Most Part 91 aircraft satisfy 14 CFR §91.409 with the annual inspection most owners know well — one comprehensive event, every 12 calendar months. But §91.409 quietly offers a second path for owners who do not want their aircraft parked for a multi-day annual: the progressive inspection under §91.409(d). It is not a shortcut and it is not less inspection. It is the same inspection content, broken into routine and detailed pieces and spread across the year on an FAA-approved schedule.
The catch — and the reason this page exists — is that a progressive inspection is a program, not just a way of timing the work. §91.409(d) requires a written request to the FAA, an approved procedures manual, qualified supervision, dedicated facilities, current technical data, and continuous records. The aircraft is only legal under the program if the documents that define and evidence it are present and current. Run the program loosely and you have neither a valid progressive inspection nor a current annual.
This guide walks the §91.409(d) text line by line: when a progressive inspection beats the annual it replaces, the four things the program must provide, the 12-calendar-month complete-inspection rule, the §43.11 records each inspection produces, and exactly what happens to your inspection clock if you ever discontinue the program. Throughout, the lens is the compliance-document layer: which records the rule generates, and what they must contain to survive FAA surveillance.
What a Progressive Inspection Actually Is
The standard Part 91 inspection regime is built around the annual inspection under §91.409(a) — and, for aircraft carrying persons for hire or used for flight instruction for hire in an aircraft the instructor provides, the 100-hour inspection under §91.409(b). Both concentrate the inspection into a single event. The progressive inspection under §91.409(d) is the rule's answer to operators for whom that concentration is operationally painful.
Under a progressive program, the inspection items are divided into routine inspections and detailed inspections that are performed in rotation. The work is timed so that, taken together, it amounts to a complete inspection of the aircraft within each 12 calendar months. The aircraft is never "out of annual" under the program because there is no single annual to expire — the obligation is continuous, governed by the approved schedule rather than a date stamp.
Routine vs. Detailed — and What "Complete" Means
§91.409(d) draws a line the records have to respect. A complete inspection of the aircraft, for the purpose of determining when the annual and 100-hour inspections are due after a discontinuance, requires a detailed inspection of the aircraft and all its components in accordance with the progressive inspection. The rule then says the part most operators miss: a routine inspection of the aircraft and a detailed inspection of several components is not considered to be a complete inspection. In records terms, you cannot stitch a year of routine entries together and call the most recent one your "complete inspection" — the complete inspection is the point at which the full detailed cycle has been accomplished.
It Substitutes for the Annual and 100-Hour — While It Is in Effect
A properly established and maintained progressive inspection satisfies the §91.409 inspection requirement in place of the annual and 100-hour intervals. That substitution is conditional: it lasts only as long as the program is actually being run as approved. The moment the program is discontinued, the annual and 100-hour clocks reappear — measured from the last complete inspection, as covered in the discontinuance section below. The airworthiness obligation never lapses; it simply switches back to the calendar-and-hours regime.
When a Progressive Inspection Makes Sense
§91.409(d) does not restrict the progressive option to a class or size of aircraft, but the economics make it a fit for some operations and a burden for others. The deciding factor is utilization weighed against administrative capacity.
Good Fit
- High-utilization aircraft where a multi-day annual is costly downtime — busy flight-training aircraft, corporate aircraft on tight schedules, charter-feeder fleets
- Operators with an IA, rated repair station, or manufacturer relationship already in place to supervise
- Operations with the facility footprint — hangar housing and equipment for disassembly and proper inspection
- Owners who can maintain a current procedures manual and disciplined, continuous records
Poor Fit
- Low-utilization aircraft that fly a few dozen hours a year — the annual is simpler and cheaper to administer
- Owners without access to IA, rated repair station, or manufacturer supervision
- Operations that cannot keep an approved procedures manual current and accessible to crews
- Anyone unwilling to carry the continuous-recordkeeping load the program demands
The program is only as compliant as its records
The single most common way a progressive program fails on review is not a missed inspection — it is a documentation gap. A procedures manual that no longer matches the approved version, a detailed-inspection record that cannot be located, an entry missing the aircraft total time in service, or an inability to state the date of the last complete inspection. Each is a finding. A progressive inspection trades a once-a-year paperwork burst for a year-round one; if you are not prepared to carry that, the annual is the safer path.
What §91.409(d) Requires the Program to Provide
§91.409(d) opens with the gating step: each registered owner or operator desiring to use a progressive inspection program must submit a written request to the responsible Flight Standards office, and must provide four things. These four are the spine of the program — and four of the documents an inspector will ask to see.
