Should we follow everything on the Maintenance Schedule?

[FlyingMonkey]

1 hour ago, Tom Baker said:

On sparkplugs why not run them for 400 hours, because that is what the checklist calls for? I suspect that number is for the new Rotax plugs, and not the NGK plugs.

I'm like you, if a plug comes out it gets replaced, and I replace them all every annual.

[sandpiper]

15 minutes ago, FlyingMonkey said:

I'm like you, if a plug comes out it gets replaced, and I replace them all every annual.

Same here. Plugs are cheap.

[Roger Lee]

" If you only fly 20 hours in a year you still have to change the oil."

Tom is correct and like he said even with 20 hrs. Rotax wants that oil changed at annual and that's what they say. If you have an SLSA you do always have a say in what happens and any mechanic that would sign something off that isn't in the book hangs his butt out on a limb with liability. Even with an ELSA you better read all the fine print. Sometimes the DAR's language may be even more strict.

I would go take all three Rotax classes. It gives people lots of things that Rotax wants and why even that they don't align with the manuals at times. I've been doing Rotax for more than 20 years and watched a lot of people cost themselves lots of money of shave hundreds of hours off their engines. 3 liters of oil & a filter is always cheaper than $18.K plus labor for a new engine. Same with plugs and other "BEST PRACTICE"  maint.

Key takeaway is BEST PRACTICES that have been learned since 1990 , 5.5K engines and almost 6 million run hours. People with little Rotax experience, Thinking their smarter than Rotax,  never read ALL the manuals through,  no Rotax class time and not seeing hundreds of others successes and failures doesn't usually go well at some point. 

The best practices is good for all endeavours in life and our jobs because even though you might be able to do something or something was done a certain way in the past doesn't mean there aren't better ways that have been learned through the decades from hard research and experience.

 

I'd rather strive to be a cut above average any day than admit and demonstrate I did less. Just because some make a video doesn't make them all knowing or even right. Some ideas are old and archaic. 

[Jim Meade]

This discussion has been going on since this site and it's predecessors have existed and will continue after we're gone.  Here are a few of the main themes.  You may add more.  Some of it is true of other enterprises in life as well.

1.  Mechanics and companies are worried about liability and everything they say has that as a factor.  CYA.  Owners know that mechanics have this bias.

2.  Mechanics do not trust owners to understand or apply maintaining on condition - mechanics  confuse it with the operator waiting for something to break and then fix it.   Because mechanics have seen some poor owner maintenance they fear all of it will be so.

3.  Mechanics develop a body of experience and based on that establish a perspective that informs their opinion in their field.  When you walk in, they put you in a mold.

4.  Owners resent being forced by some arbitrary condition such as time to spend good money to replace a good part.  Owners feel ripped off and taken advantage of.

5  Mechanics say you need a guru or school.   Rotax manuals are not current or sufficient.  Owners ask how is it that the manual is insufficient?  There are excellent tutorials online these days.

6.  Rotax knows best.  So does Boeing, General Motors, Corvair, Firestone, Dodge Caravan and on and on.  Knowing best and admitting it and being willing to do anything about it are two different things.

7.  Mechanics who worked on standard certificated airplanes developed a reputation for insisting on maintenance that has proven to not be required.  ELSA is attractive because one does not feel at the mercy of some mechanic saying, "because I said so" .

You probably identified other themes in this discussion, equally or more valid.

This issue will never be resolved because it is not in the interest of the parties involved to settle it.  It starts because everyone brings their own perspective to the problem.  By perspective I mean bias, and I do not mean bias in a negative way.  I mean, simply, what you see depends on where you stand.

Oh, I'm an ELSA guy.  I've been to the three Rotax classes and they provided good practice on things I could already do, like pull a piston or torque a bolt.  Not one time was I told anything that was not in the manual.  Not once.  I have two good friends with ELSA who have a lot mechanical background and they are excellent Rotax mechanics at the Line level just by using the manual and asking individual  questions of mechanics they respect.

 

 

 

 

[Roger Lee]

" Mechanics and companies are worried about liability and everything they say has that as a factor."

