PA.I.B.K1· K

Airworthiness requirements

General airworthiness requirements and compliance for airplanes

This element bundles four related ideas: who owns an aircraft's airworthiness, what paperwork it must carry, what inspections keep it current, and what to do when something is wrong.

Two responsibility tracks

Airworthiness has two layers. Conflating them is a common DPE trap.

Owner/operator

Keeps the aircraft in airworthy condition over time
Schedules required inspections, complies with ADs, signs off repairs
Primary maintenance responsibility, distinct from PIC responsibility

Pilot in command

Determines whether the aircraft is in condition for safe flight on this flight
Discontinues the flight if an unairworthy condition develops in flight

When you rent, you inherit PIC responsibility but not owner/operator responsibility. Both rules apply on every flight.

Required documents on board

The aircraft documents required to be carried are spelled out in and . The SPARROW mnemonic walks through them item by item in PA.I.B.K4 — what's unique to know here is where they're kept and how expiration works.

On board vs available for inspection

The airworthiness certificate must be displayed at the cabin or cockpit entrance — visible to passengers
Maintenance logbooks are not required to be on board — they must be available for FAA inspection, but are typically kept on the ground

Expiration nuance

Airworthiness certificate has no expiration date — effective so long as the aircraft is maintained per Parts 43 and 91
Registration certificate does expire — currently valid for 7 years from issuance (was 3 before 2023)
An expired registration grounds the aircraft until renewed

Inspections

Six recurring inspections cover the Part 91 compliance schedule. The AV1ATE mnemonic walks the list.

The annual is the only inspection every Part 91 aircraft needs. The other five are conditional on flight type — IFR, transponder-required airspace, for-hire operations.

Airworthiness · PA.I.B.K1

AVIATE — Required inspections

Six recurring checks under Part 91. Each one has its own interval and trigger.

Annual

Every Part 91 aircraft — the only one always required.

12 cal months§91.409

VOR check

Required for IFR operations only.

30 days§91.171

100-hour

When carrying persons for hire or providing instruction for hire.

100 hrs§91.409

Altimeter / static

For IFR operations in controlled airspace.

24 cal months§91.411

Transponder

For transponder-required airspace.

24 cal months§91.413

ELT

Battery & inspection — every 12 calendar months.

12 cal months§91.207

The 100-hour limit may be exceeded by no more than 10 hours while en route to a place where the inspection can be performed; the excess counts against the next interval. Past compliance is logged in airframe and engine maintenance records.

Airworthiness directives

An AD is a legally enforceable FAA rule issued to correct an unsafe condition in a product — aircraft, engine, propeller, or appliance . No person may operate a product to which an AD applies except in accordance with the AD .

Two flavors

One-time — comply by a stated date or hour threshold
Recurrent — comply at recurring intervals (every 100 hours, every 12 calendar months)

Past compliance is logged in airframe and engine logbooks . The owner/operator is responsible for compliance; the PIC verifies status before flight.

Special flight permits

A special flight permit (ferry permit) may be issued for an aircraft that does not currently meet airworthiness requirements but is capable of safe flight .

Permitted purposes

Flying to a base for repairs, alterations, or storage
Delivering or exporting the aircraft
Production flight testing
Evacuating from areas of impending danger
Customer demonstration of new production aircraft

Application goes to the local FSDO, which specifies route, altitude, crew, and any operating limitations on the permit.

Worked examples:

Annual lapsed mid-month — The last annual was signed off May 17 of last year. Today is May 18 of this year. The airworthiness certificate does not "expire," but it is ineffective until the new annual is signed off — flight is illegal until then . Options: schedule the annual on the home field, or apply for a special flight permit to ferry the aircraft to a maintenance facility .
Owner oil change — An owner changes the oil on their Cessna 172, follows the POH service procedure, and makes the maintenance record entry per § 43.9. This is permitted preventive maintenance under Part 43 Appendix A — the owner can sign the return-to-service themselves. The same owner cannot sign off the annual inspection, which is a separate category of work requiring an Inspection Authorization (IA) .