§91.409(d)(1) — Qualified Supervision
A certificated mechanic holding an inspection authorization, a certificated airframe repair station, or the manufacturer of the aircraft to supervise or conduct the progressive inspection. This is the same authorization tier as the annual: a standard A&P without an IA cannot supervise the program, though an A&P may perform individual maintenance and repairs that arise. For the difference between an A&P and an IA, and what the IA renewal cycle involves, see the IA renewal guide.
§91.409(d)(2) — A Current Inspection Procedures Manual
A current inspection procedures manual, available and readily understandable to pilot and maintenance personnel, containing in detail the four elements the rule enumerates:
- (i) An explanation of the progressive inspection, including the continuity of inspection responsibility, the making of reports, and the keeping of records and technical reference material
- (ii) An inspection schedule, specifying the intervals in hours or days when routine and detailed inspections will be performed, and including instructions for exceeding an inspection interval by not more than 10 hours while en route and for changing an inspection interval because of service experience
- (iii) Sample routine and detailed inspection forms and instructions for their use
- (iv) Sample reports and records and instructions for their use
Note the two operative phrases: the manual must be current, and it must be available and readily understandable to pilot and maintenance personnel. A manual locked in an office the line crew cannot reach, or one that has drifted from the approved version, does not satisfy (d)(2).
§91.409(d)(3) — Housing and Equipment
Enough housing and equipment for necessary disassembly and proper inspection of the aircraft. A progressive program involves opening the aircraft up in stages across the year, so the facility and tooling to do that work properly are part of what the FAA evaluates when approving and surveilling the program.
§91.409(d)(4) — Current Technical Information
Appropriate current technical information for the aircraft. The inspection must be performed against up-to-date data — the manufacturer's instructions, service information, and the approved data the inspection is built on. The rule's follow-on text reinforces this: the program must ensure the aircraft, at all times, will be airworthy and will conform to all applicable FAA aircraft specifications, type certificate data sheets, airworthiness directives, and other approved data.
One framing helps: §91.409(d) is less a timing rule than a systems rule. The annual asks "was the inspection done in the last 12 calendar months?" The progressive program asks "do you have the supervision, the manual, the facility, the data, and the records to run a continuous inspection system that covers the whole aircraft each year?" Four of those five answers are documents.
The Complete-Inspection-Within-12-Calendar-Months Rule
The backbone obligation in §91.409(d) is this: the frequency and detail of the progressive inspection must provide for the complete inspection of the aircraft within each 12 calendar months, and be consistent with the manufacturer's recommendations, field service experience, and the kind of operation in which the aircraft is engaged. The progressive inspection schedule must ensure that the aircraft, at all times, will be airworthy.
Calendar Months, Not a Rolling 365 Days
Like the annual, the 12-calendar-month measure is anchored to the end of a month, not to a date 365 days out. The schedule in the procedures manual has to be built so the detailed cycle that constitutes a complete inspection is accomplished within that window every year, accounting for the aircraft's actual utilization. The records must be able to show, at any moment, where the aircraft sits in that cycle.
The +10-Hour En-Route Allowance Lives in the Manual
§91.409(d)(2)(ii) requires the inspection schedule to include instructions for exceeding an inspection interval by not more than 10 hours while en route, and for changing an inspection interval because of service experience. This allowance is a feature of the schedule in the approved manual, not a free-floating right. If your manual's schedule provides for it, you may use it within those bounds; the records should reflect any interval that was exceeded under that provision.
"Complete" is a defined milestone, not a label of convenience
Because the rule expressly states that a routine inspection of the aircraft plus a detailed inspection of several components is not a complete inspection, the date of the last complete inspection is a specific, provable event — the point at which the detailed inspection of the aircraft and all its components in accordance with the program has been accomplished. Track that date deliberately. It is the figure that governs your post-discontinuance annual and 100-hour due dates, and it is one of the first things an inspector will ask you to produce.
The Records a Progressive Inspection Produces
A progressive program generates two layers of records: the program documents that define and authorize it, and the inspection entries that evidence each routine and detailed inspection as it is performed. Both layers are what an FAA review traces.
