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Educational Reference Only: Information verified as of September 27, 2026 from the sources cited below. Not legal advice. Regulations change. Verify the current rule at eCFR.gov and consult a qualified aviation attorney and your A&P/IA for your specific situation. This site is not a substitute for the advice of an attorney.

Short Course

10 Rules Every Shop Should Know

Ten FAA rules a shop works by, one short lesson each. Every lesson gives the rule in plain words, the exact words of the rule with its official source, a made up example, the steps, and one quiz question. The same rules also appear as cards on the Shop Library and Warbird Vault pages.

Operating limitations for each aircraft are controlling and may be more restrictive than the regulation.

Talk to your FSDO or principal inspector about your specific situation.

  1. Know The Certificate

    Limited or Experimental Exhibition, and the rule each one is issued under: 14 CFR 21.189 and 21.191(d).

    The rule in one sentence: A warbird generally flies on a Limited or an Experimental Exhibition airworthiness certificate, and each one is issued under its own rule with its own conditions.

    Claim
    Generally, under 14 CFR 21.189, a Limited category airworthiness certificate comes after an FAA inspection that includes a flight check by the applicant, and the FAA sets the limitations and conditions for safe operation.
    Proof
    “(2) The FAA finds, after inspection (including a flight check by the applicant), that the aircraft is in a good state of preservation and repair and is in a condition for safe operation. (b) The FAA prescribes limitations and conditions necessary for safe operation.”
    Source
    14 CFR 21.189 on eCFR, as of September 27, 2026
    Claim
    Generally, under 14 CFR 21.191(d), the exhibition purpose covers air shows, motion picture, television and similar productions, keeping up exhibition flight proficiency, and flying to and from those shows and productions.
    Proof
    “(d) Exhibition. Exhibiting the aircraft’s flight capabilities, performance, or unusual characteristics at air shows, motion picture, television, and similar productions, and the maintenance of exhibition flight proficiency, including (for persons exhibiting aircraft) flying to and from such air shows and productions.”
    Source
    14 CFR 21.191 on eCFR, as of September 27, 2026

    Example, Made Up To Teach The Rule

    A shop takes in a former military airplane with a dusty logbook and no current airworthiness certificate. The new owner wants to fly it to a museum open house next weekend. Nothing moves until the shop knows which certificate the airplane will fly on and reads that certificate’s own paperwork, because Limited and Experimental Exhibition are two different rules with two different starting points.

    Generally, Under 14 CFR 21.189 And 21.191(d), How It Is Done Right

    1. Find the aircraft’s type certificate history first. A Limited category aircraft generally traces to an existing Limited category type certificate.
    2. For Limited, expect an FAA inspection that includes a flight check before the certificate is issued.
    3. For Experimental Exhibition, the application states the experimental purpose, under 14 CFR 21.193(a).
    4. Read the operating limitations that come with whichever certificate is issued (see Lesson 2).
    5. Keep the certificate and its limitations with the aircraft records.

    Quiz: An aircraft is applying for a Limited category airworthiness certificate. What does 21.189 call for before the FAA issues it?

    1. A logbook review only
    2. An FAA inspection, including a flight check by the applicant, showing a good state of preservation and repair and a condition for safe operation
    3. A one time self certification by the owner
    4. Nothing, Limited certificates are automatic for former military aircraft
    Show The Answer

    Answer: B. “The FAA finds, after inspection (including a flight check by the applicant), that the aircraft is in a good state of preservation and repair and is in a condition for safe operation.” Source: 14 CFR 21.189 on eCFR, as of September 27, 2026.

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  2. Every Airplane Has Its Own Limits

    How 14 CFR 91.9(a) and 91.319(i) tie each aircraft to its own operating limitations.

    The rule in one sentence: Generally, an aircraft may be operated only within the operating limitations that came with it, and for an experimental aircraft the FAA may add more.

