Panel Cutout as Minor Modification?

skipnsb

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skipnsb
The Cessna Cardinal series aircraft have a sheet metal panel in which holes are punched for the instruments, in addition to the standard avionics opening. It is considered "structural" because it is fully riveted in place (I am not talking about the plastic overlay).

I would like to cut the panel out, leaving a 1 inch lip of the old panel, and fabricate a bolt in new panel to accommodate some of the newer avionics, do away with the vacuum instruments, etc. which could be changed later when the next generation comes, etc.

My current AP and IA is ok with this being a "minor mod". So here is my question:

what is the rule on the determination that it is minor? Is it that once an AP logs it in as a minor mod, that all that is required, or is it possible that if I change IA (death, move, pre-buy on sale) a subsequent IA may refuse to certify the airworthiness because in her mind, it should never have been treated as minor?

can a DER or DAR approve it as a field modification so that it is permanently "approved", if not, who can do that? I just want to be sure there is no problem down the road. My personal opinion is that an AP has the training to determine these things and her opinion should stand. But I know my opinion doesn't count. Thank you
 
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You need and and want real FAA approval for this, minor alteration is a non-starter on 177 with non-removable panels IMHO

Idk what you’re trying to accomplish but with compact function packed avionics even the 2/3 panels that most of the 177 series came with have plenty of real estate in most cases
 
what is the rule on the determination that it is minor?
Whatever your IA determines based on Part 1 and Part 43: minor or major. FYI: the key on "structural" is whether the the panel is primary (load-bearing) structure or not.
a subsequent IA may refuse to certify the airworthiness because in her mind, it should never have been treated as minor?
Unfortunately, that is the case with any previous maintenance performed. Not just alterations. But in my experience, once it's been done and properly signed off most previous changes are accepted by future AP/IAs. Why not ask your IA on this? Historically, what is airworthy is very subjective to the AP/IA making that determination.
can a DER approve it as a field modification so that it is permanently "approved", if not, who can do that?
A DER can only approve your data not the alternation. It would still require using an IA and possibly a FSDO ASI to sign off the 337 field approval which they can do on their own at a greatly reduced cost than using a DER. However, that said, one of the disqualifying items for obtaining a field approval is if the alteration/repair does not meet the definition of a major repair.
 
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A DER can only approve your data not the alternation. It would still require using an IA and possibly a FSDO ASI to sign off the 337 field approval which they can do on their own at a greatly reduced cost than using a DER. However, that said, one of the disqualifying items for obtaining a field approval is if the alteration/repair does not meet the definition of a major repair.

Think DAR not DER. In this capacity the DAR carries the same weight as a ASI.

A Designated Airworthiness Representative (DAR) is a private person designated by the United States Federal Aviation Administration to act on its behalf in the certification of type certificated and amateur-built aircraft for the issuance of airworthiness certificates, special flight permits, import aircraft, export certificates for products and articles, conformity inspections and field approvals for repair and alterations. Most DARs have limited and/or certain "functions" authorized by the FAA based on their experience and technical background. A DAR [1] may charge a fee for his or her services.
 
The Cessna Cardinal series aircraft have a sheet metal panel in which holes are punched for the instruments, in addition to the standard avionics opening. It is considered "structural" because it is fully riveted in place (I am not talking about the plastic overlay).

I would like to cut the panel out, leaving a 1 inch lip of the old panel, and fabricate a bolt in new panel to accommodate some of the newer avionics, do away with the vacuum instruments, etc. which could be changed later when the next generation comes, etc.

My current AP and IA is ok with this being a "minor mod". So here is my question:

what is the rule on the determination that it is minor? Is it that once an AP logs it in as a minor mod, that all that is required, or is it possible that if I change IA (death, move, pre-buy on sale) a subsequent IA may refuse to certify the airworthiness because in her mind, it should never have been treated as minor?

can a DER or DAR approve it as a field modification so that it is permanently "approved", if not, who can do that? I just want to be sure there is no problem down the road. My personal opinion is that an AP has the training to determine these things and her opinion should stand. But I know my opinion doesn't count. Thank you
FAR 43-A makes no distinction between structure load carrying or not.
You alter or modify structure it is a major, simply because you have altered or modified the type design, If the structure does not duplicate the blue print it was manufactured under, it was modified.
When any designee higher than an A&P-IA has authorized the modification. It won't be undone by a A&P.
 
