Why is a 337 required?

Checkout_my_Six said:
bingo....the PMA makes the part equal to the certified part removed. So, from a certification basis....they are equal and no "supplemental" certificate (STC) is required.
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Here is an example of a PMA certificate that requires an STC at initial installation.


 
How can you tell based on that PMA that an STC is required? Supplement #37?
 
bnt83 said:
Here is an example of a PMA certificate that requires an STC at initial installation.


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My a&p may or may not have installed my Parmetheus par36 without an stc under the pma authority.
 
So they took a PAR36 bulb out and installed another PAR36 bulb from a different manufacturer that is not only brighter but more energy efficient?


Oh the horror. :eek:

Edit: Sorry for the outbreak of saltiness. :redface:
 
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This is the kind of crap that makes me want to buy an RV-10.
 
Checkout_my_Six said:
bingo....the PMA makes the part equal to the certified part removed. So, from a certification basis....they are equal and no "supplemental" certificate (STC) is required.
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This is not true.

PMA does not give you authorization to use one part to substitute for another.

PMA only gives the manufacturer the authority to produce the part.

The FAA authorizes the part to be a direct replacement by the issuance of a STC. or letter of authorization.
 
Tom-D said:
This is not true.

PMA does not give you authorization to use one part to substitute for another.

PMA only gives the manufacturer the authority to produce the part.

The FAA authorizes the part to be a direct replacement by the issuance of a STC. or letter of authorization.
Click to expand...
Hmmmm....so what is PMA by identicality?....is there an STC for that?
 
Checkout_my_Six said:
Hmmmm....so what is PMA by identicality?
Click to expand...

What does the three letters stand for? Parts Manufacturing Authority.

You can not manufacture Cessna parts for resale with out one. They are not required to be exact duplicates.

You can not manufacture pistons for Lycoming with out a PMA, such as Superior has to sell after market Lycoming parts.
Cylinders are a great example, you can buy Superior cylinders install them on a Lycoming engine without any STC because they are exact duplicates and Superior has PMA. You can not buy ECI cylinders for the 0-200/0-300 with out a STC because they have been modified by adding an exhaust valve rotator, and that is a change of design. Thus there is no requirement for PMA.
 
so a TC and an STC authorizes the holder to produce that part? :D


hint....there are three basic kinds of PMAs.
 
Tom-D said:
This is not true.

PMA does not give you authorization to use one part to substitute for another.

PMA only gives the manufacturer the authority to produce the part.

The FAA authorizes the part to be a direct replacement by the issuance of a STC. or letter of authorization.
Click to expand...

An example of a PMA that allows you to replace a part with a different one

 
Timbeck2 said:
How can you tell based on that PMA that an STC is required? Supplement #37?
Click to expand...

Its only PMA'ed to replace itself, not a different part.

If it were a direct drop-in without separate approval it would say which part numbers it can replace.
 
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bnt83 said:
An example of a PMA that allows you to replace a part with a different one

Click to expand...

what you are showing is by any name an letter of authorization. Giving Aero Associates the authority to manufacture these parts as drop in replacements.
 
Tom-D said:
what you are showing is by any name an letter of authorization. Giving Aero Associates the authority to manufacture these parts as drop in replacements.
Click to expand...

I wouldn't call that a letter but the PMA certificate.

A letter looks like this,



Astonishingly similar to one for a TSO.
 
Tom-D said:
What does the three letters stand for? Parts Manufacturing Authority.

You can not manufacture Cessna parts for resale with out one. They are not required to be exact duplicates.

You can not manufacture pistons for Lycoming with out a PMA, such as Superior has to sell after market Lycoming parts.
Cylinders are a great example, you can buy Superior cylinders install them on a Lycoming engine without any STC because they are exact duplicates and Superior has PMA. You can not buy ECI cylinders for the 0-200/0-300 with out a STC because they have been modified by adding an exhaust valve rotator, and that is a change of design. Thus there is no requirement for PMA.
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you are wrong here tom, and two different post by you say opposite things.

first, superior cylinders are not exact duplicates, (from superior sales info: "to its 3-D port contour and increased wall thickness)" they have a PMA and the FAA has determined that the engineering changes in the design do not constitute a change that requires a STC to install. you can be granted a PMA to make a part that is a direct replacement for part, and you can be given a PMA to make a part that has been approved by an STC for install. the PAR light Is a perfect example. it was approved for install by the STC but whelen now has a PMA to make an identical part. so you can install their part on an aircraft with the STC , but you cannot just install it in an aircraft the does not have the stc without the stc and a 337. plane power has been given a PMA to manufacture this alternator and the FAA considers it a direct replacement for the stated piper part numbers.

