(UN) - Authorized Engine Mods?

[Mister Mystery Man]

In another forum some fliers were discussing the overhaul of a Warner 165 radial which caused me to start thinking and wondering about a few issues that were raised.

In this case of an antique engine that is no longer in production and no updated manufacturer’s information or parts available, can an AE modify Continental wrist pins (for example) and install them to fit the old engine?


Does his certificate provide him the right to authorize the substitution of non-standard parts or would it require an STC to be considered legal and in compliance with airworthiness regs?

Maybe the change could be performed and considered legal if the engine was reclassified to “experimental” status? Or would just an authorized mechanic signing off the work on the engine log be acceptable?

MMM

 

[Tom-D]

In another forum some fliers were discussing the overhaul of a Warner 165 radial which caused me to start thinking and wondering about a few issues that were raised.

In this case of an antique engine that is no longer in production and no updated manufacturer’s information or parts available, can an AE modify Continental wrist pins (for example) and install them to fit the old engine?

Big myth,, every part in the WARNER 165 is available. there are no reasons to manufacturer parts.


Does his certificate provide him the right to authorize the substitution of non-standard parts or would it require an STC to be considered legal and in compliance with airworthiness regs?

see FAR 21.9 (a) 5, and this AC http://aircraftrebuilder.com/index....parts&format=pdf&option=com_content&Itemid=29

Maybe the change could be performed and considered legal if the engine was reclassified to “experimental” status? Or would just an authorized mechanic signing off the work on the engine log be acceptable?


MMM

This is not necessary

I over haul Warner 165, mine and a couple others, parts are available.

 

[Tom-D]

After reading FAR 21.303 again I see it no longer applies to owner produced parts it's all about PMA.

but this AC does apply AC 23-27

http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgAdvisoryCircular.nsf/0/ccf7daac581048cd862575e6006ca078/$FILE/AC%2023-27.pdf

and it has a date of 5/18/09

the statement I was looking for is now in

21.9 Replacement and modification articles.

(a) If a person knows, or should know, that a replacement or modification article is reasonably likely to be installed on a type-certificated product, the person may not produce that article unless it is—

(1) Produced under a type certificate;

(2) Produced under an FAA production approval;

(3) A standard part (such as a nut or bolt) manufactured in compliance with a government or established industry specification;

(4) A commercial part as defined in §21.1 of this part;

(5) Produced by an owner or operator for maintaining or altering that owner or operator's product; or

 

[Skylane81E]

Maybe the change could be performed and considered legal if the engine was reclassified to “experimental” status? Or would just an authorized mechanic signing off the work on the engine log be acceptable?

MMM

You can do what ever you want to an engine if you don't plan on mounting it on a certificated airframe, I know of no "Experimental" engines, they are certificated or not and only Experimental airplanes can use non certificated engines.

So in that case it becomes an issue of what is the intended recipient of this engine?

 

[dmccormack]

After reading FAR 21.303 again I see it no longer applies to owner produced parts it's all about PMA.

but this AC does apply AC 23-27

http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgAdvisoryCircular.nsf/0/ccf7daac581048cd862575e6006ca078/$FILE/AC%2023-27.pdf

and it has a date of 5/18/09

the statement I was looking for is now in

21.9 Replacement and modification articles.

(a) If a person knows, or should know, that a replacement or modification article is reasonably likely to be installed on a type-certificated product, the person may not produce that article unless it is—

(1) Produced under a type certificate;

(2) Produced under an FAA production approval;

(3) A standard part (such as a nut or bolt) manufactured in compliance with a government or established industry specification;

(4) A commercial part as defined in §21.1 of this part;

(5) Produced by an owner or operator for maintaining or altering that owner or operator's product; or

Thanks for the reference, Tom. I've referenced the early FAR citation a couple of times in the logbook, but haven't had to lately. I'll download that one and add it to the library.

 

[Mister Mystery Man]

Question 4: If a mechanic manufactured parts for an owner is he considered in violation of section 21.303(b)(2)?

Answer 4: The answer would be no if it was found that the owner participated in controlling the design, manufacture, or quality of the part. The mechanic would be considered the producer and would not be in violation of section 21.303(a). On the other hand if the owner did not play a part in controlling the design, manufacture, or quality of the part the mechanic runs a good chance of being in violation of section 21.303 (b)(2).

Question 6: Is there anything else a mechanic must do?

Answer 6: The mechanic must ensure that the owner produced part meets form, fit, and
function, and within reasonable limits, ensure that the part does meet its approved type design (e.g. like looking at the approved data used to make the part). Then the mechanic installs the part on the aircraft, makes an operational check if applicable and signs off the required section43.9 maintenance entry.

Thank you for that, NC19143. That really cleared up a lot of my confusion. There was an incident at our home airport some years ago that I’ve always kind of wondered about:

There was a fellow that hangared his Piper Tri-Pacer next to me that was out flying one day and his engine lost power. (It was still running but couldn’t produce enough power to maintain altitude) He put it down in a soybean field and the bean vines ‘grabbed’ his gear and tumbled the craft over onto its back with substantial damage, but only minor injuries.