Common DPE questions

Ideal answer
Two layers. The owner or operator is primarily responsible under 14 CFR 91.403 for maintaining the aircraft in an airworthy condition — inspections, AD compliance, repairs. The pilot in command is responsible under 14 CFR 91.7 for determining whether the aircraft is in condition for safe flight on a given flight, and for discontinuing the flight if it isn't.
Key points to mention
- Owner/operator: primary maintenance responsibility (91.403)
- PIC: airworthy-for-this-flight determination (91.7(b))
- Renter pilots inherit PIC responsibility, not owner responsibility
- Both rules apply simultaneously to every flight
REF: 14 CFR 91.7, 91.403
Ideal answer
Per 14 CFR 91.203 and 91.9: airworthiness certificate (displayed at the cabin or cockpit entrance), registration certificate (current), operating limitations (POH/AFM with any supplements and required placards), and weight and balance data. A radio station license is also required if the aircraft is flown internationally. The SPARROW mnemonic walking through this set lives in PA.I.B.K4 (Airworthiness certificates). Note: the airworthiness certificate has no expiration; the registration certificate does — currently 7 years.
Key points to mention
- Airworthiness certificate — displayed at cabin/cockpit entrance (91.203(b))
- Current registration certificate (91.203(a)(2))
- Operating limitations: POH/AFM, any supplements (e.g., G1000, STCs), required cockpit placards (91.9)
- Weight and balance data (current)
- Radio station license — only required for international flight (FCC)
- Logbooks NOT required on board — kept on the ground
- Airworthiness cert has no expiration (21.181); registration expires (7-year cycle since 2023)
- SPARROW mnemonic lives in PA.I.B.K4
REF: 14 CFR 91.203, 91.9, 21.181
Ideal answer
Six things integrated. (1) Aircraft documents on board per 91.203 and 91.9 — airworthiness certificate, registration, POH/AFM, placards, weight & balance (SPARROW; details in K4). (2) Inspections current — annual (12 cal mo), 100-hour if applicable (for hire), VOR within 30 days if IFR, altimeter/static every 24 mo if IFR, transponder every 24 mo, ELT every 12 mo (AV1ATE). (3) AD compliance verified in airframe and engine logbooks per 91.417. (4) No open discrepancies, or any inop equipment is properly handled per 91.213(d) — removed/deactivated and placarded, logged, and verified non-required. (5) Owner/operator responsible for keeping the aircraft airworthy under 91.403; PIC determines safe-for-this-flight under 91.7(b). (6) Honest external preflight — cracks, leaks, control rigging, fuel, oil. Any one of these failing grounds the aircraft until corrected, deferred per 91.213, or ferried under a special flight permit per 21.197.
Key points to mention
- Documents on board (SPARROW): airworthiness cert, registration, POH/AFM, placards, W&B (91.203, 91.9)
- Inspections current (AV1ATE): annual + AVIATES variants based on use (91.409, 91.171, 91.411, 91.413, 91.207)
- AD compliance verified in airframe and engine logbooks (39.7, 91.417)
- Inop equipment handled per 91.213(d): removed/deactivated, placarded, logged, not required
- Owner/operator (91.403) maintains over time; PIC (91.7(b)) determines for this flight
- Honest external preflight
- Failure path: correct, defer per 91.213, or ferry under 21.197
REF: 14 CFR 91.7, 91.203, 91.213, 91.403, 91.409, 91.417, 39.7
Ideal answer
The decision turns on what kind of flight this is and what 91.213(d) requires. First: is the attitude indicator REQUIRED for this flight? Per 91.205(b), the day-VFR equipment list does NOT include a gyroscopic pitch-and-bank indicator. Per 91.205(d)(8), IFR flight DOES require it. So if today's flight is day-VFR in a small airplane that doesn't have it on the KOEL or AD list, I can defer the equipment per 91.213(d): remove or deactivate it, placard it 'Inoperative,' log the work per 43.9, and verify in the POH and ADs that no other rule requires it. If the planned flight is IFR or night IFR, I can't defer — fix the instrument before flying. The final 91.213(d)(4) step is mine: as PIC certificated and rated under Part 61, I determine the inop equipment doesn't constitute a hazard to the aircraft.
Key points to mention
- Decision turns on flight type: 91.205(b) day-VFR vs. 91.205(d) IFR equipment lists
- Day-VFR: attitude indicator not in the 91.205(b) list — may defer per 91.213(d)
- IFR: attitude indicator required by 91.205(d)(8) — cannot defer, must fix
- Defer flow: remove/deactivate + placard + log per 43.9 + verify not required by KOEL/AD
