What is PMAed, STDed, etc.?

[Andrew Gideon]

In researching after-market instrument lights (see:

http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&threadm=3572149.7laLzgI6iM%40no.to.be.used.news.in t.tagonline.com&rnum=1&prev=/groups%3Fhl%3Den%26lr%3D%26ie%3DUTF-8%26selm%3D3572149.7laLzgI6iM%2540no.to.be.used.ne ws.int.tagonline.com

), I've run up against some terms that I think I should understand better.
These are "STCed" and "PMAed". I understand that they're somehow related to
having these lights (or whatever is under discussion) approved for installation,
use, or some such in an aircraft. But I think I need to understand this better.

STC stands for "Supplemental Type Certificate". This "certifies" a
modification of an aircraft from its original design.

PMA stands for "Parts Manufacturer Approval". This is an approval of a
replacement part.

I don't quite have the "big picture". For example, the Nulite web site
indicates that all their products carry a PMA certification. Thus, again
according to the site, "any certified person" can make the appropriate log
book entry and the installation is "legal". That's right? Is "any
certified person" an I&A?

But I'd be using the Nulites not as a replacement for anything, but as
a new lighting solution. Does that make a difference? That is, does this
mean that a PMA is insufficient, and that an STC is required?

If not...when is an STC required instead of a PMA?

Thanks...

Andrew

[[email protected]]

A PMAed part or assembly is one that can be used as a direct replacement for
the original part or assembly. Whether or not the owner/operator can
legally install a PMAed part depends upon the type of part and whether its
replacement is within the bounds of allowed owner/operator maintenance as
defined in FAR 43.17(c). However, regardless of whether the PMAed part is
installed by the owner/operator or an A&P, it requires just a simple logbook
entry just like any other part replacement.

An STC introduces an alteration that was not covered by the airplane's
original type certificate. Installation of an STCed part or system must be
accomplished in accordance with the STC. This may be a major or minor
alteration, but as I understand it, it would in any case need to be signed
off by an A&P, and possibly an AI. In many cases a new weight and balance
would need to be calculated and recorded.

--
-Elliott Drucker

[Bob Noel]

In article >,
wrote:

> A PMAed part or assembly is one that can be used as a direct replacement
> for
> the original part or assembly. Whether or not the owner/operator can
> legally install a PMAed part depends upon the type of part and whether
> its
> replacement is within the bounds of allowed owner/operator maintenance as
> defined in FAR 43.17(c). However, regardless of whether the PMAed part
> is
> installed by the owner/operator or an A&P, it requires just a simple
> logbook
> entry just like any other part replacement.
>
> An STC introduces an alteration that was not covered by the airplane's
> original type certificate. Installation of an STCed part or system must
> be
> accomplished in accordance with the STC. This may be a major or minor
> alteration, but as I understand it, it would in any case need to be
> signed
> off by an A&P, and possibly an AI. In many cases a new weight and
> balance
> would need to be calculated and recorded.

and the OP wrote:
>But I'd be using the Nulites not as a replacement for anything,
>but as a new lighting solution. Does that make a difference?
>That is, does this mean that a PMA is insufficient, and that an
>STC is required?

If the part is not PMA'd for your aircraft, you'll need a different
"basis" for the approval of the installation in your aircraft. This
does not need to be via an STC.

As an example, a digital OAT probe I installed in my cherokee
was PMA'd for certain beechcraft aircraft but not my cherokee.
The installation this digital OAT probe was approved via a 337.

good luck.

--
Bob Noel

[aptim]

I was told in A&P school that It stands for Parts Manufactured Approved.



