The long-awaited Modernization of Special Airworthiness Certification (MOSAIC) final rule was signed by the FAA Administrator on July 18, 2025, marking the most significant change to the light aircraft landscape since the Sport Pilot/Light Sport Aircraft (LSA) rule was introduced in 2004. While the rule is complex—the final document spans over a thousand pages—its core impact on the Experimental/Amateur-Built (EAB) community can be distilled into a few key areas that represent a massive expansion of freedom and utility for pilots and a profound shift in the maintenance landscape for owners.
For years, the world of homebuilding has offered performance and capability that the factory-built LSA world could not match due to restrictive weight and speed limits. A central philosophy behind MOSAIC is to make certificated LSAs a more appealing alternative to EAB aircraft. The agency’s reasoning is that LSAs, which are built to an industry consensus standard, are “higher on the safety continuum” than EABs, which have no mandated design or production standards. To achieve this, the FAA has expanded the LSA category so dramatically that new LSAs will directly compete with high-performance homebuilts.
But in doing so, the FAA has also handed the EAB community a string of victories that will change the way we fly and maintain our aircraft. Here’s what you need to know.
Big News for Pilots
For pilots of homebuilt aircraft, particularly those flying as Sport Pilots, MOSAIC is a declaration of new freedoms. The rule decouples the aircraft a Sport Pilot can fly from the definition of a Light Sport Aircraft. Instead of being limited to aircraft that meet the old LSA definition, a Sport Pilot can now fly any aircraft—including an EAB or a legacy type-certificated plane—as long as it meets the performance parameters laid out in the regulations. And those parameters have expanded significantly.
The single biggest change is the increase in the maximum stall speed for airplanes a Sport Pilot can operate. The old limit was 45 knots calibrated airspeed (CAS) without flaps (VS1). The final rule raises this limit to 59 knots CAS (VS1). This is a big deal, as it brings a massive number of popular homebuilt designs—as well as legacy aircraft like the Cessna 172—into the Sport Pilot world.
Getting Complex (With an Endorsement)
Previously, Sport Pilots were restricted to aircraft with fixed-pitch propellers and fixed landing gear (with exceptions for seaplanes and gliders). MOSAIC opens the door to more sophisticated aircraft. A Sport Pilot can now get logbook endorsements to operate aircraft with retractable landing gear and airplanes with manually controllable-pitch propellers.
This means a Sport Pilot can now legally fly a huge portion of the existing EAB fleet, including many high-performance retractable-gear designs, after receiving the appropriate training.
Flying After Dark
The prohibition on night flight for Sport Pilots has been lifted. With specific training, a logbook endorsement, and by meeting medical requirements, Sport Pilots can now operate at night. This is a huge increase in utility, removing the pressure to “get home before dark.” To fly at night, a Sport Pilot must hold at least a third-class medical certificate or meet the requirements for BasicMed.
Four-Seat Freedom (Sort of)
Sport Pilots can now operate airplanes designed with up to four seats, but only carry one passenger. This is another major change that brings popular four-place homebuilts into the fold. However, the operational limitation remains—a Sport Pilot is still restricted to carrying only one passenger. So while you can fly a four-seater as a Sport Pilot, you can only fill two of the seats.
Condition Inspections
Perhaps the most significant change for EAB owners is a massive new privilege for repairmen. The final rule expands the privileges of a holder of a repairman certificate (light-sport) to perform the annual condition inspection on an Experimental/Amateur-Built aircraft.
This is huge. Previously, unless you were the original builder of your EAB and held the specific repairman certificate for that airframe, you had to find an A&P mechanic to perform your annual condition inspection. Now, any EAB owner can take a 16-hour LSA repairman—inspection course and, once certificated, legally perform the condition inspection on their own amateur-built aircraft, provided it is in the same category (e.g., airplane) as their training. For those who want to do more, completing a longer LSA repairman—maintenance course allows a person to perform the condition inspection on any EAB of the same category, not just one they own.
This change directly addresses a long-standing challenge in the EAB community—the difficulty and expense of finding mechanics willing and able to work on and inspect homebuilt aircraft.
To Build or To Buy?
By radically expanding the LSA category, the FAA has created a new dynamic in the marketplace. The new generation of LSAs can now have:
- Up to four seats (for airplanes)
- No weight limit (performance is limited by stall speed instead)
- A maximum speed of 250 knots ()
- Retractable landing gear and constant-speed propellers
- Alternative powerplants, including electric and turbine engines
These specifications put new LSAs in direct competition with popular high-performance EABs. This presents a new choice for someone entering the market: build a high-performance kit or buy a factory-built LSA with similar capabilities that is constructed to an accepted consensus standard.
It is important to note, however, that you cannot convert your existing EAB aircraft into an LSA. The rule makes it clear that an aircraft previously certificated as an EAB would likely not be eligible for an LSA certificate because the manufacturer cannot sign a statement of compliance for an aircraft they did not build, and the amateur builder does not hold the design and manufacturing data required to do so.
At the heart of these new, more capable LSAs is a fundamental shift in certification: a 61-knot limitation. This refers to the maximum stall speed in the landing configuration (VS0) an airplane can have to be eligible for LSA certification. By replacing the old, restrictive weight limit with this performance-based standard, the FAA is allowing manufacturers to build heavier, more robust aircraft. This single change enables designs with better handling in turbulence, increased useful load to accommodate modern passengers and fuel loads, and the structural integrity to incorporate new safety features and technologies like electric propulsion. It’s this higher stall speed that allows new LSAs to have the size and performance to truly compete with the homebuilt market, aligning them with the proven safety benchmark of the Primary Category.