So should the owner. They are liable for any injuries or damage on top of the mechanic.

[gogogo888]

Lets sum up the discussion in a few sentences here.

Me: "Rotax doesnt tell me what to do, I do whatever I want"

Others: " You need to follow what Rotax says"

Me: "Roger that! I will follow what Rotax tells me"

Others: "What are you doing following Rotax? They will kill your engine and you will be liable for all the death and destruction you caused!"

Me :

[Jim Meade]

3 hours ago, Roger Lee said:

" Mechanics and companies are worried about liability and everything they say has that as a factor."

So should the owner. They are liable for any injuries or damage on top of the mechanic.

I agree 100%.  It is incumbent on an owner-mechanic to accept responsibility for maintenance.

[Tom Baker]

 

Gogo, after looking at your sig, you will probably be okay with 100 hour oil changes. More important than time is operating conditions and the overall condition of the oil. Keep an eye on the color of the oil. As long as it stays a nice amber color it will be okay. If it starts to get darker in color, smells burnt, or oil consumption goes up I would personally change it if it were mine. These are indicators of more severe operating conditions. 

Rotax even says this about oil changes, "In case of severe operating conditions (operation in cold/hot weather areas, interference by and and/or salt), the time between maintenance intervals must generally be shorter, and in particular, the frequency of oil changes must be increased regardless of the type of fuel mainly used (MOGAS or AVGAS).".

 

 

[gogogo888]

4 minutes ago, Tom Baker said:

Keep an eye on the color of the oil. As long as it stays a nice amber color it will be okay. If it starts to get darker in color, smells burnt, or oil consumption goes up

Great tips! I will keep an eye out for the color, smells and oil consumption.

[Tom Baker]

I am just curious in all your research about maintenance induced failures, how many were due to properly performed maintenance?

 

 

 

[gogogo888]

57 minutes ago, Tom Baker said:

I am just curious in all your research about maintenance induced failures, how many were due to properly performed maintenance?

 

 

 

A lot of the maintenance induced failures happen when the mechanic is distracted(calls, texts, notifications).

Forgetting anything small when doing surgery to the engine isnt good for any pilot.

In airline environment, they have 2 sets of mechanic eyes to do the work and an additional set of eye to inspect the work. Even in this environment, sometimes they forget things.

In GA environment, we only have 1 set of mechanic eye to count on, I'm depending my life on that 1 set of eye.

Everyone get lots and lots of distractions now a day, every maintenance event is a surgery event, can we really trust anyone not forgetting anything nor get distracted every single time? Do you want to bet your life on that 1 set of eye to do more surgery than needed?

 

[Tom Baker]

 

17 minutes ago, gogogo888 said:

A lot of the maintenance induced failures happen when the mechanic is distracted(calls, texts, notifications).

That is one reason my cell phone lays on the counter when I'm working in the shop. I do have the land line to deal with, but if I am in the middle of something I will let it forward to my cell and then answer when I'm finished with wat I'm doing.

19 minutes ago, gogogo888 said:

Forgetting anything small when doing surgery to the engine isnt good for any pilot.

Humans make mistakes, and they are good for no one involved. I'm not going to claim that I have never made one. In my career working on airplanes I would like to think I have fixed far more issues than I have created. I certainly have found my share of maintenance induced errors, but I have also found my share of issues that were not maintenance based failures. The thing is I wouldn't have found them if I wasn't performing maintenance. Some of those errors and issues could have led to catastrophic failures.

As a mechanic I see the chance of a possible maintenance induced failure being out weighed by the positive benefits of the maintenance being performed. This is based on my almost 40 years working as a aircraft mechanic. That being said, I can see that from a new pilot/owners perspective how you would be concerned. Only time and personal experience will tell you where you need to be on the issue. 

[FlyingMonkey]

21 hours ago, Jim Meade said:

This discussion has been going on since this site and it's predecessors have existed and will continue after we're gone.  Here are a few of the main themes.  You may add more.  Some of it is true of other enterprises in life as well.

