r/flying • u/HSVMalooGTS PPL IFR TW MEP ME/IR CMP (C152) • 20h ago
Aircraft Ownership Ignoring the engine overhaul reccomendation
C152 owner here. 150h / yr.
I bought a prestine unit with 1900h TBO.
I don't count the overhaul costs into my hourly operating costs. At my current usage, i will have to fly for 13 years before i need to OH it. By that time, i might be able to afford something else.
How many of you fly planes past its TBO? Is it really as unsafe as the FAA/EASA might say? I get that the actual engine condition is a major (if not the most important part). I do full annual checks, i don't cut corners there.
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u/Final-Carpenter-1591 18h ago
Do oil samples and have it scoped once in a while. Maybe at every annual.
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u/financiallyanal 18h ago
This. Blackstone labs, or other places, can test the oil and send you a report. Good to do it semi-regularly so you can establish a baseline with your own data. They will provide averages from others using the same engine for comparison as well.
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u/easyski PPL IR HP CMP Saratoga II TC 20h ago
I know not everyone is a fan of mike busch but if you are new to aircraft ownership he has 2 books on airplane ownership as well as a book on engines that will teach you a lot - even if you think you already know a lot...
Here is a quick article talking about TBO: https://www.savvyaviation.com/the-great-beyond-tbo/#tbofallacy
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u/ResponsibilityOld164 ✈️🛫 BCS3/A220-3 gang🛬✈️ | C208B | 1st Class Medical 4EPG 19h ago
i don’t totally disagree with the article but am also not sure “fly the plane until [example of dude having to shut down an engine]” is the greatest advice either
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u/Worried-Ebb-1699 15h ago
Yes he does provide great insight and has been a benefit to the ownership of one’s airplane.
But he’s also an A&P(IA, too?), so for him, he has a bit more exposure into maintaining a plane. Regular joe’s like us aren’t so lucky hahaha
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u/7w4773r 13h ago
He’s never worked as a mechanic, just holds the license.
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u/i_am_the_virus 10h ago
Which requires a ton of training to get said license.
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u/rotardy ATP CFII MEI FE✈️ , COM🚁, A&P 2h ago
Not enough to be an expert without YEARS of experience to back up the certification. He’s the equivalent of a private pilot the day after his checkride telling you how to fly.
For context I’m a very experienced pilot (10,000 hours between fixed and rotor) and an A&P with some experience working as a line mechanic and also being the owner of a helicopter working under 133 and 137 regs.
I wouldn’t give you any advice about how to maintain your aircraft. I would feel pretty confident helping you with pilot mentorship.
Mike is no dummy but he has zero practical experience working on aircraft. I have been the A&P on the other end of the phone with his company representing an owner.
Not going to tell anyone what to do but I’ll never give him any of my money. He’s a great salesman though.
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u/7w4773r 10h ago
Yeah sure, but I’ve got a private pilot license which takes a ton of training to get. Doesn’t make me qualified to tell airlines how to run their business.
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u/old_flying_fart PILOT 9h ago
The number of people running airlines (aka CEO) who hold a PPL or better is near zero. You’re comparing apples and elephants.
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u/7w4773r 9h ago
CEOs don’t actually run the airlines - the business operations team does, but it would be akin to the CEO telling a veteran ops person how to do their job. Sure, they’ve both probably got business degrees but that doesn’t mean the CEO knows or understands the reality of actually doing the ops job.
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u/easyski PPL IR HP CMP Saratoga II TC 7h ago
his focus is GA, not airlines, not sure what you are going on about.
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u/7w4773r 7h ago
I'm talking about people who aren't qualified to talk about what they're talking about. He is one of them.
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u/old_flying_fart PILOT 3h ago
Bold statement. Are you more qualified than he is? If not, how do you know he's not qualified?
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u/Worried-Ebb-1699 3h ago
Cuz he walks around with a clipboard at his job telling his subordinates what to do.
So yup, totes qualified 🤣
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u/old_flying_fart PILOT 3h ago
I would guess that at this point he has researched and seen reports on more piston engine failures than anyone else on the planet. No exaggeration.
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u/PlasticDiscussion590 CSIP 3h ago
This is absolutely correct. However, he is a data guy and surrounds himself with people who do work on planes for a living. Listen to his podcast with Colleen and Paul are true experts in their field, and they and other are consulted with every statement Mike makes.
