FYI: provided you use their STC install data, 91.403(d) makes it unairworthy without the STC holders permission letter. It was the only way the FAA could protect the IP of the holder. However, there's nothing that prevents you from installing the same equipment and obtaining your own approved data. There have been several cases I know of where a person copied an engine swap but obtained their own DER data for the exchange. In one case an existing STC holder for a similar engine swap pursued a 91.403(d) violation except didn't get past 1st base when the aircraft owner presented his own approvals.
Experimental Implications
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Silvaire
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Okay thanks, you've cited a good example but here is my point: the STC process came about in the late 50's or early 60's for the express purpose of allowing either a TC holder or a non-TC holder to make MAJOR changes to the type design. If the changes you are making are MINOR then there is another method and you're not supposed to be using the STC process.
But that's neither here nor there, if they are doing it and the FAA are allowing it then it is what it is. In your example it states in the STC that it is a minor alteration and no 337 is needed. That's the first time I've seen one like that and although I've done a lot of STC installations that I could clearly see were not major alterations if that statement is not there then I have no choice but to assume, because it is an STC, that for some reason it is considered a major alteration and requires a 337. Bottom line is that it's not that big of a deal to file a 337 but if vendors are going to continue to misuse the system in this manner it would be real nice of them to follow McFarlane's lead and put the explicit statement in their STC that it is a MINOR alteration.
schmookeeg
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Dang, now we know what the FSDO critter's answer is, and he'll be entirely correct by the book. Thanks for the citation.
I hate that reg. It corrupts the FAA's purpose IMNSHO. But it's in there, so any debate over it is in the past. Sigh.
Keep in mind there are now several variants of that original STC from back then to include one called a Non-Interference STC which is defined as: “A non-interference STC addresses a convenience function modification that is not required by the applicable airworthiness standards.” Doesn’t quite meet the intent of the original requirements for a major change to type design now does it.
So it’s not so much the vendors misusing the system as them using the tools provided by the FAA. I had the same confusion until a guy at an ACO told me to forget the document title and think of an STC as a design approval process. Plus he said that it was my regulatory responsibility to determine the type/level of aircraft alteration and not the vendors as they did not have the authority to do so per Part 43. He further stated that if in fact every STC was considered a major alteration (requiring a 337) then it would be listed in Part 43 Appx A(1),(2), and (3); or, listed in the major alteration definition in Part 1.
But I know a few people who fill out a 337 for everything and never get pinged. However, I also know a number who have been pinged for sending excessive 337s with one getting a nasty-gram from the local FSDO. So it can go both ways.
Regardless, there are other STCs that include the “minor alteration” reference but not always on the document STC cover sheet. Some are included within the data package reference/drawing on the STC sheet. Here’s another McFarlane reference for a roller kit STC sheet and drawing. There are other vendors as well but McFarlane puts all the docs in public domain and easy to find.
https://www.mcfarlaneaviation.com/media/documents/doc-sa01074wi.pdf
https://www.mcfarlaneaviation.com/media/documents/1057.pdf
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Well you have no one to blame except for your fellow aviators and owners who fought for it. Was a time when after someone went through the time, effort, and cost to get a STC or a field approval then Bubba in the next hangar looked at and liked then copied the same install with your data or a duplicate 337 and you didn't get a cent. However, the way aviation law/rules are written the existing IP laws couldn't be applied for some reason and in the end the feds came up with 91-403(d). But as I mentioned still doesn't stop you from copying someone elses idea except you need to pay for your own approvals which can be cheaper in some cases.
Silvaire
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Yea and in a case like this it's all about the sign-off. If it's there is the owner supposed to question it? Is another IA down the line supposed to question, suspect or open an investigation? No, but therein lies the crust of it because we are expecting that the guy who signed it off to begin with had the fortitude and integrity to follow the rule. When the first man on earth decided not to do that well, then we ended up with lawyers.
Skyknight320
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You will be able to obtain the TSO install manual and an IA can sign the 337 to make the install legal. The only issue is the warranty which you most likely will not need anyway.
