3400 hrs since prop overhaul?

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Ray F

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Ray F
so im looking around at cherokee 6/300s, i find one that i like but am a bit concerned. The engine has 700 hrs SMOH but the prop overhaul date is Oct 1994. It says "3,385 hours since major overhaul (new hub in 2002 - eliminates Eddy Current inspection). Prop was disassembled, degreased, inspected and resealed at the time of engine overhaul." Is this a major concern, should the prop be rebuilt asap or what. How often should a prop be overhauled?
 
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Nah. That's a de facto "700 SMOH" prop without the ability to command a premium for it. Great deal for the buyer, and a good deal for the seller as long as he doesn't sell the airplane. I believe our resident "most interesting man in the world" Henning has made that point on the forum before. IRAN is just as good as OH, the difference is what kind of resale considerations you're aiming for when you commit to either avenue. I'd fly behind that prop with no reservations. Good luck on the purchase.
 
IRAN is the way to go on prop inspections. Prevents the OH shop from prematurely throwing away perfectly serviceable components. Now, it has been 12+ years since the last IRAN on the prop (2002 ?), so I would consider doing another one (usually ~$2K, depending on what needs work).
 
Jeff Oslick said:
IRAN is the way to go on prop inspections. Prevents the OH shop from prematurely throwing away perfectly serviceable components. Now, it has been 12+ years since the last IRAN on the prop (2002 ?), so I would consider doing another one (usually ~$2K, depending on what needs work).
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2K will get a full zero time overhaul around here...a reseal will be about a grand for a two blade.

Fatigue is the concern with props, but I have no idea what the actual life limit is.
 
Typical prop manufacturer overhaul times are 2000 hours/72 months, whichever comes first. There are some that can go longer, some shorter. Prop hubs are like cams and other corrosion-prone parts. They suffer from lack of exercise.
 
Ray F said:
How often should a prop be overhauled?
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Never, unless needed for 135 or for export requirements. For the rest of us the prop should never be "overhauled" only "inspected and resealed". To be an "overhaul" you have to cut the blades.
 
Ray F said:
Good deal, thanks for the replies guys.
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It's good to "ring" the blades with a hard nylon faced or bronze hammer every now and then and listen to them, if they ever don't sound equal, or if you can rock the blade in the plane of rotation, you need to look into things.
 
Henning said:
It's good to "ring" the blades with a hard nylon faced or bronze hammer every now and then and listen to them, if they ever don't sound equal, or if you can rock the blade in the plane of rotation, you need to look into things.
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so....what's the best way to look into a prop? :yikes::goofy:
 
Jeff Oslick said:
A "zero-time" overhaul could only be achieved with blades at "new" limits. The simple reseal may be a grand, but a 12-yr old hub is likely going to need some parts.
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Ummm, that wasn't my experience, got a new log book along with the old hub and blades...and the hub was built in 79 (original).

I think the blades just have to be within limits, not at new.
 
hindsight2020 said:
Nah. That's a de facto "700 SMOH" prop without the ability to command a premium for it. Great deal for the buyer, and a good deal for the seller as long as he doesn't sell the airplane. I believe our resident "most interesting man in the world" Henning has made that point on the forum before. IRAN is just as good as OH, the difference is what kind of resale considerations you're aiming for when you commit to either avenue. I'd fly behind that prop with no reservations. Good luck on the purchase.
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That.

Realistically consider is overhauled (unless you need the holy water treatment for 135 ops or something), for buying tactics, it's WAY WAY past overhaul :D
 
Clark1961 said:
Ummm, that wasn't my experience, got a new log book along with the old hub and blades...and the hub was built in 79 (original).

I think the blades just have to be within limits, not at new.
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I'll defer to an IA on this, but that doesn't seem right to me. Are you sure it doesn't say zero Time Since Overhaul? As a buyer, I'd be ticked if I was sold a plane advertised with a new prop that was really just within limits. There is a big difference in expected service life there.
 
Jeff Oslick said:
I'll defer to an IA on this, but that doesn't seem right to me. Are you sure it doesn't say zero Time Since Overhaul? As a buyer, I'd be ticked if I was sold a plane advertised with a new prop that was really just within limits. There is a big difference in expected service life there.
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What's the difference from a FRM engine? They just take used parts from bins and assemble an engine with an -R data tag and a fresh "0" time log book.:dunno:
 
Jeff Oslick said:
I'll defer to an IA on this, but that doesn't seem right to me. Are you sure it doesn't say zero Time Since Overhaul? As a buyer, I'd be ticked if I was sold a plane advertised with a new prop that was really just within limits. There is a big difference in expected service life there.
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What part of "new log book" do you fail to understand? There is no difference in service life from the manufacturer's perspective, it's a 2000 hour prop. It's the buyers responsibility to measure the blade length since that is an airworthiness item.
 
You can't "zero time" a prop. Somehow or another, engine guys can "zero time" an engine, but you can't "zero time" a prop. If there are overhauled parts in the prop, time continues. For example, you have your prop overhauled and it gets a new hub with the old blades, or, for that matter, new blades with the old hub, your log book will say "0 TSO, XXXX TSN." You can't "0 TSN" a prop, only "0 TSO."
 
