to fix all the things that broke during the "inspection" !

A quick review of all things maintence with my plane seems to bear this out... :eek:

[Creampuff]

I'm guessing you're a LAME, nitpicker?

[nitpicker330]

Me a LAME? :D. I think you just insulted LAMEies :ok:

You can hardly compare operating under War time constraints and requirements with the modern Civilian Aviation world surely?

We maintain our fleets for safety, comfort and longevity. Three things they didn't worry about in WW2 !! :D

[TBM-Legend]

Many new designed aircraft have eliminated small checks. The Emb Phenom 300 for example only requires an annual or a check every 600 hours which ever comes first. Engines are basically "on condition" save life limited parts...

Ageing aircraft or "abused" aircraft can be a different thing.

[Wally Mk2]

..............now where did I hear in recent times that ..................these new A/C need less maintenance?................
There is merit to that old saying if it ain't broke then don't fix it!

Some maint would be a feel good procedure. You know it's be checked & then you 'feel' better, doesn't guarantee a thing!

Wmk2

[Creampuff]

Nitpicker

Actually, yes I can compare now with then, and please don't call me Shirley. :p

The intended purposes of maintenance on "our fleets" are safety and longevity. So were the purposes of maintaining the fleets in WWII. A warplane stuck on the ground due to maintenance error was of zero use, other than canibalisation ...

I'll make another guess: You're not an aircraft owner. Otherwise you might have had the pleasure of spending lots of money for the annual visit to the aviation Wally World called 'picking your aircraft up after maintenance'.

It's the fun park with everything!

There's 'hide and seek': Where did they leave tools this time? :ok:

Then there's the 'disco'. Somebody - probably the LAME's kid - twiddled every knob on every avionics system. Just like a disco, you end up half-deaf and exhausted by the time you've reset everything to where it should be. :ok:

Then there's the 'room of weird mirrors'. All of the disorientation that occurs when you look through windows with grubby engineer paw marks all over them. :ok:

My favourite is the 'ghost train': What traps have been left to jump out and scare you, this time? Will it be the injector that was clogged due to 'cleaning'? Will it be the engine monitor probe that was left disconnected? Will it be 10 degree higher CHTs due to a magneto being set using the Fred Flinstone timing kit? It's an extra thrilling ride 'cause you don't find out until you're in the air! Yaaahhhhooooo! :ok:

[Paragraph377]

Creampuff, sounds like your aircraft mechanics are the same ones who work on my high performance street car :ugh:

[dubbleyew eight]

the purpose of maintenance is to ensure that the aircraft structure remains capable at all times of supporting the design loads.

:=

[Creampuff]

You mean “a” purpose, not “the” purpose. :ok:

And the point of this thread is to discuss whether the maintenance that is carried out achieves those purposes.

[tecman]

There's undoubtedly a U-curve in all this: too much and too little maintenance is bad on both cost and reliability grounds. There's a body of engineering literature and some good summaries are turned up by a just bit of googling. In private aviation at least, it looks to me like we're a victim of the one size fits all approach. Does my 800 hr TT puddle-jumper, which is hangared and does 50 hr a year really need the raft of provocative maintenance it's subjected to annually? I have my doubts. Fortunately I have a good LAME who directs his attentions sensibly but, even so, it's an expensive business. I'm certainly not deluded enough to think there's a bargain-basement path to air worthiness but I'm pretty confident I'm approaching the right-hand side of the U-curve.

[Old Akro]

We have been paying public servants for 50 years or more to collect data on aircraft faults & incidents. It would seem to me that it ought to be possible to use this to refine maintenance procedures. If not, why are we doing all this reporting and employing all those people?

A favorite story is a LAME who maintained the first turbo Bonanza in Australia. DCA (as it was) didn't understand turbo's. So they mandated a 50 hour inspection. Not only did it add significant cost, but cause un-necessary deterioration to the airframe.

Other mates have antique aircraft that fly literally a handful of hours per year. Yet each year all the covers come off regardless.

Where is the demonstration that we have learned things in the last 50 years?

[Old Akro]

It probably has its parallels in over regulation...

Dr James Reason " Managing the Risk of Organisational Accidents". p 4, 5 and a bit on pages 182-186. Then p234-235.

I think Tony Kern then takes up where James Reason leaves this book and goes on to argue for an increased focus on personal responsibility.