bob
 
unsafervguy said:
you are wrong here tom, and two different post by you say opposite things.

first, superior cylinders are not exact duplicates, (from superior sales info: "to its 3-D port contour and increased wall thickness)" they have a PMA and the FAA has determined that the engineering changes in the design do not constitute a change that requires a STC to install. you can be granted a PMA to make a part that is a direct replacement for part, and you can be given a PMA to make a part that has been approved by an STC for install. the PAR light Is a perfect example. it was approved for install by the STC but whelen now has a PMA to make an identical part. so you can install their part on an aircraft with the STC , but you cannot just install it in an aircraft the does not have the stc without the stc and a 337. plane power has been given a PMA to manufacture this alternator and the FAA considers it a direct replacement for the stated piper part numbers.

bob
Click to expand...

First things first "Bob", All, that is ALL STCs are applied to the aircraft history records by a 337 form, These 337 forms can be returned to service by any A&P-IA and need not be approved by FSDO. airworthiness inspector.

Secondly, PMA is simply that, It is authority to manufacture some one else's part. It is given by the FAA to any company that can prove thru testing that is equivalent to the OEM. These parts can have minor modifications, but they can not alter the type design. IOWs you can not substitute a alternator for a generator with a simple PMA.

Thirdly,
Any authorized part made by anyone other than the original manufacturer. must have PMA and if it is a minor modification have a letter from the FAA saying it is a replacement part for certain part numbers.

Next time you go for FAA recurrent training for your IA, ask them. they make these things well known to us every year.
 
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N801BH said:
:yes::yes::yes::yes:


Experimentals are the future......... To hell with the FAA and their double talk...
Click to expand...

The FAA has made it very clear, The use of PMAed Parts do not alter the the design, STCs Do.

It's not that difficult.
 
The best example for a PMAed part with a modification is the Incandescent bulb being replaced with a LED. The FAA has a letter out stating they are drop in replacement if they do not change any thing on the aircraft.

Whelen has the PMA. for LEDs. At one time there was an STC needed for the landing light change over, now it is no longer needed.
 
Tom-D said:
The FAA has made it very clear, The use of PMAed Parts do not alter the the design, STCs Do.

It's not that difficult.
Click to expand...

Sooooo...

If the FAA had determined the part is safe to install....

Why can't a A&P do the job WITHOUT a IA approval ???

Or is it a BIG scam to keep IA's employed and sucking up gravy work???

Are FAA licensed A&P's that dumb they need a superior looking over their shoulder???:dunno::dunno::dunno:
 
N801BH said:
Sooooo...

If the FAA had determined the part is safe to install....

Why can't a A&P do the job WITHOUT a IA approval ???
Because they would be using some one's intellectual property with out paying for it.

Or is it a BIG scam to keep IA's employed and sucking up gravy work???
That ain't worth answering, Ask a intelligent question I'll try to answer it, coping with your IA slam, WHY?
Are FAA licensed A&P's that dumb they need a superior looking over their shoulder???:dunno::dunno::dunno:
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You can't believe how many A&Ps will short cut the installation instructions, remember we are required to inspect to insure the instructions were followed. It requires time to comply with the rules, I'm sure you charge for yours.
 
Tom-D said:
You can't believe how many A&Ps will short cut the installation instructions, remember we are required to inspect to insure the instructions were followed. It requires time to comply with the rules, I'm sure you charge for yours.
Click to expand...

So....

You are saying ALOT of FAA licensed A&P's are frauds???:dunno::confused:
 
I understood it was STC'ed, now I understand it isn't/wasn't, that changes things. Let your A&P read this thread and maybe he'll buy in. Where I come from the aircraft IPC, and the "effectivity" determine part required for a specific aircraft.
 
N801BH said:
Sooooo...

If the FAA had determined the part is safe to install....

Why can't a A&P do the job WITHOUT a IA approval ???

Or is it a BIG scam to keep IA's employed and sucking up gravy work???

Are FAA licensed A&P's that dumb they need a superior looking over their shoulder???:dunno::dunno::dunno:
Click to expand...

No, they are human, and pilots should be thankful for the second set of eyes looking over some maintenance tasks, Lord knows pilots could use it with their safety record being what it is. Nearly 50% of fatal aircraft accidents attributed to pilot error and just over 5% attributed to mechanical failure.
 
GlennAB1 said:
I understood it was STC'ed, now I understand it isn't/wasn't, that changes things. Let your A&P read this thread and maybe he'll buy in. Where I come from the aircraft IPC, and the "effectivity" determine part required for a specific aircraft.
Click to expand...

