What is the overhaul cost of a turboprop engine on an older KA or TBM? If you only fly part 91, can I just do a hot section and keep flying?

Overhaul cost on a small case Pratt found on legacy 90’s and 200’s is typically $300k - $450k per side.

The TBM’s have a large Pratt and overhaul cost can be $500k to $850k, depends on the vintage and components that must be replaced.

It is widely accepted now to operate Part 91 on condition doing hot section inspections and all other required engine maintenance. I would strongly recommend Trend monitoring, and making sure the 400 hour borescopes are thorough.

The FAA did put in writing that overhauls were not mandatory, but the letter had an expiration date!

Note: we have a lot of history of small Pratts ran to 8000 hours via the MORE STC, no such data on the large Pratts. I can tell you from observing multiple hot sections and overhauls, the large Pratts don’t seem to hold up as well. When operating past TBO, expect to see a much greater impact on the resale value of a TBM than what you would experience on a legacy King Air.

Only because the temporary order gave guidance that wasn't in order 8900.1 yet. Order 89001.1 is the FSDO bible on what standards are.

Once order 8900.1 got updated with the same language as the temporary order, the temporary order no longer mattered.

Your statement is therefore misleading, there is no timeout on the "fly past TBO" FAA guidance. Don't spread FUD.

References:

The temporary order:

https://www.faa.gov/documentlibrary/med ... 00.410.pdf

Note this at the end:

"We will incorporate the information in this notice into FAA Order 8900.1 before this notice expires."

The language in order 8900.1 is consistent with the now canceled temporary order.

Mike C.

Only because the temporary order gave guidance that wasn't in order 8900.1 yet. Order 89001.1 is the FSDO bible on what standards are.

Once order 8900.1 got updated with the same language as the temporary order, the temporary order no longer mattered.

Your statement is therefore misleading, there is no timeout on the "fly past TBO" FAA guidance. Don't spread FUD.

References:

The temporary order:

https://www.faa.gov/documentlibrary/med ... 00.410.pdf

Note this at the end:

"We will incorporate the information in this notice into FAA Order 8900.1 before this notice expires."

The language in order 8900.1 is consistent with the now canceled temporary order.

Mike C.

So what's the bottom line for Part 91 operators? Are the overhauls mandatory at the specified PWC time or is it still optional?

Small details have big implications, so don't be sloppy and assume there was a timeout on the guidance.


Because the newly disorganized FAA website has now is hard to navigate and the guidance is spread over many sections.

If I could quote it neatly, I would do so. 8900.1 is a huge order, well over 1000 pages.

Mike C.

Optional.

Inspections (checking for airworthy condition) are mandatory, overhauls (adding new life) are not, for part 91.

Even if an overhaul is specified in an inspection program, it is not mandatory, unless it was included in an inspection program approved under 91.409(f)(4).

Mike C.

Small details have big implications, so don't be sloppy and assume there was a timeout on the guidance.


Because the newly disorganized FAA website has now is hard to navigate and the guidance is spread over many sections.

If I could quote it neatly, I would do so. 8900.1 is a huge order, well over 1000 pages.

Mike C.

As an example of running beyond TBO, I now have 6000 hours on my PT6A-112's, and they're still going strong. My last hot section inspection was about 500 hours ago.

That said, who's gonna buy a 40-to-50-year-old Conquest or King Air with run-out engines? I wouldn't.

Now that used PC-12's, TBM's and Meridian's are reaching maturity, the values of the legacy twin turboprops are going to really start falling off a cliff.

The regulations are not intentionally unclear.


I provide referenced quotes from official sources. No one has to listen to me, but they should listen to the official sources.


This suggest you should research the subject matter more carefully so you can be sure what you say is correct. Claiming to know the FAA's intent to be intentionally unclear seems like someone who isn't considering their professional liability.


This is a false characterization of the FAA position.


This is blatantly false.

Here is the pertinent section of the current 8900.1 order:

https://drs.faa.gov/browse/excelExterna ... 14834.0001

"Since part 91 operators are not required to comply with a manufacturer’s entire maintenance program, overhauls are not mandatory for part 91 operators who operate strictly under part 91"

This issue seems like something your customers would expect you to know in great detail since it can have a huge impact on their situation.

Mike C.

I am glad that 8900.1 does in fact clarify it, I'm also glad you spent the last two hours researching until you found it. Saved me the time and now everyone knows.

I'd much rather you be able to say na-na na-na boo-boo to me then to spend my time digging through 100's of pages of FAA legalese.

I'm not in the business of promoting past TBO operations to increase the value of my own asset, so I don't have the financial motivation you have on this particular subject.

I look at aircraft from a value and market perspective and THAT is where my clients expect me to be an expert.

You made a thread on buying old airplanes…I’d say part 91 expertise in this area would be helpful

You’re funny.

Nice try.

My old tractor needed a fuel pump. The OEM was $180, the knock off was $16 - I installed an OEM pump last time and it didn't last. No certifications needed to work on my tractor. This would have been a couple of thousand if I took it to the shop

The (imperfect) analog here is Mike can't work on his jet but he can do research, purchasing and shop/tech selection. This effort can reduce costs by exponential amounts.

Here's the challenge in both cases (tractor and jet), how much is Mike (or me) worth per hour? The good news with a jet is the ROI can be dramatic and I'm pretty sure Mike enjoys the victories so it's a double benefit. Me working on a tractor might be a less rewarding endeavor.

-j

I think the key is whether flying falls into the "hobby" category. Any hobby is, by definition, a thing into which you sink excess time and money because you find the activity enjoyable. That holds whether the hobby is golf, cars, boats, or airplanes. Flying is definitely a hobby for me and I enjoy both the flying and the wrenching. In many cases it would be cheaper for me to spend the extra labor $$ to have someone do something for me instead of doing it myself. My mechanic lets me help by doing grunt work like R&Ring panels, coiling up oxygen masks after testing them, fetching tools, cleaning up, etc). This does save me money as my mechanic can be working on other things while I am doing the grunt work but what it saves me is much less than what I earn at my day job. But I generally enjoy it (even though it can suck crawling into the tail space during the summer in Oklahoma) so the money doesn't really enter into it. My mechanic is happy to entertain my millions of questions as we are working on things.

I also hate wasting money so if I can buy a used part for a fraction of new I will do that. Obviously what constitutes wasting varies from person to person.