Should we follow everything on the Maintenance Schedule?

[gogogo888]

This is something that was not taught in school when I went through Private, Instrument and Commercial training. 

Maintenance Schedule is just a recommendation, it has no legal authority and is designed to make money for manufacturer by selling parts and also protect them from lawsuit. Inside the maintenance schedule, it may contain words like "Mandatory" or "If you dont do it, you will crash". <<<< None of these are true.

If it is really mandatory and you dont do it you will crash, it will show up as Service Bulletins or Safety Alerts. These are equivalent to Airworthiness Directive in certified aircraft, we are legally required to complied.(ex. 737 max)

Service Bulletins or Safety Alerts are the real mandatory requirements LSA have to follow.

They both can be found on Flight Design and Rotax website. You will need your Aircraft and Engine Serial number to find them.

https://flightdesign.com/service-documents

https://www.rotax-owner.com/en/support-topmenu/service-bulletins

 

The reason I bring this up is because mechanic induced accident are real. The more a mechanic do maintenance(surgery) in our plane, the more chances of them making mistakes.

FAA have documented Accidents caused by maintenance

https://www.faa.gov/about/initiatives/maintenance_hf/library/documents/media/media/accidents_caused.pdf

 

The most important maintenance we should do for our Rotax 912 engine is 50 hour oil change, 100 hour spark plug replacement, annual inspection and the 1000 hour gear box inspection(Kerry in Lockwood is the expert, he does nothing but gearboxes 40 hours a week) 

Other things on the Maintenance Schedule like the 200 hour Carburetor inspection(take it apart, look at it and put it back together) and the 2 year wings inspection, again take the wings apart, look at it and put it back together are just invasive and unnecessary.

 

The following article have more details on maintenance-induced accident.

https://blog.aopa.org/aopa/tag/maintenance-induced-failures/

 

Do you agree or do you think we need to follow exactly what is on the maintenance schedule?

[Mike Koerner]

Hell no, Gogo! You should never listen to those damn manufactures who are just trying to keep owners happy so they'll buy more of their aircraft... or their damn lawyers who are only interested in keeping your estate from having reason to sue.

You're right, you can wait for service bulletins or safety alerts from the manufactures. And you can absolutely depend on the government to protect you. Hell, I'm ripping my mask off right now.

And don't buy into that oil change nonsense. You know, years ago a guy drained his oil but forgot to add any new oil. His Rotax seized 47 seconds after startup. That's the problem with maintenance - mistakes. You don't need no oil changes. old oil works fine. 

You should make your own judgements on highly-technical matters like maintenance intervals.

Or hire mechanical, reliability, materials, and safety engineers to advise you if you don't have training in the necessary specialties. Of course, they're going to need a little time and money to conduct all the testing required to provide informed opinions.

Or you can just ask people on the internet. What could go wrong?

Mike Koerner

[gogogo888]

2 minutes ago, Mike Koerner said:

Hell no, Gogo! You should never listen to those damn manufactures who are just trying to keep owners happy so they'll buy more of their aircraft... or their damn lawyers who are only interested in keeping your estate from having reason to sue.

You're right, you can wait for service bulletins or safety alerts from the manufactures. And you can absolutely depend on the government to protect you. Hell, I'm ripping my mask off right now.

And don't buy into that oil change nonsense. You know, years ago a guy drained his oil but forgot to add any new oil. His Rotax seized 47 seconds after startup. That's the problem with maintenance - mistakes. You don't need no oil changes. old oil works fine. 

You should make your own judgements on highly-technical matters like maintenance intervals.

Or hire mechanical, reliability, materials, and safety engineers to advise you if you don't have training in the necessary specialties. Of course, they're going to need a little time and money to conduct all the testing required to provide informed opinions.

Or you can just ask people on the internet. What could go wrong?

Mike Koerner

I have cited multiple sources from credibly people. 
Do you have any sources you would like to share?

[Skunkworks85]

1 hour ago, Mike Koerner said:

 

Or hire mechanical, reliability, materials, and safety engineers to advise you if you don't have training in the necessary specialties. Of course, they're going to need a little time and money to conduct all the testing required to provide informed opinions.

Or you can just ask people on the internet. What could go wrong?

 

+1 Loved this

[Tom Baker]

3 hours ago, gogogo888 said:

This is something that was not taught in school when I went through Private, Instrument and Commercial training. 

Maintenance Schedule is just a recommendation, it has no legal authority and is designed to make money for manufacturer by selling parts and also protect them from lawsuit. Inside the maintenance schedule, it may contain words like "Mandatory" or "If you dont do it, you will crash". <<<< None of these are true.

If it is really mandatory and you dont do it you will crash, it will show up as Service Bulletins or Safety Alerts. These are equivalent to Airworthiness Directive in certified aircraft, we are legally required to complied.(ex. 737 max)

Service Bulletins or Safety Alerts are the real mandatory requirements LSA have to follow.