    Claim
    Generally, under 14 CFR 91.9(a), a civil aircraft may be operated only within the operating limitations in its approved flight manual, markings and placards, or as prescribed by the certificating authority.
    Proof
    “no person may operate a civil aircraft without complying with the operating limitations specified in the approved Airplane or Rotorcraft Flight Manual, markings, and placards, or as otherwise prescribed by the certificating authority of the country of registry.”
    Source
    14 CFR 91.9 on eCFR, as of September 27, 2026
    Claim
    Generally, under 14 CFR 91.319(i), the FAA may add limitations for an experimental aircraft, including on who may be carried.
    Proof
    “The Administrator may prescribe additional limitations that the Administrator considers necessary, including limitations on the persons that may be carried in the aircraft.”
    Source
    14 CFR 91.319(i) on eCFR, as of September 27, 2026

    Example, Made Up To Teach The Rule

    A mechanic knows the general rule for exhibition flying by heart. This particular warbird’s own operating limitations are more restrictive: day VFR only, and no passengers beyond crew. He treats the general rule as the whole answer and misses the limit sitting in the folder next to it.

    Generally, Under 14 CFR 91.9(a) And 91.319(i), How It Is Done Right

    1. Pull the actual operating limitations issued with that aircraft’s certificate. That document controls, not a summary of the regulation.
    2. Compare it against the general Part 91 rule. The aircraft’s own limitations can be more restrictive.
    3. Keep the limitations with the aircraft records, where the whole crew can read them.
    4. Brief anyone flying or riding in the aircraft on what the limitations say.
    5. A change to those limitations goes through the FAA, not the shop’s own judgment.

    Quiz: Where do an aircraft’s operating limits come from?

    1. Whatever the shop foreman decides is safe
    2. The operating limitations specified for that aircraft, plus anything the FAA prescribes under 91.319(i)
    3. The pilot’s personal experience
    4. The most common practice at other shops
    Show The Answer

    Answer: B. “no person may operate a civil aircraft without complying with the operating limitations specified in the approved Airplane or Rotorcraft Flight Manual, markings, and placards, or as otherwise prescribed by the certificating authority of the country of registry.” Source: 14 CFR 91.9(a) on eCFR, as of September 27, 2026.

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  3. Who Can Do The Work

    What 14 CFR 43.3 says about certificate holders and supervised workers, and where supervision stops.

    The rule in one sentence: Generally, a certificated mechanic may perform work as Part 65 provides, and a supervised person may help only if the supervisor watches the work as needed and is readily available in person. Required inspections are not covered.

    Claim
    Generally, under 14 CFR 43.3(b), a mechanic certificate holder may perform maintenance, preventive maintenance and alterations as Part 65 provides.
    Proof
    “The holder of a mechanic certificate may perform maintenance, preventive maintenance, and alterations as provided in Part 65 of this chapter.”
    Source
    14 CFR 43.3 on eCFR, paragraph (b), as of September 27, 2026
    Claim
    Generally, under 14 CFR 43.3(d), a person working under a certificated mechanic or repairman may do the work that supervisor is authorized to do, if the supervisor watches the work as needed and is readily available in person. That does not cover inspections required by Part 91 or Part 125, or any inspection after a major repair or alteration.
    Proof
    “A person working under the supervision of a holder of a mechanic or repairman certificate may perform the maintenance, preventive maintenance, and alterations that his supervisor is authorized to perform, if the supervisor personally observes the work being done to the extent necessary to ensure that it is being done properly and if the supervisor is readily available, in person, for consultation. However, this paragraph does not authorize the performance of any inspection required by Part 91 or Part 125 of this chapter or any inspection performed after a major repair or alteration.”
    Source
    14 CFR 43.3 on eCFR, paragraph (d), as of September 27, 2026

    Example, Made Up To Teach The Rule

    A new hire, still working toward his certificate, wants to finish a task alone while the supervising mechanic runs to the parts counter across town. Generally, under 43.3(d), the supervisor personally observes enough of the job and stays readily available in person, so a trip across town does not fit, and required inspections are off limits to the trainee no matter how close the supervisor is.

    Generally, Under 14 CFR 43.3, How It Is Done Right

    1. Confirm who holds the certificate and rating for the work being done.
    2. If a person without a certificate is helping, the certificated supervisor personally observes enough of the work to know it is done properly.
    3. The supervisor stays readily available, in person, while the work happens.
    4. Required inspections, including any inspection after a major repair or alteration, are never handed to the supervised person.
    5. The approval for return to service belongs to the person authorized to give it (see Lesson 4).

