What counts as a "Major Modification" for an E-AB?

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Vigilant1

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I'd be interested in any leads to figure out if a particular modification to an EAB will require a re-do of Phase 1 flight testing. For instance, if a builder adds an external baggage pod--back to square 1?

Thanks in advance.
 

TFF

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Structural changes, engine changes, prop changes, adding aerobatic maneuvers. Part 21.93 applies to homebuilts. The plus side is all you do is notify the FSDO that you are back in phase 1 with the changes; they cant say no. It only has to be done to prove the design, not every time you want to change it back and forth. .
 

djschwartz

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From FAA, CFR14, Part 1, Paragraph 1.1:

"Major alteration means an alteration not listed in the aircraft, aircraft engine, or propeller specifications—

(1) That might appreciably affect weight, balance, structural strength, performance, powerplant operation, flight characteristics, or other qualities affecting airworthiness; or

(2) That is not done according to accepted practices or cannot be done by elementary operations.


Major repair means a repair:

(1) That, if improperly done, might appreciably affect weight, balance, structural strength, performance, powerplant operation, flight characteristics, or other qualities affecting airworthiness; or

(2) That is not done according to accepted practices or cannot be done by elementary operations."


So, yes, adding a cargo pod to an aircraft that did not previously have one as part of its design is a "major alteration"


Dave
 

Dave Prizio

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For anything possibly affecting the airworthiness of an experimental amateur-built aircraft always start with the Operating Limitations for that aircraft. Typical language in the OLs will read something like this:
"After incorporating a major change as described in 14 CFR 21.93 the aircraft owner is required to reestablish compliance with 14 CFR 91,319(b) and notify the geographically responsible FSDO..."

So to see what a major change is we need to look at 14 CFR 21.93, which says: " (a) In addition to changes in type design specified in paragraph (b) of this section, changes in type design are classified as minor and major. A 'minor change' is one that has no appreciable effect on the weight, balance, structural strength, reliability, operational characteristics, or other characteristics affecting the airworthiness of the product. All other changes are 'major changes' (except as provided in paragraph (b) of this section).

Ultimately you ask the local FSDO if your change is major or minor and the re-enter Phase I (usually for 5 hours) if the decide it is a major change. In my experience they are not too picky when it comes to borderline major changes, btu your experience is likely to be very dependent on the mood and knowledge of the local FAA people.
 

Vigilant1

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Thanks much to you guys for the help. It sounds (to continue the example) like a new owner could add the baggage pod and it would certainly be a major modification if the owner wanted to increase the plane's max gross weight when using the pod. Even without the bump-up in MTOW, this change would likely be a major modification. I guess folks who add an aux tank internally don't need to worry about this provided the plane still stays within the originally tested (and approved) CG range.
 
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bmcj

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What counts as a "major modification"? I had a friend that designed and built his own pusher canard in the early 70's (looked kind of like a backward mid-wing Sonerai). After a hand-prop mishap when the plane decided to go flying by itself, he rebuilt the damaged craft, but it came out of the shop as a conventional (wing and tail) tractor design. I think THAT probably qualified as a major modification. :gig:
 
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