An experimental airworthiness certificate is the legal pathway that lets an aircraft fly when it is not certificated to an approved type design — a homebuilt in someone's garage, a one-off research platform, a vintage warbird flown at air shows, a manufacturer's prototype, or a light-sport aircraft. It is a special airworthiness certificate, not a standard one, and it comes with strings: the certificate is issued for a specific purpose, and it travels with an aircraft-specific operating-limitations document that controls where and how the aircraft may be operated.
Three regulations do most of the work. 14 CFR §21.191 lists the experimental purposes for which the FAA issues these certificates. 14 CFR §21.193 sets out the application data the applicant submits — the purpose, enough data to identify the aircraft, and the information the FAA needs to safeguard the public. 14 CFR §91.319 sets the operating limitations — most importantly, that you cannot fly the aircraft for any purpose other than the one the certificate was issued for, and you cannot carry persons or property for compensation or hire in the operations the rule describes.
This is a niche corner of aviation — but it is a records-heavy one. The operating-limitations document, the application data, the markings, and the maintenance and condition records are exactly the kind of paper that gets misfiled, lost, or left out of date. For the broader set of documents that must be aboard any U.S. aircraft, see our companion guide on the ARROW documents, and for the registration side specifically, our guide on Part 47 aircraft registration records.
The Three Rules That Govern an Experimental Aircraft
Most of the confusion around experimental aircraft comes from treating "experimental" as a single thing. It is not. The certificate is always issued for one specific purpose, and the purpose drives everything downstream — eligibility, duration, and the operating limitations. Three sections frame it.
| Regulation | What it controls | Key point |
|---|---|---|
| 14 CFR §21.191 | The experimental purposes | Nine listed purposes (a)–(i) plus light-sport kit-built and former-LSA; the certificate is issued for one |
| 14 CFR §21.193 | The application data | Purpose statement, data to identify the aircraft, info to safeguard the public; R&D adds time/area/3-views |
| 14 CFR §21.195 | R&D / market-survey eligibility | Who may apply (manufacturers, engine makers, design alterers) and the prior-flight-hours condition |
| 14 CFR §91.319 | The operating limitations | No off-purpose use; no carriage for hire in listed ops; stay in the assigned area until shown safe |
| 14 CFR §21.181 | Duration | R&D/compliance/training/market-survey are time-limited; amateur-built, exhibition, racing, LSA are unlimited unless the FAA sets a period |
| 14 CFR §45.23(b) | Marking | The word EXPERIMENTAL near each entrance, 2–6 inches high |
"Experimental" is a certificate category, not an aircraft type
An aircraft holding an experimental certificate has not been found to conform to an FAA-approved type design (with the limited exception of aircraft that previously held a type certificate). That is the core difference from the standard airworthiness certificate an ARROW-documents discussion usually assumes. Because there is no approved type design to fall back on, the FAA controls the risk through the operating-limitations document — the assigned area, the day-VFR-versus-IFR status, the markings, and any additional limitations under §91.319(i). The document is the safety case, which is why keeping it intact and available is a compliance obligation, not housekeeping.
The §21.191 Experimental Purposes
14 CFR §21.191 opens by stating that experimental airworthiness certificates are issued for the following experimental purposes, then lists them. The purpose your certificate is issued for is the single most important fact about it, because §91.319(a)(1) prohibits operating the aircraft for any other purpose.
Research and development
Testing new aircraft design concepts, new equipment, new installations, new operating techniques, or new uses for aircraft.
Showing compliance with regulations
Conducting flight tests and other operations to show compliance with the airworthiness regulations, including flights to substantiate major design changes.
Crew training
Training of the applicant’s flight crews.
Exhibition
Exhibiting the aircraft’s flight capabilities, performance, or unusual characteristics at air shows, motion-picture or television productions, and the like, and maintaining exhibition flight proficiency.
Air racing
Participating in air races, including practicing for and flying to and from racing events.
Market surveys
Use of aircraft for market surveys, sales demonstrations, and customer crew training (subject to the §21.195 eligibility conditions).
Operating amateur-built aircraft
Operating an aircraft the major portion of which was fabricated and assembled by persons who undertook the project solely for their own education or recreation.
Operating primary kit-built aircraft
Operating a primary-category aircraft assembled from a kit without the supervision and quality control of a production certificate holder.
Operating light-sport aircraft
Operating a light-sport aircraft that meets the conditions specified in the rule (with additional light-sport-kit and former-light-sport-category paths covered in later paragraphs).
