How often is a propeller rebuild necessary?

kicktireslightfires

kicktireslightfires

Pre-takeoff checklist
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kicktireslightfires
When it comes to propeller rebuilds, is that something one does every 6 years or so on any airplane, or only on specific airplanes? A pilot just mentioned to me that he gets his propeller rebuilt every 6 years, but he has a turboprop and wasn't sure if that's a general thing that applies to all propellers on any airplane or only specific to turboprops?
 
Mine was just IRAN’d after 18 years and about 1200 hours. Hartzell 3-blade. Had 18 years worth of grease injected at annuals etc. Current A&P accidentally overserviced it with grease so we decided to send it in. Stallings Propeller looked it over good. No damage or corrosion. Apparently not many shops are willing to do an IRAN anymore.
 
YooperMooney said:
Mine was just IRAN’d after 18 years and about 1200 hours. Hartzell 3-blade. Had 18 years worth of grease injected at annuals etc. Current A&P accidentally overserviced it with grease so we decided to send it in. Stallings Propeller looked it over good. No damage or corrosion. Apparently not many shops are willing to do an IRAN anymore.
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What is IRAN'd? Is that like IRAQ but with an N at the end? I heard Obama said that IRAN is bad. :p

Thanks for the info, but what does IRAN stand for in this case?

So it sounds like most people never get a propeller rebuild at all and the props are fine? So if I'm buying a 6 year old airplane, I should not worry at all about it?
 
kicktireslightfires said:
So if I'm buying a 6 year old airplane, I should not worry at all about it?
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Inspect the logbooks closely... have your own mechanic inspect closely before closing the purchase deal.

If problems, use info as negotiating chip. If no problems, fly on.
 
I don’t think ‘rebuilding’ a propellor is the right terminology. ;)

It really just boils down to whether or not you can file out whatever imperfections are in the blade. If the nicks or chips are too large for repair, than you’ll have to start new.
 
There is more to it than just filing out nicks on a constant speed prop. The overhaul consists of disassembly, non destructive testing of the moving components for cracks and replacing the seals. I would do this at a minimum of when the engine is overhauled and especially do the prop governor too. There are McCauley props that can only be overhauled three times and then must be replaced - has to do with drilling holes in the mechanism each time for safety wire at the hub. So if you are airplane shopping for a Centurion with a 3 blade McCauley prop check for signs of oil leaks around the base of each propellor and if it is 30 plus years old check the log books to see if the prop has had its third overhaul with more than 1,000 hours on the prop and over 6 years since recent overhaul. If it is that age and has signs of oil residue budget a potential $12,000 for a Hartzell Top Prop or McCauley upgrade. You can’t buy new McCauley components for these old props because of the sound limitations of the required new designs. Used components are rare and expensive if you can find them. And new designed McCauley prop performance has about a 2 knot slower cruise performance on an io520 than when new originally. However this is typically offset by the filing done on the old prop for nicks and having a new full dimension set of blades likely will increase your cruise speed but still slower than book numbers by 2 knots or so.
 
Ryanb said:
I don’t think ‘rebuilding’ a propellor is the right terminology. ;)

It really just boils down to whether or not you can file out whatever imperfections are in the blade. If the nicks or chips are too large for repair, than you’ll have to start new.
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Not so for all propellers

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Briar Rabbit said:
I would do this at a minimum of when the engine is overhauled and especially do the prop governor too.
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We had the hub overhauled and then did a new governor at engine overhaul. An important thing I was taught was to watch the wind screen as you do one of the prop checks. If the seals are starting to leak, you'll see a quick brief bit of oil/grease spittle on the wind screen when the blades are changing pitch. When you see this, it's time to send it off to be overhauled.
 
Ryanb said:
I don’t think ‘rebuilding’ a propellor is the right terminology. ;)

It really just boils down to whether or not you can file out whatever imperfections are in the blade. If the nicks or chips are too large for repair, than you’ll have to start new.
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The issue is not about dressing the blade leading edges.
For constant speed props it's more about corrosion over time inside the hub and on the blade roots. For fixed pitch props it's corrosion around the mounting bolts and where the prop mates to the prop flange. Especially a concern for airplanes that are tied down outside in wet/damp climates.
 
No insecta the prop, uh no flya the plane.
 
I'm squarely in the camp that one never overhauls a prop if it doesn't have major nicks. And I'm talking C.S. Speed props here, not fixed pitch.

I was told long ago by an A&P friend (and I ASSUME he knew what he was talking about) that, when a prop is overhauled, a certain amount of material has to be removed from the blades. Overhaul it two or three times and the blades will likely be to minimums and good for wall display only. What I don't know (or remember), as I type this, is if that was true for ALL C.S. props or just my Hartzell.

I.E. a prop that doesn't have excessive nicks should be IRAN'ed. Do everything that's done at an overhaul, except grind the blades in their entirely...simply dress minor nicks as necessary. That's what I did a few years ago when my 182 got an engine OH. The prop went to a prop shop in Memphis.
 
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timwinters said:
I'm squarely in the camp that one never overhauls a prop if it doesn't have major nicks. And I'm talking C.S. Speed props here, not fixed pitch.

I was told long ago by an A&P friend (and I ASSUME he knew what he was talking about) that, when a prop is overhauled, a certain amount of material had to be removed from the blades. Overhaul it two or three times and the blades will likely be to minimums and good for wall display only. What I don't know (or remember) as I type his is if that was true for ALL C.S. props or just my Hartzell.

I.E. a prop that doesn't have excessive nicks should be IRAN'ed. Do everything that's done at an overhaul, except grind the blades in their entirely...simply dress minor nicks as necessary. That's what I did a few years ago when my 182 got an engine OH. The prop went to a prop shop in Memphis.
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Agreed....but, I'd add...also, if they are not leaking grease or red oil.

