The International Cessna^® 170 Association

This refers to US A&P's & A/I's only: According to my PMI C-180 aluminum bushings can be substituted and log book sign off used. It's not a major alteration and doesn't impact the airworthiness in a negative way. Manufacturing of a bushing is NOT legal. There are many "Used" bushings floating around the market place and if not excessively worn are good to go. Part numbers have been listed in previous posts.

Why wouldn't it be legal to make the aluminum bushings as an owner made part?

The regs say that if a factory part is available you must try that avenue first (and they are as of today @ Floats Alaska 907-248-7070). OBTW; Either of 2024-T3 or 6061-T6 aluminum alloys are what you would need if you opt for self made. Both are now being used as approved float materials (EDO & Aerocet).

I completely missed that statement when I read 14CFR 21.303-b-2 or any of the rest of part 21.
Could you send me a link to where I can find that in the FAR.
Thanks

Lets not beat around the bush. The 14CFR 21.303 does not say that a part must not be in current production and available somewhere in order for an owner to make, or have made, a part under the owner produced part clause.

An owner can not make, or have made, parts and then sell them as certified parts.

• AC 20-60E
  • b. Acceptable Parts. The following parts may be found to be acceptable for installation on
    a TC’d product:
    
    • (2) Parts produced by an owner or operator for maintaining or altering their own
      product and which are shown to conform to FAA-approved data.
    n. Owner/Operator Produced Part. Parts that were produced by an owner/operator for
    installation on their own aircraft (i.e., by a certificated air carrier). An owner/operator is
    considered a producer of a part, if the owner participated in controlling the design, manufacture,
    or quality of the part. Participating in the design of the part can include supervising the
    manufacture of the part or providing the manufacturer with the following: the design data, the
    materials with which to make the part, the fabrication processes, assembly methods, or the
    quality control (QC) procedures.

A simple bushing made of a common aluminum alloy would be fairly easy to produce by an owner if they had one in hand. The hardest part would be documenting the alloy used in the certified part. Other parts can be done but it can get much more complicated.

Bruce,

Some of these posts make me want to quit the wrenching business. FAA 8100 goes into far more detail than the reg. I've taken the time to do the reading and asked the hard questions on this subject.

There are grey areas that many explore. The reg only says what it says But if you pay attention to FAA oversight, methods, materials and get the lawyers involved, I'd be buying off of the PMA'd market. I've seen what happens when people stretch those regs. The next AI down the line may elect to nix those parts at the very least. Remember you must also make record entries. Also the FED's have the 8100 manual that has many preambles outlining the intent of regulations which cover these grey areas. If it were me I'd be reading between the lines for "Intent" that being no parts available or logistical issues....

My PMI stands behind "Owner Produced " parts but he also cautions that if he finds people using the wrong materials or sloppy workmanship, he'd lower the boom on them. I'd love to challenge the "Owner" to prove after the fact as to what materials were used! This thread has suggested many materials that would fall into that category and we as professionals would and do caution the membership to use some common sense when going down this path. As I've said many times "you can't just pull to the side of the road when things go South" and "These are certificated aircraft and as such we can't go to Lowes for our parts", so try to keep things real and not go down the path of "Grey areas". These parts aren't that expensive that we need to be making them . Also pay attention to do other component parts required for those mounts. There is a ring that goes inside under the washer and over the bushing. That part is critical to properly torque the bushing in place so If you must manufacture the bushing the ring must also be made to fit that bushing and thick enough to provide grip when the bolt is torqued to specs.

Just buy the darn parts and be done with it! Or at the least keep a paper trail for your materials, methods, references as to how the part must be inspected and a detailed print of the part. On and on. You might reference the application for field approval for guidance.

If I'm coming across as "Anal" well, I am on this point. I love not "Beating around the bush" Referencing the actual reg I read it as there's more to the story! My PMI underscores that point.

OBTW: The 100 series service manual references 2024-T3 as the material used in the manufacture of Cessna aircraft. Larger sizes and shapes of that material is sometimes hard to come by.

Owner produced parts should be documented and that documentation kept in the aircraft records, which will resolve the issues of who/how/what/airworthiness. FAAs Bill O'Brien (rest his soul) wrote extensively about owner produced parts. Make certain the documentation includes the owners written "request" to the mfr'r, and the description of method and materials to be used, and the mfr's written statement as to conformity with those instructions. Don't lose them. (But I have to admit, those particular parts are cheap and plentiful...why bother otherwise?)

George,

Well put! My only additional input would be that in the past every time I've approached the FAA or Cessna on this subject and asked the first thing out of their collective mouths has been "Can it be purchased on the open market"? AND that is the crux of my points. FAA 8100 addresses that very point in the guidance preambles. Why it didn't make it into the rule is beyond me. So, that being said it should also address the outrageous cost of new parts being influenced by "Tort". That's according to the manufacturers. I think they were once doctors or pharmaceutical manufacturers by the way they bump up prices without a basis not tort.

So, Pricing, availability and logistics should be the rule according to my judgments.

Just say'in!