Everything I could find online suggests it is PMAed to replace the OEM part. I could not find the actual PMA for the p/n used on the OPs airplane or an STC related to it which lead me to believe that no STC was involved.
 
GlennAB1 said:
No, they are human, and pilots should be thankful for the second set of eyes looking over some maintenance tasks, Lord knows pilots could use it with their safety record being what it is. Nearly 50% of fatal aircraft accidents attributed to pilot error and just over 5% attributed to mechanical failure.
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I am assuming both you and Tom are IA's..:dunno::dunno::rolleyes:
 
back to the OP.....if the original part number is Piper 69670-03....the PMA is a direct replacement with no 337 needed, just a log book entry.

If he were to submit a 337 what data is he using?...there is no STC.


The key to this is that PMA specifies a part number that it applies to. In the case of the Wheelen light it applies to a Parmetheus part number....that has an STC. So the Wheelen light first needs an initial STC to install that PMA'd part.
 
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Tom-D said:
First things first "Bob", All, that is ALL STCs are applied to the aircraft history records by a 337 form, These 337 forms can be returned to service by any A&P-IA and need not be approved by FSDO. airworthiness inspector.

Secondly, PMA is simply that, It is authority to manufacture some one else's part. It is given by the FAA to any company that can prove thru testing that is equivalent to the OEM. These parts can have minor modifications, but they can not alter the type design. IOWs you can not substitute a alternator for a generator with a simple PMA.

Thirdly,
Any authorized part made by anyone other than the original manufacturer. must have PMA and if it is a minor modification have a letter from the FAA saying it is a replacement part for certain part numbers.

Next time you go for FAA recurrent training for your IA, ask them. they make these things well known to us every year.
Click to expand...

tom, I agree with everything that you have said in this post, i pointed out that you said that the superior is "an exact duplicate" which it is not. but as you have said here, if it is shown to be equivalent they will be given a PMA for a replacement for that original part number. which is the case with the alternator that the OP has had installed.

as to stc's I dont believe i have ever said that a field approval is needed, as you well know a major modification must be supported by approved data, the STC is exactly that, the approved data for the modification. a field approval is needed when that "approved data" does not exist for the mod an you are asking the FAA to make your data "approved data"

to get back to the OP's question, the PMA holder states that a 337 is not needed because they have the PMA and paperwork to support that the FAA agrees it is a equivalent part and can be installed as a such with a log book entry.


bob
 
That makes sense. Despite a few feathers being ruffled, I think I've learned a lot in this thread. I don't know why they included the STC with the part other than the alternator is used for several types of aircraft. Maybe it is "just in case you need it" paperwork. There are instructions for the A&P to construct a baffle as well. I don't need the baffle on my aircraft because it is a direct replacement and I have a one piece nose cowl.
 
Tom-D said:
That's a bit over the top isn't it? I never said anyone was a Fraud.
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I retract the word Fraud, and insert your quote..

You can't believe how many A&Ps will short cut the installation instructions...

Feel free to define a person who does NOT follow the rules...

In my book,, someone who installs a part not as per the explicit instructions is a fraud....

YMMV...


 
N801BH said:
I retract the word Fraud, and insert your quote..

You can't believe how many A&Ps will short cut the installation instructions...

Feel free to define a person who does NOT follow the rules...

In my book,, someone who installs a part not as per the explicit instructions is a fraud....

YMMV...
Click to expand...

Once again.. no one is perfect, not even you.
 
bnt83 said:
Its only PMA'ed to replace itself, not a different part.

If it were a direct drop-in without separate approval it would say which part numbers it can replace.
Click to expand...


Like the PMA I posted a link to. :yesnod:
 
THIS IS ONLY A GUESS but the stc has probably been granted for replacement of other alternators not listed in the PMA. IE. the PMA is a direct replacement for piper part xxxx and the stc covers cessna part yyy and american champion part zzz.

so the piper would not need a 337 as it is covered by the PMA part, but the cessna would need the STC and the 337.


bob
 
This is a prime example of the confusion that exists out there in regards to major vs minor alterations and the reason that manufacturers like Plane Power and Rosin Visors obtain STC's for their products. Because that puts an end to the argument.

Look, you've already PAID for the STC if one exists. All your mechanic has to do is fill out the 337 and present it with the STC paperwork to an IA to have it signed. The IA doesn't even have to see the airplane because the A&P is signing off the installation work. All the IA is doing is confirming that the approval basis (the STC) is valid.

Such a BIG DEAL over nothing :rolleyes:
 
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