The purpose is a hard boundary
A certificate issued for exhibition does not authorize air racing, and an amateur-built certificate does not authorize carrying customers for a sales demonstration. Operating outside the issued purpose is a §91.319(a)(1) violation — "for other than the purpose for which the certificate was issued." When the use of an experimental aircraft genuinely changes, the operating limitations have to be amended by the FAA; you do not get there by reinterpreting the existing certificate. The paper that proves the issued purpose is the certificate and its operating-limitations document.
Duration tracks the purpose, too. Under 14 CFR §21.181, experimental certificates for research and development, showing compliance with regulations, crew training, and market surveys are effective for a defined, renewable period the FAA prescribes, while experimental certificates for operating amateur-built aircraft, exhibition, air racing, and light-sport aircraft are effective with unlimited duration unless the FAA establishes a specific period for good cause. So a homebuilt's certificate generally has no expiry, but it does not relieve the owner of the inspection and condition requirements in the operating limitations.
The §21.193 Application Data
14 CFR §21.193 sets out what an applicant for an experimental certificate submits. The data is modest in volume but specific, and it becomes part of the record that justifies the certificate the FAA (or a designated airworthiness representative) issues.
For every experimental certificate
- A statement, in the form and manner the FAA prescribes, setting forth the purpose for which the aircraft is to be used.
- Enough data (such as photographs) to identify the aircraft.
- Upon inspection of the aircraft, any pertinent information the FAA finds necessary to safeguard the general public.
Additional, for the R&D family
- The purpose of the experiment.
- The estimated time or number of flights required for the experiment.
- The area over which the experiment will be conducted.
- Three-view drawings or three-view dimensioned photographs of the aircraft (with a narrow exception for certain previously type-certificated aircraft with no external configuration change).
Eligibility for the R&D and market-survey family (§21.195)
14 CFR §21.195 governs experimental certificates for research and development, showing compliance with regulations, crew training, and market surveys. For market surveys, sales demonstrations, and customer crew training, the rule allows a U.S. aircraft manufacturer, a person who manufactures aircraft engines and has installed one in a type-certificated aircraft, or a person who has altered the design of a type-certificated aircraft to apply.
Those market-survey applicants generally must also have an established inspection and maintenance program for continued airworthiness and have flown the aircraft a stated number of hours — with a different, shorter figure for a type-certificated aircraft that has been altered — in addition to meeting §21.193. The FAA may reduce the flight-hour figure where the applicant justifies it. Amateur-built and exhibition certificates follow different paths; the common thread is that the purpose sets both who may apply and what limitations attach.
For an amateur-built aircraft, the practical record set also includes the builder's documentation — a build log and photographs demonstrating that the major portion of the aircraft was fabricated and assembled by the amateur builder for education or recreation. That documentation supports the §21.191(g) purpose and, in practice, the inspection that precedes certificate issuance. The records you keep at application time are the foundation of the file you maintain for the life of the aircraft.
Is Your Operating-Limitations Document Where It Should Be?
FileFlo's free FAA Readiness Score flags document gaps — a missing operating-limitations sheet, an expiring R&D experimental certificate, an out-of-date weight and balance record — before a ramp inspector or a buyer's pre-purchase reviewer does. No signup, no credit card, 3 minutes.
Run the FAA Readiness Score — FreeThe §91.319 Operating Limitations
14 CFR §91.319 is the operating-rules section for aircraft holding experimental certificates. It sets the prohibitions that apply to every experimental aircraft and frames the aircraft-specific operating-limitations document the FAA issues with the certificate.
§91.319(a)(1) — Only the issued purpose
No person may operate an aircraft that has an experimental certificate for other than the purpose for which the certificate was issued. The purpose is the one from the §21.191 list that appears on the certificate. Changing the actual use means the operating limitations must be amended by the FAA first.
§91.319(a)(2) — No carriage for compensation or hire (in the listed operations)
No person may operate an experimental aircraft carrying persons or property for compensation or hire in operations that require an air carrier certificate, are listed in §119.1(e), need fractional-ownership management specifications, or fall under Part 129, Part 133, or Part 137. In short: no charter, no scheduled service, no commercial carriage of that kind in an experimental aircraft. (Narrow exceptions exist for certain experimental light-sport operations such as glider towing — read the specific operating limitations.)
