0-235 past TBO

RyanB

RyanB

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My flight school is a part 61 school and our main 152's TBO is around 2500. One of the instructors said its somewhat past TBO and still has good compressions and is going strong so they are not overhauling yet. How long can one of these go past this TBO?
 
Kiddo's Driver said:
I flew a 172 that had 3,900 on the clock. It ran well, but was going in for overhaul due to higher oil consumption.

Jim
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I knew a guy at lewis (KLOT) who eventually decided to overhaul his at around 3400. Same thing: oil consumption went up, but no metal.
 
So they can safely run after the TBO, even for awhile? the hobbs on ours is around 6700 and tach is over 8k, but has somewhere over 2500 hours on the engine SMO.
 
Ryanb said:
So they can safely run after the TBO, even for awhile? the hobbs on ours is around 6700 and tach is over 8k, but has somewhere over 2500 hours on the engine SMO.
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Yes.
It's when they come back from OH that you have to worry :eek:
 
I see, never really knew how long an engine could go after TBO
 
There is no way to accurately predict if any particular engine will make it to TBO, and if it does, how long afterwords it will last.

The life expectancy for someone in the U.S. is currently 78.7 years. How long can someone live beyond that?
 
Ryanb said:
My flight school is a part 61 school and our main 152's TBO is around 2500. One of the instructors said its somewhat past TBO and still has good compressions and is going strong so they are not overhauling yet. How long can one of these go past this TBO?
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I trained in a 152 with one that had over 4300hrs (in less than 3 years) and never had any major engine work done, just accessories. It was still going when I quit flying it, then a few months later another student pranced a landing on a PIO and collapsed the nose gear, so they took the opportunity to do an overhaul then.

Run engines on condition. If it's not making metal, carries good oil pressure and doesn't have compression leaking past the exhaust valve, it's in pretty good shape.
 
Take good care of the plane, fly it regularly in a non-training environment, preferably in a dry location, and fly with CHT's closer to 300 than 400 and an engine can last a long time.

We've got an O-360 approaching 2000 hours that seems as strong as a new one and burns almost no oil. The engine reserve set aside is enough to get a factory re-man and a new prop at 2000 but I don't think we will. We'll just pay a little more attention to the oil usage and keep an eye on the engine monitor, but the TBO is just a number based on statistics and a wide variety of usage conditions.
 
Deakin or Busch have some interesting takes on failure and TBO. One of them linked a study from an engineer who determined that the engine was more subject to catastrophic failure right after and up to 200 hours past OH. If it isn't making metal, and the comps are good keep flying and just do analysis ever oil change. Big parts in engines rarely come apart under normal use.

Also read the thread about the Aerostar that had two failures on new engines. Thread started by Stratobee.
 
Interesting, thanks for the replies!
 
Henning said:
I trained in a 152 with one that had over 4300hrs (in less than 3 years) and never had any major engine work done, just accessories. It was still going when I quit flying it, then a few months later another student pranced a landing on a PIO and collapsed the nose gear, so they took the opportunity to do an overhaul then.

Run engines on condition. If it's not making metal, carries good oil pressure and doesn't have compression leaking past the exhaust valve, it's in pretty good shape.
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BEST ANSWER....:yes:
 
SixPapaCharlie said:
6000 since Overhaul???
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It's possible if they keep fixing things on condition (what we called "IRAN", or "Inspect and Repair As Necessary" in the Air Force). They never do everything at once, so they can never say the engine was overhauled, but if you dig through in the logs, you'll see there's nothing in the engine which wasn't done as it would be in an overhaul within the last couple thousand hors. If you're never going to sell the plane, that could be a good long-term strategy.
 
Ron Levy said:
It's possible if they keep fixing things on condition (what we called "IRAN", or "Inspect and Repair As Necessary" in the Air Force). They never do everything at once, so they can never say the engine was overhauled, but if you dig through in the logs, you'll see there's nothing in the engine which wasn't done as it would be in an overhaul within the last couple thousand hors. If you're never going to sell the plane, that could be a good long-term strategy.
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I seriously doubt the case was ever split or the rods were ever out. O-235s aren't really known for eating cylinders either. I bet one that is run at a busy school will make the 6000hrs with no more than spark plugs and accessories.
 
I know we're speaking of the O-235 but I think it's worth mentioning I have a friend whose Rotax 912 is currently just shy of 7000 since major overhaul. He is an A&P as well as Rotax Maintenance Tech. No metal, no increased oil consumption, so he claims he plans to push it to 8000. That's four times the recommended TBO...
 
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