Hey flying family,

So I am looking at purchasing a plane that has a Rotax 912 ULS. I absolutely love Rotax. I think they're the best LSA engine on the market today.

The plane is a 2008 and is in (close to) PERFECT condition. And it's priced right ($80k). Or so I thought. It only has 275 hours TT. So roughly 1700 hours left TBO but from what an A&P told me, they have to be overhauled at either 2000 hours OR 15 years. I actually spoke to the guy who has done all the work on the plane since 2012 and he said it's a great plane (he really has no skin in the game). And that I could drop that engine out, sell it to experimental guys, and buy a new Rotax "for just a couple extra bucks". I don't hate the idea.

Does anyone have experience with having to do a 15 year overhaul? It's hard to buy a plane, knowing I'll need to put $10k in it in less than 4 years solely because of age. Which if I purchase this and then decide to sell it in 2-3 years, it's obviously going to affect the resale.

It has been meticulously maintained, was a show plane, and just had the 5 year Rotax rubber replacement done on it in June (along with all service bulletins).

I'm just unsure of what to do. I love the airplane and it likely doesn't need an overhaul. But I want to keep the plane S-LSA.

Let me know what y'all think and if what I said is accurate.

I hate getting emotionally attached to airplanes that aren't even mine yet, lol.

Is the 15 year overhaul mandatory or recommended? Most conti and Lycs are 12 year overhaul or x amount of hrs. For a privately flown aircraft that 12 years is a recommendation and doesn't have to be followed. I'd imagine the same to be true for the rotax.

Call Ronnie or Morris at South Mississippi Light Aircraft. You’ll find his number on the web. Their Rotax credentials are impeccable and they are truly good dudes. Give them the serial number and they’ll tell you all you need to know. Pardon my French but most A&P’s don’t know fuck all about Rotax. If yours does then my apologies.

Screw that, fly it.

FWIW: I did a fraction of the anal retentive Rotax maintenance schedule, and made the 2 K TBO with zero issues. About all I did "correctly", or as suggested, was change the oil every 50 hours, but that sometimes meant 60 or 70. CarQuest oil filters, changed the plugs about 5 or 600 hundred hours, fuel filter once a year. I also never waited for the oil and CHT to reach 120 degrees. STILL had no problems whatsoever. NOT suggesting you or anyone else do the same, just telling you my experience with that engine. I treat it like I treat my Toyota's, and it responds like them, high praise indeed. I have NO experience with that old of an engine with that low of hours, so take my advice for what it's worth!

Realistically I don't think the calendar deadline is that important, which makes E-LSA convenient. I bet that engine would go for many many more years. But if it's S-LSA and the guy signing it off every year follows the Rotax service TBO schedule...what does that mean?

In the standard category world, TBO doesn't require you to overhaul immediately if you're flying Part 91. I think you can run your engine until it shows some level of safety compromise.

S-LSA is valuable for a teaching platform, right? If that's the case, does that mean TBO is a mandatory engine service?

Easiest thing to do may be post it for sale. That's really low hours and very appealing for the experimental guy.

My plane started as an S-LSA and as Zzz alludes to, you are governed by the rules set by the plane manufacturer and all manufacturers defer to Rotax rules when it comes to the engine. Rotax says to do it and if you don't, you are no longer following ASTM certification rules and your plane can be grounded. That's not to say that there are not a lot of folks that don't overhaul and I don't know what happens then as that is more in the lawyer arena rather than the mechanical arena. As far as the overhaul, you were told correct that you are money ahead to just get a new engine rather than overhaul. To do the full, correct, Rotax overhaul would take a lot of specific ($$$$$) tools to pull it off and few to none have those or the Rotax approved rating to do such an overhaul. An A&P not certified by Rotax cannot do the overhaul. You have to go to an approved Rotax school to get that certification. I know of only three places with that certification. FYI, I converted to E-LSA. But watch even that as it depends on how the operating limitations are written. As Zzz mentioned, that does restrict your ability to use the plane for commercial instruction.

I should mention that after my 2000+ hour trouble free run, with very minimal maintenance, I decided to not find out how far I could push it, sold the old engine and bought a new one. I'm sure I could have continued to fly behind it but it just seemed like good mechanical karma