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Thread: Minor vs minor change

  1. #1

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    Minor vs minor change

    Wanting to move all of the electric from the wing root area to the instrument panel. IA says it can't be done without an STC or written approval from the FAA. Now I have produced 14 CFR sec 21.93. Expecting his response to be that since the rear seat occupant can't reach the breakers and switches, "it changes the operational characteristics" and therefore is major. Looking for "modification for safety concerns".

  2. #2
    wireweinie's Avatar
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    Nothing to do with part 21.

    First off, your aircraft was produced under CAR3, NOT FAR 23 (part 21 deals with certification of NEW parts), so it is required to be maintained under that reg. Secondly anything minor vs major is a maintenance function covered under FAR 43 Appendix A. Since electrical is an airframe system, look at paragraph (a), (1). In that section only two lines address electrical system changes: line (ix) and line (xii). (ix) says 'Hydraulic and electrical actuating system of components.' This does not apply as you are not changing the electrical of a component. (xii) states 'Changes to the basic design of the fuel, oil, cooling, heating, cabin pressurization, electrical, hydraulic, de-icing, or exhaust systems. This also does not apply to your project as you are simply moving your switches and breakers and not changing the basic design of any system. As there is no line in paragraph (a), (1) that calls your project a major alteration, it is therefore a minor.

    Move your electrical panel items to the instrument panel and sign it off in the log book. Then go find an IA that understands the regs as they pertain to small aircraft.

    Web
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    You need to look around for a better IA!!
    DENNY

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    Taledrger's Avatar
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    Did ours 10 years ago.. everything from wing root to panel... Logbook entry..
    Bob D

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    Minor vs minor change

    21.93 only delineates where an STC is required. The definition in Part 1.1 gives the difference between a major Alteration and Minor Alteration, then supported by Part 43 Appendix A. Best source for the decision is in AC43-210A.

    While Web indicated Part 21 doesn’t apply, I counter that it does, and even if it didn’t, CAR 3.23, .24, .25, .26 & .27 covers the exact same thing that 21.93 covers.

    All that said, I would likely consider it a minor alteration.


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    Defense -

    Quote Originally Posted by topcubs365 View Post
    Wanting to move all of the electric from the wing root area to the instrument panel. IA says it can't be done without an STC or written approval from the FAA. Now I have produced 14 CFR sec 21.93. Expecting his response to be that since the rear seat occupant can't reach the breakers and switches, "it changes the operational characteristics" and therefore is major. Looking for "modification for safety concerns".
    My IA is typically pretty darn good. He has had a few bad experiences with the local FSDO interpreting regulations, such as "how have you pressure tested the PA22." Same FSDO that informed me that I could not build an experimental using certified parts. I was looking for chapter and verse that I could print off and put in the records as part of my rebuild. Got them now and thanks. MK

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    Gordon Misch's Avatar
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    Doesn't CAR 3 say stuff like operable items have to be in reach of the pilot? I haven't re-checked. So - if pilot flying is in the back, then??? But if no-solo from the back, then no issue?? So would a placard or other requirement "solo or PIC from front seat only" solve the problem??
    Gordon

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    wireweinie's Avatar
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    The original PA 18 electrical panel is at the right overhead panel. No way a seated rear pilot can reach it.

    Web
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    Steve Pierce's Avatar
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    Quote Originally Posted by topcubs365 View Post
    My IA is typically pretty darn good. He has had a few bad experiences with the local FSDO interpreting regulations, such as "how have you pressure tested the PA22." Same FSDO that informed me that I could not build an experimental using certified parts. I was looking for chapter and verse that I could print off and put in the records as part of my rebuild. Got them now and thanks. MK
    I have butted my head against the same FAA wall. Like you are doing, I have to educate myself and then educate them. Research and stick to your guns.
    Steve Pierce

    Everybody is ignorant, only on different subjects.
    Will Rogers
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    Most inspectors don’t know anything about little airplanes, much less old (predecessor) regulations. Always take the stance of “show me the regulatory requirement” when a guy says “you can’t” or “you have to”. Don’t do it so much as a challenge, but as a mutual learning experience. Seems every time I get a new advisor at the ACO, I have to educate them on old regulations. One of my DER limitations is CAR 3 or before. It amazes me that these guys simply can’t understand that CAR 4 came before CAR 3!