[Avgas172]

and the point of this thread is to discuss whether the Maintenence that is carried out achieves those purposes
Or indeed causes more problems then it fixes .... I'm all for preventative maintenance, but pulling the whole aeroplane to bits every year regardless of the hours flown is excessive, regardless of the cost factor and has been a constant worry for me. Now we have the mandated Cessna SIDS program where LAME's are quoting more than the aircraft is worth, which in itself seems to just be another way of getting rid of a lot of perfectly airworthy planes.

[VH-XXX]

If you can find 20 minutes to read this Queensland Coroners Report you'll realise that under-maintained is far worse than over-maintained....

http://www.courts.qld.gov.au/__data/assets/pdf_file/0004/217795/cif-beresford-sj-20131205.pdf

[Avgas172]

XXX whilst I concour it is a good read, it is not very relevant to the subject of this post. It is however a fairly damning picture of the problems associated with under regulation, in this case of almost everything about what not to do in aviation in the one accident.
Cheers
A172 :sad:

[VH-XXX]

it is not very relevant to the subject of this post.

Thanks for your note there Chris. I'll be sure to check all of my submissions in the future to ensure that they are relevant and please all audiences.

The point is imagine if this operator decided to reduce maintenance for reliability purposes. The Gyro community is by no means under-regulated; in this case, backyard pilots and mechanics were rife, not unlike parts of the GA world in remote Australia. To suggest that maintenance could be safely reduced for operators, it's inviting issues for those taking that advice literally.

[tecman]

There's no fixing stupid, and neglect is certainly not a valid approach to maintenance. But the most cursory checks by a LAME would have turned up the bulk of the issues in the Qld coroner's report. I for one appreciate the need to go well beyond cursory checks, but that doesn't equate to annually tearing apart a near-new, low-utilization aircraft for fun or profit.

I'd venture that people who neglect even the more relaxed maintenance prescribed by the sport aviation bodies are unlikely to be compliant with stricter regulations. And in GA we all know people who push maintenance rules to the limits, often without much real long-term gain, in my view. But we're not best served by the blanket assumption that we're all irresponsible or fly junk.

[Ethel the Aardvark]

Under utilised aircraft ie 3 hrs a year require as much maintenance if not more than a regular flown aircraft, cable pulleys seize through lack of use, corrosion gets a good foothold in engines etc. mags and other components need regular use for longevity, if you expect a quick insp just because of low use then it will bite you in the bum eventually,

[dubbleyew eight]

ethel an aeroplane sitting in a warm hangar gets none of those things.

I used to worry about corrosion in my O-200. the dipstick always had corrosion on is so the rest of the engine ????

well one day I pulled off the oil sump and had a look into the engine with a 500,000 candlepower spotlight. I put a new gasket on and put the sump back.
the only part of the engine showing the remotest bit of corrosion was the mild steel dipstick.

cable pulleys sieze through lack of use??? bull****. a standard pulley has a sealed ball bearing centre.

mags need regular use for longevity???? where do you get that tripe? do you know how they work?? mine have gone 20 years between services.

[Ethel the Aardvark]

Good luck double u 8 in the lottery.
A 1 year old rv may have perfect bearings even if it's not used for several years, however a 40 year old Cessna not kept in a humidy or temp controlled hangar do suffer from lack of use, have seen mags fail through impulse springs corroded.
Glad to see yours are inspected regularly,
Fly a plane at least once a month is a good start. Not once a year

[dubbleyew eight]

ethel my little lightly built tube, wood and fabric homebuilt is 28 years old.
Wittman wasnt involved in Van's aircraft. :ok:

the reason why regular flying works is that it dries out the aircraft.
hangars do the rest.

tuesday night ethel. its a jackpot.:E

[Hasherucf]

dubbleyew eight you probably know ...and ignore the fact that most magneto manufacturers mandate a 500hr overhaul life . It was an AD some time ago and CASA canceled it in lieu of manufactures instructions.

Here is a sample from TCM : http://www.tcmlink.com/pdf2/sb643b.pdf


After reading a few of your posts about your own aircraft maintenance can you forward your Rego details so I can avoid flying in that aircraft :ok:

P.S my offer still stands

[tecman]

Ethel, before we head off on a complete tangent I can't see anyone arguing that 3 hrs a year utilization is a good thing - certainly not me. Your own comments re the two aircraft types and utilizations seem to underline that one size definitely doesn't fit all in maintenance regimes. I take a keen interest in the maintenance and inspection of my aircraft and, based on what I see and what my LAME relates, I'm not convinced that annual dismantling of a privately utilized aircraft with the stats mentioned in my earlier post is justified - or even wise - from safety and economic viewpoints.