    Quiz: A supervised worker without a certificate is helping with an alteration. What does 43.3(d) call for from the supervisor?

    1. Nothing, as long as the worker is careful
    2. Personally observe the work to the extent necessary to ensure it is done properly, and stay readily available in person for consultation
    3. Sign the logbook entry in advance
    4. Check in once at the end of the shift
    Show The Answer

    Answer: B. “if the supervisor personally observes the work being done to the extent necessary to ensure that it is being done properly and if the supervisor is readily available, in person, for consultation.” Source: 14 CFR 43.3(d) on eCFR, as of September 27, 2026.

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  4. What An A&P Can Sign

    Mechanic privileges and the airframe and powerplant ratings in 14 CFR 65.81, 65.85 and 65.87.

    The rule in one sentence: Generally, a certificated mechanic with an airframe or powerplant rating may approve work for return to service, excluding major repairs and major alterations.

    Claim
    Generally, under 14 CFR 65.85(a), a mechanic with an airframe rating may approve an airframe, or a related part or appliance, for return to service after performing, supervising or inspecting its maintenance or alteration, excluding major repairs and major alterations.
    Proof
    “a certificated mechanic with an airframe rating may approve for return to service an airframe, or any related part or appliance, after that person has performed, supervised, or inspected its maintenance or alteration (excluding major repairs and major alterations).”
    Source
    14 CFR 65.85 on eCFR, as of September 27, 2026
    Claim
    Generally, under 14 CFR 65.87(a), the same goes for a mechanic with a powerplant rating on a powerplant or propeller, also excluding major repairs and major alterations.
    Proof
    “a certificated mechanic with a powerplant rating may approve for return to service a powerplant or propeller or any related part or appliance, after that person has performed, supervised, or inspected its maintenance or alteration (excluding major repairs and major alterations).”
    Source
    14 CFR 65.87 on eCFR, as of September 27, 2026
    Claim
    Generally, under 14 CFR 65.81(b), a mechanic may use those privileges only if he or she understands the current manufacturer instructions and maintenance manuals for the job.
    Proof
    “(b) A certificated mechanic may not exercise the privileges of that person’s certificate and rating unless that person understands the current instructions of the manufacturer, and the maintenance manuals, for the specific operation concerned.”
    Source
    14 CFR 65.81 on eCFR, as of September 27, 2026

    Example, Made Up To Teach The Rule

    An A&P finishes a repair on a control surface and reaches for the pen. Before signing, he asks whether the repair might appreciably affect weight, balance, structural strength or other qualities affecting airworthiness, because a major repair needs more than his rating alone (see Lessons 5 and 8).

    Generally, Under 14 CFR 65.81, 65.85 And 65.87, How It Is Done Right

    1. Confirm the rating in hand, airframe, powerplant or both, before starting the task.
    2. Check that current manufacturer instructions or maintenance manuals cover the specific operation, and use them.
    3. Decide, using Part 43 Appendix A and the 14 CFR 1.1 definitions, whether the finished task is minor or major (see Lesson 8) before signing anything.
    4. If it is minor, the rated mechanic who performed, supervised or inspected it may approve it for return to service.
    5. If it is major, stop. The rating alone does not cover that approval.

    Quiz: A mechanic with a powerplant rating just finished routine maintenance on an engine. Under 65.87(a), what may that mechanic approve for return to service?

    1. Any powerplant work, including major repairs and major alterations
    2. The powerplant or related part or appliance he performed, supervised or inspected, excluding major repairs and major alterations
    3. Only work he personally performed, never work he supervised
    4. Airframe work as well, since the ratings overlap
    Show The Answer

    Answer: B. “a certificated mechanic with a powerplant rating may approve for return to service a powerplant or propeller or any related part or appliance, after that person has performed, supervised, or inspected its maintenance or alteration (excluding major repairs and major alterations).” Source: 14 CFR 65.87(a) on eCFR, as of September 27, 2026.