Here's the article I thought might apply (colors added by me for emphasis):

Article 110
02/21/01
AMT Magazine
FAA Feedback column
“I” verses “We"
Bill O’Brien, NRS
Along with the pilot shortage and mechanic shortage there is also a parts shortage that plagues the general aviation industry. Because supply and demand are out of balance the cost of new and used parts seem to increase every day. Let’s examine the reasons why this is so.
First, we have an old fleet. The average general aviation single engine airplane is approximately 32 years old. The average age of GA multi-engine reciprocating aircraft is close to 27 years old. The average age for the turbine powered multi-engine propeller driven aircraft average out around 19 years of age. So do to long term wear and tear the demand for replacement parts and large sub-assemblies is much greater today than it was even 10 years ago.
The second reason is our General Aviation fleet has been well maintained over the years. So well maintained in fact, the average GA aircraft with a mid time engine and decent avionics has appreciated to two or three times it’s original purchase price and is still climbing. Yet even in that land of many zeros the older aircraft are still substantially lower in price than the cost of brand new aircraft with similar performance numbers and equipment. So the value of older aircraft in good shape are proven investments that over time has beat the DOW JONES average. So we have an economic imperative on the part of the owners to keep maintaining older aircraft in flying condition which increases the demand for replacement parts.
The third reason is the increasing production costs to make a part. Today aircraft manufacturers are not making makes and models of aircraft in the same quantity they made them back in the seventies. So the production runs for parts are not as frequent and not as many parts are produced. In addition it is not cost effective for a manufacturer to make a lot of parts even if the unit price for each part is out of this world because taxes on maintaining a large inventory of parts would eat all of the profits. This low parts production keeps the supply of replacement parts low.
The fourth reason is that some manufacturers would prefer that their older makes and model aircraft that they made a million years ago would quietly disappear from the aircraft registry. This retroactive birth control on the part of the manufacturers may seem not to make any sense until you look at aircraft market dynamics of creating demand and reducing costs. First , each older aircraft that is no longer in service creates a demand for a new, more expensive aircraft to take its place. Second, despite some tort claim relief granted to GA manufacturers in the early nineties, the fewer older aircraft there are in service, the manufacturers of those aircraft enjoy reduced overall liability claims and ever decreasing continuing airworthiness responsibilities.
So how are we going to maintain these older aircraft with an ever dwindling parts supply when Part 21, section 21.303 Replacement and modification of parts requires us to use the Parts Manufactured Approval (PMA) parts on a type certificated product? Well, the same rule grants four exemptions to the PMA requirement.
1. You can use parts produced under a type or production certificate such as a Piper Cessna, or Mooney produced part;
2. A owner or operator produced part to maintain or alter their own product;
3. Parts produced under a Technical Standard Order (TSO) such as radios, life vest and rafts, and GPS; or,
4. A standard aviation part such as fasteners, washers, or safety wire.
Before I segue into the subject of “owner produced parts” as called out in section 21.303 which is the purpose of this article. I would like to create a small uproar with this statement: “ FAA Airframe and Powerplant rated mechanics can maintain, repair, and modify parts, but they cannot make a brand new part and call it a repair.” Before you accuse me of losing dendrites by the minute, check out section 65.81 General privileges and limitations. The section talks to maintenance, preventive maintenance, and alterations but not to manufacturing of parts. Nor is it implied privilege in Part 65, because Part 21 section 21.303 says “NO PERSON” may make a REPLACEMENT part for a TC product unless that person has a PMA, etc.
While I write this I can remember 25 pounds ago and when I had hair, I worked in the real world and I specialized in making engine baffles for Lycoming engines. Before someone accuses me of bureaucratic ventriloquism which is roughly translated as “talking out of both sides of my mouth.” My weak defense is, I made the parts because I thought I could.” It never dawned on me that I could not legally make a part. Some of you may be astounded that I make this confession freely. Its no big thing because I know the statue of limitations has run out years ago and a jury of my peers would never look me in the eye and convict me.
So here is our problem that we must solve. Since mechanics cannot legally make parts for aircraft and aircraft need replacement parts, how are we going to keep the fleet flying?
If we cannot find PMA, TSO, standard, or production holder replacement parts, we are left to make the part under the owner produced option under section 21.303(b)(2). However, we must remember that the part is for the owner/operator’s aircraft only and is not manufacturered for sale to other TC aircraft.
To get through confusing regulatory policy with our pride intact, lets try the question and answer routine. (Note: This policy is taken from FAA ‘s AGC-200 policy memorandum to AFS-300 on the definition of “Owner Produced Parts” dated August 5, 1993)
Question 1: Does the owner have to manufacturer the part himself in order to meet the intent of the rule?
Answer 1: No, the owner does not have to make the part himself. However to be considered a producer of the part he must have participated in controlling the design, manufacturer, or quality of the part such as:
1. provide the manufacturer with the design or performance data from which to make the part, or
2. provide the manufacturer with the materials to make the part or,
3. provide the manufacturer with fabrication processes or assembly methods to make the part or,
4. provide the quality control procedures to make the part or’
5. personally supervised the manufacturer of the part.
Question 2: Can the owner contract out for the manufacturer of the part and still have a part that is considered, “owner produced?”
Answer 2: Yes, as long as the owner participated in one of the five functions listed in
answer 1.
Question 3: Can the owner contract out the manufacturer of the part to a non-certificated person and still have a part that is considered “owner produced.”
Answer 3: Yes, as long as the owner participated in one of the five functions listed in
answer 1.
Question 4: If a mechanic manufactuered 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 5: What kind of advice you can give on how a mechanic can avoid even the appearance of violating section 21.303(b)(2)?
Answer: First, a mechanic should never make a logbook or maintenance entry saying that he made a part under his certificate number. This foopah will send up a flare and get you undue attention from your local FAA inspector which you could do without. However, the mechanic can say on the work order that he helped manufacturer an owner produced part under 21.303 (b)(2).
Second, the owner or operator should be encouraged to make a log book entry that is similar to section 43.9 maintenance entry that states: The part is identified as an owner produced part under section 21.303 (b)(2). The part was manufacturered in accordance with approved data. The owner/operator’s participation in the manufacturer of the part is identified such as quality control. The owner must declare that the part is airworthy and sign and date the entry.
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 section 43.9 maintenance entry.
Question 7: What is the owner responsible for, and what is the mechanic responsible for, concerning owner produced parts?
Answer 7: The owner is responsible that the part meets type design and is in a condition for safe operation. The mechanic is responsible for the installation of the owner-produced part is correct, the installation is airworthy, and a maintenance record for installing the part is made.

