dynamic balance of a propeller

[Tom-D]

Not quite that Tom. It's when you argue with the responses instead of corresponding reasonably that you need medication. No big deal but that's how other folks see it.

When I ask a question like this, I expect an answer that can be verified by rule or regulation.

show me how many posts in this thread did that.

and you think that is my fault.

 

[Dan Thomas]

In Canada the rules says this:


571.02 (1) Subject to subsection (2), a person who performs maintenance or elementary work on an aeronautical product shall use the most recent methods, techniques, practices, parts, materials, tools, equipment and test apparatuses that are (a) specified for the aeronautical product in the most recent maintenance manual or instructions for continued airworthiness developed by the manufacturer of that aeronautical product;
(b) equivalent to those specified by the manufacturer of that aeronautical product in the most recent maintenance manual or instructions for continued airworthiness; or
(c) in accordance with recognized industry practices at the time the maintenance or elementary work is performed.



(I highlighted the bold section.)



The equivalent FAR has a similar wording:


§ 43.13 Performance rules (general).

(a) Each person performing maintenance, alteration, or preventive maintenance on an aircraft, engine, propeller, or appliance shall use the methods, techniques, and practices prescribed in the current manufacturer's maintenance manual or Instructions for Continued Airworthiness prepared by its manufacturer, or other methods, techniques, and practices acceptable to the Administrator, except as noted in § 43.16. He shall use the tools, equipment, and test apparatus necessary to assure completion of the work in accordance with accepted industry practices. If special equipment or test apparatus is recommended by the manufacturer involved, he must use that equipment or apparatus or its equivalent acceptable to the Administrator.


Again, I highlighted the relevant section.


Another relevant FAA document, AC 20-37E:
http://www.expaircraft.com/PDF/AC-2020.pdf


Here's an excerpt:


"(d) When approved aircraft or propeller manufacturer’s procedures are not available, there are other acceptable dynamic propeller balancing procedures. These include, but are not limited to the Chadwick-Helmuth Publication No. AW-9511-2, entitled “The Smooth Propeller”, and ACES Publication No. 100-OM-01, entitled “ACES Systems Guide to Propeller Balancing”. Dynamic balancing of propellers using FAA-approved or -accepted dynamic propeller balancing procedures is not considered a major propeller repair unless the propeller static balance weights are altered or when using the Chadwick-Helmuth or ACES type documents on propeller installations of 500 horsepower or more."


Here's an FAA-Approved dynamic prop balancing manual:
http://www.acessystems.com/manual-gpb/gpb.pdf


Page 2 has the relevant references to the legalities. It says that IF there's prop balancing info in the maintenance manuals, it takes precedence over this document. In other words, if there's no reference to prop balancing in the MM, this document is legally usable.



And a good FAA article on the legalities:


http://www.faa.gov/about/office_org/field_offices/fsdo/lnk/local_more/plane_talk/media/mar05.pdf


Scroll down to page 5.



Dan

 

[CMTowner]

The few dynamic prop balance jobs I've seen have added the weight to the starter right support assy.

 

[VanDy]

When I ask a question like this, I expect an answer that can be verified by rule or regulation.

show me how many posts in this thread did that.

and you think that is my fault.

At least 1,

This kind of manual?

That has this section on dynamic balance?

-VanDy

But that only applies to 1 specific prop/airframe in this instance.


-VanDy

 

[Tom-D]

The bottom line in this discussion is that unless the manufacturer of the prop has placed the dynamic balance instructions in the ICAs of the prop as minor maintenance, You have no authority as an A&P to work on that prop.

ACs do not give you that authority because it does not carry the weight of a regulation.

 

[Geico266]

Nice thing about experimentals. I do what I want. I have a dynamic balancer and would not fly a plane I owned without having it dynamically balanced to within .05 IPS or less. Best money you can spend on your plane to reduce maintenance cost and improve the ride. Actually adds speed also.

 

[Clark1961]

When I ask a question like this, I expect an answer that can be verified by rule or regulation.

show me how many posts in this thread did that.

and you think that is my fault.