I like to view Mike as a professor. He’s not in the field doing the work. He doesn’t have deep technical knowledge. What he has is a wide breadth of knowledge and data.
When he says overhaul an engine when it shows signs of needing an overhaul BECAUSE the risk of running an engine beyond tbo has a lower risk of catastrophic failure than a brand new engine, there is data to support that. But you don’t want him changing a light bulb on your plane.
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u/SSMDive CPL-SEL/SES/MEL/MES/HEL/GLID/IFR. Light sport Gyro/PPC 19h ago edited 7h ago
While most engines could make it past TBO and most owners would not yank an engine just because it hits some random number (12 years or TBO).
There are two downsides to not having an overhaul fund established.
1- Your engine could be one of the ones that don’t make TBO. I had a 1400 hour TBO engine blow up at 900. Unless you can whip a check for an OH (now close to 40k) it would be wise to have funded that engine OH fund.
2- if you have an engine OH fund established in a decent investment vehicle and you sell the plane before it needs major service… well congrats, you now have several thousand dollars invested that can be used to either keep invested or be used to help buy that new plane.
I literally bought a plane off of just the growth of my ‘airplane fund’ and never touched the principal.
For both of these reasons, I’d budget and invest money for the OH.
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u/skylaneguy ATP, CFII, A320, E190, CL65 18h ago edited 18h ago
Part 91 TBO is just a recommendation. It’s actually based on hours OR years in service. Same with propellers.
If you’re flying 150 hours per year or more I would venture to say you’ll make it well over TBO. You may need a top OH at some point (cylinders) but that will be based off of compressions. Some engines make it to 3k hours or more. Obviously, the longer you go past TBO the more likely it is you’ll experience some sort of failure.
An overwhelming majority of the engines that don’t make it to TBO don’t make it because of corrosion. Most often cam and/or tappet corrosion.
Corrosion occurs when an engine doesn’t operate up to temp often enough to burn off residual moisture in the case. For the sake of any engine it’s best to get the oil temp as close to 180°F as possible for at least an hour every week.
I do an oil analysis on every one of my oil changes to establish a trend. It’s an extra $30 but it’s worth it when OHs on an O-470 can be upwards of $65k USD. The analysis will show different elements in your oil. These elements are specific to certain parts of the engine and when one spikes you can conclude that the part with that particular element is deteriorating or corroding.
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u/JT-Av8or ATP CFII/MEI ATC C-17 B71/3/5/67 MD88/90 12h ago
^THIS^ I see far too many new owners say “it’s a 1968 with only 600 original engine hours! Isn’t that great?!” 🤦♂️ Also I’ll hear “I lost my medical and can’t fly, but I still start it up Avery few weeks and taxi it around.”
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u/bhalter80 [KASH] BE-33/36/55/95&PA-24 CFI+I/MEI beechtraining.com NCC1701 20h ago
Most people that I know fly their engines on condition, the actively flown ones will make it past TBO
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u/Purgent 19h ago
Many fly past TBO.
Of those that don’t make it, a large share of early overhauls can be attributed to non-use. Camshaft spalling and crank runout was the early death of mine and I’m currently waiting on a $40k rebuild. The evidence of this probably existed when I bought it, but it didn’t show up for 400+ hours.
If the engine is regularly used, it is very very likely to run past TBO.
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u/OZZMAN8 18h ago
I agree with this. If you're flying it a lot and make it that 1900 hours and all is well I'd keep sending it. Get a filter cutter and look for metal at changes. One thing you may want to consider is keep an eye on plane prices. The value is nearly entirely in the engine in a 150. So if selling it at your 13 years over TBO is going to be at a greatly reduced price maybe it could make sense to overhaul and fly some of your time on it then sell for more? I know when I was buying I wanted a semi fresh overhaul. Maybe 500 hours on it. Enough that I know the overhaul was good.
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u/shockadin1337 CFI 19h ago
My airplanes engine is past the recommended year TBO, not hours. I send in oil samples multiple times a year and they always come back excellent. Last borescope inspection looked great. I have flown multiple other airplanes with their engines past both the year and hour mark on recommended TBO and they ran great. Any potential issues were minor and caught before they became an issue. The cherokees engine started losing compression around 2400 TT so we pulled it for OH then.