Tim A&P PP-SEL IA
> wrote in message
...
> A PMAed part or assembly is one that can be used as a direct replacement
for
> the original part or assembly. Whether or not the owner/operator can
> legally install a PMAed part depends upon the type of part and whether its
> replacement is within the bounds of allowed owner/operator maintenance as
> defined in FAR 43.17(c). However, regardless of whether the PMAed part is
> installed by the owner/operator or an A&P, it requires just a simple
logbook
> entry just like any other part replacement.
>
> An STC introduces an alteration that was not covered by the airplane's
> original type certificate. Installation of an STCed part or system must
be
> accomplished in accordance with the STC. This may be a major or minor
> alteration, but as I understand it, it would in any case need to be signed
> off by an A&P, and possibly an AI. In many cases a new weight and balance
> would need to be calculated and recorded.
>
> --
> -Elliott Drucker

[Ron Natalie]

> wrote in message ...

> An STC introduces an alteration that was not covered by the airplane's
> original type certificate. Installation of an STCed part or system must be
> accomplished in accordance with the STC. This may be a major or minor
> alteration, but as I understand it, it would in any case need to be signed
> off by an A&P, and possibly an AI. In many cases a new weight and balance
> would need to be calculated and recorded.

An IA must sign off the 337, which is required of any major alteration. An STC
provides authority to make the major alteration. A minor alteration requires
neither a 337 nor an STC.

[Ron Natalie]

"aptim" > wrote in message ...
> I was told in A&P school that It stands for Parts Manufactured Approved.
>
Parts Manufacturer Approval.

[Dan Thomas]

Aircraft manufacturers publish parts manuals for the airplanes they
build. The law says that you must use the parts specified in the
manual when replacing things. If the part has an industry-standard
number, like an AN bolt or fitting or wheel bearing, you can buy it
from any aircraft parts supplier.
If the number is a proprietary number (invented by and belonging to
the airplane manufacturer), such as a throttle control cable, the
requirement to use only that part means that you have to buy it from
the airplane dealer. The manufacturers are inclined to take advantage
of this and we see some ridiculous prices.
The PMA (Parts Manufacturer Approval) provision relieves us of
some of the robbery. McFarlane Aviation, for example, manufactures
engine control cables, seat parts, hinges, and a lot of other common
stuff that fits common airplanes, and their prices are much more
reasonable. Their numbers are the original proprietary number with an
identifying prefix added to it to avoid the copyright mess on the
original part numbers, while still qualifying as meeting the parts
manual requirements. Their competition often forces airframe
manufacturers to lower their prices, and some of the stuff they build
is actually better or stronger, such as the McFarlane Cessna seat
rails and roller washers.
It's still wise to shop around. Sometimes the dealer's OEM prices
are better than the PMAd stuff.

Dan

[Jim Weir]

Nope. Parts Manufacturing Approval

Jim


"Ron Natalie" >
shared these priceless pearls of wisdom:

->
->"aptim" > wrote in message
...
->> I was told in A&P school that It stands for Parts Manufactured Approved.
->>
->Parts Manufacturer Approval.
->
->


Jim Weir (A&P/IA, CFI, & other good alphabet soup)
VP Eng RST Pres. Cyberchapter EAA Tech. Counselor
http://www.rst-engr.com

[Ron Natalie]

"Jim Weir" > wrote in message ...
> Nope. Parts Manufacturing Approval
>
> "Ron Natalie" >
> shared these priceless pearls of wisdom:
> ->Parts Manufacturer Approval.

Sorry, Jim. I disagree. While the FAA abuses the term term as "manufacturing"
in a few advisory circulars. The term is "manufacturer" in both the FAR (Part 21,
subpart K) and in order 8110.42A (the PMA process itself).

[Andrew Gideon]

Ron Natalie wrote:

> An IA must sign off the 337, which is required of any major alteration.
> An STC
> provides authority to make the major alteration. A minor alteration
> requires neither a 337 nor an STC.

It sounds from the above like an STC is required before any major alteration
because it "provides authority to make the major alteration". Is that
right?

A lot seems to hinge on the distinction between "major" and "minor"
alterations. What is the difference? Given a particular change (ie.
replacing a panel overlay, or adding instrument lights), how does one know
into which category the change falls?

- Andrew

[Andrew Gideon]

Bob Noel wrote:


> If the part is not PMA'd for your aircraft, you'll need a different
> "basis" for the approval of the installation in your aircraft. This
> does not need to be via an STC.

