The Infernal 912 ULS Overhaul Question

[Danno]

Is the owner of a 2006 912 ULS at 1500 hrs or 12 years (whichever comes first) in a S-LSA required to overhaul their engine if either parameter is exceeded? As I understand it, only legacy piston engines in aircraft operated under Part 23 are eligible for overhaul on condition decisions, and Light Sport owners have to go with the aircraft manufacturer's overhaul requirements (even though Rotax publishes their own requirements in its SBs), which seems contradictory. I also understanding there have been some varying FAA opinions issued on this topic depending on the FSDO that issued them, so I thought it would be worth revisiting. Is there a nationally-applicable FAA legal opinion or other nationally controlling FAA interpretative document answering this infernal question?  The engine is running fine, but I've read that the intent is there are some internal parts that wear out and need to be replaced even to extend the TBO to 15 years or 2000 hours.  So it would appear that the owner of a 2006 Rotax 912 ULS (in a S-LSA) with 600 hours would be required to overhaul it because it has exceeded the number of allowable years?  Thank you!

[Anticept]

The issue is this:

Your airworthiness certificate says you must follow all manufacturer operating, inspection, and maintenance procedures.

However, a procedure is a process for performing maintenance, and inspections are for assessing the condition of an aircraft using data which guides the process. A mechanic can't just say its un-airworthy because of a life limit unless that life limit is in a legally enforceable place. Finally, operating an aircraft is a PILOT issue, not a maintenance one, so only the instructions for operating an aircraft apply here; time limits are not an operating instruction.

The FAA is having issues with this because their original intent was to actually have everyone follow all of these instructions, but someone raised a stink a couple years after the light sport rule came out, pointing out that the FAA has no delegation authority. The FAA can't give a blank check to manufacturers like that. Congress never gave the FAA delegation authority.

Since the FAA approved the ASTM standards, and wrote the regulations around "approved standards", the only thing that can be enforced are ASTM compliant instructions and procedures.

The ASTM standards, at least for older models, do not mandate time limits, and later revisions cannot be made retroactive. Specific things can be made mandatory through safety directives, however, including engine overhauls.

Unfortunately, the person who was superbly knowledgeable on this has retired a few years back (Edsel Ford) and with the old light sport regulatory support division now defunct and its functions barely picked up by other divisions, there's no one to set this straight now, and its a very low priority for the chief council to sort this out (they have repeatedly contradicted themselves too).

So the safe answer, is overhaul it. The realistic answer is nobody is going to bother you until you are in court and then it will finally be put to the test. You have to decide the risk.

 

 

[Batjac]

An incidental anecdote.  A local club bought a Tecnam that is close to time limited.  They contacted one FAA official, and got "Replace it".  Another FAA official said, "Naw, you don't have to replace it."  So they contacted another FAA office and asked which one of the letters they had to follow.  The answer from the third was, "We're not gonna rule on this."  So the club has money set aside for a new 912, but they're not going to replace the current one unless someone from the FAA comes down and says they're gonna get in trouble, or the engine has problems.

[GlennM]

I ended up replacing my original engine at just under 1000 hours and 15 years. I sold the engine to a homebuilder, so a new engine was cheaper than an overhaul in this case.

[Roger Lee]

I’ve already talked to FAA legal and explained how misunderstood this is and they agreed their own people are mixed up. I’m in the process of writing this up and sending it to FAA legal at their request so they will come out with a definitive answer. Plus I’m asking that this come out quickly and not take a year, be short, direct and not be wishy washy in the explanation.

[Jim Meade]

Roger,

I assume when you draft your letter to FAA legal, you'll post it online before you send it in so we can review it and offer any suggestions we may have?  How far along are you in your letter?  

[Jim Meade]

Batjac, where can we see copies of the two letters you mention?  I'd like to see what the letters cite for authority.

[Madhatter]

I don't see how the FAA can mandate overhaul at calendar or time limits. For certified part 91 it is on condition and has been this way forever. Also foreign entities can not mandate US law with the FAA. I think there would be a huge legal issue with this. Of all the aircraft engines out there Rotax is the best engine for "on condition", aluminum cylinders, sealed case, minimal or no lead contamination. Far less corrosion issues unlike Continental or Lycoming.

[Towner]

If we have to replace engines at hour, or especially calendar limits, it kinda throws the affordability for LSA out the window.

[Batjac]

4 hours ago, Jim Meade said:

Batjac, where can we see copies of the two letters you mention?  I'd like to see what the letters cite for authority.

I do not have access to these letters.  This is what I have been told by the club president.

[Tom Baker]

4 hours ago, Jim Meade said:

Batjac, where can we see copies of the two letters you mention?  I'd like to see what the letters cite for authority.

I don't have time to look them up, but both have been posted here before.

[Jim Meade]

Thanks, Tom, I'll search.

[shiny.ice]

Previously:

https://www.ctflier.com/topic/6118-mandatory-tbo/

 

[Mike Koerner]

I don't know why any CT owner would pursue this question further with the FAA, or want it pursued further.

Dispite the ambiguity in FAA interpretation (as well as in light of it) current regulations allow us to address the TBO issue however we want.

