Building an airplane produces two artifacts: an aircraft, and a paper trail. The kit invoices, the builder log, the weight and balance, the N-number reservation, the registration, the notarized FAA Form 8130-12 swearing you built the majority of it, the airworthiness application, and finally — the day the DAR hands over the pink slip — the operating limitations that govern everything the aircraft does from that moment on.
Most builders think the paperwork ends there. It doesn’t. There’s one last form: FAA Form 8610-3, the application for a repairman certificate (experimental aircraft builder). It’s the most misunderstood document in homebuilding — the certificate it produces is not a license to maintain your airplane, doesn’t expire, costs nothing, and grants exactly one privilege you’ll exercise exactly once a year.
This post covers what the certificate actually is, the regulations behind it, what it does and doesn’t let you do, and what the application process looks like — so when your build reaches its last form, you’ll know exactly what to expect.
What It Is — and Isn’t
Here’s the part that surprises almost everyone, including A&Ps: you don’t need any certificate to maintain an experimental amateur-built aircraft. Not this one, not any. Anyone — you, a friend, your car mechanic — can legally perform any work on an E-AB, from oil changes to re-skinning a wing to overhauling the engine. The rules that restrict who may maintain an aircraft live in 14 CFR Part 43, and Part 43, by its own terms, does not apply to amateur-built experimentals — as the EAA’s own FAQ confirms. We’ll walk the exact regulatory chain in the next section, because it’s worth seeing with your own eyes.
So what does the repairman certificate grant? Exactly one thing: the authority to perform and sign the annual condition inspection on the one aircraft you built. That’s the inspection your operating limitations require every twelve calendar months — the experimental world’s equivalent of an annual. Without the certificate, that signature requires an A&P mechanic. With it, the loop closes in your own hangar.
The certificate’s character matches its narrow scope. It’s issued for one specific airframe, by serial number. It never expires. It costs nothing. And it’s non-transferable — if you sell the aircraft, the certificate doesn’t convey; the new owner relies on an A&P (though you, the builder, may keep signing its condition inspections for as long as the new owner will have you).
One privilege, one airplane, once a year, forever, for free. Misunderstood mostly because people assume it must be more complicated than that.
The Regulatory Chain
The rules deserve a close look, because the conclusion above sounds wrong until you trace it yourself. It takes three steps.
Step one: the restrictions live in Part 43. 14 CFR Part 43 governs maintenance, preventive maintenance, rebuilding, and alteration. Within it, § 43.3 lists who may perform that work and § 43.7 lists who may approve an aircraft for return to service. This is the machinery that, in the certified world, limits an owner to the short list of preventive maintenance items in Appendix A and reserves everything else for certificated mechanics.
Step two: the exclusion. § 43.1(b)(1) states that Part 43 does not apply to any aircraft holding an experimental certificate, unless the FAA previously issued that aircraft a different kind of airworthiness certificate. An amateur-built aircraft certificated as experimental from birth has never held another certificate — so the entire part, restrictions included, simply doesn’t apply. Note what this means: there is no rule permitting anyone to work on an E-AB. There’s an absence of any rule prohibiting it. (The carve-out matters, though: a certified aircraft later moved to experimental, like many exhibition warbirds, stays under Part 43.)
Step three: the re-entry. If Part 43 doesn’t apply, why does your airplane need an inspection at all? Because your operating limitations — which carry regulatory force through § 91.319 — require a condition inspection within the preceding twelve calendar months, performed in accordance with the scope and detail of Appendix D to Part 43. Appendix D applies to your aircraft not because Part 43 says so, but because your op lims incorporate it by reference. And those same op lims name who may perform it: typically the holder of a repairman certificate issued under § 65.104, or an appropriately rated mechanic.
That last reference is where this post’s subject finally enters the regulations. § 65.104 sets four eligibility requirements — you’re at least 18, you’re the primary builder of the aircraft, you can show the FAA you have the requisite skill to determine whether it’s in condition for safe operation, and you’re a U.S. citizen or permanent resident. Its single privilege mirrors the op lims: condition inspections, on that aircraft.
Notice the standard, too: condition for safe operation — not “airworthy.” An E-AB has no type certificate to conform to, so the inspection asks a different question than a certified annual: not “does it match its approved design?” but “is it safe to fly?”
What Changed in 2025
If you research this certificate the way most builders do — forum threads and decade-old blog posts — you’ll find two pieces of advice that are now wrong. Both changed in 2025.
The form is 8610-3, not 8610-2. For decades, repairman applicants used FAA Form 8610-2, and nearly every guide online still says so. The FAA has since consolidated all repairman certificate applications onto the new Form 8610-3, with a dedicated section (II-B) for the experimental aircraft builder certificate — make, model, serial number, and certification date, entered exactly as they appear on the airworthiness certificate. The current guidance lives in Advisory Circular 65-23B. If you show up with a filled-out 8610-2 from an old checklist, you’ll be redoing paperwork.