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  5. What An IA Adds

    Who can hold an inspection authorization and what it covers, in 14 CFR 65.91 and 65.95.

    The rule in one sentence: Generally, an inspection authorization adds the privilege to approve for return to service after a major repair or major alteration done under approved technical data, and to perform an annual inspection, or perform or supervise a progressive inspection.

    Claim
    Generally, under 14 CFR 65.91(c), an applicant for an inspection authorization holds a current mechanic certificate with both airframe and powerplant ratings, each in effect for a total of at least 3 years, plus the other items the paragraph lists.
    Proof
    “Hold a currently effective mechanic certificate with both an airframe rating and a powerplant rating, each of which is currently effective and has been in effect for a total of at least 3 years;”
    Source
    14 CFR 65.91 on eCFR, paragraph (c)(1), as of September 27, 2026
    Claim
    Generally, under 14 CFR 65.95(a), an inspection authorization holder may inspect and approve for return to service after a major repair or major alteration done under technical data approved by the Administrator, and may perform an annual inspection, or perform or supervise a progressive inspection.
    Proof
    “(1) Inspect and approve for return to service any aircraft or related part or appliance … after a major repair or major alteration to it in accordance with part 43 … of this chapter, if the work was done in accordance with technical data approved by the Administrator; and (2) Perform an annual, or perform or supervise a progressive inspection according to §§ 43.13 and 43.15 of this chapter.”
    Source
    14 CFR 65.95 on eCFR, as of September 27, 2026

    Example, Made Up To Teach The Rule

    A major structural repair on a warbird wing is finished, built to a technical data package the shop believes is approved. The A&P who did the work cannot close it out alone. The file goes to an IA, who checks that the data really was approved before signing the return to service.

    Generally, Under 14 CFR 65.91 And 65.95, How It Is Done Right

    1. Confirm the person approving a major repair or major alteration is authorized under 43.7. For an individual mechanic, that means an inspection authorization, not only an A&P certificate.
    2. Confirm the technical data used is approved data. The IA privilege in 65.95(a)(1) is tied to it.
    3. An IA may perform an annual inspection, or perform or supervise a progressive inspection, under 43.13 and 43.15.
    4. Record the major repair or alteration on the form Part 43 Appendix B describes (see Lesson 8).
    5. Remember Lesson 7: under 91.409(c)(1), the 91.409(a) annual does not apply to an aircraft with a current experimental airworthiness certificate.

    Quiz: What can an IA approve that an A&P rating alone cannot?

    1. Routine oil changes
    2. Return to service after a major repair or major alteration done under technical data approved by the Administrator, plus annual and progressive inspections
    3. Any paperwork the shop asks for
    4. Parts installation only
    Show The Answer

    Answer: B. “(1) Inspect and approve for return to service any aircraft or related part or appliance … after a major repair or major alteration to it in accordance with part 43 … of this chapter, if the work was done in accordance with technical data approved by the Administrator; and (2) Perform an annual, or perform or supervise a progressive inspection according to §§ 43.13 and 43.15 of this chapter.” Source: 14 CFR 65.95(a) on eCFR, as of September 27, 2026.

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  6. The Maintenance Entry

    Reading 14 CFR 43.9(a) paragraph by paragraph, in the rule’s own words.

    The rule in one sentence: Generally, under 14 CFR 43.9(a), a maintenance entry holds a description of the work, the date of completion, the name of the person who did it if not the approver, and the approver’s signature, certificate number and kind of certificate.

    Claim
    Generally, 14 CFR 43.9(a) lists what goes in a maintenance record entry. Read the paragraph itself, quoted here.
    Proof
    “(1) A description (or reference to data acceptable to the Administrator) of work performed. (2) The date of completion of the work performed. (3) The name of the person performing the work if other than the person specified in paragraph (a)(4) of this section. (4) If the work performed … has been performed satisfactorily, the signature, certificate number, and kind of certificate held by the person approving the work. The signature constitutes the approval for return to service only for the work performed.”
    Source
    14 CFR 43.9 on eCFR, paragraph (a), as of September 27, 2026

    Example, Made Up To Teach The Rule

    A logbook entry for a brake job reads only “brakes fixed”, with no date and no signature. Nobody reading it later can tell what was done, when, by whom, or whether anyone with the authority to approve it for return to service ever did. The entry needs all of its parts before the airplane flies again.