1.  Mechanics and companies are worried about liability and everything they say has that as a factor.  CYA.  Owners know that mechanics have this bias.

2.  Mechanics do not trust owners to understand or apply maintaining on condition - mechanics  confuse it with the operator waiting for something to break and then fix it.   Because mechanics have seen some poor owner maintenance they fear all of it will be so.

3.  Mechanics develop a body of experience and based on that establish a perspective that informs their opinion in their field.  When you walk in, they put you in a mold.

4.  Owners resent being forced by some arbitrary condition such as time to spend good money to replace a good part.  Owners feel ripped off and taken advantage of.

5  Mechanics say you need a guru or school.   Rotax manuals are not current or sufficient.  Owners ask how is it that the manual is insufficient?  There are excellent tutorials online these days.

6.  Rotax knows best.  So does Boeing, General Motors, Corvair, Firestone, Dodge Caravan and on and on.  Knowing best and admitting it and being willing to do anything about it are two different things.

7.  Mechanics who worked on standard certificated airplanes developed a reputation for insisting on maintenance that has proven to not be required.  ELSA is attractive because one does not feel at the mercy of some mechanic saying, "because I said so" .

You probably identified other themes in this discussion, equally or more valid.

This issue will never be resolved because it is not in the interest of the parties involved to settle it.  It starts because everyone brings their own perspective to the problem.  By perspective I mean bias, and I do not mean bias in a negative way.  I mean, simply, what you see depends on where you stand.

Oh, I'm an ELSA guy.  I've been to the three Rotax classes and they provided good practice on things I could already do, like pull a piston or torque a bolt.  Not one time was I told anything that was not in the manual.  Not once.  I have two good friends with ELSA who have a lot mechanical background and they are excellent Rotax mechanics at the Line level just by using the manual and asking individual  questions of mechanics they respect.

 

 

 

 

That about sums it up.  I'm in the same boat as you, but having not been to the Rotax classes I'm not going to do anything to the engine other than superficial items like plugs and oil.  If it needs a cylinder replaced or other major maintenance I'll either gather the knowledge I need to do it myself competently, or take it to an expert.

[FlyingMonkey]

20 hours ago, Roger Lee said:

" Mechanics and companies are worried about liability and everything they say has that as a factor."

So should the owner. They are liable for any injuries or damage on top of the mechanic.

That's true, but the liability on the owner is really limited to passenger injury.  I suppose also ground damage, but that's usually not a factor huge for a crashing LSA, especially one under control at impact like in an engine out.  Anything else is just a potential out-of-pocket expense to the owner.  A mechanic or manufacturer's liability extends to the airframe, pilot, passengers, and ground damage.

I'm not discounting liability on the owner, just pointing out it's  bit more limited.

 

[FlyingMonkey]

Regarding oil changes, I view them like plugs:  oil and filters are pretty cheap, especially compared to certified airplanes.  100 hours on mogas is probably fine, but at 50hrs my oil is a much deeper brown than at 0hrs where it's almost clear.  That color shift is contaminants suspended in the oil, I'd like to get that stuff out of the engine sooner rather than later.

My goal is to have my engine last 2x the TBO interval.  I know that is possible with the Rotax 912 engine, and that will probably get me close to the end of my flying career.  If I'm still flying at 3000-4000hrs on my 912, I'll happily spring for a new engine knowing I got well beyond my money's worth.

[gogogo888]

3 hours ago, FlyingMonkey said:

My goal is to have my engine last 2x the TBO interval

Are there any prove that changing oil every 50 hours can 2x the TBO?

Or the Rotax engine is already bullet proof and designed for 4000 hour TBO with the 100 hour oil change interval, but Rotax recommend 2000 hour TBO, just like the 5 year rubber change recommendation, they are designed to last 10 years.

But again, if it makes you more comfortable about your engine lasting longer by changing oil at 50 hours(auto gas) do it. Just understand that all it does is to make you feel better

GlennM said it best.

On 10/21/2020 at 6:02 PM, GlennM said:

For years, everyone said you had to change your oil at 3k miles.