§91.319(b) — The assigned flight-test area
No person may operate the aircraft outside the area assigned by the FAA until it is shown that the aircraft is controllable throughout its normal range of speeds and throughout all the maneuvers to be executed, and that the aircraft has no hazardous operating characteristics or design features. The assigned area and the flight-test conditions are spelled out in the operating-limitations document, and completion of the phase is reflected in the aircraft's maintenance records.
§91.319(d) — Notice, day-VFR default, and ATC
The operator of an experimental aircraft must advise each person aboard of the experimental nature of the aircraft, operate under day-VFR unless otherwise authorized, and notify air traffic control of the experimental nature of the aircraft when operating into or out of certain airports. These conditions, and any additional limitations the FAA prescribes under §91.319(i), live in the operating-limitations document.
The operating-limitations document is part of the certificate
When the FAA (or a DAR) issues the experimental airworthiness certificate, it issues an aircraft-specific operating-limitations document with it. Those limitations are made a part of the certificate — the certificate is not complete or valid without them. The document is where the assigned area, the phase limits, the day-VFR-or-IFR status, the required markings and placards, and any §91.319(i) additional limitations are recorded.
Practically, that means the operating-limitations document needs to be available in the aircraft alongside the airworthiness certificate and the registration certificate that 14 CFR §91.203 requires aboard, with the airworthiness certificate displayed at the cabin or cockpit entrance so it is legible to passengers or crew under §91.203(b). And the word EXPERIMENTAL must be displayed near each entrance to the cabin, cockpit, or pilot station in letters not less than 2 inches nor more than 6 inches high (§45.23(b)). Losing the operating-limitations sheet is not a paperwork annoyance — it is a hole in the certificate itself.
Operating outside the limitations carries real penalties
Operating an experimental aircraft for an unauthorized purpose, for compensation or hire of the kind §91.319(a)(2) prohibits, or outside the assigned area is a regulatory violation that can draw an FAA enforcement action. Under the FAA's civil-penalty schedule at 14 CFR §13.301, the maximum civil penalty for a person other than an individual or small business is $75,000 per violation (with a $1,875 figure for an individual or small business in many cases) for violations occurring on or after December 30, 2024. The specific amount depends on the violation and the violator — the point is that the operating limitations are enforceable, not advisory.
The Records an Experimental Aircraft Generates
Experimental aircraft are document-driven precisely because there is no approved type design behind them. The file that proves an experimental aircraft is being operated as authorized is a defined set, and it should travel with the aircraft through its life — including a sale, where a buyer's reviewer will want to see all of it.
The Experimental-Aircraft Record Set
The experimental airworthiness certificate (FAA Form 8130-7) stating the issued §21.191 purpose.
The aircraft-specific operating-limitations document issued with the certificate — part of the certificate, available in the aircraft.
The §21.193 application data: the purpose statement, the identifying data/photographs, and (for R&D) the time/area/three-view drawings.
The effective U.S. registration certificate (§91.203(a)(2)) — see the Part 47 registration records guide.
For amateur-built: the builder log and photographs supporting the §21.191(g) purpose; the airworthiness-inspection record that preceded issuance.
The maintenance and condition records, including the entry reflecting completion of the §91.319(b) flight-test phase, and condition-inspection entries required by the operating limitations.
Current weight and balance data and equipment list reflecting the aircraft as configured today.
The operating limitations frequently require a recurring condition inspection (often annual) for many experimental aircraft; the exact requirement is stated in each aircraft's operating-limitations document — read yours rather than assuming.
A few of these deserve their own treatment. The maintenance-record entries follow the same discipline as any aircraft — see our guide on §43.9 maintenance record entries for what a compliant entry must contain. If your experimental aircraft has had a major change recorded on a Form 337 or carries an STC, that documentation belongs in the file too. And the weight and balance side is covered in our weight and balance records guide. If you ever need to relocate the aircraft beyond its limitations — for example, to a maintenance facility — that is a special flight permit question, a different special-airworthiness pathway with its own records.
The most common experimental-aircraft document gaps
In our experience indexing aviation records, the recurring problems with experimental aircraft are: a missing or illegible operating-limitations document (a hole in the certificate); a condition-inspection lapse against the recurring inspection the operating limitations require; a use that has quietly drifted past the issued §21.191 purpose without an amendment; and a stale weight and balance record after an equipment change. None of these are exotic — they are filing and tracking failures, which is exactly the layer a document-intelligence system addresses.
