Park two identical kit aeroplanes side by side. Same kit, same engine, same paint. One owner may sign off his own annual condition inspection; the other, with exactly the same training, may not. The difference is not in the aircraft, the pilots or the regulations. It is in a few printed pages that came with each aeroplane’s certificate.

Those pages are the operating limitations, and every aircraft holding an experimental airworthiness certificate in the United States has its own set. Homebuilts, prototypes, display warbirds, former military jets such as the Czech-built L-39 Albatros: none of them flies on a standard airworthiness certificate. Each flies under a rulebook issued to one registration and one serial number.

In late August 2026 the FAA rewrote the template for those rulebooks. Order 8130.2M, dated 22 July 2026 and published as one of the final pieces of the MOSAIC rule rollout, sets new standard operating limitations for experimental aircraft. It is a good moment to look at the document itself: where it comes from, what is printed on it, and why it binds.

A certificate with terms attached

A Cessna 172 carries a standard airworthiness certificate, and its limits live in the approved flight manual, markings and placards. An experimental aircraft carries FAA Form 8130-7, the special airworthiness certificate, and the most important part of it is a block headed “Conditions and Limitations”. Order 8130.2M tells inspectors to draft the operating limitations per its Appendix D; when they use the FAA’s online Airworthiness Certification system, printing the certificate automatically includes them.

The legal hook is short. The order cites Title 49 of the United States Code, section 44704(d), as the authority for operating limitations, and quotes it directly.

From there the Code of Federal Regulations does the enforcement. Section 91.9(a) says no person may operate a civil aircraft without complying with the operating limitations specified in the approved flight manual, markings and placards, “or as otherwise prescribed by the certificating authority of the country of registry.” Section 91.319 adds the experimental basics: no operation for any purpose other than the one the certificate was issued for, day VFR unless specifically authorised, and every person carried must be told of the experimental nature of the aircraft. Paragraph (i) closes with an open door: the Administrator may prescribe additional limitations considered necessary.

Sixty-nine limitations to choose from

The rulebook is not written freehand. Appendix D of Order 8130.2M contains Table D-1, a menu of standard limitations numbered up to 69, each tagged with the aircraft category or experimental purpose it applies to and the conditions under which it is issued. The instruction to the inspector or designee is blunt: begin at the top of the table and work downward, and issue the limitations as worded, except for italicised or bracketed instructions where the aircraft-specific detail goes.

Each limitation on the finished document is numbered from 1, with the Table D-1 number in brackets at the end. That is why two aircraft can carry different rulebooks: the menu is common, but the selection, and the details filled into the brackets, belong to one airframe. Anything beyond the standard menu, whether an addition, a change or an omission, needs a written justification, an equivalent level of safety and coordination with FAA headquarters through a dedicated mailbox before the certificate may be issued.

The template is not frozen either. When a recurrent special airworthiness certificate is issued, the order requires the limitations to be reissued from the current version of Appendix D, and inspectors should not reuse limitations from an earlier certificate.

The FAA’s own video on risk assessment for certain experimental aircraft operating limitations.

Phase I: the flight test box

A newly built aircraft has not yet proved it can fly safely, and 91.319(b) says so in law: no operation outside an area assigned by the Administrator until the aircraft is shown to be controllable throughout its normal range of speeds and manoeuvres, with no hazardous operating characteristics. The operating limitations turn that into Phase I. Under Table D-1 they are issued to every experimental purpose except research and development, showing compliance, crew training and market survey, whose operators must flight test under an R&D certificate instead.

For an amateur-built aircraft, Order 8130.2M sets the minimum hours. Forty when a non-type-certificated engine, propeller or combination is fitted, or a certificated one has been altered. Twenty-five with an unaltered, type-certificated engine and propeller combination. Ten hours and at least five takeoffs and landings for gliders, balloons and airships. Five hours after any major repair or alteration. Builders may instead follow the task-based flight test programme in Advisory Circular 90-89.

During Phase I, limitation 52 says no person may be carried unless they are a required crew member or authorised under the Additional Pilot Program of AC 90-116. Limitation 53 bans aerobatics unless the manoeuvres were tested and logged in Phase I, tested under an R&D certificate, the aircraft was previously type-certificated for aerobatics or, for former military aircraft, flown within manufacturer or military manoeuvring limits.

Revision M changed where that testing happens. According to EAA and Kitplanes, the FAA no longer assigns a specific Phase I flight test area automatically, typically a radius around the home airport. The standard limitations now accept any location in the United States that meets 14 CFR 91.305, which reads in full: “No person may flight test an aircraft except over open water, or sparsely populated areas, having light air traffic.” The FAA keeps the right to assign an area when safety requires it.

Cleared Direct on the task-based alternative to hours-based Phase I flight testing for homebuilt aircraft.

The ex-military jet gets its own pages

For a former military jet, the document is noticeably thicker. Limitation 3, issued to every special airworthiness category, removes the aeroplane from the military world entirely.

Some limitations are written for one family of aircraft by name. Limitation 39 applies to all Aero Vodochody L-29 and L-39 series aeroplanes certificated for research and development, crew training, exhibition, air racing or operating former military aircraft. Any emergency stores release handle or master armament safety switch must be disabled and disconnected, weapon-related buttons and switches likewise, and the selection of simulated failure modes from the rear, instructor cockpit must be disabled.

The order also names very high-risk characteristics that must be mitigated by specific limitations: former military or large aircraft in which a single system failure could make the aircraft uncontrollable, aircraft that cruise clean below 10,000 feet at more than 250 knots, rocket power, hydrazine and variable-sweep wings. For those, the limitations prohibit passengers, prohibit flight over densely populated areas in every phase of flight, prohibit night flight and restrict IFR operations to visual conditions. Separately, the operating limitations of all turbine-powered former military aircraft must be coordinated with FAA headquarters.

Why the paperwork date matters

Back to the two identical kit aeroplanes. Since the first phase of MOSAIC took effect on 22 October 2025, light-sport repairmen may perform the annual condition inspection on any experimental amateur-built aircraft. But, as Kitplanes reports, most amateur-built limitations list who may do that inspection, and the FAA’s position is that if light-sport repairmen are not listed, they cannot do it. The enabling wording arrived with Revision L in January 2026; older limitations generally lack it. Owners can apply for amended limitations, which then pick up the current standard wording.

The same logic runs through the rest of the system. A flight school that wants to teach in an experimental or limited category aircraft needs a letter of deviation authority under 14 CFR 91.326, and the application must include copies of each aircraft’s airworthiness certificate, including the FAA-issued operating limitations. Letters issued under the old 91.319 before 2 December 2024 terminate on 1 December 2026.

When the certificate is handed over, the order tells the inspector to review the limitations with the applicant and remind them of their obligations under 91.9 and 91.203. It is good advice for anyone who flies, owns or buys an experimental aircraft. The rulebook that governs that aeroplane is not in a library. It is in the aeroplane, and it was written for that one alone.

Sources: eCFR (14 CFR 91.9, 91.305, 91.319, 91.326), FAA Order 8130.2M Airworthiness Certification of Aircraft (22 July 2026), FAA Amateur-Built Aircraft airworthiness certification guidance, EAA, Kitplanes

Header photo: Alan Wilson / Wikimedia Commons, CC BY-SA 2.0