They both can be found on Flight Design and Rotax website. You will need your Aircraft and Engine Serial number to find them.

https://flightdesign.com/service-documents

https://www.rotax-owner.com/en/support-topmenu/service-bulletins

 

The reason I bring this up is because mechanic induced accident are real. The more a mechanic do maintenance(surgery) in our plane, the more chances of them making mistakes.

FAA have documented Accidents caused by maintenance

https://www.faa.gov/about/initiatives/maintenance_hf/library/documents/media/media/accidents_caused.pdf

 

The most important maintenance we should do for our Rotax 912 engine is 50 hour oil change, 100 hour spark plug replacement, annual inspection and the 1000 hour gear box inspection(Kerry in Lockwood is the expert, he does nothing but gearboxes 40 hours a week) 

Other things on the Maintenance Schedule like the 200 hour Carburetor inspection(take it apart, look at it and put it back together) and the 2 year wings inspection, again take the wings apart, look at it and put it back together are just invasive and unnecessary.

 

The following article have more details on maintenance-induced accident.

https://blog.aopa.org/aopa/tag/maintenance-induced-failures/

 

Do you agree or do you think we need to follow exactly what is on the maintenance schedule?

The maintenance schedule is based on the feed back given to the manufacture from aircraft being used in service, so I think they are in the best position to establish the maintenance schedule. Certainly they are in a better position than some internet expert who doesn't want to spend money on needed maintenance. When in service issues show up, the manual gets changed. Sometimes a SB also gets issued. The question of whether it needs to be followed exactly depends. I'm certain the manufacturer has times set on the conservative side, but are you willing to bet your life on how conservative their numbers are? From a legal stand point if you airplane is a SLSA you have to follow the aircraft manufacturers schedule as spelled out in their maintenance manual. 

Now I know maintenance induced failures happen, I recently addressed several maintenance induced items on a CT that could have had catastrophic consequences. That being said if you have a mechanic who takes things seriously, and tries to do things right the chances of having a maintenance induced failure is greatly reduced. Plus if you have someone who is knowledgeable about your specific airplane they will know the areas that need real attention. 

[gogogo888]

3 hours ago, Tom Baker said:

Certainly they are in a better position than some internet expert who doesn't want to spend money on needed maintenance. 

I completely agree that listening to some internet expert who doesnt want to spend money on maintenance is a really bad idea.

But if an IA and a CFI with 50+ years mechanic experience in addition to the FAA' National Aviation Maintenance Technician of the Year award said to us: following everything on the Maintenance Schedule is a bad idea, maybe we should take a second look.

-Things like oil change at 50 hours is a must!(Maintenance Schedule says to change it at 100 hour!) 

-Changing spark plug at 100 hours is also a must(Maintenance Schedule says to change it at 200 hour!) 

*Notice following everything on the Maintenance Schedule is a bad idea?

Taking the Carburetor apart every 200 hour just to look at it and put it back together and take the wings apart every 2 years just to look at it and put it back together does not seem like a good idea at all.

[Tom Baker]

7 hours ago, gogogo888 said:

Changing spark plug at 100 hours is also a must(Maintenance Schedule says to change it at 200 hour!) 

For the NGK sparkplugs I generally replace them any time they are removed. They are designed with a non replaceable one time use gasket.

 

7 hours ago, gogogo888 said:

Taking the Carburetor apart every 200 hour just to look at it and put it back together and take the wings apart every 2 years just to look at it and put it back together does not seem like a good idea at all.

Almost all of the carbs I have disassembled with anywhere close to 200 hours has black gooey junk on the inside where the parts need to be able to move. If you are running 100LL it can be worse because of the dye. Having had customers with rough  running engines because the carb was gummed up I think the 200 hour inspection is important.

 

7 hours ago, gogogo888 said:

But if an IA and a CFI with 50+ years mechanic experience in addition to the FAA' National Aviation Maintenance Technician of the Year award said to us: following everything on the Maintenance Schedule is a bad idea, maybe we should take a second look.

Just because they have an opinion and have voiced it loudly doesn't necessarily make it right, it is just an opinion. How much of that opinion is based on specific knowledge of the CT? I have almost 40 years as a mechanic, and 30 as an IA, plus 30 as a CFI. For the CT I have not seen anything on the inspection checklist that I felt should be ignored. That is based on my experience working on the specific airplane the past 13 years, and not a generalization based on all of the other airplanes I have worked on.

[gogogo888]

So, to properly maintain the aircraft we follow the maintenance manual and change oil at 100 hour and change spark plug at 200 hour? 