    Generally, Under 14 CFR 43.9(a), How It Is Done Right

    1. Write what was done, or reference the data used, clearly enough that someone else understands the work later.
    2. Record the date the work was completed.
    3. If the person who did the work is not the person approving it, name that person.
    4. The person approving the work signs, with certificate number and kind of certificate. That signature approves only the work performed.
    5. Keep the entry with the aircraft’s maintenance records.

    Quiz: An entry lists what was done and the date, but has no certificate number next to the signature. Under 43.9(a), is that entry complete?

    1. Yes, a signature alone is enough
    2. No, the entry calls for the signature, certificate number and kind of certificate held by the person approving the work
    3. Only if the shop has a company policy on it
    4. Only for major repairs, not routine maintenance
    Show The Answer

    Answer: B. “the signature, certificate number, and kind of certificate held by the person approving the work.” Source: 14 CFR 43.9(a)(4) on eCFR, as of September 27, 2026.

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  7. The Inspection Entry And The Annual

    What 14 CFR 43.11 and 91.409 say about inspection entries and the annual.

    The rule in one sentence: Generally, an inspection entry states the type and extent of the inspection, the date and total time, and who approved or disapproved it, and the 91.409(a) annual does not apply to an aircraft with a current experimental airworthiness certificate.

    Claim
    Generally, under 14 CFR 43.11(a), an inspection entry includes the type and extent of the inspection, the date and aircraft total time in service, and the signature, certificate number and kind of certificate of the person approving or disapproving for return to service.
    Proof
    “(1) The type of inspection and a brief description of the extent of the inspection. (2) The date of the inspection and aircraft total time in service. (3) The signature, the certificate number, and kind of certificate held by the person approving or disapproving for return to service”
    Source
    14 CFR 43.11 on eCFR, as of September 27, 2026
    Claim
    Generally, under 14 CFR 91.409(a), an aircraft may not be operated unless, within the preceding 12 calendar months, it has had an annual inspection under Part 43 and has been approved for return to service by a person authorized by 43.7, or an inspection for issuing an airworthiness certificate under Part 21.
    Proof
    “no person may operate an aircraft unless, within the preceding 12 calendar months, it has had— (1) An annual inspection in accordance with part 43 of this chapter and has been approved for return to service by a person authorized by § 43.7 of this chapter; or (2) An inspection for the issuance of an airworthiness certificate in accordance with part 21 of this chapter.”
    Source
    14 CFR 91.409 on eCFR, paragraph (a), as of September 27, 2026
    Claim
    Generally, under 14 CFR 91.409(c)(1), paragraphs (a) and (b) do not apply to an aircraft with a current experimental airworthiness certificate.
    Proof
    “Paragraphs (a) and (b) of this section do not apply to … (1) An aircraft that carries … a current experimental airworthiness certificate”
    Source
    14 CFR 91.409 on eCFR, paragraph (c), as of September 27, 2026

    Example, Made Up To Teach The Rule

    A Limited category warbird and an Experimental Exhibition warbird sit side by side in the same shop. The crew chief assumes both run on the same annual clock. They do not. The Limited airplane generally follows the 91.409(a) annual, while the Experimental airplane’s inspection is generally set by its own operating limitations (see Lesson 2).

    Generally, Under 14 CFR 43.11 And 91.409, How It Is Done Right

    1. Confirm the aircraft’s certificate first. It decides which inspection rule applies (see Lesson 1).
    2. For a Limited or standard category aircraft, track the 12 calendar month clock under 91.409(a).
    3. For an Experimental aircraft, read the operating limitations for the inspection that applies, since 91.409(c)(1) takes a current experimental airworthiness certificate out of paragraphs (a) and (b).
    4. Whatever the inspection, the entry states its type and extent, the date and total time, and the signature, certificate number and kind of certificate of the person approving or disapproving return to service.
    5. If the aircraft is not approved, the owner or lessee gets a signed list of discrepancies under 43.11(b).

