Who may do what

Standard airworthiness certificate

Normal, utility, acrobatic, commuter, transport category, manned free balloons, special classes 14 CFR 21.175(a). Part 43 applies in full 14 CFR 43.1(a).

1. Any holder of a part 61 pilot certificate except a sport pilot may perform preventive maintenance on an aircraft owned or operated by that pilot that is not used under part 121, 129 or 135. A sport pilot's preventive-maintenance privilege is limited to aircraft with a light-sport category certificate. 14 CFR 43.3(g)
2. At least a private pilot certificate is needed to approve the aircraft for return to service after performing preventive maintenance under 43.3(g). 14 CFR 43.7(f)
3. Light-sport repairman privileges do not extend to any aircraft with a standard airworthiness certificate, regardless of whether a sport pilot may fly it. AC 65-32B ¶¶2.6.1, 2.8.2.2
4. Only for work the mechanic has satisfactorily performed before (or shows ability to do under FAA observation or under supervision of an experienced, appropriately rated mechanic or repairman), and only while understanding the current manufacturer instructions and maintenance manuals. 14 CFR 65.81(a)–(b)
5. A mechanic may perform or supervise work for which rated, excluding major repairs to, and major alterations of, propellers, and any repair or alteration of instruments. 14 CFR 65.81(a)
6. Airframe- and powerplant-rated mechanics approve for return to service only after work "excluding major repairs and major alterations." 14 CFR 65.85(a), 65.87(a)
7. The annual inspection is an IA privilege. 14 CFR 65.95(a)(2)
8. Airframe rating: airframe and related parts/appliances; powerplant rating: powerplant or propeller and related parts/appliances. 14 CFR 65.85(a), 65.87(a) Recent experience (6 months in the preceding 24) applies. 14 CFR 65.83
9. An IA may inspect and approve for return to service after a major repair or major alteration only if the work was done in accordance with technical data approved by the Administrator (not for aircraft maintained under a part 121 continuous airworthiness program). 14 CFR 65.95(a)(1)
10. An IA may perform an annual, or perform or supervise a progressive inspection. 14 CFR 65.95(a)(2)

Repair station: may maintain, alter and approve for return to service any article for which it is rated, within its operations specifications; after a major repair or alteration only if the work followed approved technical data. 14 CFR 145.201(a), (c) Manufacturer: may rebuild or alter what it manufactured under a type or production certificate, perform the part 91 inspections on aircraft it manufactured under a type certificate or currently manufactures under a production certificate, and approve its own work for return to service — with approved technical data except for minor alterations. 14 CFR 43.3(j), 43.7(d) Helper: may do what the supervising mechanic or repairman is authorized to do if the supervisor personally observes the work and is readily available in person — but never an inspection required by part 91 or after a major repair or alteration. 14 CFR 43.3(d)

Special airworthiness — light-sport category (S-LSA)

Issued under 14 CFR 21.190. Part 43 applies, except that for products not produced under an FAA approval the Form 337, Appendix B recording and the Appendix A major lists do not apply 14 CFR 43.1(d). Operating and maintenance rules: 14 CFR 91.327.

1. A sport pilot may perform preventive maintenance on an aircraft owned or operated by that pilot that holds a light-sport category certificate, and approve it for return to service afterward; higher pilot certificates also qualify. 14 CFR 43.3(g), 43.7(f), 43.7(h)
2. LSR-I privileges cover only the annual condition inspection of an owned, experimental aircraft certificated under 21.191(g), (i), (k) or (l). 14 CFR 65.109(a)
3. Only in the category (and class, if limited) of the holder's training; only for work previously performed satisfactorily (or demonstrated to the FAA, or done under direct supervision of an experienced, appropriately rated mechanic or repairman); and only while understanding the manufacturer's current instructions. 14 CFR 65.109(b)(3), (c)
4. Each major repair or alteration to a consensus-standard product must be authorized by the manufacturer or a person acceptable to the FAA and done and inspected per their procedures. 14 CFR 91.327(b)(5) Before performing a major repair, an LSR-M must complete additional training acceptable to the FAA. 14 CFR 65.109(b)(3); AC 65-32B ¶2.8.5
5. The LSR-M return-to-service privilege excludes a major repair or major alteration on a product produced under an FAA approval (TC, STC, PMA, TSO…). Only a repair station or an IA may approve those. 14 CFR 65.109(b)(1); AC 65-32B ¶2.8.2.1
6. Condition inspection once every 12 calendar months by an LSR-M, an appropriately rated mechanic, or an appropriately rated repair station, using the manufacturer's (or an FAA-acceptable person's) procedures. 14 CFR 91.327(b)(2)
7. Required within the preceding 100 hours of time in service only when towing a glider/unpowered ultralight for hire, or giving flight training for hire in an aircraft the instructor provides. 14 CFR 91.327(c)
8. A&P airframe/powerplant ratings may approve for return to service after performing and inspecting a major repair or alteration on a light-sport product not produced under an FAA approval, if authorized by and done per instructions from the manufacturer or a person acceptable to the FAA. 14 CFR 65.85(b), 65.87(b)

Experimental — amateur-built and light-sport

Part 43 does not apply to an aircraft with an experimental certificate unless it previously held a different kind of airworthiness certificate — and former S-LSA now experimental under 21.191(i)(3) or (l) stay outside part 43. 14 CFR 43.1(b) The aircraft's operating limitations (issued under 91.319) set the inspection interval, scope and who may sign. AC 65-32B ¶2.6.3

1. The holder of a repairman certificate (experimental aircraft builder) may perform condition inspections on the aircraft constructed by the holder, in accordance with that aircraft's operating limitations. Eligibility includes being the primary builder. 14 CFR 65.104(a)–(b)
2. LSR-I: only an aircraft the holder owns, with an experimental certificate under 21.191(g), (i), (k) or (l), in the category/class trained. Ownership is a limitation of privileges, not an eligibility requirement. 14 CFR 65.109(a); AC 65-32B ¶2.6.2.3
3. LSR-M may perform the annual condition inspection on any aircraft with an experimental certificate under 21.191(g), (i), (k) or (l) — ownership not required — in the trained category/class. 14 CFR 65.109(b)(2); AC 65-32B ¶2.8
4. Towing a light-sport glider or unpowered ultralight, or flight training, for hire in a 21.191(i)(1) aircraft requires an inspection within the preceding 100 hours by an LSR-M, an appropriately rated mechanic, or an appropriately rated repair station. 14 CFR 91.319(g)
5. A repair station may not approve an experimental aircraft for return to service after a major repair or alteration done under 43.1(b) unless done with methods and data acceptable to the FAA. 14 CFR 145.201(c)(3)