§43.11 Governs the Entries — Not §43.9
This trips people up. The general maintenance-record entry rule, §43.9, expressly does not apply to inspections — §43.9(c) states it does not apply to persons performing inspections in accordance with Part 91, 125, §135.411(a)(1), or §135.419. Inspection entries are made under §43.11 instead. So a progressive-inspection entry is a §43.11 entry, with §43.11's content requirements — including the progressive-specific certification statement in §43.11(a)(6).
What Each Progressive Inspection Entry Must Contain (§43.11)
Each routine and detailed inspection entry carries the §43.11(a) basics, plus the progressive-specific certification:
- §43.11(a)(1) — The type of inspection and a brief description of the extent of the inspection
- §43.11(a)(2) — The date of the inspection and aircraft total time in service
- §43.11(a)(3) — The signature, the certificate number, and kind of certificate held by the person approving or disapproving for return to service
- §43.11(a)(6) — For progressive inspections, a statement (or similarly worded) that, in accordance with a progressive inspection program, a routine inspection of the identified aircraft or components and a detailed inspection of the identified components were performed and the aircraft or components are approved (or disapproved) for return to service
- If disapproved — a statement that a list of discrepancies and unairworthy items, dated, has been provided to the aircraft owner or operator
Alongside the entries, the program documents themselves are part of the compliance record set: the written FSDO request and any approval correspondence, the current inspection procedures manual, evidence of the supervising IA / rated repair station / manufacturer, and the current technical data the inspections are performed against. These feed the broader Part 91 aircraft records set — and the aircraft's current inspection status under the program is the kind of record that must travel with the aircraft and be available to the FAA. For a fuller picture of what a Part 135 charter operator's records look like alongside this, see what records a Part 135 operator must keep and the aviation records retention schedule.
Don't Lose Sight of the Adjacent Records
A progressive inspection covers the §91.409 inspection obligation, but it does not absorb the other recurring airworthiness records that run on their own clocks. These remain separate documents the program does not replace:
- Altimeter / static and transponder tests: the 24-calendar-month §91.411 and §91.413 tests for IFR and transponder operations — tracked separately. See the altimeter and transponder inspection records guide.
- Airworthiness directives and life-limited parts: AD compliance and life-limited part records continue on their own applicability and replacement-time schedules, independent of the inspection program.
- The ARROW documents: registration, airworthiness certificate, and the rest of the required onboard documents are unaffected by the choice of inspection program.
Keep the progressive-program records audit-ready — without running the program for you
FileFlo is a compliance document intelligence platform — a read-only proof layer. It does not approve, supervise, or conduct any inspection, hold a certificate, or replace your IA or repair station. What it does is keep the document side of a §91.409(d) program organized and current:
- Classifies each uploaded record against the governing CFR — routine and detailed inspection entries (§43.11), the procedures manual, the FSDO correspondence, and the supporting technical data
- Extracts the date of the last complete inspection so the figure that drives your post-discontinuance annual and 100-hour clocks is never guessed
- Tracks the adjacent records that run on their own schedules — §91.411 / §91.413 24-month tests, AD compliance, life-limited parts — and sends 90/60/30-day alerts before any of them lapse
- Generates an audit-ready inspection-program binder organized by CFR section for an FAA surveillance review or a pre-purchase inspection
FileFlo sits alongside your maintenance provider, your logbooks, and your approved program — it keeps the documents that prove your compliance audit-ready. Starter $89/mo · Professional $299/mo · 5-day free trial, no credit card required.
Discontinuing the Program — and the Clock It Restarts
A progressive inspection is not a one-way door, but exiting it has precise records consequences that §91.409(d) spells out. Get the date wrong and you can fly an aircraft you believe is current when it is not.
Notify the FSDO in writing — immediately
If the progressive inspection is discontinued, the owner or operator must immediately notify the responsible Flight Standards office, in writing, of the discontinuance. That written notice is itself a record to retain — it marks the moment the program ended and the calendar-and-hours regime resumed.
The first annual is due within 12 calendar months of the last complete inspection
After the discontinuance, the first annual inspection under §91.409(a)(1) is due within 12 calendar months after the last complete inspection of the aircraft under the progressive inspection — not 12 months from the date you discontinued. The clock runs from the last complete inspection.
The 100-hour is due within 100 hours of that same complete inspection
Where the aircraft is one to which §91.409(b) applies, the 100-hour inspection is due within 100 hours after that last complete inspection. Again, the anchor is the complete inspection, measured in aircraft total time in service from that point.