Ah, so a PMA is aircraft-specific? That's a little suprising - although
reasonable in retrospect - as a number of aftermarket instrument lighting
vendors advertise that their product is "PMA certified", or some such. No
mention is made of "...for the following aircraft...".

>
> As an example, a digital OAT probe I installed in my cherokee
> was PMA'd for certain beechcraft aircraft but not my cherokee.
> The installation this digital OAT probe was approved via a 337.

I'm confused about the role of a 337. When is one required?

One example is what you've cited: a change for which neither PMA nor STC
exists. But is one required for a replacement with a PMAed "part"? Is one
required for an STCed alteration?

- Andrew

[Ron Natalie]

"Andrew Gideon" > wrote in message online.com...

> It sounds from the above like an STC is required before any major alteration
> because it "provides authority to make the major alteration". Is that
> right?

An STC is one way of getting approval for the alteration. Other "data
acceptable to the administrator" is allowed as well. This is called a
field approval (or sometimes incorrectly, a one time STC).

> A lot seems to hinge on the distinction between "major" and "minor"
> alterations. What is the difference? Given a particular change (ie.
> replacing a panel overlay, or adding instrument lights), how does one know
> into which category the change falls?

The definitions are here (I'm not going to post them inline as they are a bit long):
http://www.access.gpo.gov/nara/cfr/cfrhtml_00/Title_14/14cfr43_00.html

Some of it is a gray area. Somethings people read more into it than others.
For example, just because something changes the w&b, it is not a major
alteration. It is only a major alteration if it changes the permissable envelope.

[Ron Natalie]

"Andrew Gideon" > wrote in message online.com...

>
> Ah, so a PMA is aircraft-specific?

No. PMA ce

> I'm confused about the role of a 337. When is one required?

A 337 is required to report any major alterations whether the are supported by
an STC or just "other acceptable data." Some people sometimes use "approved
by 337" to mean field approval.

> One example is what you've cited: a change for which neither PMA nor STC
> exists. But is one required for a replacement with a PMAed "part"? Is one
> required for an STCed alteration?

There are two principles here:

1. Approval of the modification, that is authority to make this change to the aircraft.
2. Approval of the part itself (It's manufacture, quality control, etc..).

The first is accomplished by either being supported by the Type Certificate, or an STC,
or other approved data, or being so minor as being inconsequential.

The second, can be accomplished by a PMA, a TSOA, the type certificate itself (for the original
manufacturer), by recognition of certain non-FAA standards (like MilSpec's for things like fasteners),
or by the owner himself producing the part in accordance with FAA-approved data.

[Montblack]

I did a Google search for "owner produced parts" then started clicking.

Very interesting reading!!

1. http://www2.faa.gov/avr/afs/news/archive/Jul_Aug2002/Parts.htm

2. http://www.dvcfi.com/aviation/stc.php

3. http://makeashorterlink.com/?L2A512696

4. http://makeashorterlink.com/?H1C521696

Talked to a guy at my airport who is doing much of this with his 177
project. He said he's surprised more owners don't make parts for their
planes, or have the parts made for them. Measure it, build it - is his
motto.

--
Montblack

("Dan Thomas" wrote)
> Aircraft manufacturers publish parts manuals for the airplanes they
> build. The law says that you must use the parts specified in the
> manual when replacing things. If the part has an industry-standard
> number, like an AN bolt or fitting or wheel bearing, you can buy it
> from any aircraft parts supplier.
> If the number is a proprietary number (invented by and belonging to
> the airplane manufacturer), such as a throttle control cable, the
> requirement to use only that part means that you have to buy it from
> the airplane dealer. The manufacturers are inclined to take advantage
> of this and we see some ridiculous prices.
<snip>

[G.R. Patterson III]

Andrew Gideon wrote:
>
> Ah, so a PMA is aircraft-specific?

Not exactly. If the item is (for example) a Cessna wing flap, then the answer
is yes. If it's a replacement for something more generic, it can be used to
replace that item on any aircraft that uses it. A good example would be one of
these lightweight starter motors. Since the part is legally a direct replacement
part, no STC is required.