How FileFlo Fits — the Document Layer, Not the Airplane
What FileFlo does — and what it does not
FileFlo is a compliance document intelligence platform — a read-only proof layer that sits alongside your existing aircraft records and keeps the documents audit-ready. For an experimental aircraft, it classifies the operating-limitations document, the experimental certificate, the application data, the registration, and the maintenance and condition records against the governing CFR section, so each one is recognized for what it is and filed against the airframe. It surfaces expirations and recurring obligations — a renewable R&D experimental certificate's term, a recurring condition inspection, a registration renewal date — at 90/60/30 days, and it generates inspector-format binders on demand for a ramp check, a FSDO request, or a pre-purchase review.
FileFlo does not issue or hold the certificate, does not perform the inspection or the build evaluation, does not replace your A&P, your IA, your DAR, or your FSDO, and does not set the operating limitations — the FAA does that. It does not run the operation. It keeps the documents that prove your compliance — the certificate, the operating-limitations document, the application data, the condition-inspection entries — organized, indexed against the relevant CFR, and ready when someone asks to see them. We never claim a live integration with FAA systems.
For operators who also fly under other parts, the same discipline carries across: the Part 135 operator records, Part 91 aircraft records, and Airworthiness Directive compliance records all benefit from being classified, tracked, and provable. An experimental aircraft is simply a case where the document layer carries even more weight, because the operating-limitations document is the airworthiness case.
Related Aviation Compliance Guides
The ARROW Documents
What must be aboard any U.S. aircraft (§91.203 & §91.9)
Part 47 Aircraft Registration
The effective registration certificate behind §91.203(a)(2)
Special Flight Permit (Ferry Permit)
The other special-airworthiness pathway and its records
Part 91 Aircraft Records (§91.417)
The maintenance history every aircraft must keep
Part 43.9 Maintenance Entries
What every maintenance record entry must contain
Weight & Balance Records
Keeping the W&B data current after equipment changes
FAA Form 337 Major Repair/Alteration
Where a major change (including an STC install) is recorded
Aircraft Import Airworthiness
Standard vs. special airworthiness certificates compared
Frequently Asked Questions
What is an experimental airworthiness certificate?
An experimental airworthiness certificate is a special airworthiness certificate the FAA issues under 14 CFR §21.191 for one of a defined list of experimental purposes — research and development, showing compliance with regulations, crew training, exhibition, air racing, market surveys, operating amateur-built aircraft, operating primary kit-built aircraft, and operating light-sport aircraft. It is not a standard airworthiness certificate, and an aircraft holding one is not certificated to a type design. The certificate is issued together with a separate, aircraft-specific operating-limitations document, and the two have to be read as a set: the operating limitations are made a part of the certificate and the aircraft may not be flown legally without them. Because §21.191 lists the purposes by letter, the purpose your certificate was issued for controls what you may and may not do with the aircraft.
What are the experimental purposes under 14 CFR §21.191?
Section 21.191 lists the experimental purposes for which the FAA issues experimental airworthiness certificates: (a) research and development, (b) showing compliance with regulations, (c) crew training, (d) exhibition, (e) air racing, (f) market surveys, (g) operating amateur-built aircraft, (h) operating primary kit-built aircraft, and (i) operating light-sport aircraft. The section also covers light-sport-category kit-built aircraft and former light-sport-category aircraft in later paragraphs. The certificate is issued for the specific purpose you applied for, and 14 CFR §91.319(a)(1) prohibits operating the aircraft for any purpose other than the one for which the certificate was issued. So an amateur-built aircraft certificated under §21.191(g) is being operated for personal education or recreation — not, for example, for hire.
Can you carry passengers or cargo for hire in an experimental aircraft?
Generally no. 14 CFR §91.319(a)(2) prohibits operating an aircraft that has an experimental certificate carrying persons or property for compensation or hire in operations that require an air carrier certificate, are listed in §119.1(e), need fractional-ownership management specifications, or fall under Part 129, Part 133, or Part 137. In plain terms, you cannot run charter, scheduled, or commercial carriage in an experimental aircraft. Experimental aircraft can carry the owner and guests for non-commercial purposes within the operating limitations, but the document layer matters: if a flight is for compensation or hire of the kind §91.319(a)(2) describes, the experimental certificate does not authorize it. This is one of the cleanest lines in the rules and one the FAA and NTSB take seriously.
What is the operating-limitations document and do I have to keep it in the aircraft?