[dubbleyew eight]

P.S my offer still stands

you've lost me there.

500 hours is engine run time. that took 20 years in my case.

a bendix maggie. hmmmm sorry I've never seen one of those.

[Arnold E]

well one day I pulled off the oil sump and had a look into the engine with a 500,000 candlepower spotlight.

You are a LAME with the appropriate groups I take it.:confused::E

[Hasherucf]

How about Slick then ?
http://www.csobeech.com/files/SlickMagneto-SB3-08A.pdf

Bendix and Slick are the two most popular .Otherwise check your magneto manufactures data . If they don't exist anymore then define your own SOM in the logbook statement. I would suggest 20 years is too long between inspections.

[Aussie Bob]

well one day I pulled off the oil sump and had a look into the engine with a 500,000 candlepower spotlight.

Yep, did you pull the cylinders to properly inspect the camshaft, that's where the rust will be if there is any.

[currawong]

One should remember, in Waddingtons time, the aircraft were mostly new(ish), they did not last long, the technicians involved were mostly wartime trained and not always volunteers.

I don't know the life expectancy of the Coastal Command aircraft in his study but seem to recall that a Lancaster lasted on average 40 hours. I stand to be corrected. Therefore any maintenance at all would probably have an adverse effect on availability.

[dubbleyew eight]

my take on maintenance is that you need to maintain the actual machine in front of you.

if you have only done 5 hours for the year do you automatically replace the bracket air filter or do you change it when it looks like it needs to be?

if you taxy in after rain and drop the wheel through a deep puddle you really need to pull the wheels off and dry out and regrease the wheel bearings to stop them corroding.

if you pull off the inlet fuel filter on a marvel schebler carburettor every service you will wear out the threads long before anything untoward occurs with clean fuel and be up for an expensive carby replacement.

if it needs attention then attend to it, also if it doesnt achieve the performance numbers then attend to it. if it meets all the requirements then go and fly it.

[Avgas172]

Thanks for your note there Chris. I'll be sure to check all of my submissions in the future to ensure that they are relevant and please all audiences.
Well done xxx? But just sticking to the subject matter will do. However I would prefer you addressed me as A172 unless you care to put your name to your post as well.::ugh:

[Tee Emm]

"if it needs attention then attend to it, also if it doesnt achieve the performance numbers then attend to it."


A quarter of a century ago I got a job with Security Express. Did a couple of ICUS on one particular Aero Commander and told by the captain that the ADF was crook with range only 5 miles. It had been snagged but signed off as serviceable. Eventually I was cleared to line and flew same Aero Commander. ADF was useless outside of 5-10 miles. The needle swung all over the place, useless for tracking - unsafe in let downs for sure. Maintenance Release clean as a whistle. Wrote up the ADF defect and was promptly castigated by chief pilot who had been rung up by the owner about the scumbag who had dared record the defect in the MR. Chief pilot said to me why did you write it up - we all know the ADF is F**ked.

Dropped into the maintenance hangar and saw LAME working on ADF so I thought. Find the problem with the ADF sez I to him? Yeah we know what the problem is; corrosion everywhere replies LAME.


Why not fixit, sez I? The owner told us not to fix it, sez LAME. So we sign it off as ground tested serviceable every time some idiot writes it up..

[Propstop]

That LAME needed his nuts tightened if he was happy to be directed to sign it off without fixing:ugh::ugh::ugh:

[Creampuff]

There are two main issues here: (1) Whether there is too much mandated scheduled maintenance. (2) Whether the maintenance that is done is done competently.

The ‘Waddington Effect’ is the answer to (1). The suggestion that there’s a difference between the intended aims and outcomes of war time maintenance activities versus peace time maintenance activities is, in my view, specious. The RAAF moved to the ‘RAMP’ system of maintenance in the 80s because of the Waddington Effect, although the justification was not expressed in those terms.

All you need to do is reflect on the type certification process and how the instructions for continuing airworthiness for an aircraft type are determined, and by whom. It’s inevitable that there are going to be lots of wild-*ss guesses and ‘conservative’ judgments made about what bits need to be checked or replaced, and how often. The mystique of aviation and the thinking that led to the Waddington Effect is that more maintenance more often must surely result in a safer aircraft. But, as with many things in this world, it’s counter-intuitive. More maintenance more often does not result in a safer aircraft.