Think DAR not DER.
Welcome back. DAR?? OP had asked about DERs as noted in his quote? But I agree, a DAR-T with Function code 51 can approve field repair data. However, code 51 is next to impossible to get with only a handful in the entire US. It's quicker and free to have a local ASI sign the approval.
 
Thank you all so far. My IA thinks its minor, I just don't want to get grounded somewhere or have an issue when she wins the lottery and moves away. My friend of a friend rebuilds B17's and may owe me a favor. I got the impression that his contact had the kind of authority to approve engineering changes on big stuff, but I never asked him about a code 51. So, do I understand this properly, I see 3 options:
1. rely on current IA determination that it is minor, C'est la vie
2. Have a DAR T code 51 draw up a plan that my IA is comfortable with, IA files 337 based on that data after ap makes mod
3. have my ap draw up plans and I go to local FSDO and meet with ASI and obtain a field approval

My IA thinks I worry too much that its no big deal-the minor remaining aluminum between the holes is not significant in a real world sense of keeping the wings on, but of course, cutting it all out could be the straw that broke the camel's back. The new panel would be bolted to the remaining lip of the old panel, using a thicker aluminum sheet.

I want to have a bit screen HDX right in front of me is the reason to modify, and for later when it all changes, be able to easily change out the panel to a new one. Also, I have a few more design changes I am interested in pursuing, and want to understand the process. Thanks again.
 
Talk the the guys at Chief Avionics and see what they say.

http://www.chiefaircraft.com/avionics-upgrades

TP-litL.jpg
 
I see 3 options:
Couple tidbits are your options:
1) DARs are designated by state. So unless you have a code 51 locally with a limitation that includes your type aircraft only DER is option.
2) If your #1 is not your personal favorite option then may want to move your #3 up to the top and have your IA inquire with local ASI first. As mentioned above, if ASI doesn't think alteration meets the "major" definition per Part 1 and Part 43 then no field approval is possible:
The Flight Standards District Office may meet to assess the scope, complexity of change in light of 14 CFR 1.1 definitions and 14 CFR part 43, Appendix A. The Flight Standards District Office determines that either:
  • The data is adequate and no field approval is required.
https://www.faa.gov/aircraft/air_cert/design_approvals/field_approvals/field_approv_proc/
 
Welcome back. DAR?? OP had asked about DERs as noted in his quote? But I agree, a DAR-T with Function code 51 can approve field repair data. However, code 51 is next to impossible to get with only a handful in the entire US. It's quicker and free to have a local ASI sign the approval.
Agreed.
 
Thank you all so far. My IA thinks its minor, Thanks again.

she is wrong, and any A&P_IA spotting it on her signature is going to have a fit about it.
Couple tidbits are your options:
1) DARs are designated by state. So unless you have a code 51 locally with a limitation that includes your type aircraft only DER is option.
2) If your #1 is not your personal favorite option then may want to move your #3 up to the top and have your IA inquire with local ASI first. As mentioned above, if ASI doesn't think alteration meets the "major" definition per Part 1 and Part 43 then no field approval is possible:
The Flight Standards District Office may meet to assess the scope, complexity of change in light of 14 CFR 1.1 definitions and 14 CFR part 43, Appendix A. The Flight Standards District Office determines that either:



    • The data is adequate and no field approval is required.
https://www.faa.gov/aircraft/air_cert/design_approvals/field_approvals/field_approv_proc/
Wouldn't you simply submit a 337 for pre-approval?
 
This is what my Cessna panel looks like with the shock-mounted sub panels removed. Not much structure there other than yoke supports.


2CB5EA5F-F871-4F56-894B-AAD38F9233B6.jpeg
 
^^^ Wow - that looks clean!
 