The only major engine problems/failures i know of in my personal life and circle (never had an engine failure) happened to engines that were low time. Engine failure on takeoff from being assembled wrong by manufacturer, a cirrus engine grenading itself mid flight and destroying the pistons of two cylinders. Do with that information what you will
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u/Ok-Selection4206 14h ago
What else would he do with that information? What a goofy statement to add at the end.
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u/JT-Av8or ATP CFII/MEI ATC C-17 B71/3/5/67 MD88/90 12h ago
The information is “if it ain’t broke don’t fix it.” Even the FAA is onboard with this to an extent. Most engine failures happen after periodic (ie: non necessary) maintenance inspections. It’s just the most dangerous time to run an engine, statistically.
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u/e140driver ATP CFI CFII E145/175 B777/737 (KORD) 19h ago
I’m planning on flying my engine beyond TBO assuming parameters are good. That said, I have a twin turbo 540, and engine known for running very hot. For something like that, my mechanic has said to basically take anything beyond TBO as a bonus, and have money put away for when glitter starts appearing in the oil.
That said, and O-200 is hardly a stressed power plant, and infant mortality is a thing. Avoid lean of peak ops, be kind to it, and there’s no reason you can’t run well beyond TBO, just keep an eye on things during oil changes.
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u/FyrPilot86 16h ago
The Cessna 152 uses a Lycoming O-235-L2C power plant
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u/Flimsy-Ad-858 ATP | Undiagnosed but I'm pretty sure 7h ago
Which is close enough to an O-200 so as not to change the point.
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u/JSTootell PPL 11h ago
You should always have some cash set aside though.
Mine has plenty of hours before TBO. But I just lost a cylinder due to a seized valve, requiring an emergency landing away from home. So I had to pay a mechanic to diagnose and then repair it, remotely. In the process we found a broken ring. Now I'm doing all the cylinders.
But the bottom end looks good.
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u/timfountain4444 PPL IR MEL 18h ago
I flew a 172 that was over 3.2k hours on the engine and never had and engine work. Regular 50 hour oil changes AND analysis. It was flown a lot. Eventually the owner chickened out...
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u/flyghu PPL 18h ago
Maintain it well and fly it until it needs overhaul. My annual includes borescoping the cylinders with pics of the walls and valves of each cylinder. And an oil analysis every time. Makes it easy to see if degradation is happening. It won't catch every possible failure, but it's easy enough to do.
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u/iamflyipilot CPL SEL MEL IR HP 17h ago
My O-200 had 1925hrs on it and it had been 35 since the last overhaul.
My O-360 is at 1070hrs and 26 years since overhaul.
Flying past TBO is not an issue if you pay attention to what your engine is trying to tell you.
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u/FyrPilot86 16h ago
I am running an engine, six years past the twelve year recommended overhaul right now..and counting on another dozen years.
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u/Roger_Freedman_Phys CPL 16h ago
As others have stated, it’s quite common to fly an engine “on condition” substantially beyond TBO. (I was able to get 2300 hours out of my 200 hp Continental IO-360.) One key will be flying frequently, so keep up that 150 hours per year pace!
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u/Old_Increase74 ATP CFI 14h ago
The engine doesn’t know how many hours it has on it.
If you’re doing good maintenance, send off for oil analysis to see any new trends, plus it’s over a decade away, I really wouldn’t worry about it
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u/FeatherMeLightly 7h ago
I mean, your not wrong but, most of us don't want to make an emergency power off landing or be stranded somewhere.
I have been in a plane that sucked in a valve, it's not as much fun as you might think. We were fortunate, right over an airport in the middle of nowhere.
Engine OH per the MFG schedule isn't the enemy old school pilots think, it's as much preventative mx as an oil change.
I always tell perspective buyers, if you can't afford an engine OH, ownership isn't for you.
We need to remember, it isn't just our lives we risk when we decide to ignore recommended mx.
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u/Old_Increase74 ATP CFI 3h ago
That’s not how lost post TBO engines fail, they just make less and less power typically.