A couple of examples, out of many, of maintenance requirements that bear little or no relationship with the real world.

I note the requirement to replace vacuum pumps every 500 hours TIS on some aircraft. In the real world, some vac pumps of that kind fail in 5 hours, and many, many more of that kind fitted to other aircraft last for over 1000 hours. The real world data show that the 500 hours was just a wild-*ss guess.

Replacing a vac pump that could go another 500 hours contributes nothing to safety. If the vac pump is replaced and the new one fails at 5 hours, that’s perfectly OK from a regulatory perspective: just a random failure. If the vac pump is left on the aircraft beyond 500 hours, a heinous regulatory sin has been committed and heads must roll, notwithstanding that the pump in fact lasts for another 500 hours TIS. :ugh:

Example two: An aircraft has an injected engine with balanced fuel injectors and an engine monitor that the pilot knows how to use. It will be patently clear whether the injectors are working properly, without having to remove them. The dumb thing to do with that engine is remove the injectors for cleaning, thereby unnecessarily risking (1) damaging or dirtying an injector; (2) mixing the injectors up and refitting them in the wrong position; (3) cross-threading or over-torquing the injectors on refitment, damaging them or the cylinder heads; (4) cross-threading or overtorquing the fuel tube connections to the injectors, damaging the tubes or the injectors. Yet that’s what the rules require, in the interests of ‘safety’. :ugh:

(That’s why I like W8’s approach: maintain what’s in front of you. The LAME should have the regulatory discretion not to remove, clean and refit the fuel injectors if the owner says: “Here are the data from the engine monitor. They prove the injectors are working perfectly. I'm happy to continue to trust my life to them. Please DO NOT TOUCH THEM!”)


Re (2), incompetently-performed maintenance never helps. More mandated scheduled maintenance, if done incompetently, will do more damage than less mandated scheduled maintenance done incompetently.

[Old Akro]

The dumb thing to do with that engine is remove the injectors for cleaning

What do we clean them in? What do they normally operate in?

I vividly remember reading a book by one of the performance tuning guru's on Weber carburettors (might have been Vizard - who remembers his books?) where he lambasted those who disassemble carburettors to "clean them". He reckons there was a bigger chance of introducing contaminants than removing them.

The bit that Creampuff missed is why with the passage of decades and rows of public servants in air-conditioned office blocks collecting incident reports, why we haven't refined the initial wild-*ssed guesses.

To illustrate creamy's point a little - a mate flew his new cabin class twin to Yarrawonga last weekend. Straight out of a major refurb and with a fresh 100 hourly. One vac pump failed on the way up. The other failed on the way back. You can't beat bad luck.

[Creampuff]

Gotta love those vac pumps!:D [T]he passage of decades and rows of public servants in air-conditioned office blocks collecting incident reports, why we haven't refined the initial wild-*ssed guesses.Technically, that’s the job of the holder and issuer of the Type Certificate.

There are occasional glimmers of hope. Although the AD authorising ‘on condition’ maintenance for certain piston engines sits very oddly with the purposes of an AD, at least the practical outcome is sensible. :ok: (Of course, the ‘more maintenance more often means more safety’ crowd are plotting to get rid of it! :ugh:)

[Old Akro]

Technically, that’s the job of the holder and issuer of the Type Certificate.

What about the good old CASA Schedule 5 which the vast majority of GA aircraft use?

[Creampuff]

Would that Schedule 5 dealt exhaustively with the ‘when’ of maintenance of aircraft to which it applies. Unfortunately, it doesn’t. :ugh: Engine maintenance is an example.

PS added:

AO, I’m intrigued by your mate’s “cabin class twin” that had one vac pump fail on the way to Yarrawonga and the other fail on the way back. I am not surprised that it happened, but I’m intrigued to know when the pumps were fitted to the aircraft, and why.

When were those pumps fitted to the aircraft? Was it during the “major refurb”? If yes, were the old pumps working before the “major refurb”?

If yes, that’s about the clearest example of the Waddington Effect as you can get. Two serviceable vac pumps go into the refurb, two unreliable ones come out!