The date of the last complete inspection is the whole ballgame
Both post-discontinuance due dates hang on one figure: when the last complete inspection occurred. If your records cannot establish that date — because the detailed cycle was tracked loosely, or routine entries were conflated with the complete inspection — you have no defensible basis for either clock. Flying compliance is, at root, regulated by civil penalties — a current maximum of $75,000 per violation generally, or $1,875 for an individual or small business under the on/after December 30, 2024 figures — so the records that prove airworthiness are not bureaucratic nicety; they are the difference between a defensible position and an enforcement exposure.
Progressive Inspection vs. Annual vs. AAIP
The progressive inspection is one of several ways to satisfy an aircraft's inspection obligation, and it is frequently confused with the annual it replaces and with the AAIP used by charter operators. They are distinct paths under distinct rules.
| Path | CFR | Who Holds / Requests It | Timing Model |
|---|---|---|---|
| Annual inspection | §91.409(a) | Default — no request needed | One complete inspection every 12 calendar months |
| 100-hour inspection | §91.409(b) | Default for for-hire / instruction-for-hire aircraft | 100 hours TIS (+10 ferry), layered on the annual |
| Progressive inspection | §91.409(d) | Part 91 owner/operator requests in writing from the FSDO | Routine + detailed inspections in rotation; complete aircraft within 12 cal. months |
| AAIP | §135.419 | Held by a Part 135 operator in its certificate | Approved program schedule; a §91.409(f)(2) selectable option when in current use |
The cleanest way to keep them straight: a progressive inspection is a Part 91 owner's way of distributing the annual across the year, requested from the FSDO under §91.409(d). An Approved Aircraft Inspection Program (AAIP) is a Part 135 operator's program approved under §135.419 and carried in its operating certificate. They overlap only at one seam — §91.409(f)(2) lets a Part 91 owner select an AAIP, but only if that AAIP is approved under §135.419 and currently in use by a Part 135 operator. For the annual and 100-hour paths in depth, and for how an AAIP differs in scope and approval, the companion guides cover each:
Frequently Asked Questions
What is a progressive inspection under 14 CFR §91.409(d)?
A progressive inspection is an FAA-authorized alternative to the standard annual and 100-hour inspections. Instead of one comprehensive inspection event per cycle, the required inspection items are divided into routine and detailed inspections performed in rotation on a defined schedule. Under 14 CFR §91.409(d), the frequency and detail of the program must provide for the complete inspection of the aircraft within each 12 calendar months. To use a progressive inspection, the registered owner or operator must submit a written request to the responsible Flight Standards office and provide the four things §91.409(d) lists: a qualified person to supervise or conduct it, a current inspection procedures manual, enough housing and equipment for necessary disassembly and proper inspection, and appropriate current technical information for the aircraft.
Who can supervise or conduct a progressive inspection?
Under §91.409(d)(1), a progressive inspection must be supervised or conducted by a certificated mechanic holding an inspection authorization, a certificated airframe repair station, or the manufacturer of the aircraft. This is the same authorization tier as the annual inspection — a standard A&P without an inspection authorization cannot supervise the program. The point of confusion: an A&P may still perform individual maintenance tasks and repairs that arise during the program, but the inspection itself and its return-to-service approval flow from the IA, the rated repair station, or the manufacturer.
What must the progressive inspection procedures manual contain?
Under §91.409(d)(2), the program requires a current inspection procedures manual that is available and readily understandable to pilot and maintenance personnel and that contains, in detail: (i) an explanation of the progressive inspection, including the continuity of inspection responsibility, the making of reports, and the keeping of records and technical reference material; (ii) an inspection schedule specifying the intervals in hours or days when routine and detailed inspections will be performed, including instructions for exceeding an inspection interval by not more than 10 hours while en route and for changing an interval because of service experience; (iii) sample routine and detailed inspection forms and instructions for their use; and (iv) sample reports and records and instructions for their use. The manual is itself a compliance document — if it is missing, out of date, or not accessible to the personnel who use it, the program is not being run as approved.
How does a progressive inspection differ from an AAIP under §135.419?
They are different programs under different rule sets. A progressive inspection is a Part 91 path under §91.409(d) that an aircraft owner or operator requests from the responsible Flight Standards office to substitute for the annual and 100-hour inspections. An Approved Aircraft Inspection Program (AAIP) is a Part 135 path approved under §135.419 and held in the operating certificate of a Part 135 operator. The §91.409(f)(2) option that lets a Part 91 owner select an AAIP requires that the AAIP be approved under §135.419 and currently in use by a Part 135 operator. A single-aircraft Part 91 owner who wants distributed maintenance generally uses the §91.409(d) progressive path; a charter operator inspecting under §135.411(a)(1) generally uses a §135.419 AAIP. See the AAIP guide and the annual-inspection guide for the full comparison.