Your responses are entirely your responsibility Tom. No ifs, ands, or buts.

Keep in mind that your expectations have little influence on other's responses. Or don't keep it in mind. There are plenty of folks who're quite willing to argue with you when that's obviously what you want to do.

 

[Geico266]

The bottom line in this discussion is that unless the manufacturer of the prop has placed the dynamic balance instructions in the ICAs of the prop as minor maintenance, You have no authority as an A&P to work on that prop.

ACs do not give you that authority because it does not carry the weight of a regulation.

Tom, love ya man, but your panties are too tight this morning.

To suggest that dynamically balancing a propeller on any airplane would be against regulation is silly. Ask any prop shop, manufacturer, or FSDO.

 

[VanDy]

He actually said quite the opposite.

Tom, love ya man, but your panties are too tight this morning.

To suggest that dynamically balancing a propeller on any airplane would be against regulation is silly. Ask any prop shop, manufacturer, or FSDO.

Nice, they make balancing a minor maintenance item.

finally an answer.

 

[Tom-D]

Tom, love ya man, but your panties are too tight this morning.

To suggest that dynamically balancing a propeller on any airplane would be against regulation is silly. Ask any prop shop, manufacturer, or FSDO.

Is it ??

Show me the rule that counters the rule set forth in FAR 65.81. Just show it to me and end the discussion.

 

[Henning]

Is it ??

Show me the rule that counters the rule set forth in FAR 65.81. Just show it to me and end the discussion.

Show me where the spinner back is considered 'the propellor', I asked for that way back and you didn't provide that. Legal vocabulary is exacting for a reason.

 

[Geico266]

Is it ??

Show me the rule that counters the rule set forth in FAR 65.81. Just show it to me and end the discussion.

The rule is clearly laid out in Geico 266.334 paragh 2.756. Stating "What Geico says trumps the FAA.".

Take a deep breath Tom, we all get it. The regs don't support it. You found another hole in the regs. There are millions of them. Regs can't cover every eventuality as common sense does apply also. Dynamically balancing a prop / engine is good maintenance.

Let's call it engine balancing in which all engine manufacturers suggest (even Rotax) that an aircraft be dynamically balanced to reduce vibration and wear and tear.

Avionics manufacturers call out an operating environment free of vibration as possible.

Vibration in an aluminum aircraft is never a good thing. Minimizing vibration from an engine and airframe is always a good thing. So says the rules of Geico.

And so on.

 

[N801BH]

So, I guess when I have a question I need medication.

Nice Ben!

Sorry if my joking around upset you.....

What peaks my interest is you have been a A&P / IA for a long time and by the way you asked the question I have to assume you have never balanced a prop before... And you should know the balancing is done on the spinner / backing plate,, not the blades themselves.

 

[Tom-D]

Sorry if my joking around upset you.....

What peaks my interest is you have been a A&P / IA for a long time and by the way you asked the question I have to assume you have never balanced a prop before... And you should know the balancing is done on the spinner / backing plate,, not the blades themselves.

No Ben, I do not have a dynamic balancer, and can't comply with 43. So I do not do it.

But you are wrong about where the weights go. Not all props have spinners or backing plates, plus the Mc Cauley 2 blade fixed pitch has attachment points for weight directly on the prop.

This is an area where the FSDO could really bust the chops of the A&P who balanced a prop that had no ICAs that made the balancing a minor maintenance.

Specially when they are investigating an accident and really scrutinizing the log books after an accident.

like they just did to mine.

 

[N801BH]

No Ben, I do not have a dynamic balancer, and can't comply with 43. So I do not do it.

But you are wrong about where the weights go. Not all props have spinners or backing plates, plus the Mc Cauley 2 blade fixed pitch has attachment points for weight directly on the prop.

This is an area where the FSDO could really bust the chops of the A&P who balanced a prop that had no ICAs that made the balancing a minor maintenance.

Specially when they are investigating an accident and really scrutinizing the log books after an accident.

like they just did to mine.

Thanks Tom.. I didn't know that about Mc Cauley fixed pitch prop.. I wonder what the balancing proceedure is for it ? and who is actually allowed to balance one ?

