Why is a 337 required?

Timbeck2

Timbeck2

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Timbeck2
I (with an A&P) changed my alternator from the Chrysler/Prestolite to a Hartzell Plane Power. It was a direct replacement requiring no modifications to the engine or airframe. My mechanic (the same one as above) now says that it has to be inspected by an IA and a 337 sent off to Oklahoma.

I'm wondering why.
 
Timbeck2 said:
I (with an A&P) changed my alternator from the Chrysler/Prestolite to a Hartzell Plane Power. It was a direct replacement requiring no modifications to the engine or airframe. My mechanic (the same one as above) now says that it has to be inspected by an IA and a 337 sent off to Oklahoma.

I'm wondering why.
Click to expand...

Are you certain it was a direct replacement? what paper work do you have stating that ?

Remember that all A&Ps do not read and understand the rules the same.
 
I have the paperwork from the manufacturer which states that X alternator is a direct replacement to Y alternator. The only "modification" was a recommendation that a baffle be installed but in my case, it was not necessary; nor was it necessary on the old one.

I'm still reading FAR part 43 and haven't come up with anything as of yet.
 
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I changed out the Prestolite starter with a Sky-Tec and didn't have to go through this.

This stated in the Plane Power Paperwork:

PMA certied to replace the alternators listed for the following aircraft:​
Note:​
Installation requires only a logbook entry, No F.A.A. Form 337 required, on applicable installations.​
All PMA Approved Alternators state voltage in the name - e.g. - AL12 is 12 volt AL24 is 24 volt.​
Be certain you get the proper voltage Alternator for your airplane as some airplanes could be covered by 12 and 24 volt alternators.​
If the airplane originally had a generator check our Generator to Alternator Conversion Kits at www.plane-power.com/stc.pdf
 
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It is very simple. The FAA makes it very clear..........
According to the FARs, if it is not a minor modification it is a MAJOR and requires a Form337.
To make it even easier, the FAA provides guidance for MAJOR and minor modifications. IF it is not a MAJOR, then it is a minor.

Simple........ :wink2::no::confused::yes:
 
was the part an approved PMA replacement for your make, model, and serial numbered engine?.... if not there was an STC or a field approval involved and that requires a 337 form.
 
Yes.

Quote:

Plane-Power alternators are FAA-PMA certified to replace the alternators listed for the following aircraft:
...
Piper PA-140 AL12-C60
...
 
if it is a PMA direct replacement then your AP is wrong, no 337 required.

bob
 
The person performing the work is to determine whether or not the alteration or repair is major in nature using 14 CFR Part 43 Appendix A as a guide.

Major alteration means an alteration not listed in the aircraft, aircraft engine, or propeller specifications -
(1) That might appreciably affect weight, balance, structural strength, performance, powerplant operation, flight characteristics, or other qualities affecting airworthiness; or
(2) That is not done according to accepted practices or cannot be done by elementary operations.
Minor alteration means an alteration other than a major alteration.
 
Cruiser said:
It is very simple. The FAA makes it very clear..........
According to the FARs, if it is not a minor modification it is a MAJOR and requires a Form337.
To make it even easier, the FAA provides guidance for MAJOR and minor modifications. IF it is not a MAJOR, then it is a minor.

Simple........ :wink2::no::confused::yes:
Click to expand...

And IF it was an STCed unit?? what then?
 
Timbeck2 said:
I'm still reading FAR part 43 and haven't come up with anything as of yet.
Click to expand...

You won't, it's in FAR 23. under parts authorization section.

I'm too lazy to look it up. :)
 
GlennAB1 said:
The person performing the work is to determine whether or not the alteration or repair is major in nature using 14 CFR Part 43 Appendix A as a guide.

Major alteration means an alteration not listed in the aircraft, aircraft engine, or propeller specifications -
(1) That might appreciably affect weight, balance, structural strength, performance, powerplant operation, flight characteristics, or other qualities affecting airworthiness; or
(2) That is not done according to accepted practices or cannot be done by elementary operations.
Minor alteration means an alteration other than a major alteration.
Click to expand...

It's actually FAR 43-A, under A/F alterations in the electrical section as a alteration of the primary electrical circuit.
(xii) Changes to the basic design of the fuel, oil, cooling, heating, cabin pressurization, electrical, hydraulic, de-icing, or exhaust systems.
 
Tom-D said:
It's actually FAR 43-A, under A/F alterations in the electrical section as a alteration of the primary electrical circuit.
(xii) Changes to the basic design of the fuel, oil, cooling, heating, cabin pressurization, electrical, hydraulic, de-icing, or exhaust systems.
Click to expand...



