N95598 gets a new prop (reconditioned like new)

[NY86]

Re: N95598 gets a new prop (reconditioned like new)

illegal
il·le·gal
   [ih-lee-guhl]
–adjective
1.
forbidden by law or statute.
2.
contrary to or forbidden by official rules, regulations, etc.

If your prop is a McCauley then it may be deemed prohibited by virtue of the fact that their service information specifically states the prop is to be painted. However, that does not make every instance of a polished prop illegal, nor is it by any means the end of the story.

[lfries]

Re: N95598 gets a new prop (reconditioned like new)

We have several polished props on the airport ranging from a luscombe to a very nice V35. I believe there are at least two seperate shops involved in signing off the annuals. One small shop and one very large shop. I respect both IA's.

[Mark Julicher]

Re: N95598 gets a new prop (reconditioned like new)

Propellers have Type Certificate Data Sheets. If a finish is specified in the TCDS and your propeller is not compliant, then you are not compliant. If no finish is specified... dunno, need to do more research. Somebody call a propeller shop!

[swoeric]

Re: N95598 gets a new prop (reconditioned like new)

they anodize treatment they use will not be any different than what was first used or used by anybody else. second lets hope they did not end for end your prop especially on the hub. frome appearance it looks to be chromic or thin sulfuric anodize. this over lap would be caused by a lamination. anodize is buildup is half into substrate and half thickness on top. if it were end for end the light area would be over thickness. as it gets too thick anodize will powder off. mean while reanodizing an area will mean that the voltage in that area was not sufficiant to break the thickness and the acid solution will actually attack the part. if this was at the solution surface oxidation would happen at a greater rate with less control.


The other option would be that the mark is where contact for electrical current was made using a wire. if we knock out the math that they were pulling several amps per ft square i would bet they was uneven current density or coating weight. i would also question the professionalism or experience of a shop that would not just build a tank if they planned on doing props.

yes anodize does create a surface much closer to ceramic. yes it can be easily penetrated depending on thickness. yes in severe cases thick anodize can be a source or crack propogation. yes it is still the best corrosion inhibiting coating available to aid in paint adheasion.

if there is something i have left out let me know.......

ps polished props are fabulous i have never heard of aircraft confiscation over a polished prop and very few cases percentage wise of grounding till another prop was found. (and then replaced back)

[jim cooper]

Re: N95598 gets a new prop (reconditioned like new)

If I still had my polished prop I would sure as hell fly it! It was an old mccauley and the tips were red white and blue to match the airplane. It was GOOD LOOKING! In my area, Balt. Wash. area, AI's are very cautious as there is alot of Faa around. In western N.Y. just the opposite. (This is where my T Craft was rebuilt.) Much more relaxed attitude. I polished it with Mothers metal polish and you could shave in it! Really miss it. JC

[Edwin Otha]

Re: N95598 gets a new prop (reconditioned like new)

I think it come down to the manufacturers repair instructions. Sensenich manual says after repair it's painted with Polane paint. My prop got repaired by polishing and painted with Polane clear paint. That's my story!
EO

[avenger1949]

Re: N95598 gets a new prop (reconditioned like new)

Was told by a local FAA guy.... if all the planes that had illegal parts on them, out of annual, pilot with no license or improper license, pilot with no current bi-annual, bad or missing ELT and about a half dozen other no no's were to fall out of the air at the same time..... you would think it was raining.

[jim cooper]

Re: N95598 gets a new prop (reconditioned like new)

this brings us back to.....the INSURANCE CO.! IF YOU fall out of the sky then they will investigate everything! When the hangar collapsed and ruined my T-Craft, the insurance co. paid in 10 days. However the appraiser stated that "if it had been an in flight or moving accident it would have been far more complicated". This means that they would have turned every stone to avoid payment. The prop shop(East Coast Propeller) explained to me that polished props have microscopic pits that can , in time, lead to failure. (It stands to reason that each time you polish it, you remove something.) JC

[NY86]

Re: N95598 gets a new prop (reconditioned like new)

I still say, they can't just say "it's illegal". They have to at least make a rational argument, citing regulations or approved data, justifying the claim. In fact, if a plane came from the factory with a polished prop and was "legal" at that time, the only way it can become illegal is through an AD.