The NTSB discovered that a previous owner had replaced a vacuum tube on the intake manifold that caused the problem of manifold vacuum loss. The original tube had only a very small inside diameter (which wouldn’t adversely affect engine power in case it broke in two).

The tube that had been installed had a much larger inside diameter, allowing the manifold pressure to drop significantly and to cause the emergency off-airport landing.

I have often wondered how much trouble (if any) the previous owner and / or his A&P received as a result of the NTSB report.

According to the information you provided, I rather assume that nobody was taken to task. If the mechanic did a test flight after installing the vacuum line, everything would probably seem quite normal. The problem would only be apparent if the line broke again. (which it actually did for another owner several years later)

..MMM

 

[Henning]

In another forum some fliers were discussing the overhaul of a Warner 165 radial which caused me to start thinking and wondering about a few issues that were raised.

In this case of an antique engine that is no longer in production and no updated manufacturer’s information or parts available, can an AE modify Continental wrist pins (for example) and install them to fit the old engine?


Does his certificate provide him the right to authorize the substitution of non-standard parts or would it require an STC to be considered legal and in compliance with airworthiness regs?

Maybe the change could be performed and considered legal if the engine was reclassified to “experimental” status? Or would just an authorized mechanic signing off the work on the engine log be acceptable?

MMM

Actually, any OWNER is authorized to "Produce Parts" for his aircraft.

 

[Tom-D]

Actually, any OWNER is authorized to "Produce Parts" for his aircraft.

Not really.... the FAA will require you to prove fit, form and function,, think about how you would do that.

 

[Tom-D]

Thank you for that, NC19143. That really cleared up a lot of my confusion.
MMM

I'd like to know which web page you were talking about the warner 165 being overhauled..

 

[Henning]

Not really.... the FAA will require you to prove fit, form and function,, think about how you would do that.

Pretty simple typically, you build a part to match the original spec or modify a like material part to fit. Take the wrist pin example. If you pull a wrist pin that is from a similar HP engine that has a slightly larger dimension and turn it to fit and weigh within manufacturers tolerance, you'll have an acceptable part. I never said the part didn't need to be proper & acceptable, I said when pressed to it the owner is authorized to produce an acceptable part and you referenced the FAR.

 

[Tom-D]

Pretty simple typically, you build a part to match the original spec or modify a like material part to fit. Take the wrist pin example. If you pull a wrist pin that is from a similar HP engine that has a slightly larger dimension and turn it to fit and weigh within manufacturers tolerance, you'll have an acceptable part. I never said the part didn't need to be proper & acceptable, I said when pressed to it the owner is authorized to produce an acceptable part and you referenced the FAR.

Remember the wrist pin manufacturer of the Warner engine is no longer in business, where are you going to get the OEM spec for the pin, which you must duplicate?

The FAA will not except any other manufacturers data for the pin for the WARNER.

In most cases the owner will provide a blue print of the item to the machine shop that is considered compliance with the FAA's requirement for supervision of the part manufacturing process.

 

[Mister Mystery Man]

I'd like to know which web page you were talking about the warner 165 being overhauled..

Tom, The page must have been removed or archived because I haven't been able to pull it back up. I was, however, able to find one of the links in my 'history' folder still on my computer....

http://radialengines.com/overhauls/warner/warner.htm

MMM

 

[Henning]

Remember the wrist pin manufacturer of the Warner engine is no longer in business, where are you going to get the OEM spec for the pin, which you must duplicate?

The FAA will not except any other manufacturers data for the pin for the WARNER.

In most cases the owner will provide a blue print of the item to the machine shop that is considered compliance with the FAA's requirement for supervision of the part manufacturing process.

It's probably changed over the years but I made a lot of bits and pieces for a Kinner including wrist pins turned to fit. There wasn't much issue showing "reverse engineering" for the acceptable data. "Testing of the part replaced showed it was "xxx" spec of "XX" dimension. Most wrist pins are made out of the same stuff, you show same spec of metal and build to correct dimensions. Really wasn't much of an issue.

 

[Tom-D]

Tom, The page must have been removed or archived because I haven't been able to pull it back up. I was, however, able to find one of the links in my 'history' folder still on my computer....

http://radialengines.com/overhauls/warner/warner.htm

MMM

That's the Curry Brother in Guthry OK, they have stopped rebuilding the Warners because they say they had difficulties getting parts, But Allan Holloway of Quincy Ca still overhauls them, as I and several others do, we trade parts and supplies and part numbers of old stock still held on the shelf of Harlan Dickerson of Columbus Mo.

We have a problem looming on the horizon Harlan mentioned he was getting up in years and wanted to sell his stock of parts, but when he goes away so does his memory of what will interchange with what.

Allan said to me when we last talked, he was hating going to work because almost every day there is a new engine at his door, so he is about a year behind in getting caught up.

Right now a Warner 165 ready to install with no accessories is selling over $30K, I have a serviceable crank, and master rod assembly for a Warner 145 or 165 and a set of 4 ring pistons that I will sell for $20k. a single serviceable
cylinder will bring $2500.