FYI: A TSO does not come with an installation manual nor does the TSO provide approval to install that article/part in an aircraft. The install method/approval is totally up to the person installing the item which if it needs a 337 is theirs to determine also.
So long as the second half of the definition of airworthy is subjective to the person making that determination, there is always the chance of someone questioning previous work performed regardless of topic. Now whether that questioning is based on personal opinion or based on available guidance has always been the crux of the matter.
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Skyknight320
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I was referring to the TSO installation manual, Garmin normally has two installation manuals, a TSO manual and the STC AML install manual. They will provide the TSO install manual for experimental installs, but for certificated installs the STC AML install manual is only available to dealers. The exception to this is their OTC line of products like the Garmin GPS 175, this does not need to be installed by a dealer and Garmin provides the STC AML install manual, STC permission letter and AFMS.
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Skyknight320
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The Garmin install manual does not cite 91.403(d) regarding the permission letter it only mentions FAA Order 8110.4B and AC 21-40.
Jesse Saint
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This discussion has gotten way off topic, but I will add something that bothers me about record keeping. You always hear people talking about logbook entries. I watched a video that very clearly explained what is a major versus minor alteration and what requires a 337 and what doesn't, and at the end, he said, then you have to make a logbook entry about the modification. I have looked and can't find any reference to a logbook in the FAR's. I may not have looked far enough, but I haven't seen it. They refer to maintenance records. How in the world is a 337 not an entry in the maintenance records. Yes, most planes have logbooks, and I always give my customers and entry because that is what they want, but there is nowhere that I can find that would require on as long as the information needed is in a 337 form or other records of a modification. Maybe I am completely missing something, but I haven't found a basis for people always saying it requires a logbook entry.
Skyknight320
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91.417
(i) A description (or reference to data acceptable to the Administrator) of the work performed; and
(ii) The date of completion of the work performed; and
(iii) The signature, and certificate number of the person approving the aircraft for return to service.
The 337 contains all of this so it would seem a logbook entry is not needed.
A Form 337 is considered an additional requirement to the maintenance record entry per 43.9(d). So both are required.
Don't quite follow the context of your comment, but the permission letter per 91.403(d) is still required regardless what Garmin lists in their documents provided you want to use Garmin's STC data. However, there is nothing that prevents you from purchasing a Garmin product and installing it under your own data. Same goes for your use of "TSO installation manual." Perhaps its just semantics, but while some TSOA's require certain data to be distributed with the TSO article, there is no requirement to use that data unless you have a regulatory requirement to meet that specific TSO like ELTs.
Skyknight320
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How would someone go about getting their own data? You mean install without using Garmin's STC? This sounds expensive.
It depends. Some vendors will use certain STC processes to approve their articles (parts) to meet the requirements of Part 21 in order to design/produce/sell them. So while the article has a STC attached to it might not require approved data to install it on a TC’d aircraft.
In those cases were the actual installation of the article does not meet the level of a major alteration then a simple logbook entry by a mechanic will suffice with acceptable data. In cases where the article installation does meet the level of a major alteration then discussion with an FAA DER can provide the necessary approved data. FWIW: at one time a field approval would have been an option as well, however, since the big fiasco back in the early 2000s very few ASIs are willing to go that route. But there are still some that do.
Now whether it’s cheaper than purchasing the vendors approved data that would depend on the install and article. However, a discussion with your mechanic up front on what is required for a particular installation will set your basic foundation regardless if it’s a Garmin STC’d product, or a non-TSO product, or whatever you want to install on your aircraft. Because it is your installer that determines what install data is needed and not the vendor.
Skyknight320
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I asked in another tread about installing a Garmin GI 275 into a TC'd aircraft, even though Garmin says it is a major alteration if the mechanic thinks a Nav indicator is minor no 337 needed. However what if at the next annual the IA doesn't agree with this?
Does Garmin specifically state “major alteration” in their paperwork or do you infer this from the type of documentation included with the unit?