    Quiz: An aircraft with a current experimental airworthiness certificate is due for its recurring inspection. Does the 91.409(a) 12 calendar month annual apply to it?

    1. Yes, every aircraft needs a 91.409(a) annual
    2. No, 91.409(c)(1) says paragraphs (a) and (b) do not apply to an aircraft that carries a current experimental airworthiness certificate
    3. Only if it flew commercially that year
    4. Only if the owner asks for it
    Show The Answer

    Answer: B. “Paragraphs (a) and (b) of this section do not apply to … (1) An aircraft that carries … a current experimental airworthiness certificate”. Source: 14 CFR 91.409(c)(1) on eCFR, as of September 27, 2026.

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  8. Major Or Minor, And The 337

    How Part 43 Appendix A and 14 CFR 1.1 tell major from minor, and what Appendix B says about Form 337.

    The rule in one sentence: Generally, the person performing a major repair or major alteration records it on a form and handles that form the way Part 43 Appendix B says, and Appendix A plus the 14 CFR 1.1 definitions help tell major from minor.

    Claim
    Generally, under 14 CFR 43.9(d), the person performing a major repair or major alteration records it on a form and handles that form the way Part 43 Appendix B says.
    Proof
    “major repairs and major alterations shall be entered on a form, and the form disposed of, in the manner prescribed in appendix B, by the person performing the work.”
    Source
    14 CFR 43.9 on eCFR, paragraph (d), as of September 27, 2026
    Claim
    Generally, Part 43 Appendix B(a) covers filling out FAA Form 337 in at least 2 copies, giving the owner a signed copy, and sending a copy to the FAA within 48 hours after return to service.
    Proof
    “(1) Execute FAA Form 337 at least in duplicate; (2) Give a signed copy of that form to the aircraft owner; and (3) Forward a copy of that form to the FAA Aircraft Registration Branch in Oklahoma City, Oklahoma, within 48 hours after the aircraft, airframe, aircraft engine, propeller, or appliance is approved for return to service.”
    Source
    14 CFR Part 43 Appendix B on eCFR, paragraph (a), as of September 27, 2026
    Claim
    Generally, 14 CFR 1.1 defines major alteration and major repair, and Part 43 Appendix A lists examples. Read both, and ask your IA or FSDO when it is close.
    Proof
    “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.”
    Source
    14 CFR 1.1 on eCFR and Part 43 Appendix A on eCFR, as of September 27, 2026

    Note: under 14 CFR 43.1(b)(1), Part 43 does not apply to an aircraft with an experimental airworthiness certificate, unless the FAA previously issued a different kind of airworthiness certificate for that aircraft. For those aircraft, read the operating limitations (see Lessons 1 and 7).

    Example, Made Up To Teach The Rule

    A shop replaces a damaged section of structure on a Limited category airplane. The mechanic reads Appendix A and the 1.1 definitions and decides the repair is major. That one check changes the paperwork, from a logbook entry alone to a Form 337 with an owner copy and an FAA copy inside 48 hours.

    Generally, Under 14 CFR 43.9(d) And Part 43 Appendices A And B, How It Is Done Right

    1. Compare the finished work against Appendix A and the 1.1 definitions before deciding minor or major.
    2. If it is major, fill out FAA Form 337 in at least 2 copies.
    3. Give the aircraft owner a signed copy.
    4. Send a copy to the FAA Aircraft Registration Branch in Oklahoma City within 48 hours after the work is approved for return to service.
    5. Confirm the aircraft’s certificate first (Lesson 1). Part 43 generally does not apply to an experimental that never held another kind of airworthiness certificate.

    Quiz: A repair is finished and confirmed major. Under Part 43 Appendix B(a)(3), what happens within 48 hours after the aircraft is approved for return to service?

    1. Nothing more, the logbook entry alone is enough
    2. A copy of the Form 337 is forwarded to the FAA Aircraft Registration Branch in Oklahoma City
    3. A different mechanic inspects it again
    4. The owner phones the FSDO
    Show The Answer

    Answer: B. “Forward a copy of that form to the FAA Aircraft Registration Branch in Oklahoma City, Oklahoma, within 48 hours after the aircraft, airframe, aircraft engine, propeller, or appliance is approved for return to service.” Source: 14 CFR Part 43 Appendix B on eCFR, as of September 27, 2026.

