Over Maintenance
Would that Schedule 5 dealt exhaustively with the ‘when’ of maintenance of aircraft to which it applies. Unfortunately, it doesn’t. 
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.
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.
Last edited by Creampuff; 19th Jan 2014 at 03:53.
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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.
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.
Thread Starter
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.
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.
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?
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?
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.
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.
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.
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.
I've seen a fire caused by a cleaning gun shorting out the positive battery terminal against the structure.
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.
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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!
My father's favourite saying.
"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.
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.
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.
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.
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.
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.
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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.
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.
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.
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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.
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.
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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.
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.
... 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.
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.
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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.
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.
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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.
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.
Last edited by dubbleyew eight; 22nd Jan 2014 at 07:43.
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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!
Is Dennis Byfield still the senior airworthiness inspector in Perth ? Seems a reasonable straight up guy!
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.
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.
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?
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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.
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.