Another 337 Question

F

farmrjohn

Pre-takeoff checklist
Joined
Mar 26, 2018
Messages
405
Display Name
Display name:
farmrjohn
Looking forward when it is time to replace the battery ( currently an RG-25XC ) I’d like to replace with an SBS J-16 which will require a 337 field approval. There are some previous 337s available to use as acceptable data for the application that “should” help with the approval process. How far in advance can that request be made, or how soon after approval is granted does the installation need to be made-is there a time limit?
 
Wow, I’m glad you asked as I was logging on to post the identical question, down to the battery model on replacment end and having a previous example of an approved 337. Mines for a Cessna 140, what are you looking to lighten up #farmrjohn?
 
There are some guys on the 120/140 forum who beleive the 337 is overkill that their IA and them agree that it’s not in the list of what’s considered a “major” modification therefore it’s not a major change and a logbook entry from the IA is all that’s necessary... but their is not full consensus on that it doesn’t sound like.
 
My project will be an Alon A2 (TCDS A-787). I would really like to put in an EarthX and while there is a 337 for that from what I’ve heard the local FSDO wouldn’t look favorably on that one.
 
Who decides, if it is a major or minor alteration. ?
 
farmrjohn said:
How far in advance can that request be made, or how soon after approval is granted does the installation need to be made-is there a time limit?
Click to expand...
Your AP/IA can answer these questions. But as an FYI: the AP/IA will fill out the 337 detailing the alteration as it will be performed. He will attach supporting data like the other listed STCs or PMAs for the battery. He will then give the FSDO a call and arrange to have Block 3 on the 337 signed. I've driven to the FSDO and had the field approval signed the same day.
 
Tom-D said:
Who decides, if it is a major or minor alteration. ?
Click to expand...
That's easy. I've got a technical publication from Western Region HQ that says literally that "it is the installing mechanic's opinion as to whether an alteration is major or minor."

The hiccup is when my local FSDO liason disagrees with my opinion.

Jim
 
My .02 is that all the information and approval needed exists already in AC43.13-2B, even if considered a major mod.
 
JAWS said:
My .02 is that all the information and approval needed exists already in AC43.13-2B, even if considered a major mod.
Click to expand...
Even if you have all the data needed for a field approval, it can not be done, because a STC already exists.
The FAA can not give away intellectual property.
SO... you must follow the instructions contained in the installation instructions contained in the STC.
 
...and you must have the permission of the STC holder to “use” such data.... usually in the form of a letter or on the STC.
 
The STC's I saw are for ragwing Pipers and a few Cessnas. The OP is talking about an Ercoupe.

-2B is considered approved data for such an aircraft. No other approval is needed. :)
 
farmrjohn said:
Looking forward when it is time to replace the battery ( currently an RG-25XC ) I’d like to replace with an SBS J-16 which will require a 337 field approval. There are some previous 337s available to use as acceptable data for the application that “should” help with the approval process. How far in advance can that request be made, or how soon after approval is granted does the installation need to be made-is there a time limit?
Click to expand...

You need to read AC43.13-2B chapter 10. It deals with replacing and/or relocating a lead acic battery and tells you how. Visit the opening paragraphs of the AC for instructions how to use the AC as approved data for a major alteration should your mechanic believe it’s a major. Your IA can return the plane to service without FAA involvement. It’s all right there in the AC. You don’t need a PMA’d battery, either. You can use an Odyssey PC-680 (non-PMA version of the SBS J-16) and save money. Better yet, use a PC-625. It’s a better battery. I’ve had one on the firewall of my 180 for 20 years.

https://www.faa.gov/documentLibrary/media/Advisory_Circular/AC 43.13-2B.pdf
 
Tom-D said:
Even if you have all the data needed for a field approval, it can not be done, because a STC already exists.
Click to expand...
Not exactly. 91.403(d) only provides protection to the data used in an STC, not any other approved data. There is nothing stopping anyone from altering their aircraft in a similar manner provided they obtain their own approved data. There is existing guidance to this. Here’s one:
https://www.faa.gov/about/office_or...mcafee&taft - (2016) legal interpretation.pdf
 
Bell206 said:
Not exactly. 91.403(d) only provides protection to the data used in an STC, not any other approved data. There is nothing stopping anyone from altering their aircraft in a similar manner provided they obtain their own approved data. There is existing guidance to this. Here’s one:
https://www.faa.gov/about/office_org/headquarters_offices/agc/practice_areas/regulations/interpretations/data/interps/2016/donnell-mcafee&taft - (2016) legal interpretation.pdf
Click to expand...
I'll give ya that,, But
It must be done in a different manor and on approved data other than the STC.
 
Tom-D said:
It must be done in a different manor and on approved data other than the STC.
Click to expand...
Actually there has been a lot of discussion on that issue over the years. But unless a person obtains a separate patent and trade mark for the exact parts/processes, the STC provides no similar protection for like alterations.
 
Bell206 said:
Actually there has been a lot of discussion on that issue over the years. But unless a person obtains a separate patent and trade mark for the exact parts/processes, the STC provides no similar protection for like alterations.
Click to expand...

I think now we are getting into the patten rules.

I believe modifying your aircraft to achieve the same thing as a STC, comes so close to giving away intellectual property that most FSDOs/ ASIs will not approve the request for field approval.
Just my humble opinion, But I would not submit the request.
 
You must log in or register to reply here.
Back
Top