Hard to keep up here today, running errands, but just one point to clarify:
I think AC 43-9C change 2 does apply to EA-B regardless of the title because it says it applies to general aviation and 14CFR 91 in paragraph 1:
Subject: Maintenance Records
Advisory Circular
Date: 5/8/18 AC No: 43-9C Initiated by: AFS-300 Change: 2
1. PURPOSE. This advisory circular (AC) describes methods, procedures, and practices that have been determined to be acceptable means of showing compliance with the General Aviation (GA) maintenance record-making and recordkeeping requirements of Title 14 of the Code of Federal Regulations (14 CFR) parts 43 and 91. This material is not mandatory, nor is it regulatory, and it acknowledges that the Federal Aviation Administration (FAA) will consider other methods that may be presented. It is issued for guidance purposes and outlines several methods of compliance with the regulations.
It "applies" in the sense that it "applies" to anything, but even in the paragraph you reference, it clearly states that it's "not mandator, nor is it regulatory", so it's just advice - no more.
@Toobuilder (and others) position is that logging maintenance is not required for E-AB aircraft - mine is that it is. If the EAA disagrees with me, well, their lawyers are better than mine (none), so I'll defer to their position if
@Toobuilder can provide a reference that indicates what it is. Now, a bit of web surfing turns up two Kitplanes articles that support
@Toobuilder's position:
Aircraft maintenance records. By Dave Prizio.
www.kitplanes.com
and
What's required for Experimental/Amateur-Built Aircraft? By Owen C. Baker.
www.kitplanes.com
but if I were teaching a logic class, Mr. Baker's statement that:
"But persons working on E/A-B aircraft are not required to have a certificate, nor any training for a certificate, nor any specific knowledge of, or training on, all of the provisions of 91.417. So Section 91.417, in the context of requiring E/A-B aircraft to have maintenance records, is not an applicable general operating rule."
would earn him a D- at best. Lisa Turner, writing in Sport Aviation, seems to imply that logging maintenance is required:
There is an argument that as the owner of your own airplane, you will actually be the best person to maintain it, assuming you have the skills or are willing to acquire them.
inspire.eaa.org
but doesn't come right out and say it.
So, Prizio makes claims but doesn't support them, Baker makes claims but his logic about 91.417 isn't logical, and Turner is vague on the matter.
My position is that the clauses in 91.417 are separable, and the inability to meet the requirements for one issue (certificate #) do not invalidate the requirements for the rest (creation and retention of maintenance records).
Obviously, there's a difference of opinion, and there are no logbook police, so...

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