That is possible no matter what the topic or item. Same reason after having a reputable mechanic perform a pre-buy in one location, you receive a $10k bill from your APIA at it 1st annual after the purchase for those items he determines not to be airworthy. As I mentioned several posts earlier, so long as part of considering something airworthy is subjective to each person, you will have what one mechanic believes to be okay and another does not. But that is their right to do so. Perhaps if you and your mechanic determine the GI275 to be a minor, discuss the install plan with your IA prior and get his input. In my experience, if the planned write up and references are above board you have a good chance on the IA accepting it. However, there are some that will flatly not accept it. It is what it is.
Skyknight320
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The Garmin install manual says it is a major alteration
Is it possible to post a snapshot of the Garmin manual paragraph that states that?
Skyknight320
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"The installation of the GI 275 Multi-Function Instrument in accordance with
this STC is a major alteration to the aircraft. Following a major alteration,
the aircraft must be returned to service in a means acceptable to the
cognizant aviation authority. An example would be compliance with
14 CFR 43.9, 14 CFR 91.417, and submission of an FAA Form 337 completed
in accordance with AC43.9-1F."
this STC is a major alteration to the aircraft. Following a major alteration,
the aircraft must be returned to service in a means acceptable to the
cognizant aviation authority. An example would be compliance with
14 CFR 43.9, 14 CFR 91.417, and submission of an FAA Form 337 completed
in accordance with AC43.9-1F."
Silvaire
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That, I believe is why so many manufacturers such as Rosin and others choose to go the STC route even though their product (clamp-on sun visors) is clearly not a major alteration. It increases the cost of the product but as long as people are willing to pay $500 for a sun visor it at least eliminates that "what if the next guy..." scenario.
As Bell206 pointed out there may be other reasons for them taking that route but I think that's a major one (pun intended)
I've been an A&P for about 40 years now and back in the old days, when everything was written on paper or on a Microfiche AD's were usually about a paragraph or two long. Nowadays in our electronic paperless society they seem to average 15 to 20 pages.
Along with that there seem to be a lot more people over-interpreting the meaning of certain text or second guessing another person's interpretation. It didn't seem to be so much like that in the good ol' days (ha, ha)
Is the Garmin document containing this statement listed on the STC MDL?
Does the GI275 replace any original instruments/indicators required by FAR or certification? If so, which specific instrument(s)? And, are any a vacuum powered instrument?
Is this a VFR or IFR installation?
What aircraft will the 275 be installed?
FYI: Having been through the STC process I can tell you most vendors use the AML-STC design approval to save money. Pull up any Approved Model List and every one of those diverse aircraft was approved under a single baseline design approval. Pull up any PMA listing and each model listed was required to have a separate design approval for each model which equates to major dollars when compared to an AML-STC design approval. Is the STC design process more expensive, yes. But in the long run it’s cheaper with multiple aircraft and TCs vs a PMA.
Agree. And in those same 40 years, I believe part of the problem started when they changed the process to get an IA and then subsequently the method on how they renew the IAs. Back in the day, most IAs worked a certain way and you got mostly the same answers when they were asked due to the FAA control of the process. Now its multiple choice questions and self-renew by online test with half of them not knowing what their function actually is or where to find things. 90% of what I was taught was from 30+ years ago. The FARs haven't changed much and most of the same processes are still used yet the IAs who are now the 1st level of oversight of those rules seem to change their tune at the flip of a switch and cater more toward the owner than the rules they're suppose to enforce and comply with. Unfortunately, as the numbers of old-school APIAs dwindle or move on it has only gotten worse from my experience. Time will tell.
Skyknight320
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I don't have the MDL but STC SA02658SE lists the MDL part number which most likely contains the p/n of the installation manual, so yes I think the STC MDL would reference the document containing that statement.
The MEL for the aircraft shows that the Nav #2 indicator can be inop so the gage is not required. The GI 275 would be replacing the Nav #2 which is a King KNI-520 Nav indicator. It is not vacuum powered. The installation would be IFR, but since it is the #2 Nav does that matter? The aircraft is a Cessna 320.