It is important to distinguish this aircraft certification standard from the pilot operational limitation. While a new airplane can be certificated as an LSA with a stall speed up to 61 knots VS0, a Sport Pilot is limited to flying airplanes with a maximum stall speed of 59 knots in the clean configuration (VS1). This means that some newly designed, higher-performance LSAs may require a pilot to hold a private pilot certificate or higher to legally fly them.
Based on the FAA’s final rule document, the elements of MOSAIC will go into effect on a staggered timeline with two key dates after its publication in the Federal Register. New Sport Pilot privileges will become effective 90 days after the rule is published. The more fundamental changes to aircraft certification, which require time for industry to develop and revise consensus standards, will go into effect one year after publication. Changes to operating limitations for Restricted Category and certain Experimental aircraft will also take effect at this later date to allow the FAA time to develop and publish the associated procedures.
Ultimately, the MOSAIC rule is a landmark regulation that reshapes the landscape for personal aviation. For the homebuilder community, it offers expanded freedoms for pilots and a long-sought-after solution for maintenance, ensuring the vibrant EAB world will continue to thrive.
Good review. I just noticed one thing, I believe the rv10’s clean stall speed is 62 kts which would make it ineligible for sport pilots (<=59). One interesting thing to comment on will it be at all possible to squeeze a borderline plane like the rv10 down to the sport pilot requirement (with vortex generators, or something else)?
You’re right, Yuriy. I’ve changed that to “four-seater” instead.
Best description I’ve read so far (in the first 24 hours since release)
The 61 KCAS VS1 for Light Sport Aircraft and 59 KCAS VS0 for Sport Pilots seems like a strange dichotomy. Previously we thought of LSA’s (at least I did) as aircraft Sport Pilots can fly. Now it seems like LSA is just an aircraft certification whereas the Sport Pilot rules can apply to any aircraft — including LSA.
Still a little unclear when all this takes effect. Looks like it’s 90 days after it’s “published”. When will that be?
It’s on the list of public inspection documents on the Federal Register’s website. It is scheduled to be published tomorrow, the 24th: https://www.federalregister.gov/public-inspection/2025-13972/modernization-of-special-airworthiness-certification
Thank you
According to the link you provided:
“This final rule is effective October 22, 2025, except for amendatory instructions 3, 8, 9, 13, 15, 17, 21, 23 through 26, 71, 72, 75, 76, and 80, which are effective July 24, 2026.”
Good reviewđź‘Ś
The question that is on every (older) RV builder-pilot’s mind right now is “can I fly my RV (-3,4,6,7,8) with driver’s licence medical?” I finished my RV3 in 1990, have about 1600 hours flying it in the years since (with Private Pilot license), many Class 3 medicals and BFR’s, switched to Basic Med in 2019, and would LOVE to never have to go see an AME again! My VS1 (stall, idle power, no flaps, standard day, near sea-level) is 48 knots, so my airplane easily meets the 59kts CAS stall limit in the new rules. So, my assessment is, Yes: after October 22 2025, I can fly this airplane within the Sport Pilot performance envelope as recently expanded by MOSAIC. What do you think – have I missed anything?
59kt CAS VS1 is the key, so if the airplane stalls at or below 59kt clean, you are ok with just the driver’s license for daytime flights. For night flying, you’ll need at least BasicMed.
Thank you for the nice article. In my research so far, I have found a lot of confusion and conflicting information regarding if an owner of an experimental amateur built aircraft (of which they did not build) can perform a conditional inspection. Your article suggests that the new MOSAIC rules allow this but after reviewing the final ruling FAA document (below), there is no reference to this that I can find. The only reference is what you cited as that an individual with an LSA repairman certificate (the 80 to 120 hour course) can perform this conditional inspection.
From what I can tell, the statement from the article: “Now, any EAB owner can take a 16-hour LSA repairman—inspection course and, once certificated, legally perform the condition inspection on their own amateur-built aircraft” is incorrect. My understanding is that the “LSA repairman—inspection course” applies to ELSA’s only and not EAB. Can you please clarify where in the MOSAIC ruling that allows an EAB owner to perform a conditional inspection with the 16 hour course. Thank you!
The final ruling FAA document: (below from page 25)
https://www.faa.gov/newsroom/MOSAIC_Final_Rule_Issuance.pdf
“The final rule expands privileges for a holder of a repairman certificate (light-sport) to perform an annual condition inspection on § 21.191(g), experimental amateur-built aircraft.”
Jamie, see page 705 of the Final Rule PDF:
§ 65.109 Repairman certificate (light-sport): Privileges and limitations.
(a) The holder of a repairman certificate (light-sport) with an inspection rating may perform the annual condition inspection on an aircraft:
(1) That is owned by the holder;
(2) That has an experimental airworthiness certificate issued in accordance with § 21.191(g), (i), (k), or (l) of this chapter; and
(3) That is in the same category, and class as applicable, of aircraft for which the holder has completed the training course specified in § 65.107(c) of this part.
Refer to § 21.191 (g) which is how EAB aircraft get an Experimental certificate:
https://www.ecfr.gov/current/title-14/chapter-I/subchapter-C/part-21/subpart-H/section-21.191
§ 21.191 Experimental certificates.
Experimental certificates are issued for the following purposes:
…
(g) Operating amateur-built aircraft. Operating an aircraft the major portion of which has been fabricated and assembled by persons who undertook the construction project solely for their own education or recreation.
Thank you Omar. I think the FAA wording is confusing and makes interpretation difficult. I believe your point is that the “repairman certificate (light-sport) with an inspection rating” (called LSRI by some) does not need anything more to do conditional inspections on what is defined in (1), (2) and (3) above. That isn’t the way I originally interpreted it. Thank you for the clarification.
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