Over Maintenance
Join Date: Apr 2012
Location: Perth, WA
Posts: 326
Likes: 0
Received 0 Likes
on
0 Posts
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.
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.
Join Date: Sep 2003
Location: Back too the hot bits again
Posts: 78
Likes: 0
Received 0 Likes
on
0 Posts
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,
Join Date: May 2013
Location: have I forgotten or am I lost?
Age: 71
Posts: 1,126
Likes: 0
Received 0 Likes
on
0 Posts
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.
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.
Join Date: Sep 2003
Location: Back too the hot bits again
Posts: 78
Likes: 0
Received 0 Likes
on
0 Posts
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
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
Join Date: May 2013
Location: have I forgotten or am I lost?
Age: 71
Posts: 1,126
Likes: 0
Received 0 Likes
on
0 Posts
ethel my little lightly built tube, wood and fabric homebuilt is 28 years old.
Wittman wasnt involved in Van's aircraft.
the reason why regular flying works is that it dries out the aircraft.
hangars do the rest.
tuesday night ethel. its a jackpot.
Wittman wasnt involved in Van's aircraft.
the reason why regular flying works is that it dries out the aircraft.
hangars do the rest.
tuesday night ethel. its a jackpot.
Join Date: Jun 2007
Location: NSW
Posts: 436
Likes: 0
Received 0 Likes
on
0 Posts
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
P.S my offer still stands
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
P.S my offer still stands
Join Date: Apr 2012
Location: Perth, WA
Posts: 326
Likes: 0
Received 0 Likes
on
0 Posts
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.
Join Date: May 2013
Location: have I forgotten or am I lost?
Age: 71
Posts: 1,126
Likes: 0
Received 0 Likes
on
0 Posts
P.S my offer still stands
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.
well one day I pulled off the oil sump and had a look into the engine with a 500,000 candlepower spotlight.
Join Date: Jun 2007
Location: NSW
Posts: 436
Likes: 0
Received 0 Likes
on
0 Posts
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.
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.
well one day I pulled off the oil sump and had a look into the engine with a 500,000 candlepower spotlight.
Join Date: Sep 2002
Location: Australia
Posts: 1,082
Likes: 0
Received 0 Likes
on
0 Posts
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.
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.
Join Date: May 2013
Location: have I forgotten or am I lost?
Age: 71
Posts: 1,126
Likes: 0
Received 0 Likes
on
0 Posts
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.
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.
Join Date: Dec 2004
Location: -28.1494 / 151.943
Age: 68
Posts: 463
Likes: 0
Received 0 Likes
on
0 Posts
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.
Join Date: Jun 2006
Location: Australia
Posts: 1,186
Likes: 0
Received 0 Likes
on
0 Posts
"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..
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..
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.
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’.
(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.
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.
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’.
(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.
Thread Starter
The dumb thing to do with that engine is remove the injectors for cleaning
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.
Gotta love those vac pumps!
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. (Of course, the ‘more maintenance more often means more safety’ crowd are plotting to get rid of it! )
[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.
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.
(Of course, the ‘more maintenance more often means more safety’ crowd are plotting to get rid of it! )
Thread Starter
Technically, that’s the job of the holder and issuer of the Type Certificate.