Was the aircraft being maintained to Schedule 5? If the answer is yes, why were the pumps replaced during the “major refurb”? If it’s because of the consequences of the AAT’s decision in Brazier and the regulatory link to the component time life limits in the Manufacturer’s maintenance manual, that’s relevant to the point I made about the Type Certificate holder and issuer being responsible for changing the ICA that perpetuate the Waddington Effect.

[dubbleyew eight]

can I ask a question.

how did the vac pumps fail?

I've had two fail on me for the same reason. the flexible frangible link disintegrates.
I looked at this with my engineer eye and thought the frangible link to be a bit of twaddle that sounded good in theory.
I machined a replacement for both (occurred about 6 years apart) in etalon6 which is a type of nylon. in all the years the original I made has been flying there has been no deterioration.

I also take my vac pump apart about every 5 years and clean it and dust it with moly disulphide dust. so far in 10 years or so I've seen no internal wear.

yes I know it is all bloody illegal. I own the aircraft though.

[Old Akro]

My mates vac pumps haven't been replaced yet, so I don't know. Typically, the carbon vanes fail. Sacs sky ranch or someone like that had a really excellent tutorial on vac pump failures.

I believe you can buy vane kits in the US --- but that's illegal here too.

Of course life is a bit related to how hard they work. They typically drive a lot more stuff in IFR aircraft.

[stevef]

Vacuum pump failure is usually due to vane contamination. A common cause is cleaning down the engine with an avgas spray gun without tying a plastic bag over the pump. Maybe that's why two pumps failed so quickly after maintenance if that was the case.
Something that should be considered regarding the engineer/mechanic/technician (or whatever you want to call them) 'needlessly' disturbing aircraft components is that the inspection workpack is a legally binding document once it is signed. The litigation lawyers would rip the certifier to shreds if there was an accident due to stipulated work signed for and not carried out and the aircraft owner (if he survived) is hardly likely to confirm that he asked for maintenance items to be skipped.
Who's going to take a chance in the face of a possible multi-million dollar lawsuit?

[Andy_RR]

...cleaning down the engine with an avgas spray gun...

:eek:

I think we've perhaps found the cause of maintenance failure. Chronic lead ingestion leading to decreasing cognitive ability...

[Creampuff]

Errrrm … yes.

Hi Steve

Do you or people you know clean down engines with avgas spray guns? If so, it would be great if you could post their names and addresses. Thanking you in advance. :ok:

[stevef]

Do you or people you know clean down engines with avgas spray guns?

No, I don't do it - I've seen a fire caused by a cleaning gun shorting out the positive battery terminal against the structure. Quite spectacular but fortunately little damage done to the C172.
Anyway, it's done in some places and as I said, it can kill the vacuum pump pretty quickly.

[Creampuff]

I've seen a fire caused by a cleaning gun shorting out the positive battery terminal against the structure.Jesus wept. :eek: The Waddington Effect strikes again.

Something that should be considered regarding the engineer/mechanic/technician (or whatever you want to call them) 'needlessly' disturbing aircraft components is that the inspection workpack is a legally binding document once it is signed.That was my point about the Waddington Effect being perpetuated by the instructions for continuing airworthiness enshrined in the TCDS. Functional and conforming aircraft components are usually only ‘disturbed’ because ‘the manual’ says they must be. Usually ‘the manual’ requirements are wild-*ssed guesses or ‘conservative estimates’ based on the incorrect assumption that more maintenance more often always results in more safety. :ugh:

[Jabawocky]

Indeed............like pulling apart a perfectly functioning engine with good leak downs, borescoped all good and and not burning oil excessively, just to see why it ran so perfectly! Then overhauling it and putting back in with a period of infant mortality awaiting!

[Horatio Leafblower]

"Rules are for the guidance of wise men - and the obedience of fools."

When I was a teenager and my father first trotted out this gem I took it as carte blanche to disregard the rules as and when it suited me - it goes without saying that I was the smartest guy in the room and without doubt I fell into the category of "wise men".

The results were fairly spectacular. :ouch:

Now that I am a fair bit older and, evidently, dumber, I would interpret my father's favourite saying somewhat differently.

In my original interpretation I thought that only a fool would slavishly work to the rules and a smart fellow, a member of this secret yet poorly-defined group of "Wise men", should work to the rules when it suits, and intelligently work around them when required by circumstances. These circumstances might be safety, or economy, or... well, anything. Including laziness and convenience.

Many black eyes later, I would suggest that the rules fall into two categories. To borrow from Tony Kern, there are the RED rules that someone has spilt blood to discover, and there are the BROWN rules which are usualy handed down from a government office somewhere to make life easier in the government office.