Wouldn't you simply submit a 337 for pre-approval?
Yes. But my answer was in general. Pre-approval is the only way to go in my book.
she is wrong, and any A&P_IA spotting it on her signature is going to have a fit about it.
Depends. As I mentioned above, if IA determined the alteration does not meet the requirements of Part 1 and Part 43 (definition/list) the feds won't grant a field approval. There are also a few memos on this and an Order I believe. A quick call by the OPs IA to an ASI will confirm it plus she/he can note this call and ask the ASI to include their discussion in his daily notes or a letter as support for future inquiries if she/he so chooses.

As an example, we had a number of field approvals blocked at my old Part 135 job. Our QA dept tended to be ultra conservative with documentation but the local FSDO balked at the paperwork especially when it was a fleet wide alteration after duplicate 337s were no longer an option. You'll get a letter from the feds on why it was denied but usually states it didn't meet the major definition in Part 1.
 
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Yes. But my answer was in general. Pre-approval is the only way to go in my book.

Depends. As I mentioned above, if IA determined the alteration does not meet the requirements of Part 1 and Part 43 (definition/list) the feds won't grant a field approval. There are also a few memos on this and an Order I believe. A quick call by the OPs IA to an ASI will confirm it plus she/he can note this call and ask the ASI to include their discussion in his daily notes or a letter as support for future inquiries if she/he so chooses.

As an example, we had a number of field approvals blocked at my old Part 135 job. Our QA dept tended to be ultra conservative with documentation but the local FSDO balked at the paperwork especially when it was a fleet wide alteration after duplicate 337s were no longer an option. You'll get a letter from the feds on why it was denied but usually states it didn't meet the major definition in Part 1.

So what was the problem? Not needing a field approval/337 because its only a minor alteration is a good thing.
 
Practical question: how many IAs are likely to (a) pick up on this potential issue and (b) attempt to override a prior A&P's determination that it's a minor alteration (a determination that is left to the altering mechanic)? I don't want an A&P/IA that does (2).
 
So what was the problem? Not needing a field approval/337 because its only a minor alteration is a good thing.
None that I can see. The OP was concerned that some future IA may not accept the "minor" determination and was looking for input. I'm all for going the minor route when possible. FYI: the answers you quoted were not to the OPs question.
 
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Practical question: how many IAs are likely to...
In my experience very few and usually revolved around an alteration/repair that was pushing the extremes of the dark gray area or involved personal reasons. I've seen installs I didn't agree with but never saw anything un-airworthy with them.
 
If your IA considers it a minor mod, then it is a minor mod. He has access to the aircraft and can make the determination far better than anyone on the internet. I actually looked in my 177 service and parts manuals and didn't see anything too crazy. AC43.13-2 I think has a section on instrument panels which might have more information.

If worried, go with an STC'ed panel.
 
If your IA considers it a minor mod, then it is a minor mod. He has access to the aircraft and can make the determination far better than anyone on the internet. I actually looked in my 177 service and parts manuals and didn't see anything too crazy. AC43.13-2 I think has a section on instrument panels which might have more information.

If worried, go with an STC'ed panel.
That's what I did. After talking to my IA and the local FSDO inspector, I decided to go with an STC'd custom panel from Avion Research. This was in 2000-2002 when field approvals were easier to get than they are now, but the potential risk of somebody disputing the approval years after the installation spooked me and the STC'd panel minimized that risk.

PanelBeforeandAftermed.jpg
 
^^^ incredible - hard to believe it’s the same airplane!
 
I am on a different planet from many of you. I own a $25k old cessna, want to put the new big Dynon in the middle of the panel. I got a quote for $6000 a for the stc and the metal panels, I presume cut for my new layout. No installation, no parts other than the panel. That's 25 percent of my plane value. So for those of you who say "just get the stc panel", more power to you because your discretionary spending far exceeds mine.
 
The mfgr needs an STC to sell it. That doesn't mean you need an STC to install it or something similar. Roll your own.
 
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