The 337 is required for any change that the local FSDO believes is a "major"
modification.

An STC is legally a change to the original type certificate that allows you do
do something the original manufacturer didn't do.

George Patterson
A man who carries a cat by the tail learns something that can
be learned no other way.

[Gene Kearns]

On Wed, 19 Nov 2003 14:01:52 -0600, "Montblack"
> wrote:

>I did a Google search for "owner produced parts" then started clicking.
>
>Very interesting reading!!
>
>1. http://www2.faa.gov/avr/afs/news/archive/Jul_Aug2002/Parts.htm
>
>2. http://www.dvcfi.com/aviation/stc.php
>
>3. http://makeashorterlink.com/?L2A512696
>
>4. http://makeashorterlink.com/?H1C521696
>
>Talked to a guy at my airport who is doing much of this with his 177
>project. He said he's surprised more owners don't make parts for their
>planes, or have the parts made for them. Measure it, build it - is his
>motto.

I'd be interested in knowing if this guy is generating approved data
for these parts. If he isn't, he is doing no more than producing
numerous unapproved parts with which to get himself and his mechanic
and/or inspector violated. ... not a clever money-saving scheme.

[Jim Weir]

And your background and authority for making this statement are?


Jim



Gene Kearns >
shared these priceless pearls of wisdom:


->>Talked to a guy at my airport who is doing much of this with his 177
->>project. He said he's surprised more owners don't make parts for their
->>planes, or have the parts made for them. Measure it, build it - is his
->>motto.
->
->I'd be interested in knowing if this guy is generating approved data
->for these parts. If he isn't, he is doing no more than producing
->numerous unapproved parts with which to get himself and his mechanic
->and/or inspector violated. ... not a clever money-saving scheme.


Jim Weir (A&P/IA, CFI, & other good alphabet soup)
VP Eng RST Pres. Cyberchapter EAA Tech. Counselor
http://www.rst-engr.com

[Bob Noel]

In article e.com>,
Andrew Gideon > wrote:

> > If the part is not PMA'd for your aircraft, you'll need a different
> > "basis" for the approval of the installation in your aircraft. This
> > does not need to be via an STC.
>
> Ah, so a PMA is aircraft-specific? That's a little suprising - although
> reasonable in retrospect - as a number of aftermarket instrument lighting
> vendors advertise that their product is "PMA certified", or some such.
> No
> mention is made of "...for the following aircraft...".

I'm sorry. I was sloppy with my language. I shouldn't have
said "not PMA'd for your aircraft", but something more like
"not a PMA replacement for a part for your aircraft."


> > As an example, a digital OAT probe I installed in my cherokee
> > was PMA'd for certain beechcraft aircraft but not my cherokee.
> > The installation this digital OAT probe was approved via a 337.
>
> I'm confused about the role of a 337. When is one required?
>
> One example is what you've cited: a change for which neither PMA nor STC
> exists. But is one required for a replacement with a PMAed "part"?

It is my understanding that replacing an existing part with
a PMA replacement part wouldn't require a 337.

> Is one required for an STCed alteration?

Yes.

are we confused yet?

--
Bob Noel

[Gene Kearns]

On Wed, 19 Nov 2003 16:21:09 -0800, Jim Weir > wrote:

>
>And your background and authority for making this statement are?
>
>


Are you the credentials police?



If you take issue with the substance of what I have said, offer
information contrary to my assertion. FAR 21.303 does not give blanket
authority to an owner to produce any sort of part using any sort of
materials and any sort of means available. (Nor does it give a
mechanic permission to install an unapproved part.) If you do disagree
with my assertion, I suggest you read FAR 43.13 and FAA Order 8300.10
Chapter 83 for content and then offer some means available to the
owner/operator for legal approval of owner/operator produced parts
other than:

(1) reverse engineering and field approval or
(2) securing original manufacturing data from the TCD or PMA holder
or
(3) securing original manufacturers data via freedom of information
act from the FAA Aircraft Certification Directorate

In any event, the part must be certified as airworthy in the
maintenance records by the owner/operator and that assertion should
not be made unless the part conforms to the original type design. A
mechanic that installs owner/operator parts not so (accurately)
certified in just asking for trouble.