No new interpretation can improve on that current situation.

Let the sleeping dog lie.

[Eddie Cesnalis]

8 hours ago, Mike Koerner said:

No new interpretation can improve on that current situation.

Let the sleeping dog lie.

Wisdom

[Tom Baker]

9 hours ago, Mike Koerner said:

I don't know why any CT owner would pursue this question further with the FAA, or want it pursued further.

Dispite the ambiguity in FAA interpretation (as well as in light of it) current regulations allow us to address the TBO issue however we want.

No new interpretation can improve on that current situation.

Let the sleeping dog lie.

Do the current regulations allow us to address the TBO issue however we want? If you are maintaining a SLSA, you better be well versed in what the regulations say to be able to prove it. It is not the same for all airplanes, and even not the same for some airplanes of the same make and model depending on when they were built. Even if you think it is not required for your airplane you will have people who disagree. 

As a general rule I agree with the don't ask because you might not get the answer you want attitude, but this has already moved past that point. You have mechanics receiving Rotax training who are being told that overhaul is mandatory, and you are at risk by maintaining one past TBO. Airtime Aviation has told me that an airplane was illegal because the engine was more than 15 years old, and stated that Flight Design Germany says to follow TBO. There are a number of people converting their airplanes to ELSA because of the TBO issue. All of this because of one of the competing FAA legal interpretations. 

[sandpiper]

On 7/4/2024 at 9:34 PM, Mike Koerner said:

I don't know why any CT owner would pursue this question further with the FAA, or want it pursued further.

Dispite the ambiguity in FAA interpretation (as well as in light of it) current regulations allow us to address the TBO issue however we want.

No new interpretation can improve on that current situation.

Let the sleeping dog lie.

Agreed. Don't ask a question to which you may not like the answer!

[Anticept]

This is not a question you want to ignore.

Read your insurance policies. It's valid if the aircraft is airworthy (bit more mealy mouthed than that but that's what it says) .

If there is an engine failure and get a book thrown at you and it is upheld that the regulations *do* require TBO, the insurance company has a hell of a basis to deny your claim.

This was a discussion I had with Candy Eichenberger @ Avinsure about TBO, who emailed our underwriter at the time, Phoenix Aviation Managers (now Old Republic Aerospace), who came back saying they will follow the FAA's lead. Note this was a commercial policy for rental and instruction. This was in 2013.

I replaced my engine at TBO because it wasn't worth the risk.

[Madhatter]

Commercial operations always follow recommended TBO guidelines by law in certified.  I assume this would apply to LSA as well. 

[Roger Lee]

When I did a research project on this when the FAA was working on this subject the FAA said the insurance companies would follow what the FAA said.

[Tom Baker]

14 minutes ago, Madhatter said:

Commercial operations always follow recommended TBO guidelines by law in certified.  I assume this would apply to LSA as well. 

I guess it depends on the definition of commercial operations. It is only when your operations go beyond part 91 that TBO becomes regulated. A flight school doing only instruction and rental is not required to follow TBO, at least per my understanding of the regulations. That being said I would hate to be sitting in the witness chair trying to defend not following TBO on a rental airplane.

[Tom Baker]

2 hours ago, Anticept said:

I replaced my engine at TBO because it wasn't worth the risk.

It is a fairly accepted standard practice to overhaul or replace engines base on hours of operation per TBO guidelines. Doing overhauls based on calendar years is a much less followed practice. I have a hard time imagining any of the structural parts of an engine failing based on calendar years of operation. Sure seals and sealants can break down, but I think they would have to be grossly overlooked before you would have a catastrophic failure. 

[Anticept]

1 hour ago, Madhatter said:

Commercial operations always follow recommended TBO guidelines by law in certified.  I assume this would apply to LSA as well. 

Does not apply to rental and instruction. 

AC 120-113 section 6 lays out when TBO is required for what operations, and cites the relevant CFRs. It has guidance for extending TBO under these limitations too. None of which are flight instructing under part 91. Part 141 could be required if it is in their opspecs.

https://www.faa.gov/documentLibrary/media/Advisory_Circular/AC_120-113.pdf

 

[Anticept]

47 minutes ago, Tom Baker said:

It is a fairly accepted standard practice to overhaul or replace engines base on hours of operation per TBO guidelines. Doing overhauls based on calendar years is a much less followed practice. I have a hard time imagining any of the structural parts of an engine failing based on calendar years of operation. Sure seals and sealants can break down, but I think they would have to be grossly overlooked before you would have a catastrophic failure. 

Wholeheartedly agree, and courts have held insurance companies against blanket exclusion clauses before. Generally, courts don't take too kindly on claim denials period if the basis for denying a claim was not the reason for the loss (ex: aircraft ran off the runway and the insurance company denies because a radio AD wasn't complied with).

It's still an uphill battle though, and Rotax will be real quick to pull out all the stops to pass blame to maintenance because otherwise they're the ones on the chopping block.

[Madhatter]

The FAR's are written for the lawyers. This coming from Bill O'brien who wrote the FAR's for the FAA at the time. Most lawyers are a scourge to our country in my opinion, it's all about money and nothing else.