Question 8: How does the owner or operator get the approved data to make a part if the manufacturer and other sources are no longer in business?
Answer 8: For aircraft that the manufacturer is no longer supporting the continuing airworthiness of then the owner or operator can petition the FAA Aircraft Certification Directorate under the Freedom of Information Act for the data on how the part was made. Or the owner or operator can reverse engineer the part and have the data approved under a FAA field approval or if it is a real complicated part, have the data approved by a FAA engineer or FAA Designated Engineering Representative.
Question 9: What happens to the owner produced part on the aircraft if the original owner sells the aircraft?
Answer 9: Unless the part is no longer airworthy, the original owner produced part stays on the aircraft.

Please pardon my ignorance, but what is the advantage of aluminum engine mount bushings?

cessna170bdriver wrote:Please pardon my ignorance, but what is the advantage of aluminum engine mount bushings?

You can make em on a lathe as an owner produced part.

I my case, I have approved data from the IO-360 STC. The drawings were included with the engine mount drawings but I only have license to make one set for my airplane...and it's still considered an owner made part.

I think the biggest advantage of aluminum bushings is your engine wont sag over time as the rubber goes bad. But if your mount was sagging, you'd need to replace the bushings on condition anyway.

Regarding the FAA trying to interpret their own regulations, I think this speaks to the core problem with GA today.

Everyone is afraid of being responsible for doing something that someone else might disagree with.

The mechanic doesn't want to make a decision because the AI might not approve it at next annual and both are victim to the current mood of the guy at the local FSDO. So 'just to be safe' everyone takes this passive aggressive approach that if the regs don't 100% explicitly address and approve the exact procedure to the last nut and bolt...we can't do it.

1. The local sheriff is interpreting the constitution in a way that he thinks is best and you have no way to appeal to a higher law. Rules are useless if the local guy can say, "Well, what they meant to say was..." or "I don't know why they wrote it that way but..." and you don't have a higher authority that can correct these actions in a timely manner. And even when we DO get clarification on something, the local guy can still find some trivial difference where it doesn't apply in this specific case.

2. If you want the regs to say something different ( "If not readily available" ) then you have to change the regs vs enforcing your point of view. Else every A&P/IA/FSDO is simply flexing their opinion on the subject and not following the the given regulation. Even if their opinion is BETTER than the regs, they shouldn't have the right to enforce their opinions over the regs.

By the way, i was still wondering if anyone has the dimensions, it would be greatly appreciated, otherwise I can just do some measuring and figuring.

bagarre wrote:Regarding the FAA trying to interpret their own regulations, I think this speaks to the core problem with GA today..... Even if their opinion is BETTER than the regs, they shouldn't have the right to enforce their opinions over the regs.

I think it boils down to this: In order for any IA to approve an airplane for "return to service" then HE has to feel good about it being legal to do so. (THAT is where the OWNER gets to make some input...when he HIRES a particular IA.)

But..in order for an FAA Inspector to create a problem for an owner/operator... that FAA Inspector has to be willing to make a WRITTEN complaint about the matter...and HE knows that HIS opinion is only that...an opinion...AND he knows that if he is wrong...he's going to have some egg on his face both in the public eye AND in the eye of his peers....maybe even in the eye of his legal dept. He doesn't want that.

However, all ANYONE has to do to find what is right/wrong/enforceable/non-enforceable... is to ask FAA-OKC for a legal opinion.... and EVERYONE can take that to the bank with some degree of confidence. I.E., if you have a set of SR-71 instrument lights in your 170 and you want to avoid trouble over them... then before you install them take pics, and submit documentation to OKC and ask for the FAA Legal dept to make the call. Keep their response in your aircraft records.