>
>
>
>Gene Kearns >
>shared these priceless pearls of wisdom:
>
>
>->>Talked to a guy at my airport who is doing much of this with his 177
>->>project. He said he's surprised more owners don't make parts for their
>->>planes, or have the parts made for them. Measure it, build it - is his
>->>motto.
>->
>->I'd be interested in knowing if this guy is generating approved data
>->for these parts. If he isn't, he is doing no more than producing
>->numerous unapproved parts with which to get himself and his mechanic
>->and/or inspector violated. ... not a clever money-saving scheme.
>
>
>Jim Weir (A&P/IA, CFI, & other good alphabet soup)
>VP Eng RST Pres. Cyberchapter EAA Tech. Counselor
>http://www.rst-engr.com

[James M. Knox]

Bob Noel > wrote in
:

>> Is one {PMA} required for an STCed alteration?
>
> Yes.

Not quite.

A part may be manufactured by the owner/operator and installed under
STC, or it may be manufactured *and installed* by the holder of the STC
without PMA. Both these minor points are seldom worthy of note, but
they are there.

For example: GAMI designed their new fuel injectors. They went through
testing and the STC was awarded. They were then allowed to make them
and install them on all aircraft/engines for which the STC applied.

The FAA would not allow the PMA application to be even be submitted
until the STC was approved. [It's not clear that this is a rule, so
much as an FSDO made up rule.] Until the PMA was approved GAMI could
not sell the injectors to anyone else for installation elsewhere. You
wanted the injectors, you flew to Oklahoma and had GAMI put them in.

Once the PMA was approved the restriction went away.

-----------------------------------------------
James M. Knox
TriSoft ph 512-385-0316
1109-A Shady Lane fax 512-366-4331
Austin, Tx 78721
-----------------------------------------------

[Jim Weir]

Gene Kearns >
shared these priceless pearls of wisdom:


->
->Are you the credentials police?


No, just been wrenching, inspecting, designing, and engineering on airplanes for
forty-five some years now.



->In any event, the part must be certified as airworthy in the
->maintenance records by the owner/operator

Izzat so? Hm. Didn't know the owner/operator could certify things as
airworthy. I'll have to let the rest of the gang know.


and that assertion should
->not be made unless the part conforms to the original type design.

Nope.


A
->mechanic that installs owner/operator parts not so (accurately)
->certified in just asking for trouble.

Hm. Interesting heresy.

Jim



Jim Weir (A&P/IA, CFI, & other good alphabet soup)
VP Eng RST Pres. Cyberchapter EAA Tech. Counselor
http://www.rst-engr.com

[Andrew Gideon]

Ron Natalie wrote:

> The definitions are here (I'm not going to post them inline as they are a
> bit long):
> http://www.access.gpo.gov/nara/cfr/cfrhtml_00/Title_14/14cfr43_00.html

Appendix A(a) defines "major alteration". Anything else is "minor"?

> Some of it is a gray area. Somethings people read more into it than
> others. For example, just because something changes the w&b, it is not a
> major
> alteration. It is only a major alteration if it changes the permissable
> envelope.

Where do you see that? I only see a list of items in A(a); nothing that
refers to the W&B.

- Andrew

[Andrew Gideon]

Bob Noel wrote:

> are we confused yet?

I'm not sure.

- Andrew

[Ron Natalie]

"Andrew Gideon" > wrote in message online.com...
> Ron Natalie wrote:
>
> > The definitions are here (I'm not going to post them inline as they are a
> > bit long):
> > http://www.access.gpo.gov/nara/cfr/cfrhtml_00/Title_14/14cfr43_00.html
>
> Appendix A(a) defines "major alteration". Anything else is "minor"?
>
> > Some of it is a gray area. Somethings people read more into it than
> > others. For example, just because something changes the w&b, it is not a
> > major
> > alteration. It is only a major alteration if it changes the permissable
> > envelope.
>
> Where do you see that? I only see a list of items in A(a); nothing that
> refers to the W&B.