Surely you don't have to fly the plane back to the Mc Cauley factory.

 

[Tom-D]

Thanks Tom.. I didn't know that about Mc Cauley fixed pitch prop.. I wonder what the balancing proceedure is for it ? and who is actually allowed to balance one ?

That is the quandary isn't it.

 

[RotorAndWing]

What peaks my interest is you have been a A&P / IA for a long time and by the way you asked the question I have to assume you have never balanced a prop before... And you should know the balancing is done on the spinner / backing plate,, not the blades themselves.

Ben,

I balanced a lot of propellers (dynamic) using the Aces 2020 Probalancer. Here is their FAA Approved Manual http://www.acessystems.com/manual-gpb/gpb.pdf if you want more information on the subject.

The other system commonly used is the Chadwick, however I've only tracked helicopter blades using one of those.

 

[VanDy]

Found this in a Mcauley owners manual/ica and found it interesting:

-VanDy

 

[Clark1961]

Found this in a Mcauley owners manual/ica and found it interesting:

-VanDy

That disapproval boarders on the insane: You can't reduce fatigue because it might cause cracks.

 

[Henning]

That disapproval boarders on the insane: You can't reduce fatigue because it might cause cracks.

But is it a disapproval? They say "some" which is ambiguous.

 

[Clark1961]

But is it a disapproval? They say "some" which is ambiguous.

True. Dunno what it really is.

 

[VanDy]

But is it a disapproval? They say "some" which is ambiguous.

Sounds like a 'cover your a$$' for mcauley, placing responsibility on the mech for checking the airframe manual very thoroughly. Without checking EVERY airframe service manual, who knows if its true or a 'legality' I'm not going to waste that much of my time looking!


-VanDy

 

[Henning]

Exactly, it's basically a warning that they will deny liability for cracked spinners and the results there of in a court of law. LOL, Reminds me of Harold Miller, my Ag instructor. Dude drops in on us at a marked private airport with an ultralight and asks if he can tie it down there and how much it would cost. Harold looks at the guy and says, "Look, you can keep your plane here if you want, just don't sue me."

 

[Tom-D]

Ben,

I balanced a lot of propellers (dynamic) using the Aces 2020 Probalancer. Here is their FAA Approved Manual http://www.acessystems.com/manual-gpb/gpb.pdf if you want more information on the subject.

The other system commonly used is the Chadwick, however I've only tracked helicopter blades using one of those.

So, now are we saying that the operators manual for the balancer equipment supersedes FAR 65.81 ?

 

[RotorAndWing]

Surely you don't have to fly the plane back to the Mc Cauley factory.

Ben,

On a fixed pitch propeller it's possible to bring it into balance without weights. The first method is to check prop track, if the track exceeds 1/4 inch then remove the prop, move one bolt hole over, torque and recheck track. A closer track will result in a smoother prop.

The next step on a fixed pitch with the old "skull cap" spinner or no spinner is to once again establish track. If that doesn't fix it (it usually improves) then the prop needs a static balance, then followed with a dynamic balance.

Worn spark plugs, bad mags or an imbalanced fuel injection will give bad readings (ips) as well as worn engine mounts. All of these must be considered when performing a dynamic balance.

And the worst to attemp to balance are 3 bladed props on a 4 cylinder engine. It can be done but can be labor intensive.

 

[N801BH]

Ben,

I balanced a lot of propellers (dynamic) using the Aces 2020 Probalancer. Here is their FAA Approved Manual http://www.acessystems.com/manual-gpb/gpb.pdf if you want more information on the subject.

The other system commonly used is the Chadwick, however I've only tracked helicopter blades using one of those.

R&W... That is the exact balancer I use..... The unit works perfectly for all applications and is repeatable to amazing accuracy...:wink2:

 

[N801BH]

Ben,

On a fixed pitch propeller it's possible to bring it into balance without weights. The first method is to check prop track, if the track exceeds 1/4 inch then remove the prop, move one bolt hole over, torque and recheck track. A closer track will result in a smoother prop.