It certainly make you feel better about having new oil in your car every 3k miles. But thats all it does, making your feel better.

[sandpiper]

45 minutes ago, gogogo888 said:

 

Or the Rotax engine is already bullet proof and designed for 4000 hour TBO with the 100 hour oil change interval, but Rotax recommend 2000 hour TBO, just like the 5 year rubber change recommendation, they are designed to last 10 years.

 

 

Somewhere on this forum I recently posted that I did not replace the fuel hoses at 5 years (I had a good reason) and that I lost engine power on my last flight before doing the 10 year change.

The cause was debris in the carb float bowels which I believed to be hose particles. 

So, it appears you are correct about being designed to last 10 years. At least in my case.

But, I do not advocate a 10 year hose change because that took my hoses to failure - while I was in the air. Not smart. 

When exceeding Rotax limits you become a test pilot. Or, is there a reliable way to extend fuel hose life "on condition" that I don't know about. When I changed them at 10 years they certainly looked OK, but they weren't. So, how is that going to play with the FAA, not to mention personal liability, when you have a accident in your S-LSA related to hose failure? Heck, your accident may not even be related to overdue or skipped maintenance items but, especially if you injure or kill someone, you can bet the FAA and/or the NTSB will mention your lack of following established maintenance procedures in the accident report. And that will be used by the deceased partys legal action against you as they paint you as being a nonresponsibe pilot.

Having said this, I have no intention of replacing my perfectly good engine at 12 years. I think there are proven ways to exceed that limit "on condition" which is what I'll do even if I have to go E-LSA.

OK. That clunk you just heard is me falling off my soapbox. 

 

 

[FlyingMonkey]

1 hour ago, gogogo888 said:

Are there any prove that changing oil every 50 hours can 2x the TBO?

Or the Rotax engine is already bullet proof and designed for 4000 hour TBO with the 100 hour oil change interval, but Rotax recommend 2000 hour TBO, just like the 5 year rubber change recommendation, they are designed to last 10 years.

But again, if it makes you more comfortable about your engine lasting longer by changing oil at 50 hours(auto gas) do it. Just understand that all it does is to make you feel better

GlennM said it best.

It certainly make you feel better about having new oil in your car every 3k miles. But thats all it does, making your feel better.

Nope.  But simple physics leads me to bet it's better on the engine wear profile than changing oil every 500hrs.  And by extension, every 200hrs...or 100hrs.

My airplane is not my car.  It's a largely aircooled system (except the heads on a Rotax) where oil is crucial to cooling, not just lubrication.  This is not true in a water cooled auto engine.  Also an auto engine lives its life 80% of the time at less than 50% of max RPM; your Rotax lives 80% of it's life at 70-90% max RPM.  They are not the same.  Drawing complex maintenance conclusions about aircraft engines from car engines is folly.

[gogogo888]

4 minutes ago, FlyingMonkey said:

Nope.  But simple physics leads me to bet it's better on the engine wear profile than changing oil every 500hrs.  And by extension, every 200hrs...or 100hrs.

Since "Drawing complex maintenance conclusions about aircraft engines from car engines is folly. "

If Rotax's official data tells you to change oil at 100 hrs interval, will you believe them?

[FlyingMonkey]

22 minutes ago, gogogo888 said:

Since "Drawing complex maintenance conclusions about aircraft engines from car engines is folly. "

If Rotax's official data tells you to change oil at 100 hrs interval, will you believe them?

Sure, that interval is sufficient, if your goal is the engine lasting to TBO, which is all Rotax cares about.  I want my $19k engine to go much longer than that, as stated.  

Doing the  minimum is generally just that...the minimum.  If you want results beyond "minimum acceptable", sometimes you have to plan for that.  Engine longevity is not entirely luck. 

[gogogo888]

43 minutes ago, FlyingMonkey said:

Sure, that interval is sufficient, if your goal is the engine lasting to TBO, which is all Rotax cares about.  I want my $19k engine to go much longer than that, as stated.  