43xA.a (1)(xi).
Changes to the empty weight or empty balance which result in an increase ...

[Andrew Gideon]

Ron Natalie wrote:

> 43xA.a (1)(xi).
> Changes to the empty weight or empty balance which result in an increase
> ...

Ah. Hidden in plain site.

Thanks...

- Andrew

[Gene Kearns]

On Thu, 20 Nov 2003 08:46:34 -0800, Jim Weir > wrote:

>Gene Kearns >
>shared these priceless pearls of wisdom:
>
>
>->
>->Are you the credentials police?
>
>
>No, just been wrenching, inspecting, designing, and engineering on airplanes for
>forty-five some years now.
>
>
>
>->In any event, the part must be certified as airworthy in the
>->maintenance records by the owner/operator
>
>Izzat so? Hm. Didn't know the owner/operator could certify things as
>airworthy. I'll have to let the rest of the gang know.
>
>

Maybe you missed http://makeashorterlink.com/?L2A512696 , question &
answer 5.


It is hard to believe that after 45 years you haven't picked up on the
pitfalls of the owner having a part reverse engineered by a local
machine shop and not certifying that the part is airworthy, himself.

Are *you* going to certify the part airworthy? How do *you* know that
the materials, processes, and workmanship meet the applicable type
design? Or are you going to take their word for the type of aluminum,
welding rod, heat treat designation, plating technique, etc.....and
make the entire maintenance entry yourself?

After 45 years you should have an understanding that the path of
liability follows those remunerated for the effort. Put another way,
you are only liable for the work you personally accomplished. Don't
sign off things you didn't do.... especially if you didn't make the
part. Once you sign off the installation of an un-airworthy part
(without due diligence in determining if the part *was* airworthy) you
are just as guilty as the owner/operator trying to save a few dollars.

My guess is the rest of the gang actually read the articles and, thus,
already knew this.....

[Gene Kearns]

On Wed, 19 Nov 2003 14:00:26 -0500, Andrew Gideon >
wrote:

>Ron Natalie wrote:
>
>> An IA must sign off the 337, which is required of any major alteration.
>> An STC
>> provides authority to make the major alteration. A minor alteration
>> requires neither a 337 nor an STC.
>
>It sounds from the above like an STC is required before any major alteration
>because it "provides authority to make the major alteration". Is that
>right?
>
>A lot seems to hinge on the distinction between "major" and "minor"
>alterations. What is the difference? Given a particular change (ie.
>replacing a panel overlay, or adding instrument lights), how does one know
>into which category the change falls?
>
> - Andrew

What is *required* before a major alteration is approved data. How
you obtain that can vary, STC, Field Approval, etc....

Well, technically, you don't really need it until the work is
inspected.......BUT..... Trust me, though, you want the approved data
*before* beginning *any* work.

[Jim Weir]

Gene Kearns >
shared these priceless pearls of wisdom:

->
->Maybe you missed http://makeashorterlink.com/?L2A512696 , question &
->answer 5.

I didn't miss a damn thing. My sources and information comes from the FAA
websites, not from some magazine that carries no official weight.


->
->
->It is hard to believe that after 45 years you haven't picked up on the
->pitfalls of the owner having a part reverse engineered by a local
->machine shop and not certifying that the part is airworthy, himself.
->

I'm not about to argue technique with a person that refuses to tell us how he
comes to what he believes. Kind of like an instructor arguing with a student
now, isn't it?


->My guess is the rest of the gang actually read the articles and, thus,
->already knew this.....

My guess is that the gang read this same list I posted back on the 9th of June
and has already made up their minds as to who knows what they are talking about.

Jim

Jim Weir (A&P/IA, CFI, & other good alphabet soup)
VP Eng RST Pres. Cyberchapter EAA Tech. Counselor
http://www.rst-engr.com