I also, do not add grease at each annual (even when removing the other grease fitting). Many do that and find that it blows seals and creates more problems.

If it ain't loose or leaking or nicked up......keep flying it.
 
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Checkout_my_Six said:
Agreed....but, I'd add...also, if they are not leaking grease or red oil.
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Maybe I wasn't clear. We still did all the hub work when we overhauled the engine. Made sure there was no corrosion, made sure everything was within limits, replaced the seals, & everything else that goes with that. We also overhauled the prop governor. The only thing we didn't do was grind the blades. We simply dressed what needed to be dressed, which in this case was some very minor nicks.
 
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There are both TIS and calendar time recommendations for each prop model. I vote for treating them like the overhaul recommendations on engines...but that's just me :)

Shout out for Tiffin Air, in Tiffin, Ohio...

When we bought the R182, the two-bladed prop hadn't been touched for a l-o-n-g time...18 years as I recall. We put it off as long as we dared, then finally took it over to them for an overhaul, and the whole thing failed inspection due to the corrosion over the years (still have the pieces/parts as evidence). Replaced it with a Black Mac....delivered to BJJ free of charge. within a week.

The Citabria prop also hadn't been done in a long time, so we had them do that also during annual last month. Smooth and sweet!

Wednesday we took the R182 and had them dynamically balance its' prop. Took it from .4 to below .1....standard 'that's good enough place' is supposed to be .15, so over-achievers.

Good folks, good service!

Jim
 
MacCauley hubs aren't painted and are subject to external corrosion. All constant speed hubs are subject to internal corrosion. When my Mac was 6 years old (from factory new) I had it overhauled. It required some new internal parts but had enough external corrosion that if I had waited another year or two the hub would have been scrapped. Private operators aren't required to overhaul on the factory specified dates but the attitude that it never needs attention is incorrect. Let them go too long and they get more and more expensive to repair.

My experimental requires hub disassembly and inspection every 500 hours. That's one place the standards for experimentals are more stringent than certificated.
 
In Canada a CS prop has to be overhauled every ten years or less. Corrosion inside that hub is an issue. Crankcase moisture gets into it via the oil, through the governor, and starts some pitting. Pits weaken metal, leading to cracking, and sometimes catastrophic failure. Lose a blade and you'll likely lose the whole engine. Lose the engine off the nose and you die.

Maybe our colder climate aggravates the problem.

An overhaul also involves NDI on the blades as well as the hub. Nicks not properly dressed out can start cracks in the blade. A prop that has been filed a lot might be under the minimum thickness and/or width specs, risking blade flutter and failure.
 
My prop has 3k hrs on it. The seal is leaking ever so slightly. Based on its age, I don’t think there is any way I’m going to be able to get an IRAN done. McCauley A34C66-O. So I think I’m looking at a $15k annual this year...I can afford it, but it makes one re-think their ownership decision. At least it’s not the engine, yet.
 
A prop overhaul requires that the overhaul manual be adhered to. When in most times the prop only needs to be repaired.
 
McCauley service bulletin 137-AF says my prop’s overhaul interval is 1200 hrs or 60 months. No new parts are available either. Just reading the tea leaves insofar as a prop shop that would actually just do a reseal and sign it off back to service without overhaul. Don’t see that happening.
 
Bell206 said:
It depends. Are you asking about a TC'd aircraft or a E/AB aircraft or a LSA?
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Agreed. This is the important part that must be known before an answer is given. There is a lot of assuming going on in this thread without having all the information.
 
Checkout_my_Six said:
how many hubs fail inflight per year?
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Very few. Most cracking hubs will show oil or grease leakage. But as the fleet ages we'll see increasing failures of all sorts. I wouldn"t want to be the one that suffers a catastrophic hub failure.
In the late '80s or early '90s a 185 threw a blade in South Americs when its hub failed. The engine tore loose and rotated to the left almost 90 degrees and was simply sitting on the bed mount. The control cables pulled the mixture to ICO before they broke. The pilot landed in a small field. At night.
 
Dan Thomas said:
Very few. Most cracking hubs will show oil or grease leakage. But as the fleet ages we'll see increasing failures of all sorts. I wouldn"t want to be the one that suffers a catastrophic hub failure.
In the late '80s or early '90s a 185 threw a blade in South Americs when its hub failed. The engine tore loose and rotated to the left almost 90 degrees and was simply sitting on the bed mount. The control cables pulled the mixture to ICO before they broke. The pilot landed in a small field. At night.
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Yea, but look at all the money he saved!
 
Dan Thomas said:
Very few. Most cracking hubs will show oil or grease leakage. But as the fleet ages we'll see increasing failures of all sorts. I wouldn"t want to be the one that suffers a catastrophic hub failure.
In the late '80s or early '90s a 185 threw a blade in South Americs when its hub failed. The engine tore loose and rotated to the left almost 90 degrees and was simply sitting on the bed mount. The control cables pulled the mixture to ICO before they broke. The pilot landed in a small field. At night.
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A beach robi (sp) prop failed and the blade pulled out, the pilot reduced RPM and flew it home..
Fairchild 24 R. all 4 engine mounts were broken completed off, but the mount design kept the engine in place.. tough old aircraft.
 
Checkout_my_Six said:
how many hubs fail inflight per year?
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Whether it's hubs throwing blades inflight or 737 MCAS systems, it only takes a couple before the rules are changed to try to prevent any more...
 
Just to clarify, a hub that is throwing grease needs to be resealed. During that reseal a full hub inspection can be performed. Calling it an "Overhaul" also means you have to grind the blades down, reducing the lifespan of the prop. Most prop shops recommend not doing overhauls for part 91. Just open, full inspection, replace parts as necessary and reseal.
 
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