Doing the  minimum is generally just that...the minimum.  If you want results beyond "minimum acceptable", sometimes you have to plan for that.  Engine longevity is not entirely luck. 

We all want our $19k engine to go much longer. We all want to feel good about it, I agree, doing the minimum is just minimum.

Rotax says to change rubber at 5 years, why not change them out at 2.5 years? Rotax says to inspect carbs every 200 hours, why not inspect them every 100 hours?

While the cowling is open, why not also inspect the gears every 500 hour and do an annual inspection every 6 months?

"You can pay now or pay later"

P.S. I'm just trolling because weather has been bad and I cannot fly, nothing personal

[Jim Meade]

Changing rubber is probably partly based on the shelf life of rubber as a material, which beings at the cure date of manufacture.  I've heard 10 years is the shelf life of rubber but don't have a reference to cite.

What kind of condition inspection would one make on a rubber hose in a Rotax engine environment?   The first issue is the fire sleeve which block easy visual inspection.  If there are no visible leaks or other signs of problems after five years, I'd think one should disconnect one end of the hose and flex it to see if it is hard or brittle or still flexible.  I'd think one should remove the fire-sleeve so one can inspect the hose to make sure the hose is not distended, worn, kinked, twisted, misshapen or otherwise not in a normal condition.  Most are not likely to be eager to disconnect the hose and remove the fire sleeve, but how else does one perform a condition inspection if one can't visually inspect the outside of the hose for it's condition?

[gogogo888]

17 minutes ago, Jim Meade said:

Most are not likely to be eager to disconnect the hose and remove the fire sleeve, but how else does one perform a condition inspection if one can't visually inspect the outside of the hose for it's condition?

I have heard Prof Shuch says "you might as well replace the hose if you disconnect them to inspect them". Other people might have other ideas.

Kind of like cheaper to replacing the spark plugs at 100 hour when we remove them rather than cleaning them.

[GrassStripFlyBoy]

As pointed as this trail has been at times, I can honestly share I've enjoyed the dialog, and what is largely restraint and keeping the debate on topic and not becoming nasty.  I see both perspectives.  Considering we're talking about $60k - $180k machines here we've invested in, with fixed costs perhaps running $5k per year, and variable costs on top of that, I view money on maintenance as an almost non-event.  Point being some of my recent posts, tire and battery replacements, could I have milked them further, sure thing, but why - grand scheme these are nothing.  So, the point about on condition and pushing oil changes, not for me, and guess who will be placing qty 8 plugs on next order just because.  My take here is if money is a factor in what maintenance is being performed, or rather not performed, that's both sad and shortsighted.

On topic of maintenance induced failure.  Sure, there is risk in everything around the game we choose to participate in.  I'll take the risk of actively "doing something" as the fleet history, manufacture, and insightful mechanics guide us, compared to "not doing something" because it's fine today and/or just maybe doing the act will lead to some unintentional bad outcome?  The wording Preventative Maintenance is really a misnomer in aviation, a vast majority of what we do is based on Predictive Maintenance, being that a studied / known / proven time in service statistically established a safe line in the sand based from point of failures.  This is why aviation enjoys the safety record we do, is the line perhaps too safe, probably - but that's by design.  Can you push over the line, yes.  For how long, we'll that starts the guessing game.

Around all the chatter of what the manual says, verse what people do, I'll follow BEST PRACTICES every day.  Don't care if that's the Rotax Line Manual, FD Manual, the forum, or otherwise.  Add up both the FD manual and the Rotex manual, that's a lot of pages, to say it's always black and white I'll quote a fella I saw on TV last night - "C'mon Man!"  Take something as simple as tire pressure.  Sure I could set it exactly at the PSI manual states, but history tells us a bit more pressure is wise, or rather low tire pressure is really bad.  And logic tells me that tires loose pressure over time, and I don't feel like topping them off every other week, so hey - keep them on the safe side.  That's one small example of a much more complex list.

 

[gogogo888]

44 minutes ago, GrassStripFlyBoy said:

"C'mon Man!" 

I will change my oil at 50 hours now

Borat might come to my defense soon