The next step on a fixed pitch with the old "skull cap" spinner or no spinner is to once again establish track. If that doesn't fix it (it usually improves) then the prop needs a static balance, then followed with a dynamic balance.

Worn spark plugs, bad mags or an imbalanced fuel injection will give bad readings (ips) as well as worn engine mounts. All of these must be considered when performing a dynamic balance.

And the worst to attemp to balance are 3 bladed props on a 4 cylinder engine. It can be done but can be labor intensive.

Agreed.... Some applications can be a bugger to balance... Personally I have seen mechanics clean and repaint a prop during an annual and they will use the white, outer section of the prop to add very slight amounts of weight by applying slighty more paint to to. The plane does not leave the shop till the IPS is .03 or less... And they can do that every time.... Darn good mechanics in my book.

Less Vibration = A safer and more enjoyable plane.

 

[mvferrer]

So, now are we saying that the operators manual for the balancer equipment supersedes FAR 65.81 ?

From AC20-37E Aircraft Propeller Maintenance (page 28)....

(c) For aircraft or propeller manufacturers that provide procedures for dynamic balancing of the propeller in their maintenance manuals or instructions for continued airworthiness, propeller balancing is not considered a major airframe alteration.

(d) When approved aircraft or propeller manufacturer’s procedures are not available, there are other acceptable dynamic propeller balancing procedures. These include, but are not limited to the Chadwick-Helmuth Publication No. AW-9511-2, entitled “The Smooth Propeller”, and ACES Publication No. 100-OM-01, entitled “ACES Systems Guide to Propeller Balancing”. Dynamic balancing of propellers using FAA-approved or -accepted dynamic propeller balancing procedures is not considered a major propeller repair unless the propeller static balance weights are altered or when using the Chadwick-Helmuth or ACES type documents on propeller installations of 500 horsepower or more.

 

[timwinters]

So, now are we saying that the operators manual for the balancer equipment supersedes FAR 65.81 ?

What's the conflict? The manual has FAA approval. It also states that a 337 must be filed to return the aircraft/propellor to service after balancing (if weights are installed on the spinner bulkhead) thus implying that an A&P, IA must be involved.

 

[Geico266]

Show me where the spinner back is considered 'the propellor', I asked for that way back and you didn't provide that. Legal vocabulary is exacting for a reason.

After I thought about this for a day (thanks Tom) most of the props I have dynamically balanced the weights go on the flywheel. There are holes clocked at pretty convenient intervals. I use the spinner backing plate usually only when balancing a Rotax 912.

Yes, I use Nyloc nuts north of the firewall.

 

[flyingmoose]

From AC20-37E Aircraft Propeller Maintenance (page 28)....

(c) For aircraft or propeller manufacturers that provide procedures for dynamic balancing of the propeller in their maintenance manuals or instructions for continued airworthiness, propeller balancing is not considered a major airframe alteration.

(d) When approved aircraft or propeller manufacturer’s procedures are not available, there are other acceptable dynamic propeller balancing procedures. These include, but are not limited to the Chadwick-Helmuth Publication No. AW-9511-2, entitled “The Smooth Propeller”, and ACES Publication No. 100-OM-01, entitled “ACES Systems Guide to Propeller Balancing”. Dynamic balancing of propellers using FAA-approved or -accepted dynamic propeller balancing procedures is not considered a major propeller repair unless the propeller static balance weights are altered or when using the Chadwick-Helmuth or ACES type documents on propeller installations of 500 horsepower or more.

Oh thats a good one. Nice find.

 

[Dan Thomas]

Oh thats a good one. Nice find.

It sure is. I posted that back in post #42.

Dan

 

[kgruber]

What's the conflict? The manual has FAA approval. It also states that a 337 must be filed to return the aircraft/propellor to service after balancing (if weights are installed on the spinner bulkhead) thus implying that an A&P, IA must be involved.

Like I said previously, the mechanic who balanced my C-185 filed a 337.

 

[flyingmoose]

It sure is. I posted that back in post #42.

Dan

Oh well then. Good for you too then.