This case is no different that replacing the "factory" Champion oil filter with a Tempest.

:mad2:

No 337 required!
 
I'm kinda looking forward to the response of the A&P-IA.

Specially when they don't believe it is a major mod. :)

But then again, the A&P may just have the STC in hand. and the OP is looking for it :)
 
bnt83 said:
This case is no different that replacing the "factory" Champion oil filter with a Tempest.

:mad2:

No 337 required!
Click to expand...

That's a good possibility. Neither you or I have seen ALL the paper work that came with the new part. :)
 
Tom-D said:
It's actually FAR 43-A, under A/F alterations in the electrical section as a alteration of the primary electrical circuit.
(xii) Changes to the basic design of the fuel, oil, cooling, heating, cabin pressurization, electrical, hydraulic, de-icing, or exhaust systems.
Click to expand...

No kidding. You said it was in "FAR 23. under parts authorization section"
 
Timbeck2 said:
I'm wondering why.
Click to expand...
Because your A&P thinks it is.

If your A&P didn't think that it was, then he/she wouldn't send one in.

And, later on, 20 years down the road, some sharp eyed AI would conclude that one should have been submitted and may or may not decide that the aircraft is not airworthy without one.

Ask 3 different A&P/AIs and you will likely get 4 different opinions.

This is how the FAA keeps us safe.
 
Tom-D said:
It's actually FAR 43-A, under A/F alterations in the electrical section as a alteration of the primary electrical circuit.
(xii) Changes to the basic design of the fuel, oil, cooling, heating, cabin pressurization, electrical, hydraulic, de-icing, or exhaust systems.
Click to expand...

its not a change to the basic design, it is replacing a part that is PMA approved as a direct replacement for the original part. the PMA holder even states that in their paperwork that a 337 is not required.

bob
 
Capt. Geoffrey Thorpe said:
Because your A&P thinks it is.

If your A&P didn't think that it was, then he/she wouldn't send one in.

And, later on, 20 years down the road, some sharp eyed AI would conclude that one should have been submitted and may or may not decide that the aircraft is not airworthy without one.

Ask 3 different A&P/AIs and you will likely get 4 different opinions.

This is how the FAA keeps us safe.
Click to expand...

Using your scenario, the airplane has been flying for 20 safe years before someone discovered it "may or may not" be airworthy.

This system sucks folks.


The STC states in the aircraft type column: The New Piper Aircraft, Inc. - PA-28-140 - Original type certificate number 2A13 - Regulation/Part CAR3
 
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Which takes precedence, PMA or STC? Why would it state in one place that "this is FAA PMA approved and does NOT require a 337" yet I get the STC which lists the type aircraft it is approved for?

I'm all new to this process and I just don't get it. Why didn't I have to do this with the Sky-Tec starter. At least in MY eyes it is the same principle/process.

How is a one-for-one swap (albeit a different manufacturer) a "major" alteration? Not trying to be argumentative here, I'm trying to learn.
 
do you have the PMA #....or post the PMA letter? We can give you a better response with that.

your make, model and serial number needs to be listed in the AML or PMA letter or an STC is needed.
 
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It's STC'ed. It's a major alteration. A 337 is required. Now if you ever have to replace it again, a 337 wouldn't be required since it's already been documented that the STC was done to that aircraft.
 
This http://www.aircraftspruce.com/catalog/pdf/plane-power-pma2013.pdf states no 337 is required. Plane Power states no 337 is required for PMA approved aircraft which in the previous link including the PMA number was proven. The C in the part number denotes it is a direct replacement of the Chrysler part originally installed. It is the same process as replacing the Prestolite starter with a Sky-Tec which didn't require a 337.

What am I missing here?

Again...I'm trying to learn which is why I asked here. If the manufacturer states that no 337 is required and the part has been approved by the FAA for replacement. Why do I need an IA's signature and a 337? I'm not buying, "because I said so."
 
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1. Serious
2. Smartass

You've left me with yet another decision to make. :dunno: :sigh:
 
Timbeck2 said:
Using your scenario, the airplane has been flying for 20 safe years before someone discovered it "may or may not" be airworthy.

This system sucks folks.


The STC states in the aircraft type column: The New Piper Aircraft, Inc. - PA-28-140 - Original type certificate number 2A13 - Regulation/Part CAR3
Click to expand...

GlennAB1 said:
RIF, see post #22
Click to expand...

:dunno:
 
arnoha said:
STC should be irrelevant, as the PMA takes precedence, and that was provided and seems to match his aircraft.
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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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