[Skunkworks85]

8 minutes ago, gogogo888 said:

So, to properly maintain the aircraft we follow the maintenance manual and change oil at 100 hour and change spark plug at 200 hour? 

If you burn more than 30% 100LL you need to shorten you oil change intervals. The current manual shows 50 hours, the 100 hour option is no longer listed. They do have a note showing shorter intervals for leaded fuel, but don't provide a specific number.

I change my oil at 25 hours, I run, on average, 60% 100LL due to my mission, ALOT of X-country, At my last annual, There was very little sludge in my tank, ( Tom Noted) And that was on 130 hours from last clean out. Engine in operated at higher than 5100rpm for 95% of the time.

Spark Plugs, 100 hours inspection requirement, And to Toms point, They gaskets are 1 time use. so you will need to replace the gaskets at the very least for that requirement, Most people will just put new plugs in.

[Madhatter]

Many owners are cheap.  An old mechanic once told me there should be a slot in the panel to correct all maintenance problems in real time. So when engines begin to fail in flight the more money you put in the slot the better the engine runs. So let's see how cheap they are now. You pay now or pay later☺

[gogogo888]

15 minutes ago, Madhatter said:

Many owners are cheap.  An old mechanic once told me there should be a slot in the panel to correct all maintenance problems in real time. So when engines begin to fail in flight the more money you put in the slot the better the engine runs. So let's see how cheap they are now. You pay now or pay later☺

The “pay now OR pay later” certainly make some sense. However, by looking at the maintenance record of my plane, they have spent tens of thousands of dollars following all the recommendation to maintain the plane. They still had an engine failure mid flight at 1500 hour Hobbs. Rotax did not compensate them even though they have binder full of maintenance record. In their case they “pay now AND pay later”

[gogogo888]

39 minutes ago, Skunkworks85 said:

If you burn more than 30% 100LL you need to shorten you oil change intervals. The current manual shows 50 hours, the 100 hour option is no longer listed. They do have a note showing shorter intervals for leaded fuel, but don't provide a specific number.

I change my oil at 25 hours, I run, on average, 60% 100LL due to my mission, ALOT of X-country, At my last annual, There was very little sludge in my tank, ( Tom Noted) And that was on 130 hours from last clean out. Engine in operated at higher than 5100rpm for 95% of the time.

Spark Plugs, 100 hours inspection requirement, And to Toms point, They gaskets are 1 time use. so you will need to replace the gaskets at the very least for that requirement, Most people will just put new plugs in.

 

 

The Jan 2020 Maintenance Schedule says to change oil at 100 hour if using auto gas and change oil at 50 hours if using 100LL more than 30% of the time.

Since doing proper maintenance means following the Maintenance Schedule and to avoid any lawsuit. Should we all change oil at 100 hour if we use auto gas?

[gogogo888]

2 hours ago, Tom Baker said:

Almost all of the carbs I have disassembled with anywhere close to 200 hours has black gooey junk on the inside where the parts need to be able to move. If you are running 100LL it can be worse because of the dye. Having had customers with rough  running engines because the carb was gummed up I think the 200 hour inspection is important.

So, that means if the engine is running smoothly, the 200 hour carb inspection can be skipped. If something is working well, no reason to take it apart to look at it and put it back in together.

 

[Skunkworks85]

36 minutes ago, gogogo888 said:

So, that means if the engine is running smoothly, the 200 hour carb inspection can be skipped. If something is working well, no reason to take it apart to look at it and put it back in together.

 

NO. It means that even if it is working well, Due to past problem history, there is a high likely hood of failure, It should be inspected/serviced to prevent you from death.

 

[gogogo888]

2 minutes ago, Skunkworks85 said:

NO. It means that even if it is working well, Due to past problem history, there is a high likely hood of failure, It should be inspected/serviced to prevent you from death.

 

Where are you getting the high likely hood of failure information from? Any links to show the past problem history?

 Any NTSB or official accident reports citing not inspecting or servicing the carbs was the cause of the accident?

[Tom Baker]

1 hour ago, gogogo888 said:

So, that means if the engine is running smoothly, the 200 hour carb inspection can be skipped. If something is working well, no reason to take it apart to look at it and put it back in together.

 

With the issues that I know about the engine ran fine right up to the point that it didn't, and in one instance it was a takeoff from a short grass strip climbing out over some tall trees. How do you decide how much longer you can run past the interval before it becomes a problem?

 

[gogogo888]

1 minute ago, Tom Baker said:

With the issues that I know about the engine ran fine right up to the point that it didn't, and in one instance it was a takeoff from a short grass strip climbing out over some tall trees. How do you decide how much longer you can run past the interval before it becomes a problem?

 

What is the maintenance history of that plane? How many year since last rubber change? How many hours since inspecting the carb?

