How to create a STC?

Discussion in 'Hangar Flying' started by K-Rigg, Sep 8, 2009.

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  1. Sep 8, 2009 #1

    K-Rigg

    K-Rigg

    K-Rigg

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    What is the process with the FAA to get a modification approved for a STC?

    For example, if i want to create a system to place a turbo on a motor that did not have one to begin with on a certified airplane?
     
  2. Sep 8, 2009 #2

    LArzfromarz

    LArzfromarz

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    You can find information here
    Supplemental Type Certificates
    but you'll likely find it a daunting task- unless you like paperwork-
    I'm also not sure this is the forum to ask as STCs typically apply to certified aircraft and not homebuilts.
    Have fun...
    LArz
     
  3. Sep 8, 2009 #3

    vortilon

    vortilon

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    Let me save you and your family much money and grief. Forget about it.

    I tried it once, a simple structural beef up to a small non-pressurized door that was clearly in need of a mod. This little door had Hartwell latches and after three years of battle with these idiots the last request was for me to prove it was not a stress panel. How many stress panels have Hartwell latches? Mind you I had been all the way through a conformity check on an aircraft and passed with flying colors. When the project manager at the ACO office made this stupid request I hung up the phone and never looked back. I suppose that is what he wanted me to do.
     
  4. Sep 8, 2009 #4

    LArzfromarz

    LArzfromarz

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    My condolences Vort.
    Larz
     
  5. Sep 8, 2009 #5

    bmcj

    bmcj

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    Is the process any different if you transition from certified to something like exhibition or some other special class/category?
     
  6. Sep 8, 2009 #6

    PTAirco

    PTAirco

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    Sometimes things like implementing the Sport PIlot license give me hope for the future. Then I read things like this and get reminded that aviation still suffers from the most mindless bureaucracy and I want to throw up my hands and just say s..w it all and become and an FAA outlaw aviator a la Richard Bach. I have no problems with rules that make sense but making rules and then making it impossible to show compliance to them just makes me mad. Especially when it all boils down to one man's opinion rather than hard facts.
     
  7. Sep 9, 2009 #7

    Ivan

    Ivan

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    K-Rigg,

    As others have pointed out, the STC process is not for the faint of heart. My experience is with Transport Canada and not the FAA, but both operate similarly. You've got two huge strikes against you: first, you don't come into this mod with a long, pleasant professional relationship with the certification people at the FAA. Second, what you describe has got to be one the the worst sorts of things to try to certificate. About the only way to make it worse is if the plane in question is a twin, and your turbo is homemade.

    I once worked on an STC effort to switch props on Metroliners. (The props were slightly quieter--ever flown in a Metroliner? It's like being rolled downhill in a 45 gallon drum full of hammers) This was using a proper prop from a proper manufacturer that was mildly supportive of the switch. We were working for a small operator that could supply the plane and pilots for flight testing. They had already gotten another consulting firm to establish the baseline performance and vibration data. We knew all the DOT people well, and they were being as reasonable as you could hope. It was still a huge undertaking (I think it was about 8 months for the five of us on and off).

    The only reason it was even possible was that we spent our time proving that the mod didn't affect performance or function in any appreciable way (One FAR at a time, for both the engine and the airframe). Thank goodness performance wasn't improved--we would have been sunk. It really would have been a whole new certification effort, and nobody had the money for that. That's basically what you'd be looking at, and without the manufacturer's original approved design data, you've got to reverse-engineer the plane and the engine, and then substantiate the new configuration. It feels like a bigger job than the original certification effort.

    But really, that all boils down to the advice you've got above: you're probably not in the right time or place to get this STC through.
     
  8. Sep 9, 2009 #8

    Topaz

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    If you don't mind completely wrecking the resale value of the airplane, you can bypass all of this by re-registering the airplane as an Experimental. But once that's done, it's done. There's no returning the airplane to 'certified' status.
     
  9. Sep 9, 2009 #9

    orion

    orion

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    Converting a certified product into an experimental one is generally frowned upon by the FAA but it can be done however, only under very specific conditions and subheadings of the "Experimental" category. For a mod as you describe it would have to be something like Experimental - Product Development, which has a time limit as well as flight limits. This category is generally used when you are developing a new product line or STC and is used only for the purpose of that development.

    I think I recall someone saying that this type of change (Certified to Experimental) is only possible in Canada.
     
  10. Sep 9, 2009 #10

    PTAirco

    PTAirco

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    Canada does have this "Owner maintained" category - you can take a standard airplane and move it into that category, but it can never be moved back. Once it's in there, you can pretty much treat it like a US experimental.
     
  11. Sep 10, 2009 #11

    Othman

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    The process to develop and STC is fairly straight forward, but there is a lot of work involved. It's all about understanding what regualations are affected by the modification and demonstrating how the regulations are met post mod (testing, analysis, design features etc). The better you document this process and communicate with the regulatory authorities, the smoother things will go.