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  9. ADs And The Records

    How 14 CFR 39.3, 91.403 and 91.417 connect ADs, the owner and the AD status record.

    The rule in one sentence: Generally, airworthiness directives are legally enforceable rules, the owner or operator is primarily responsible for compliance, and the records show the current AD status.

    Claim
    Generally, under 14 CFR 39.3, ADs are legally enforceable rules for aircraft, engines, propellers and appliances.
    Proof
    “FAA’s airworthiness directives are legally enforceable rules that apply to the following products: aircraft, aircraft engines, propellers, and appliances.”
    Source
    14 CFR 39.3 on eCFR, as of September 27, 2026
    Claim
    Generally, under 14 CFR 91.403(a), the owner or operator is primarily responsible for maintaining the aircraft in an airworthy condition, including compliance with Part 39.
    Proof
    “The owner or operator of an aircraft is primarily responsible for maintaining that aircraft in an airworthy condition, including compliance with part 39 of this chapter.”
    Source
    14 CFR 91.403 on eCFR, as of September 27, 2026
    Claim
    Generally, under 14 CFR 91.417(a)(2)(v), the records include the current status of applicable ADs, with the method of compliance, AD number and revision date, and for recurring ADs, when the next action is required.
    Proof
    “(v) The current status of applicable airworthiness directives (AD) including, for each, the method of compliance, the AD number and revision date. If the AD involves recurring action, the time and date when the next action is required.”
    Source
    14 CFR 91.417 on eCFR, as of September 27, 2026
    Claim
    FAA AC 39-7D paragraph 9 says an AD’s applicability statement tells you when it reaches non type certificated aircraft, such as experimental exhibition, or the engines, propellers and appliances installed on them. It also says an AD for a model “certificated in any category” applies to all airplanes of that model, regardless of the type of airworthiness certificate issued to the type certificated aircraft.
    Proof
    “Non-TC’d aircraft (e.g., amateur-built aircraft, experimental exhibition) are aircraft for which the FAA has not issued a TC under part 21. The AD applicability statement will identify if the AD applies to non-TC’d aircraft or engines, propellers, and appliances installed thereon.”
    “certificated in any category … makes the AD applicable to all airplanes of the model listed, regardless of the type of airworthiness certificate issued to the TC’d aircraft.”
    Source
    AC 39-7D on faa.gov, paragraph 9, as of September 27, 2026

    Note: we found no FAA Chief Counsel interpretation on AD applicability for exhibition warbirds, so we cannot verify more than the AC says. Check each AD’s applicability statement, and ask your IA, your FSDO or an aviation attorney about your aircraft.

    Example, Made Up To Teach The Rule

    A shop is told an AD “does not apply, the airplane is experimental.” The crew chief reads the AD’s own applicability paragraph instead of assuming, because some ADs reach the engine or propeller installed on a non type certificated airplane. Reading the applicability line, every time, is the habit.

    Generally, Under 14 CFR 39.3, 91.403 And 91.417, How It Is Done Right

    1. Read each AD’s applicability paragraph. It decides whether that AD reaches this aircraft, engine, propeller or appliance.
    2. Under 91.403(a), the owner or operator is primarily responsible for compliance.
    3. Record, for every applicable AD, the method of compliance and the AD number and revision date.
    4. For recurring ADs, record when the next action is required.
    5. Keep the AD status record with the rest of the aircraft records.

    Quiz: What do the aircraft records show for each applicable airworthiness directive under 91.417(a)(2)(v)?

    1. Only that the aircraft passed its last annual
    2. The method of compliance, the AD number and revision date, and for recurring ADs, when the next action is required
    3. A general statement that all ADs are current
    4. Nothing beyond the mechanic’s initials
    Show The Answer

    Answer: B. “(v) The current status of applicable airworthiness directives (AD) including, for each, the method of compliance, the AD number and revision date. If the AD involves recurring action, the time and date when the next action is required.” Source: 14 CFR 91.417(a)(2)(v) on eCFR, as of September 27, 2026.