KRyan said:
You can't "zero time" a prop. Somehow or another, engine guys can "zero time" an engine, but you can't "zero time" a prop. If there are overhauled parts in the prop, time continues. For example, you have your prop overhauled and it gets a new hub with the old blades, or, for that matter, new blades with the old hub, your log book will say "0 TSO, XXXX TSN." You can't "0 TSN" a prop, only "0 TSO."
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Why do you say this? Did I not get a new log book with my prop overhaul? Should I just throw away the new log book because you say it isn't valid? So many questions...
 
Yes....throw it in the trash.

Better yet, burn it and put the video on YouTube. :lol:
 
Clark1961 said:
What part of "new log book" do you fail to understand? There is no difference in service life from the manufacturer's perspective, it's a 2000 hour prop. It's the buyers responsibility to measure the blade length since that is an airworthiness item.
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FAA regs address how only the engine manufacturers can "re manufacture" and engine to new tolerances and zero time it. I've never seen such a process for a prop. "A new log book" may be different from "zero time". As an owner aren't you curious about that?
 
Stewartb said:
FAA regs address how only the engine manufacturers can "re manufacture" and engine to new tolerances and zero time it. I've never seen such a process for a prop. "A new log book" may be different from "zero time". As an owner aren't you curious about that?
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Been on the internet long? As the owner who went through the process and understands what was done to zero time the prop, no I'm not the least bit curious about someone on the internet telling me it can't be done.
 
Not from me. I'm curious how the shop did it and whether you had investigated whether it was legit. I think I stand with the majority that have never heard of a used prop being zero-timed, and I'm one of the few private operators who subscribes to scheduled prop maintenance.
 
Stewartb said:
Not from me. I'm curious how the shop did it and whether you had investigated whether it was legit. I think I stand with the majority that have never heard of a used prop being zero-timed, and I'm one of the few private operators who subscribes to scheduled prop maintenance.
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You didn't ask if I investigated and had knowledge, you asked if I was even curious. In other words, you assumed I didn't know and that, sir, is disrespectful.
 
I've no doubt that you DID receive a new log book at the time of overhaul, but the log certainly says "0 TSO, XXX TSN. It certainly should NOT say "O TSO, 0 TSN."
 
KRyan said:
I've no doubt that you DID receive a new log book at the time of overhaul, but the log certainly says "0 TSO, XXX TSN.
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Nope, it doesn't. Sorry.
 
Henning said:
What's the difference from a FRM engine? They just take used parts from bins and assemble an engine with an -R data tag and a fresh "0" time log book.:dunno:
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There is a difference between a prop being dimensionally new a being within service limits, same as with engine parts. There is also a difference between a New engine and a FRM engine. Yes, for some bizarre reason they are both allowed to be called zero-time, but there is a difference. I haven't heard of a zero-timed prop before this.
 
Jeff Oslick said:
There is a difference between a prop being dimensionally new a being within service limits, same as with engine parts. There is also a difference between a New engine and a FRM engine. Yes, for some bizarre reason they are both allowed to be called zero-time, but there is a difference. I haven't heard of a zero-timed prop before this.
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Can you find anything that disallows it? :dunno:
 
Henning said:
Can you find anything that disallows it? :dunno:
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I would just like to know what it means, assuming it is legal. Particularly with respect to prop dimensions, I would assume "new" means "new", not "been filed down annually for the last 10 years but still serviceable". This isn't a "caveat emptor" I've heard of previously.
 
Jeff Oslick said:
I would just like to know what it means, assuming it is legal. Particularly with respect to prop dimensions, I would assume "new" means "new", not "been filed down annually for the last 10 years but still serviceable". This isn't a "caveat emptor" I've heard of previously.
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Why does it have to be new? A 0 SFRM engine isn't 'new', yet it is zero timed with a fresh log book and serial number.
 
Henning said:
Why does it have to be new? A 0 SFRM engine isn't 'new', yet it is zero timed with a fresh log book and serial number.
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I didn't say it had to be; I understand the difference between "new" and SFRM when it comes to engines.
 
there is no such thing as a zero-timed used prop. By definition it cannot exist except as new manufacture never installed on an aircraft. It is common to receive a new logbook after an overhaul but the first entry should read "total time XYZ carried forward".

The ability to "zero time" an overhaul is a special circumstance that is limited to only engines, and only when overhauled by the original engine manufacturer. Doesn't make any logical sense but that's the way it is.

The earlier posters ignoranance of what he has with his prop and how things are documented, should be a lesson to all about taking a seller at their word. Most people are honest enough, but many of them are clueless. The end result is the same as far as getting useful information.
 
JHW said:
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The ability to "zero time" an overhaul is a special circumstance that is limited to only engines, and only when overhauled by the original engine manufacturer. Doesn't make any logical sense but that's the way it is.
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or....the manufacturer's approved representative. :D

§91.421 Rebuilt engine maintenance records.

(a) The owner or operator may use a new maintenance record, without previous operating history, for an aircraft engine rebuilt by the manufacturer or by an agency approved by the manufacturer.
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