    Although small mods can documented and managed by someone with some technical knowledge it is always best to seek some level of professional help, at least for guidance on what needs to be done to satesfactorly get the project done.

    Even some engineers in the business of aircraft mods make the process painful, or a lot more complicated than it needs to be. In my opinion I feel that some of them do it to make a bit more money on a project... afterall all that fancy analysis software costs money to operate.

    One of the last ingredients, and an important one, is diplomacy. In many cases showing compliance with a regulation is not a black and white issue, and therefore you need to learn to negotiate with the authorities to come up with the most effective decisions (remember safety first). Document all of the decisions!

    A project like beefing up that door sounds like a no brainer... I think with the right help you could have gotten your project done and approved without much grief.

    If you're impatient and want to get the approval quicker, you can go to a DER (or DAR in Canada) and have them do the approval... of course at a price.

    By the way, if you want to put your mod on only one or a few specific aircraft, you can apply for a "one time STC" or a Limited Suplemental Type Certificate (LSTC) in Canada. This is tail number specific, and because of that is easier to get approved.

    Hope this helps.

    Ashraf
     
  12. Sep 10, 2009 #12

    K-Rigg

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    more info on this please....
     
  13. Sep 10, 2009 #13

    bmcj

    bmcj

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    D'oh!!!! I assumed we were already discussing a "one time" STC, but you are correct... it sounds like some are discussing a full STC.
     
  14. Sep 10, 2009 #14

    vortilon

    vortilon

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    If my first post did not detour your ambition then your first step is to contact a DER and he or she will direct you through the ominous serious of joyous communications with your ACO office. It is doable but just becomes a question of how deep your pockets are and how much patience you have. First question will be has that specific engine had a turbo certified for it before. If you can install it without any mods to the cowl you will be money ahead avoiding aerodynamic changes. Fuel flows will have to verified and flows at various angles of attack during climb and dives. Propeller harmonics will no doubt creep into the equations. A known engine, turbo and prop combination will be helpful.

    Here is a directory of DER's

    http://www.faa.gov/other_visit/avia...gations/designee_types/media/derdirectory.pdf
     
  15. Sep 11, 2009 #15

    Othman

    Othman

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    K-Rigg,

    A One-time STC is an STC that is only applicable to one aircraft (one serial number) or to a specific group of aircraft that are specified by serial number on the STC.

    Regular STC's can be installed on any aircraft that is on the approved models list of the STC. This is usefull if you're trying to sell a modification, but of course undergoes more scruteny from the FAA.

    In Canada we have LSTC's (L for Limited) instead of the one-time STC. A DAR may issue an LSTC but not an STC, that is reserved for Transport Canada only. I imagine the same type of limitation is applied to DERs in the US... I don't know.

    Since I'm not a powerplants guy I can't tell you how difficult it will be get an approval for the installation of a turbo on a certified engine. Sounds like you're into a bit of FAR Part 33 requirements and also see FAR 23 Subpart E (Powerplants), particularily paragraph 909.

    http://ecfr.gpoaccess.gov/cgi/t/tex...de=14:1.0.1.3.10&idno=14#14:1.0.1.3.10.5.89.6

    Good luck.

    Ashraf
     
  16. Sep 11, 2009 #16

    Othman

    Othman

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    K-Rigg,

    A One-time STC is an STC that is only applicable to one aircraft (one serial number) or to a specific group of aircraft that are specified by serial number on the STC.

    Regular STC's can be installed on any aircraft that is on the approved models list of the STC. This is usefull if you're trying to sell a modification, but of course undergoes more scruteny from the FAA.

    In Canada we have LSTC's (L for Limited) instead of the one-time STC. A DAR may issue an LSTC but not an STC, that is reserved for Transport Canada only. I imagine the same type of limitation is applied to DERs in the US... I don't know.

    Since I'm not a powerplants guy I can't tell you how difficult it will be get an approval for the installation of a turbo on a certified engine. Sounds like you're into a bit of FAR Part 33 requirements and also see FAR 23 Subpart E (Powerplants), particularily paragraph 909.

    Electronic Code of Federal Regulations:

    Good luck.

    Ashraf
     
  17. Sep 12, 2009 #17

    vortilon

    vortilon

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    We have another way of issuance for a field approval that not many people are aware of. It is called a blanket field approval that allows the holder to modify any applicable aircraft of type himself or herself in accordance with the blanket field approval.

    In other words if could obtain a blanket field approval for your turbo mod then you alone could set up shop modifying aircraft under that approval. Your shop can have employees.

    These are rarely granted these days since most of the Feds with common horse sense have retired or died. The new generation of feds can't look at something and say "ya that will work"
     

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