Maintenance rules and Systems of Maintenance are (generally speaking) an embodyment of common sense, risk management and operating experience, mixed with an aversion to spilled blood. Yes there is the occasional bit of poo added to the mixture. :hmm:

The rules are for the guideance of wise men: not because wise men are smarter than the rules but because a wise man would probably be operating in a way that is pretty close to what the rules require anyway.

The rules are for the obedience of fools: not simply because only a fool would stick to the rules - but because only a fool would be operating in a way that a big stick is required to force them into obedience.

When we see rogue pilots and shonk companies chased and prosecuted by CASA, or d!ckheads hanging off helo skids, or pilots flying adventure flights without medicals, or Day VFR pilots crashing into hills in cloud and/or at night, most of us think "No I would not have done that". These are areas that we as pilots understand and risks that we can assess based on our experience and knowledge.

...but we don't know all the rules, we can't be professionals in every field and we can't always adequately assess all the risks in the fields in which we are not specialists.

And it is there, my friends, where we find the difference between the "Wise men" and the fools. :=

[tecman]

HLB, your points are well made. The version I learned was "...for the guidance of wise men and the protection of fools". There are some interesting differences in the semantics which could be discussed over a beer or three.

One point I'd make is that many of us indeed consider that a regime "close" to the present rules is not a bad thing. We're not talking order-of-magnitude changes but the putative factors of (e.g.) 2 or 3 in maintenance scope and intervals (for some aircraft and operations) are significant in terms of keeping us flying.

[Andy_RR]

Just wanted to point out that the fools/wise-men quote is attributed to Douglas Bader, but there seems to be some disagreement on t'interweb as to the actual phasing and order.

[SgtBundy]

Outside input - in the IT field you can guarantee most failures (outages) will come from maintenance of some sort - applying patches to fix "known issues" will break something after the fact or the act of enacting the change goes wrong causing a cascading failure. In my experience more work comes from fixing faults caused trying to prevent failure, then the actual failures you are working to avoid.

Clearly aviation is not the same thing (the restore from backup post incident is not yet perfected in flying) but the concept is the same. Change of any sort creates risk, but eventually so does lack of preventative change (IT - getting hacked, Aviation - corrosion/wear).

In IT you use development systems to test with first - evaluate the risks, confirm there are no issues, test the process. Its not 100%, as production tends to be more complex or not the same scale, but it gives feedback and some assurance. I would have thought in aviation the longer an airframe type is in service, the more history and accuracy there would be in where problems are and in what lifespan components have. Rather than hard coding lifespans (which initially may be a guess or estimate based on materials) that factual information would become available on the longevity of components and guidelines could be adjusted to be more economical or change service behaviour to induce less change into the components life.

[dubbleyew eight]

once upon a time a LAME and I were working through schedule 5 and striking out entry after entry as ....stroke not applicable stroke.
in the schedule 5 there were 6 pages with entries all struck out as not applicable.

said LAME knew I was computer literate, and said lets fix this bull****.
he performed all the annuals on all the aircraft on the field so he knew what was needed.

we took a copy of schedule 5 and looked at every aircraft on the airfield.
no that clause applies to none. strike it out.
ah yes there is one aircraft with that, leave it in. ....and so on.

we ended up with a pretty tidy document that had no rubbish in it.
the LAME submitted it and it was approved.
about 3 years passed with all the LAME's using the document praising the removal of bull**** items.

a staff change occurred in CASA. what's this? why arent you using Schedule 5, we'll have to sort this nonsense out pretty smart.....

it is schedule 5 just with all the redundant non applicable items removed.

but it isnt schedule 5....
you have to use schedule 5.

so schedule 5 went back into use. pressurisation systems ...not applicable.
radar installation ...not applicable and so on. :mad::mad::mad:

[Creampuff]

... and don't forget to maintain that lavatory on your 152.

There's an American comedian, whose name escapes me, that advocates giving idiots a sign to hang around their neck, so that others are aware of the proximity of one.

To the new CASA person: Here's your sign. :ok:

[Hasherucf]

dubbleyew eight just take schedule 5 as an example. Strip it and expand it to cover anything that is not covered and make it look nothing like the original (format wise ).

Call it something completely different and reapply to make it your SOM. Not everyone uses Sched 5. Looking at my paperwork about 70% , the other 30% are smart operators.