What happens to the inspection records if a progressive program is discontinued?
Under §91.409(d), if the progressive inspection is discontinued, the owner or operator must immediately notify the responsible Flight Standards office, in writing, of the discontinuance. After the discontinuance, the first annual inspection under §91.409(a)(1) is due within 12 calendar months after the last complete inspection of the aircraft under the progressive inspection, and the 100-hour inspection under §91.409(b) is due within 100 hours after that complete inspection. This is why the date of the last complete inspection is a load-bearing record: it sets the due dates for both the annual and the 100-hour the moment the program ends. An owner who cannot evidence when the last complete inspection occurred has no defensible basis for the post-discontinuance compliance clock.
What does the progressive inspection logbook entry have to say?
Inspection record entries are governed by §43.11, not §43.9 (§43.9(c) excludes inspections performed under Part 91 from §43.9). For a progressive inspection, §43.11(a)(6) calls for the following or a similarly worded statement: that, in accordance with a progressive inspection program, a routine inspection of the identified aircraft or components and a detailed inspection of the identified components were performed and the aircraft or components are approved or disapproved for return to service. If disapproved, the entry further states that a list of discrepancies and unairworthy items dated as of that date has been provided to the aircraft owner or operator. The entry also carries the §43.11(a)(1)-(3) basics: the type and extent of the inspection, the date and aircraft total time in service, and the signature, certificate number, and kind of certificate held by the person approving or disapproving return to service.
When does a progressive inspection make sense instead of an annual?
A progressive inspection suits high-utilization aircraft where a single annual would mean an extended down period. By distributing routine and detailed inspections across the year, the aircraft spends less consecutive time out of service. The trade-off is administrative weight: a written FSDO request, an approved procedures manual that must stay current and accessible, dedicated housing and equipment for disassembly, current technical data, and continuous recordkeeping. For an aircraft that flies a few dozen hours a year, the annual is usually simpler; for a busy training, charter-feeder, or corporate aircraft, the progressive program can reduce operational downtime — but only if the records discipline is real. The program is only as compliant as the documents that prove it is being followed.
What does an FAA inspector look for when reviewing a progressive inspection program?
An inspector confirms the structural pieces §91.409(d) requires are actually present and current: the written FSDO request and any correspondence, the inspection procedures manual (and whether the on-site copy matches the approved version), evidence that an IA, rated repair station, or the manufacturer is supervising, and that the housing, equipment, and technical data exist. Then they trace the records: do the routine and detailed inspection entries show a complete inspection within each 12 calendar months, are the §43.11 entries complete, and can the operator produce the date of the last complete inspection on demand. Gaps in any of these — a stale manual, a missing detailed-inspection record, an undated entry — are the findings that surface in surveillance. FileFlo organizes the document side of that review so the binder is ready before the inspector asks.
Related Aviation Compliance Guides
Part 91.409 Annual, 100-Hour, Progressive & AAIP
The four inspection regimes — when each applies, who can sign, and the records each produces
Part 91 Annual Inspection Requirements
The annual a progressive program replaces — the 12-calendar-month window and §43.11 entry
§43.9 Maintenance Record Entries
Why inspection entries fall under §43.11 — and what the general §43.9 maintenance entry requires
§135.419 AAIP Records
The Part 135 Approved Aircraft Inspection Program — distinct from the Part 91 progressive path
Part 91 Aircraft Records Requirements
The full Part 91 maintenance and inspection record set the progressive program feeds into
Airworthiness Directive Compliance Records
AD tracking runs on its own clock alongside any inspection program
Aviation Records Retention Schedule
How long each inspection and maintenance record must be kept
Preparing for an FAA Surveillance Audit
What inspectors trace, and how to have the program binder ready before they ask
Prove your inspection program is current — before an inspector asks
Whether you run a §91.409(d) progressive program or a standard annual, FileFlo classifies your inspection records against the governing CFR, extracts the date of the last complete inspection, and tracks the adjacent §91.411, §91.413, AD, and life-limited-part records on their own clocks — with 90/60/30-day alerts before anything lapses. The document side of airworthiness, organized by CFR section and ready for any FAA review.
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