Visual guide 6 of 6
Airworthiness certificates: standard vs special
Part 21 sorts every civil aircraft into a standard or a special airworthiness certificate. That one line on the certificate decides which maintenance rules apply, who may sign, and what the aircraft may be used for.
Family tree 14 CFR 21.175
- Airworthiness certificate
- Standard 21.175(a)
- Normal, utility, acrobatic, commuter, transport category
- Manned free balloons
- Special classes of aircraft
- Special 21.175(b)
- Primary, restricted, provisional, limited category (type-certificated)
- Light-sport category — S-LSA, 21.190; eligibility in Part 22
- Experimental — 21.191 purposes (a)–(l): amateur-built (g), light-sport (i), (k), (l)…
- Special flight permit — 21.197
- Standard 21.175(a)
Four aircraft you'll meet in an LSA shop
| Standard (e.g. Cessna 172, J-3 Cub) | S-LSA — light-sport category | E-LSA — experimental light-sport | E-AB — experimental amateur-built | |
|---|---|---|---|---|
| Issued under | 21.183 (type certificate) | 21.190 + Part 22 (consensus standards, manufacturer's statement of compliance) | 21.191(i), (k) or (l) | 21.191(g): major portion built by persons for their own education or recreation |
| Part 43 applies? | Yes | Yes, minus 337/App. B/App. A lists for non-FAA-approved products (43.1(d)) | No (43.1(b)) | No, unless it previously held a different kind of airworthiness certificate (43.1(b)(1)) |
| Recurring inspection | Annual (+100-hr if for hire) — 91.409 | Condition inspection every 12 cal. months (+100-hr for paid towing/training in provided aircraft) — 91.327 | Per operating limitations (typically a condition inspection within the preceding 12 months, App. D scope) — AC 65-32B ¶2.6.3 | |
| Who maintains | Mechanic, repair station, IA for majors; pilot PM (43.3) | LSR-M, appropriately rated mechanic or repair station (91.327(b)(1)); sport-pilot owner PM (43.3(g)) | Part 43 n/a — follow operating limitations; condition inspection by LSR-I (owned), LSR-M, builder repairman (E-AB own build), or as limitations allow | |
| Data for repairs | Acceptable data (minor), approved data (major) | Manufacturer's procedures or person acceptable to FAA; SOC consensus standards (91.327(b)) | Per operating limitations; repair station majors need FAA-acceptable methods/data (145.201(c)(3)) | |
| For hire | Per operating rules (Parts 91/119/135…) | Only towing, training/checking/testing, POH-listed aerial work (91.327(a)) | Not for carrying persons/property for hire in operations needing a 119 certificate etc. (91.319(a)); (i)/(k)/(l): no compensation except listed exceptions (91.319(e)) | |
| Disclosure | — | Advise each person carried of the special nature of the aircraft (91.327(e)) | Advise each person carried of the experimental nature; VFR day unless authorized; tell ATC (91.319(d)); "EXPERIMENTAL" near each entrance, 2–6 in. letters (45.23(b)) | |
| Marks | 12 in. (fixed-wing) | 12 in. (fixed-wing) | 3 in. allowed if max cruise ≤ 180 KCAS (45.29(b)(1)(iii)) | |
Experimental purposes — 21.191
| Para. | Purpose | Note |
|---|---|---|
| (a) | Research and development | Duration 3 years from issue/renewal unless shorter (21.181(a)(4)) |
| (b) | Showing compliance with regulations | 3 years |
| (c) | Crew training | 3 years |
| (d) | Exhibition | Unlimited unless FAA sets a period (21.181(a)(5)) |
| (e) | Air racing | Unlimited |
| (f) | Market surveys | 3 years; only as provided in 21.195 |
| (g) | Operating amateur-built aircraft | Unlimited |
| (h) | Operating primary kit-built aircraft | Unlimited |
| (i) | Operating light-sport aircraft: (1) non-103 ultralight-type, issued by Jan 31, 2008; (2) kit-built; (3) former S-LSA | No new (i)(2)/(i)(3) after Oct 22, 2025 |
| (j) | Operating former military aircraft (ferry, storage, repositioning) | Unlimited |
| (k) | Operating light-sport category kit-built aircraft | Type must have an S-LSA counterpart (21.193(h)) |
| (l) | Operating former light-sport category aircraft | Unlimited |
How long does it last? 14 CFR 21.181
- Standard, primary, restricted, limited: effective as long as maintenance, preventive maintenance and alterations are performed per parts 43 and 91 (and the aircraft stays U.S.-registered).
- Light-sport category: as long as the aircraft meets 21.190(b) eligibility, conforms to its original or properly altered configuration, has no unsafe condition — and legacy aircraft stay within the old limits. 21.181(a)(3)
- Special flight permit: the period stated in the permit. Purposes include ferrying to a repair base or storage, delivery/export, production flight testing, evacuation, and customer demonstrations. 21.197(a)
- All of them: only while the aircraft is registered in the United States, unless surrendered, suspended, revoked or terminated. 21.181(a)
Must be on board
Certificates 91.203
- Appropriate and current airworthiness certificate, displayed at the cabin or cockpit entrance, legible to passengers or crew
- Effective U.S. registration certificate (or the second copy of the application as temporary authority, 47.31(c))
- Form 337 if a fuel tank is installed in the passenger or baggage compartment
Registration 47.40
- A Certificate of Aircraft Registration expires seven years after the last day of the month in which it was issued
- Renew during the six months before expiration
Flight manual & marks 91.9; 45
- Operate within the approved flight manual, markings and placards
- Fireproof identification (data) plate — builder, model, serial, TC/PC numbers (45.11, 45.13)
- No person may remove or install the data plate without FAA approval, except as needed during part 43 maintenance (45.13(c)–(d))