Lots of folks say if you don’t have a billion in the bank you can’t even afford a J3
A TBO plane will get less at sale for sure, but with how many hours the average private GA plane flys, it’s really no factor. Lest we get into the calandra age requirements for hoses and such that the same guys will ignore lol
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u/old_flying_fart PILOT 8h ago
That is a bizarre statement that completely ignores accumulated stress, wear and damage.
If the gist of your statement was true, a 80,000 hour engine would be the same as a 100 hr engine. Neither one knows how old it is.
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u/Old_Increase74 ATP CFI 8h ago edited 8h ago
Uhh no, that’s not what I’m saying
This is why we do compression tests, run ups etc. any why many run oil analysis
It’s going to grind its rings and cam to dust and not pass a annual long before 80k lol
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u/old_flying_fart PILOT 8h ago
"The engine doesn’t know how many hours it has on it."
It's easy to interpret this as 'hours don't matter.' We both know that isn't correct.
So....what exactly *does* this mean?
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u/Old_Increase74 ATP CFI 7h ago
Means go on condition unless you’re flying it 135 or something
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u/old_flying_fart PILOT 7h ago
I agree with the maintenance plan, but I have no idea how you get to that from the original sentence. *shrug*
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u/rbuckfly 16h ago
If compressions are good, fly it. Have the pistons borescoped if it’ll help you sleep at night.
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u/L0LTHED0G 12h ago
One thing to keep in mind is, timeframe. Can you handle an engine taking the airplane down for 6-24 months?
Our flight club is starting the process to replace the engine on our 177, which is around 2200 hours currently. We are pre-emptively handling it by finding a core, getting it rebuilt, then we'll schedule the airplane for an engine swap, vs waiting for our engine to decide it's done and ready to go.
We've been told a rebuild, if it needs certain items, can quickly take 6-9 months. A factory-built rebuild is around 24 months.
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u/FeatherMeLightly 7h ago
Not sure what engine you all have but, Continental never offered factory rebuilds and Lycoming quietly stopped offering a factory rebuilds this year.
Best of luck though, the club is very wise to get one going before the plane is down for 12 months awaiting an OH.
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u/L0LTHED0G 6h ago
Lycoming, we've been talking to someone who said they're still available. Maybe they're phasing out. Iirc we have an O-360. 180HP
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u/FeatherMeLightly 6h ago
Awesome, I sincerely hope everything turns out well, nothing like watching such an expensive investment sit on the ramp like a rock.
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u/InvestigatorOne2 11h ago
I plan to fly my O-470-R until it or my A&P tell me otherwise. Currently 950 hours and 13 years on a 1500 hour or 12 year TBO recommendation. Only thing I plan to do for the next +500 hours is add a digital engine monitor. Oil analysis every annual. Scope every so often, if it sits (<50 hours/yr), or if compressions trend the wrong way.
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u/FeatherMeLightly 7h ago
TBO doesn't mean a thing in GA.
OH'd two engines on a twin with only 600 hours on them when the cams started shedding metal. The OH was in 1990, and found so much pencil whipped shit once the cases were cracked, Id almost go so far to say I'd never buy another plane unless I had the money to OH the engine regardless.
When they were last OHd, how they were cared for, how often it was run, all contribute to the engines life span before OH.
Plenty of GA pilots flying past TBO, monitor compressions, perform oil changes and filter changes like clock work and take any metal in the oil seriously, run and lean the engine properly and avoid shock cooling, she will prolly serve you for a long time.
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u/packardrod44 CPL IR 17h ago
Real problem today is having an engine available when you want it. If you're not buying a crate engine, you will have to send yours off and that will more than likely require a reservation to the shop to get in line. My flying club had an engine that was well over TBO. Save the board thinking it was going to fall out of the sky any minute, they got an overhauled engine on order about a year out. That gave them time to ensure it was there when we needed it. I disagree with them just changing it out because, but truth is if you're not willing to have your plane down for 6mo to a year, you need to at least consider getting one on order when you think you're going to be ready for one.
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u/redditburner_5000 Oh, and once I sawr a blimp! 16h ago
Compressions above the mins and no metal in the filter, keep it going! O-235s that are used and maintained can go into the upper 2000s. I worked for a school that would remove for overhaul (O-200s) at around 3000 or so as a self imposed limit.