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  10. Training And Rides In Warbirds

    Where the LODA rule (14 CFR 91.326) and Living History exemptions (Part 11) fit.

    The rule in one sentence: Generally, flight training in a Limited or Experimental warbird runs under 14 CFR 91.326 and calls for a letter of deviation authority (LODA) unless an exception applies, while paid Living History passenger rides need the operator’s own FAA exemption, asked for through a Part 11 petition.

    Claim
    Generally, flight training, checking or testing in a Limited category or Experimental aircraft runs under 14 CFR 91.326, which calls for a LODA unless an exception in 91.326(c) or (d) applies.
    Proof
    “No person may operate under this section without a letter of deviation authority (LODA) issued by the Administrator.”
    Source
    14 CFR 91.326 on eCFR, paragraph (b)(1), as of September 27, 2026
    Claim
    Generally, under 14 CFR 91.326(d), a LODA issued under 91.319 before December 2, 2024 terminates on December 1, 2026. The old LODA paragraph, 91.319(h), now reads “[Reserved]”.
    Proof
    “(d) Previously issued letters of deviation authority. For deviation authority issued under § 91.319 prior to December 2, 2024, the following requirements apply … (4) The letter of deviation authority terminates on December 1, 2026.”
    Source
    14 CFR 91.326 on eCFR, paragraph (d); final rule 89 FR 80310 (October 2, 2024, effective December 2, 2024), as of September 27, 2026
    Claim
    Living History Flight Experience (LHFE) passenger flights have no section of their own in Part 91. Generally, an operator asks for relief through a Part 11 petition for exemption under 14 CFR 11.61(b), and the FAA’s 2015 policy statement at 80 FR 43012 covers those exemptions.
    Proof
    “Using a petition for exemption, you may ask FAA to grant you relief from current regulations in 14 CFR.”
    “the Federal Aviation Administration (FAA) cancels all previous agency policies pertaining to the carriage of passengers for compensation on Living History Flight Experience (LHFE) flights. This policy statement announces the end of FAA moratorium on new petitions for exemption”
    Source
    14 CFR 11.61 on eCFR; 80 FR 43012 (July 21, 2015, policy statement), as of September 27, 2026

    Example, Made Up To Teach The Rule

    A made up museum, the Example Air Museum, flies a restored two seat warbird. It holds a LODA for flight training and now wants to sell rides to the public. The LODA covers training, not paid passenger rides. For rides, the museum would need its own FAA exemption, asked for through a Part 11 petition, with its own conditions.

    Generally, Under 14 CFR 91.326 And 11.61, How It Is Done Right

    1. Decide what the flight is: flight training or checking (91.326), or a paid Living History passenger ride (Part 11 exemption). They are two different paths.
    2. For training in a Limited or Experimental aircraft, the path is a LODA under 91.326(b)(1), unless an exception in 91.326(c) or (d) applies.
    3. If the operation relies on a LODA issued under 91.319 before December 2, 2024, it terminates on December 1, 2026 under 91.326(d)(4).
    4. A training LODA does not cover paid Living History rides. That relief comes from the operator’s own exemption, granted on a Part 11 petition.
    5. Keep the LODA or exemption, with its conditions, in the operation’s records.

    Quiz: A shop wants to charge passengers for Living History rides in a warbird. Generally, what authorizes that: a 91.326 training LODA or a Part 11 exemption?

    1. A Part 91 training LODA under 91.326 covers both training and paid passenger rides
    2. A Part 11 petition for exemption, separate from a 91.326 training LODA
    3. Neither, no authorization is involved
    4. A verbal FSDO approval
    Show The Answer

    Answer: B. “Using a petition for exemption, you may ask FAA to grant you relief from current regulations in 14 CFR.” Source: 14 CFR 11.61(b) on eCFR, as of September 27, 2026.

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Sources Verified

Each source was read on September 27, 2026. eCFR Title 14 text was pulled from the eCFR, up to date as of September 24, 2026. U.S. Government works, public domain. Every example above is made up to teach the rule and names no real operator.