    Do your research ahead of time. Figure out what you ant to do, and have the regulatory basis figured out BEFORE you contact the FSDO. That way, when they say you can’t, you can counter with “but what about XXX, it says right here that can!”


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  11. #11

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    Sure agree with that. The new guys will try to steamroller you. Come armed with hard copies of regs, advisory circulars, and “Orders.” Older FSDO hands will watch in amusement, but apparently won’t interfere.

    And memorize the definitions pertaining to major/minor alterations.
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  12. #12
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    I’m not coming down on one side or the other on this. But at a Clyde Smith seminar a several years ago he said an airplane type certificate is like its birth certificate. It represents everything that went into making that airplane. Including all the drawings. So, if one follows that interpretation anything that changes the way things were drawn like the position of switches should require an STC. I’m not an A&P so I don’t understand how field approvals work in this regard.

    clyde’s example I think was leaving the landing gear un covered. If you need an STC to fly some planes with the door off, how is that different when flying a cub with parts of the airframe un covered when the drawings say it should be?

    Rich

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    It is a minor alteration. They can be done without STC or Field Approval, and if you submit a 337 the ASI is supposed to reject it with a written explanation.
    ASIs no longer look at 337s, so who knows . . .

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    I get the theory behind Clyde’s argument, but manufacturers drawings and tc’s don’t spell out what is major/minor. Piper also had drawings for pk screw layout for fairings, interior panels, etc. Is adding one not on the drawing a major by his definition? You have to go by part 43, appendix A- it’s what the FAA will judge you with...

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    Gordon Misch's Avatar
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    The regs say major is "changes to the basic design" of the electrical system. So reasonable people might disagree whether such changes are "basic", but I'd sure as heck side with the advocates of minor. https://www.law.cornell.edu/cfr/text...x-A_to_part_43
    Gordon

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  16. #16
    Steve Pierce's Avatar
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    Appendix A to Part 43 - Major Alterations, Major Repairs, and Preventive Maintenance
    (a) Major alterations -
    (1) Airframe major alterations. Alterations of the following parts and alterations of the following types, when not listed in the aircraft specifications issued by the FAA, are airframe major alterations:
    (i) Wings.
    (ii) Tail surfaces.
    (iii) Fuselage.
    (iv) Engine mounts.
    (v) Control system.
    (vi) Landing gear.
    (vii) Hull or floats.
    (viii) Elements of an airframe including spars, ribs, fittings, shock absorbers, bracing, cowling, fairings, and balance weights.
    (ix) Hydraulic and electrical actuating system of components.
    (x) Rotor blades.
    (xi) Changes to the empty weight or empty balance which result in an increase in the maximum certificated weight or center of gravity limits of the aircraft.
    (xii) Changes to the basic design of the fuel, oil, cooling, heating, cabin pressurization, electrical, hydraulic, de-icing, or exhaust systems.
    (xiii) Changes to the wing or to fixed or movable control surfaces which affect flutter and vibration characteristics.

    If it isn't major it is minor. I have sat across the table from the Justice Department trying to tell me my snap vents were a major alteration and caused a mid-air. Know your stuff or they will try and eat you alive.
    Steve Pierce

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  17. #17

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    In my book, a change to the basic design of an electrical system would be a change from generator to alternator, change from lead acid battery to a different chemistry battery, adding or removing bus bars, a change from fuses to circuit breakers. That sort of thing. Moving the location of items doesn’t necessarily mean a change in the basic design. That said, a comment was made earlier about placement of controls, CAR 3.384 says all controls need to be within reach of the pilot (paraphrase).

    Years ago, the FAA used to interpret this as adding a CB or fuse to power a new radio was a basic change to the system. Thank God they gave up on that idea!


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  18. #18
    wireweinie's Avatar
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    Quote Originally Posted by dgapilot View Post
    In my book, a change to the basic design of an electrical system would be a change from generator to alternator, change from lead acid battery to a different chemistry battery, adding or removing bus bars, a change from fuses to circuit breakers.

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    Sorry but I'll argue those points to the death (and I'm Irish). Generator to alternator? Both are engine driven 'generators' of electricity. Even more similar if both driven by belts or if the drive forces meet the specs of the accessory drive (vacuum drive). How is adding a bus bar a major? This is simply a standard shop practice when joining multiple circuit fuses or breakers. How else would it be done? Daisy chaining them with wire is more danger prone than a simple bar. All batteries are simply a container full of chemicals made to produce electrical power, just use a safe style, of the correct voltage for your system. And fuses and breakers are both thermally operated so very similar and required circuit protection.