Still not enough info but given this is not a standalone indictor replacement and IFR your chances are getting slime on a minor. The MEL is moot. You would need to look at the aircraft equipment list, preferably the original list, to see if the #2 NAV indicator is listed as “required.” Cessna usually is good at marking those items with an “R” on the List. Is your NAV 1/2 radio two radios in one or separate units?
Also if the 520 is part of a navigation system installation, especially at the time of manufacture, then you get into interface issues that may exceed the major alteration threshold. Did the 275 documentation have an “Interface Section” which listed your current NAV radio as acceptable?
Skyknight320
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The aircraft equipment list provided by Cessna when the aircraft was new does not list any avionics because the original owner purchased it without avionics and then had Yingling, across the field from the factory, install King Gold Crown avionics. So there is nothing that says the Nav #2 OBS indicator King KNI-520 is required. Maybe none of my avionics are required since Cessna didn't put them in? Currently the KNI-520 is interfaced to a Bendix/King KX165A Nav/Com. Yes the GI 275 manual does show an interface to a KX165A.
Doc Holliday
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Avionics are only required by the type of operation where they are needed and by regulation.
No, they are required. As mentioned above the Yingling install was to meet the equipment requirement for IFR. There should be an addendum to your equipment list for that installation. Given the 520 was installed as a system with the 165 I think you’re at the slim and none point on a minor alteration. Since IFR equipment follows certain TSO requirements/limits you would have to go down the TSO research route which I seriously doubt any AP would follow you.
However, if you want to know with certainty, apply the 275/520 swap to the flow chart in AC 43.210, Fig. 3-1 and 3-2, to include using the Part 1 definition of a major alteration as your filter. Then apply the swap to the Data Approval Job Aid below and see what you determine. If you still think you’re on the fringe ask your local ASI at this point as you have nothing to lose. Regardless, it never hurts to spend the 30 minutes to go through this entire exercise as it can provide certain benefits with any number of installs or alterations.
https://www.faa.gov/documentLibrary/media/Advisory_Circular/EDITORIAL_UPDATE_AC_43-210A_CHG_1.pdf
http://fsims.faa.gov/wdocs/other/major_repair_alteration_job-aid.pdf
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Clip4
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So if the Garmin GI 275 is a major alteration, why would installing a RC Allen 2610-3 digital attitude indicator be minor or at least it looks to me like it would be. This attitude indicator is TSO'd but has no STC and field approvals are almost impossible to get so it must be minor.
Depends on the context you are installing the RC2610. In the case of replacing certain vacuum powered indicators there is FAA guidance (below) that allows the install of a 2610 or similar indicator as a minor alteration. But that same guidance does not provide the same exceptions for all 2610 installs. Comparing the 275 to the 2610 in this context is definitely an apple to orange exercise.
https://rgl.faa.gov/Regulatory_and_...8a886257fa40060e9f9/$FILE/PS-ACE-23-08-R1.pdf
Skyknight320
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So the bottom line is, a #2 OBS Nav indicator is a major alteration and a primary attitude indicator is a minor?
Not at all. The point you’re missing is the determination whether it’s a major or minor alteration is not based on the specific part but rather on the specific installation. In your case, based on what I’ve seen, your #2 Nav 520 replacement is a major alteration due your specific aircraft and installation. However, for a different 520 installation I could see where it would be a minor alteration in some cases. On the 2610, I’ve installed them both as a minor (replaced a vacuum AI) and as a major for a IFR panel upgrade. A quick call to your local ASI will put this bed in 5 minutes. Who knows maybe he'll agree with you its a minor. It is what it is.
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I bought a so called experimental Garmin GTR200B Com but no need for a 337 or STC permission letter. I would be leary about buying an GTX345 because of the absence of data that needs to come with it. There is another route. Im an IA and I wanted to install a G3X in my Tiger. I called 5 Garmin dealers and asked if they would sell to an IA and let me install it and sign my own 337. 3 dealers told me to go pound sand. 1 dealer said I would have to do it in his shop under his supervision and the last said OK as long as you are signing the 337. So it is not common but it is possible. It took me 6 weeks to install and boy is it awesome. You may find a dealer that may work with you.
AlphaPilotFlyer
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This is yet another reason why experimental is so much better.