The operating-limitations document is the aircraft-specific sheet (or set of sheets) the FAA issues with the experimental airworthiness certificate. It states the conditions under which that individual aircraft may be operated — the assigned flight-test area, the phase-by-phase limits, day-VFR or authorized-IFR status, the markings and placards required, and any additional limitations the FAA prescribed under §91.319(i). Because the operating limitations are made part of the experimental certificate, the certificate is not complete without them. As a practical and regulatory matter, the operating limitations need to be available in the aircraft along with the airworthiness certificate and the registration certificate that 14 CFR §91.203 requires aboard, and the airworthiness certificate must be displayed at the cabin or cockpit entrance so it is legible to passengers or crew under §91.203(b). Losing the operating-limitations document is a real compliance problem, because it is part of the certificate, not a convenience copy.
Does an experimental airworthiness certificate expire?
It depends on the purpose. Under 14 CFR §21.181, experimental certificates issued for research and development, showing compliance with regulations, crew training, or market surveys are effective for a defined period the FAA prescribes (commonly limited and renewable), while experimental certificates for operating amateur-built aircraft, exhibition, air racing, and light-sport aircraft are effective for an unlimited duration unless the FAA establishes a specific period for good cause. So an amateur-built aircraft's experimental certificate generally does not carry a calendar expiry, but an R&D or market-survey certificate does and must be renewed. Separately, the aircraft still has to be maintained and inspected in accordance with its operating limitations and the applicable maintenance rules — a certificate with no expiry does not mean an aircraft with no inspection requirement.
What does the applicant have to submit for an experimental certificate?
Under 14 CFR §21.193, an applicant for an experimental certificate submits a statement, in the form and manner the FAA prescribes, setting forth the purpose for which the aircraft is to be used; enough data — such as photographs — to identify the aircraft; and, upon inspection of the aircraft, any pertinent information the FAA finds necessary to safeguard the general public. For experimental certificates in the research-and-development family, §21.193 also calls for the purpose of the experiment, the estimated time or number of flights required, the area over which the experiment will be conducted, and three-view drawings or three-view dimensioned photographs of the aircraft. The records you keep — the application, the identifying data, the operating-limitations document the FAA issues, and the maintenance and condition records — are the paper trail that proves the aircraft is being operated as authorized.
Who is eligible for an experimental certificate for research and development or market surveys?
14 CFR §21.195 governs experimental certificates for research and development, showing compliance with regulations, crew training, and market surveys. For market surveys, sales demonstrations, and customer crew training, the rule allows a U.S. aircraft manufacturer, a person who manufactures aircraft engines and has installed one in a type-certificated aircraft, or a person who has altered the design of a type-certificated aircraft to apply — and the aircraft generally must have been flown a stated number of hours (with a different, shorter figure for type-certificated aircraft that have been altered) and have an established inspection and maintenance program, on top of meeting §21.193. The eligibility differs by purpose, which is why amateur-built and exhibition certificates follow different paths from the R&D and market-survey family. The common thread is that the purpose you apply under sets both who may apply and what operating limitations attach.
How is an experimental aircraft marked, and where does the word EXPERIMENTAL go?
Under 14 CFR §45.23(b), when an aircraft holds an experimental airworthiness certificate, the operator must display the word EXPERIMENTAL near each entrance to the cabin, cockpit, or pilot station, in letters not less than 2 inches nor more than 6 inches high. That marking is in addition to the nationality and registration marks (the N-number) required under Part 45. The point of the marking is to put crew and passengers on notice that the aircraft is operating under an experimental certificate rather than a standard one — which ties to §91.319(d)'s requirement that the operator advise each person aboard of the experimental nature of the aircraft. From a records standpoint, the marking, the certificate, and the operating-limitations document should all describe the same aircraft and the same purpose.
Where can an experimental aircraft be flown — what is the assigned area?
When an experimental certificate is first issued, the FAA assigns a flight-test area, and under 14 CFR §91.319(b) no person may operate the aircraft outside that assigned area until it is shown that the aircraft is controllable throughout its normal range of speeds and throughout all the maneuvers to be executed, and that the aircraft has no hazardous operating characteristics or design features. The operating-limitations document spells out the assigned area and the flight-test requirements for the specific aircraft. After the flight-test phase is satisfactorily completed and the limitations are amended accordingly, broader operation is authorized within the remaining limitations. The records that document completion of the flight-test phase — typically a maintenance-record entry reflecting that the aircraft meets the §91.319(b) conditions — are part of the compliance paper trail.
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Written by Chad Griffith, Founder & CEO, FileFlo · Reviewed June 13, 2026 · Primary sources: Cornell LII 14 CFR §21.191, §21.193, §21.195, §91.319, §45.23, §91.203, §21.181, §13.301