MOSAIC widened who can inspect — with a catch. The MOSAIC rule, effective October 22, 2025, extended condition inspection privileges on experimental amateur-built aircraft to holders of light-sport repairman certificates with maintenance (LSRM) or inspection (LSRI) ratings. On paper, that means a builder without a repairman certificate — or a second owner — now has options beyond an A&P. The catch is the same document that’s been running this show all along: your operating limitations. Under § 91.319, op lims take priority, and most E-ABs flying today carry op lims that name only the § 65.104 repairman or an appropriately rated mechanic. Until those limitations are amended, the new privilege may not reach your particular airplane. Read your op lims; they are, as ever, the controlling document.
Roci’s own operating limitations, issued March 18, 2026 — five months after MOSAIC took effect — already carry the updated language: “An experimental aircraft builder certificated as a repairman for this aircraft under § 65.104, a light-sport repairman certificated under § 65.107 (in accordance with their certificate privileges under § 65.109), an appropriately rated FAA-certificated mechanic, or an appropriately rated FAA-certificated repair station may perform the condition inspection required by these operating limitations.” If your aircraft was certificated before October 22, 2025, your op lims likely use the older template — check yours to see which one you have.
Neither change alters the fundamentals. The builder’s repairman certificate remains the only path to signing your own condition inspection — and the only credential that exists because you built the airplane.
The Process
The application has no fee, no test, and no deadline — you can apply the week after certification or years later. Here’s the sequence.
1. Fill out FAA Form 8610-3. Normally, IACRA — the FAA’s online portal — is the way to apply for any airman certificate. Not this one, for now: the 8610-3 is new enough that IACRA doesn’t yet support it, so as of this writing you download the PDF, complete it by hand, and bring it in. Section II-B covers the experimental aircraft builder certificate: make, model, serial number, and certification date, copied exactly from your airworthiness certificate. Mismatches between the form and the certificate are the most common reason for a redo.
2. Contact your FSDO for an appointment. The certificate is issued by the FSDO’s airworthiness side. Some offices handle the whole thing remotely; most want you in person. Ask what they’d like you to bring when you schedule.
3. Prepare a folder anyway. Whatever the answer, it costs nothing to arrive with: government photo ID, the completed 8610-3, copies of your airworthiness certificate and operating limitations, your Form 8130-12 eligibility statement, the aircraft logbook with the airworthiness sign-off, your builder log, and a condition inspection checklist showing how you intend to exercise the privilege. Eligibility rests on “primary builder” and “requisite skill” — the folder is your evidence for both, even if nobody opens it.
4. The appointment. Expect a wide range. Builders report everything from a five-minute meeting — verify the information on the form, sign the back of the 8610-3, done — to a detailed interview with a page-by-page review of multiple builder logbooks. Both are the process working; FAA guidance gives inspectors discretion in how they establish requisite skill, and evidence that you built the aircraft generally satisfies it. Which experience you get depends on your office, your inspector, and what your certification paperwork already established.
5. Walk out with a temporary certificate. You’ll receive a temporary airman certificate (Form 8060-4) on the spot, valid while the permanent card is processed and mailed — the same plastic-card format as a pilot certificate, and arguably the better-earned of the two.
Now What — Exercising the Privilege
The certificate in hand, the obvious question is when to use it. The answer I’ve landed on: not immediately.
Authority and competence are different things, and the regulation only verifies the first. My plan for N117ZS(Roci’s) first condition inspection is to take it to an experienced shop and work alongside them — an owner-assisted inspection where the A&P signs the logbook and I do the learning. A professional who has been through dozens of airframes knows where to linger, which wear items the maintenance manual undersells, and what a healthy example should look like at one year old. Year two, with that calibration, the signature becomes mine.
In the meantime, the certificate’s real homework is the checklist. The op lims require the inspection to follow the scope and detail of Part 43 Appendix D, which is organized by zone — fuselage, cabin, engine, landing gear, wings, empennage, propeller, radios. The working document for a Sling TSi is a merge of three sources: the Sling maintenance manual’s annual schedule, the Rotax 916 iS maintenance manual’s scheduled checks, and Appendix D as the completeness test — anything the appendix requires that the manuals don’t cover gets added. Build it once, refine it every year, and keep the completed copy with each inspection’s records.
The last piece is the signature itself. Your operating limitations prescribe the exact logbook endorsement — typically a variant of “I certify that this aircraft has been inspected on [date] in accordance with the scope and detail of Appendix D to Part 43 and found to be in a condition for safe operation.” Note again what you’re attesting: condition for safe operation. Not airworthy, not conforming — safe. That word is the whole job, and it’s why the certificate, narrow as it is, is worth taking seriously.
One privilege, once a year. The last form turns out to be the one that keeps working.
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