- 91.213(d)(4): PIC certificated and rated under Part 61 makes the no-hazard determination
- An A&P could also make the no-hazard determination per 91.213(d)(4)
REF: 14 CFR 91.205, 91.213, 43.9
Ideal answer
Use the AV1ATE mnemonic. Annual — every 12 calendar months for ALL Part 91 aircraft (§ 91.409(a)). VOR check — within 30 days for IFR flight (§ 91.171), N/A if you don't fly IFR. 100-hour — every 100 hours for aircraft used for hire or for flight instruction for hire in an aircraft provided by the instructor (§ 91.409(b)), N/A for personal use. Altimeter and pitot-static — every 24 calendar months for IFR in controlled airspace (§ 91.411). Transponder — every 24 calendar months when used in airspace requiring a transponder (§ 91.413). ELT — every 12 calendar months for installation and operation (§ 91.207(d)).
Key points to mention
- Annual: 12 cal months, ALL Part 91 aircraft (91.409(a))
- VOR check: 30 days, IFR only (91.171)
- 100-hour: every 100 hours, for-hire or instruction-for-hire only (91.409(b))
- Altimeter/static: 24 cal months, IFR in controlled airspace (91.411)
- Transponder: 24 cal months, transponder-required airspace (91.413)
- ELT: 12 cal months for installation; battery at 1 cum hour or 50% useful life (91.207)
- Annual is the only one ALL aircraft require — the rest are conditional
- 100-hour may be exceeded by up to 10 hours en route to inspection; excess counts against next interval
REF: 14 CFR 91.409, 91.171, 91.411, 91.413, 91.207
Ideal answer
An AD is a legally enforceable FAA rule issued under 14 CFR Part 39 to correct an unsafe condition in an aircraft, engine, propeller, or appliance. To find applicable ADs, check the FAA's online AD database against the aircraft's make/model and serial number, and review the engine and airframe logbooks where prior compliance is recorded under 91.417.
Key points to mention
- AD = legally enforceable rule under 14 CFR Part 39 (39.3 defines, 39.7 mandates compliance)
- Issued to correct an unsafe condition in a type-design product
- Find applicable ADs via the FAA AD database (faa.gov)
- Past compliance is recorded in engine and airframe logbooks (91.417)
- Owner/operator (91.403) is responsible for compliance; PIC verifies status before flight
REF: 14 CFR 39.3, 39.7, 91.403, 91.417
Ideal answer
A special flight permit — also called a ferry permit — is issued under 14 CFR 21.197 for an aircraft that does not currently meet airworthiness requirements but is capable of safe flight. Common uses: flying to a base for repairs, delivering or exporting an aircraft, evacuating from impending danger, production flight testing, or operating above max certificated takeoff weight for extended-range fuel.
Key points to mention
- Issued under 14 CFR 21.197 (purposes) and 21.199 (application)
- Required when the aircraft is not currently airworthy but is safe to fly
- Common purposes: ferry to repair base, delivery/export, evacuation, production test, extended-range fuel
- Apply through the local FSDO (or a delegated DAR)
- Permit specifies route, altitude, crew, and operating limitations
REF: 14 CFR 21.197, 21.199
Ideal answer
Don't fly. Per 91.7(b), the PIC must discontinue the flight when an unairworthy condition occurs. Notify the owner/operator so it can be corrected by a qualified mechanic and properly logged. If the discrepancy is on the inoperative-equipment list and can be deferred under 91.213, follow that procedure (placard, log, and verify the equipment isn't required by 91.205, the type certificate, an AD, or the KOEL). If the aircraft cannot be made airworthy in place but is safe to fly to a repair base, apply for a special flight permit under 21.197.
Key points to mention
- 91.7(b): PIC must discontinue the flight on an unairworthy condition
- Option 1: have a qualified mechanic correct and log it
- Option 2: if eligible, defer the equipment under 91.213 (placard, log, verify not required)
- Option 3: if not currently airworthy but safe to ferry, apply for a special flight permit under 21.197
- Never just 'fly it home and fix it' without one of the above paths
REF: 14 CFR 91.7, 91.213, 21.197

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Multiple choice

Per 14 CFR 91.7, who is directly responsible for determining whether the aircraft is in condition for safe flight?

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PA.I.B.K2 · Preventive maintenance

Preventive maintenance is a narrow privilege: a defined list of simple tasks on aircraft you own or operate, logged and signed off by you. Step outside that …

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