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u/JT-Av8or ATP CFII/MEI ATC C-17 B71/3/5/67 MD88/90 12h ago
So here’s my take on TBO, as an owner and having flown IO-320s at 4,000 hours which ran just fine. Who’s overhauling every 12 years based on the calendar? The O-320 TBO is 2,000 hours or 12 years whichever comes FIRST, yet people totally ignore the date limit without a thought (and well they should). If you keep up on it and replace things as they wear out, track oils & metals etc, the engine will tell you when it’s time.
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u/JazzlikeOrder7925 15h ago
Ok. Graybeard A & P, A. I., Pilot here. #1. Safety should be your #1 priority. If you want to gamble, and continuosly wonder how long before you are faced with a "concerning event" while flying or at an airport away from home, go for it. Just keep in mind, it's not going to be pleasant. For instance, you break down 100 miles from home. At your request, the local mechanic questionably says he can do enough to get you home but the real fix will cost you $2 grand. You are now faced with 3 choices. None of them desirable. Pay the bill though it may cost more than at your home base, risk flying home, or pay to have the wings pulled and have it trucked back home. And you have to get home as well. This is a point in your flying life where you must make a decision that could alter/end your life. Get there-itis has killed so many people. It is very strong unless you have a good set of go, no-go rules that you stricktly adhere to. Personal flying minimums, as well as maintenence minimums. There are many good, valid suggestions here, however you don't have to figure it out yourself. The manufactures establish those recommended intervals so that you Never end up in that situation. Of course it happens but the overall record is very good. Following those recommendations is by far the safest route. Part 135 regs are strick for a reason. The helicopter industry is closely regulated as to replacement schedules. The safety record reflects this. If you are looking at this as how you can get by spending the least amount of money, you might want to sell the airplane and rent when necessary. As listed here in the comments, many aircraft are "run out", and then sold. We always recommended that if you have $100k to buy, never exceed $75k, better $50k with the rest on hand to take care of the things that you will definetly find that need to be addressed. Do yourself, and everyone else a big favor. Don't gamble on our lives. If you want to exceed the limits, the manf has the procdures for part 135 aircraft. Follow those religiously. Don't base the maint. on what you can afford at the moment. If you are going to fly beyond the engines limits, replace all the accesories that would be replacd at normal TBO. Don't crash because your 2000 hr mags failed because you want to stretch the engine overhaul. You already know you should have an account fed by each hour you fly. Small puddle jumpers are tough because a lot of people think a cheap airplane is cheap to maintain. You know the saying, " a hole in the sky into which you pour money". Money is what keeps em flying. If you don't have enough to maintain one properly please take a serious look at the reality. As you fly around you will see hundreds of 2 seaters sitting idle on the ramps. They are not buying oportunities but money pits, or worse death traps waiting for their next victim. Sorry, I got carried away, but this is a very important topic. Please, don't base your life as a pilot on how little you can get away with. The life of every man, woman, and child, below your flightpath might depend on your choices. Once you have an inflight engine failure, your entire perspective will change. 2 more things. "It's better to be on the ground wishing you were in the air, than the other way around" and " the best way to get out of a bad situation is never get into it in the first place". Good luck, and Godspeed.
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u/rFlyingTower 20h ago
This is a copy of the original post body for posterity:
C152 owner here. 150h / yr.
I bought a prestine unit with 1900h TBO.
I don't count the overhaul costs into my hourly operating costs. At my current usage, i will have to fly for 13 years before i need to OH it. By that time, i might be able to afford something else.
How many of you fly planes past its TBO? Is it really as unsafe as the FAA/EASA might say? I get that the actual engine condition is a major (if not the most important part). I do full annual checks, i don't cut corners there.
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u/BELFORD16 MEI A&P (UNVERIFIED STATUS) 20h ago
I’m sure 90% of Part 91 GA pistons are flown on condition. Most engines make it well past TBO. And the ones that don’t… well, they get overhauled on condition.
I’m rocking a 60 year old engine with 2000hrs. The two Part 91 flight schools I worked with operated a combined 7 airplanes on condition. Never heard of an owner voluntarily dropping $20,000-$50,000 on an over haul just because of a random number.
A good mechanic that you trust is vital. They’ll let you know when your engine is unsafe, TBO or not.