    The one thing I will state, though, is that it's up to the mechanic to insure that the change/install is done to a high quality. I.e., proper shop practices and torques. Wire and breakers/fuses sized as per manufacturer or AC43.13. Proper routing and bundling of wires, etc.

    I once helped change a PA18 from 12 volt to 24 volt on rebuild. It was signed off as minor. Just one DC voltage to another. Surprisingly very few components need to be changed due to the voltage change. Mainly the starter motor and voltage regulator. Many other items such as lights and avionics are already made to function on either voltage. Couple of new placards though!

    Web
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    Quote Originally Posted by dgapilot View Post
    a change from fuses to circuit breakers.
    So would an IA use some kind of approved data and just submit a 337 or lacking any approved data use some acceptable data and request a field approval? I would love to be a fly on the wall and listen to that FAA Field Approval Commitee discussion.

  20. #20
    BC12D-4-85's Avatar
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    There's no time to be fiddling with a blown fuse in flight. Too much of a chance when busy or in turbulence for dropping the cap and blown fuse, plus it takes two hands to replace the fuse if it can even be located. Not a topic here just a consideration from my experience.

    Gary
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  21. #21

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    Quote Originally Posted by bubb2 View Post
    So would an IA use some kind of approved data and just submit a 337 or lacking any approved data use some acceptable data and request a field approval? I would love to be a fly on the wall and listen to that FAA Field Approval Commitee discussion.
    Try AC 43.13-1b Chapter 11. I’d have to look up the paragraph, but that’s the approved data.


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  22. #22

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    I maintain aircraft without electrical "systems." There was a FSDO question about said "system," and I managed to de-fuse it by stating that battery powered nav lights were on the type certificate. A few wires, switches, and breakers do not seem to comprise a system.

    One can find lots of comments about an electrical system needing, among other things, a component that supplies electricity coninuously (alternator or generator). I am with Web - keep the paperwork simple, and use good components with adequate circuit protection.

  23. #23
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    Quote Originally Posted by Steve Pierce View Post
    Appendix A to Part 43 - Major Alterations, Major Repairs, and Preventive Maintenance
    (a) Major alterations -
    (1) Airframe major alterations. Alterations of the following parts and alterations of the following types, when not listed in the aircraft specifications issued by the FAA, are airframe major alterations:
    (i) Wings.
    (ii) Tail surfaces.
    (iii) Fuselage.
    (iv) Engine mounts.
    (v) Control system.
    (vi) Landing gear.
    (vii) Hull or floats.
    (viii) Elements of an airframe including spars, ribs, fittings, shock absorbers, bracing, cowling, fairings, and balance weights.
    (ix) Hydraulic and electrical actuating system of components.
    (x) Rotor blades.
    (xi) Changes to the empty weight or empty balance which result in an increase in the maximum certificated weight or center of gravity limits of the aircraft.
    (xii) Changes to the basic design of the fuel, oil, cooling, heating, cabin pressurization, electrical, hydraulic, de-icing, or exhaust systems.
    (xiii) Changes to the wing or to fixed or movable control surfaces which affect flutter and vibration characteristics.

    If it isn't major it is minor. I have sat across the table from the Justice Department trying to tell me my snap vents were a major alteration and caused a mid-air. Know your stuff or they will try and eat you alive.
    Side note, with one of the airmens cubs they put a bunch of carbon concepts stuff on and tried to get a field approval, the fsdo said the tank covers were a minor. If you need that paperwork I can send it to you. With what’s above, fairings are a major but they said no.


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  24. #24
    wireweinie's Avatar
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    Sorry, there is no way installing breakers in place of fuses rises to the level of a major alteration. Both operate thermally. In other words they both trip when they get hot. Both have been used on aircraft ever since electricity was first installed and they are not 'unique'. Neither fuses nor breakers are built for specific models of aircraft. They are basically hardware items used by electrical guys. What would I consider a major alteration with breakers or fuses? Electronic breakers. Think Vertical Power units as they use complex circuits to monitor current flow and are programmable.

    The wording is 'basic' design change.

    Web
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