Of course if you make ridiculous claims like engine TBO is 4000 hours for your piston banger then you will be knocked back.

I cant see the problem ! As with this whole thread it seems people are too lazy to write their own SOM of maintenance and just accept Sched 5 as their only default choice.

[dubbleyew eight]

Hasher....
if you look at all this in overview what CASA want is for all maintenance to look like it used to in the RAAF.

if you put the head of CASA in disguise and had him sit through the sort of screaming session the morbidly obese fat bastard in Perth is capable of even he would cringe in horror.

I have no schedule list that I use for my own maintenance.
I use a very detailed sectioned perspective drawing.
when I am finished there is a tick on every item on that sectioned drawing.
a final check that no items have been missed and I screw up the print of the drawing and destroy it. they'll hate that.

[Hasherucf]

Spent probably 2 days with our inspector last year , Plus an audit and a few conferences with much 1 on 1 time. Also countless emails. Of course it depends on your office rep. But found if their is an issue it generally it can be worked out with creative thinking.

Is Dennis Byfield still the senior airworthiness inspector in Perth ? Seems a reasonable straight up guy!

[Creampuff]

dubbleyew eight just take schedule 5 as an example. Strip it and expand it to cover anything that is not covered and make it look nothing like the original (format wise ).

Call it something completely different and reapply to make it your SOM. Not everyone uses Sched 5. Looking at my paperwork about 70% , the other 30% are smart operators.

Of course if you make ridiculous claims like engine TBO is 4000 hours for your piston banger then you will be knocked back.

I cant see the problem ! As with this whole thread it seems people are too lazy to write their own SOM of maintenance and just accept Sched 5 as their only default choice.It’s an extra special regulatory system that produces that kind of thinking and outcome.

So if I take a copy of Schedule 5 and take out the line about maintaining the lavatory because my aircraft doesn’t have one, I’m in trouble with CASA if the aircraft’s maintained to that Schedule. If I take a copy of Schedule 5 and change the font and take out the line about maintaining the lavatory because my aircraft doesn’t have one, put in a Mickey Mouse heavy landing inspection and lightning strike inspection and call it System of Maintenance, CASA will approve it as an SOM? And I’m lazy if I don’t put myself through such an utterly pointless exercise?

CASA says Schedule 5 is inadequate for ageing aircraft, but they’ll approve an SOM that results in less maintenance for that aircraft? Have I got that right?

[dubbleyew eight]

if you want to maintain your homebuilt you need to do a two day maintenance course, approved by CASA, that is run by the SAAA.

how much maintenance is covered in a two day CASA approved course?

none.

the entire course is spent instructing on CASA's regulations and the reams of paperwork needed to satisfy the regulators.

if you believe the CASA world, the take home message from the course is actually that there is no technology to aviation, there is nothing that needs to be understood about how aircraft are all engineered. none of that.
just fill in the paperwork and all will be well.

I honestly believe that CASA have no idea just how dangerous their stupidity can get. There is a technology approach, often it is subtle, if you attack it with brass bolts and bailing wire you'll kill someone.

maybe CASA dont actually realise that there is a technology to it all.

[Hasherucf]

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 !!

[Creampuff]

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.

[Horatio Leafblower]

if you want to maintain your homebuilt you need to do a two day maintenance course, approved by CASA, that is run by the SAAA.

how much maintenance is covered in a two day CASA approved course?

none.

the entire course is spent instructing on CASA's regulations and the reams of paperwork needed to satisfy the regulators.

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:

[Jabawocky]

if you want to maintain your homebuilt you need to do a two day maintenance course, approved by CASA, that is run by the SAAA.

how much maintenance is covered in a two day CASA approved course?

none.

the entire course is spent instructing on CASA's regulations and the reams of paperwork needed to satisfy the regulators.

if you believe the CASA world, the take home message from the course is actually that there is no technology to aviation, there is nothing that needs to be understood about how aircraft are all engineered. none of that.
just fill in the paperwork and all will be well.

I honestly believe that CASA have no idea just how dangerous their stupidity can get. There is a technology approach, often it is subtle, if you attack it with brass bolts and bailing wire you'll kill someone.

maybe CASA dont actually realise that there is a technology to it all.

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.

[Sunfish]

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.

[Creampuff]

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.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?

[currawong]

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

[dubbleyew eight]

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.

[Arnold E]

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:

[Jabawocky]

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.