Propeller maintenance question /propeller logs

[rturbett]

I see a number of propeller logs that show 100 hour / annual inspections, are way under on hours to overhaul, but are well beyond the calendar time to tbo-   ie- 700 hours, but nine years on a six year calendar TBO.

I'm curious about  the thought process from owners on the decision to go beyond TBO.  Any thoughts or concerns?

Thanks

Rob

[EricJ]

If the condition is good, there's no reason to take it out of service.   This is true for engines as well, and nearly everything in the typical Part 91 flying that we do.

 

[0TreeLemur]

As important as the propeller is,  you want to know that it is in good shape.  From the nature of your question, it seems that you might have some doubt.  The manufacturers have recommended schedules, but as @EricJ wrote, in Pt 91 it's left up to the owner.   I suppose it depends to some extent on whether your aircraft is hangared as that affects how often the propeller is exposed to moisture.  Seals sometimes leak and let water into the hub.  Corrosion happens inside propeller hubs.  I'm sure others can tell stories about it.

Removing a propeller and shipping it to a shop for IRAN is a pain in the arse, but might be worth it for piece of mind, especially if it hasn't been opened up and inspected in over 10 years, maybe 5 if unhangared.

Our C model had the 100 hour eddy-current inspection AD. About 5 years ago the shop doing the ECI told me that Hartzell wanted it opened up and inspected.  That turned into a painful experience because the blade roots were determined to be "undercut" and the blades were condemned.   We wound up buying a new prop (ouch).

In the end, it's all about risk management.   If you are not certain that your prop is in top condition and you have some reason to suspect that it might not be, you can use dollars to ameliorate that risk.

[rturbett]

Thank You - very good perspective and advice, and now I have a new word in my vocabulary! (ameliorate)

[jetdriven]

  On 10/7/2023 at 5:55 PM, 0TreeLemur said:

As important as the propeller is,  you want to know that it is in good shape.  From the nature of your question, it seems that you might have some doubt.  The manufacturers have recommended schedules, but as @EricJ wrote, in Pt 91 it's left up to the owner.   I suppose it depends to some extent on whether your aircraft is hangared as that affects how often the propeller is exposed to moisture.  Seals sometimes leak and let water into the hub.  Corrosion happens inside propeller hubs.  I'm sure others can tell stories about it.

Removing a propeller and shipping it to a shop for IRAN is a pain in the arse, but might be worth it for piece of mind, especially if it hasn't been opened up and inspected in over 10 years, maybe 5 if unhangared.

Our C model had the 100 hour eddy-current inspection AD. About 5 years ago the shop doing the ECI told me that Hartzell wanted it opened up and inspected.  That turned into a painful experience because the blade roots were determined to be "undercut" and the blades were condemned.   We wound up buying a new prop (ouch).

In the end, it's all about risk management.   If you are not certain that your prop is in top condition and you have some reason to suspect that it might not be, you can use dollars to ameliorate that risk.

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About 5 years ago the shop doing the ECI told me that Hartzell wanted it opened up and inspected.  That turned into a painful experience because the blade roots were determined to be "undercut" and the blades were condemned.   We wound up buying a new prop (ouch).

 

a lot of prop shops never saw a prop that didnt need an overhaul. I dont see where hartzell tells the shop what to do. But how convenient

 

[ArrowBerry]

Canada has a 10 year requirement to overhaul constant speed props regardless of use. We went through one on a different plane in 2020 and I learned a little bit from the shop doing the work. They told me that most blades or hubs fail inspection because of corrosion on GA planes. Typically they come off of birds which spend a lot of time sitting outside without use. The owners are usually sticker shock at the price of repairing something they don't use often, which is why the corrosion existed in the first place. They will also check the pitch of the blades and "rebend" them back to spec, plus strip and repaint. 

I couldn't tell you if 10 years is a good time or not to look at a prop but its what we have to do here.

[0TreeLemur]

  On 10/7/2023 at 9:08 PM, jetdriven said:

About 5 years ago the shop doing the ECI told me that Hartzell wanted it opened up and inspected.  That turned into a painful experience because the blade roots were determined to be "undercut" and the blades were condemned.   We wound up buying a new prop (ouch).

 

a lot of prop shops never saw a prop that didnt need an overhaul. I dont see where hartzell tells the shop what to do. But how convenient

 

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The shop that I used for ECI's was located in Marianna, Florida, because they would do it with the prop mounted on the plane.  I guess some wont.   They told me that Hartzell instructions were to not to sign off on further ECI inspections for props that were not opened up and inspected in the last 10 years or so-  I don't remember the exact number.   They went ahead and gave me the inspection, but said they wouldn't do it again.   Some time in the following year, I took the prop off and took it to a prop shop in Bessemer, Alabama, for IRAN.   That's where they told me that the blades were undercut.  One by 0.003" and the other by 0.001".  Wow.

[jetdriven]

  On 10/8/2023 at 12:45 AM, 0TreeLemur said:

The shop that I used for ECI's was located in Marianna, Florida, because they would do it with the prop mounted on the plane.  I guess some wont.   They told me that Hartzell instructions were to not to sign off on further ECI inspections for props that were not opened up and inspected in the last 10 years or so-  I don't remember the exact number.   They went ahead and gave me the inspection, but said they wouldn't do it again.   Some time in the following year, I took the prop off and took it to a prop shop in Bessemer, Alabama, for IRAN.   That's where they told me that the blades were undercut.  One by 0.003" and the other by 0.001".  Wow.

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how coincidental thoise blades were a hair under the limit. Did they make them available for another shop to measure?