[avenger1949]

Re: N95598 gets a new prop (reconditioned like new)

I build show cars... I have imperfections ...pits and such in my paint when it is first shot. I polish it to take out the imperfections and make the pain smooth as glass... not sure why they would stay in a metal polish job. Ok... so if I polish a prop... and clear coat it... is it painted and then ok. Just wondering

[Hank Jarrett]

Re: N95598 gets a new prop (reconditioned like new)

I think we are all arguing a dead issue. It doesn't MATTER if the prop is safe polished or not. If the manufacturer doesn't approve of polishing the prop the insurance company (or some totally annal Fed) is going to give you trouble. If your mechanic doesn't want you to use a polished prop, he isn't going to sign your paperwork. End of story.
I asked the question here because a bunch of local "Ramp Rats" told me I couldn't polish the prop. Of course these guys have been full of BS more times than not and I agree with John, if you are going to claim something is "illegal" you should be able to back it up. That is completely different than actually DOING it. If the manufacturer says it is OK, then the mechanic will agree. If a Fed says you can't do it, you can show him the letter and tell him to pound sand (politely). If the insurance company refuses, you have a good case with a letter from the manufacturer. What is safe or reasonable doesn't really matter.
I plan to go to the manufacturer and get them to put it in writing. I have a feeling they won't like polished props (since a lot of guys won't KEEP them polished and new pits could lead to failure). I just hope a polish followed by a clear coat from a prop shop is good. If not, I will get it painted and go on my way.
Sometimes being right isn't enough. You have to look at the practical side and just do what you are told by the man in charge.
Hank

[NY86]

Re: N95598 gets a new prop (reconditioned like new)

You have to look at the practical side and just do what you are told by the man in charge.

"All that is necessary for the triumph of evil is that good men do nothing"

[Hank Jarrett]

Re: N95598 gets a new prop (reconditioned like new)

You CAN make changes. When I was a Maintenance Officer in the navy we found MANY things wrong in the maintenance manuals. The typical response in the fleet was, "That is C**P and we have NEVER done it that way. We do it THIS way and always have". Typically almost EVERY squadron had a Chief who ignored the manual and did it "the right way". The point I tried to make to my Chief was that if it was WRONG, why not put a Manual Change Request in and FIX THE MANUAL so the poor slob that doesn't know there is a better way can take advantage of his vast aeronautical knowledge.
I have to say, there were MANY cases where Grumman came back and said my Chief's way was better, and they changed the manual. There were, however, WAY TOO MANY times where the Tech Rep came out and showed us how our "JACK LEG, IDIOTIC, MISGUIDED, BRAIN ADDLED, JUST PLAIN STUPID" activity had significantly reduced the life of the part or basically destroyed it. When we started submitting more Manual Change Requests than the rest of the Wing combined we started getting pretty quick response to grab the good ideas and make sure we weren't doing something stupid with the bad ones.
If we are told we can't polish our props, and you REALLY WANT ONE, we need to get our facts straight, go to the manufacturer, and make our case. As good as a polished prop looks, I am sure they will welcome our method, if it works. If not, we need to look at WHY they say no, and LISTEN. We should NOT do nothing, but the manufacturer is not evil. (The wink is acknowledged John, we have known each other long enough to recognize what we are really saying.) They don't need a law suit, and we don't need to get dead.
Hank
I still want a polished prop. I plan to use the knowledge I gain here to try and get the manufacturer to accept them and change the recommendation. That or they will get tired of listening to me and show me why we SHOULDN'T polish them. If they have good reasons, I will accept them (because I said so is NOT a good reason).

[barnstmr]

Re: N95598 gets a new prop (reconditioned like new)

I have been looking for something specifically from McCauley on this topic. I have come up short. But I found an interesting file (attached) regarding the "10 Commandments" for Klip-Tip Props". It is an interesting read. I also found and attached a McCauley service bulletin that addresses a manufacturing defect on a fixed pitch model (NOT KLIP-TIP) but made from same materials. It has a detailed description of the method to strip paint, inspect, and re-finish. Interestingly, they recommend either alodine or anodize coating prior to paint.

"Propellers must be chemically recoated per MIL-C-5541 (alodine) or MIL-A-8625
(anodize) prior to painting. Paint per McCauley Manual 730720."

I talked to our 'prop man' at work. He said Hartzell's and McCauley's position if you ask them would be focused on corrosion prevention and would not recommend polishing out of the fear that some people would neglect the upkeep.

So far, nobody has been able to produced any manufacturer's data that PROHIBITS polishing. So from a regulatory standpoint the prop simply must be in a condition for safe operation. And it is the pilot's ultimate responsibility to make this determination.

My advice is, if you are going to fly any airplane with a polished (or un coated) prop. Look it over really well to determine if corrosion is present before you fly. If you are thinking about polishing a prop, ask yourself whether you want to do the necessary maintenance. If you aren't planing to keep up the up-keep... anodize and/or paint it.

[magman]

Re: N95598 gets a new prop (reconditioned like new)

Yes; I KNOW this would not apply to a T.

Recently my FSDO announced that any AIRCRAFT that was not originally bare aluminum could NOT be stripped & polished.

"You are removing the corrosion protection that the mfg provided".

Hence; early 150's & 172's would be ok but a Cherokee would not.

It may have been a mfg. SL that brought this about.

FYI- Up till about 1962 paint was an OPTION on a Cessna.

Normal was just a little stripe.

Recent events with far newer 737's may affect us with " fallout".

Or is it "Collateral Damage".