[Tom Baker]

2 hours ago, gogogo888 said:

So, to properly maintain the aircraft we follow the maintenance manual and change oil at 100 hour and change spark plug at 200 hour? 

Think of the values in the maintenance schedule like VNE for you aircraft. You can operate anywhere from the minimum to the maximum, but the maximum should not be exceeded. Just like flying the airplane you don't have to VNE every time you fly, and for most they never will. With maintenance you don't have to go to the maximum time allowed in the schedule every time you perform maintenance, and most individuals don't. 

[Jim Meade]

I attended one of Mike Busch's weekend seminars in Rapid City, SD a dozen or so years ago.  I talked with him there and several times since, and I've followed many of his webinars and sat-in on several of his Oshkosh presentations, so to me, Mike Busch is not some unknown guy on the internet.  I've meet Tom Baker, the Gutmans, Adrain Foldan and Tom Peghiny, and Brian and Carol Carpenter and perhaps because of that have a pretty high confidence level in the competence of these people.  Other internet gurus not so much.  So, saying internet guru may be a question of perspective.

Mike Busch spends a considerable amount of his time explaining how engines work and how mechanics misunderstand that and develop ideas and shop practices that are not substantiated either by science or the regs, but rather by the mechanic's own preferences and comfort zone.

The lean-of-peak practices are one example of where engine manufacturers take a position that is not consistent with known, demonstrable facts.  Charles Lindbergh can teach how to get more range from a P-38 by LOP and be a hero, while George Braly can show how to get better engine performance and life using the same methods and be sneered at by Lycoming.

As Roger points out, liability seems to be a big issue with manufacturers and mechanics.  It is reasonable to assume that some positions taken by both have one eye on liability as well as one on airworthiness.   That can make the owner wonder if there is a conflict of interest on the part of the "expert".

As Busch points out, airlines and the military maintain airplanes based on a different set of premises than time.  Those institutions appear to use a philosophy based more on condition.  It is strange that what is the rule for airlines and the military is frowned on in general aviation.

Rotax has a rotten reputation for standing behind warranty and for the ways they distance themselves from US courts and legal remedies.  Maybe now that the Chinese are building a copy-cat engine Rotax will have to face competition for the first time and may be less rigid in their policies.

AMST and the FAA have different approaches to maintenance.  Tom Baker will correct me if I'm wrong, but my understanding is an oil hose on a Taylorcraft can be inspected on condition while the identical hose on a Rotax sold on a European LSA is maintained on a time line.

Bottom line - the main reason my airplanes are all ELSA is that I can legally, and I believe competently, maintain them with considerable more flexibility than if they were SLSA.

 

 

 

[Tom Baker]

28 minutes ago, gogogo888 said:

What is the maintenance history of that plane? How many year since last rubber change? How many hours since inspecting the carb?

It had less than 200 hours since new, and if I remember correctly it was before the first hose change. It was several years ago the customer passed in 2013. I think the blue dye from 100LL exaggerated the issue. That being said almost all of the Bing carbs I disassemble have the black gooey junk in them, it is just not to the point of causing issues. The carbs on the Rotax are considerably different than your traditional aircraft carburetor that can go years without any issues. 

[Tom Baker]

I should add that a wise mechanic once told me the cheapest part of an airplane is the pilot.

[gogogo888]

3 hours ago, gogogo888 said:

The “pay now OR pay later” certainly make some sense. However, by looking at the maintenance record of my plane, they have spent tens of thousands of dollars following all the recommendation to maintain the plane. They still had an engine failure mid flight at 1500 hour Hobbs. Rotax did not compensate them even though they have binder full of maintenance record. In their case they “pay now AND pay later”

Nothing cheap about going above and beyond to follow all the TBO and maintenance schedule and STILL have a midflight engine failure. One would think is this cause by maintenance induced failure? 

[AGLyme]

4 hours ago, Roger Lee said:

If you choose not to do something and something happens the FAA may tag you, the insurance company won't pay because they say you contributed to your own problem and you're liable in court

Yup, throw away your logic and go with what Roger said... keep in mind, in plane accidents, everyone wants to blame the pilot... the airframe manufacturer, engine manufacturer, avionics... blah... the Government, the airport authority, the ATC people,  the passengers, the Geese,  everyone... the last thing you need is someone pouring over your documents in a aha moment... 

If this stuff truly drives you nuts, there is always hang gliding and RC... 

[Tom Baker]

1 hour ago, gogogo888 said:

Nothing cheap about going above and beyond to follow all the TBO and maintenance schedule and STILL have a midflight engine failure. One would think is this cause by maintenance induced failure? 

Not a maintenance induce failure! What was the serial number of the failed engine?

[gogogo888]

1 hour ago, Tom Baker said:

Not a maintenance induce failure! What was the serial number of the failed engine?

S/N of failed engine is 5647326