MOSAIC is in effect: what changed, who it affects, and which date applies

You keep hearing that MOSAIC is in effect. Does it change what you fly, build, maintain or sell, and which of the dates in the headlines applies to you? Short version: the rule took effect in two stages that have both passed, a few related actions have followed, and one more date is still upcoming.

What MOSAIC is

MOSAIC is the FAA’s Modernization of Special Airworthiness Certification final rule, published July 24, 2025 (90 FR 35034). It amends the rules for the design, manufacture, airworthiness certification, operation, maintenance and alteration of light-sport category aircraft, so it reaches pilots, owners, builders, manufacturers and maintenance providers.

What it means for you

Pilots. The FAA says sport pilots are no longer limited to the Part 1.1 “light-sport aircraft” definition; new section 61.316 now governs which aircraft they may operate. With training and instructor endorsements, the FAA lists retractable landing gear, manual controllable pitch propellers, high-performance airplanes and complex airplanes. New night privileges need training, endorsements and an FAA medical or BasicMed.

Owners, builders and maintenance providers. MOSAIC expands light-sport repairman privileges, subject to the holder’s rating and applicable category and class privileges. An E-AB condition inspection also depends on the operating limitations issued with the aircraft; an inspection-rating holder must own the aircraft. The FAA also lists minor repairs and alterations done to Part 43 standards without manufacturer approval, and voluntary compliance with manufacturer safety directives. For kit-built light-sport aircraft, the rule’s requirements apply to kits purchased on or after the applicable effective date.

Manufacturers. The FAA describes new design, production and airworthiness standards and new kinds of light-sport aircraft, such as gyroplanes, rotorcraft and powered-lift. Under Part 22, compliance runs through consensus standards the FAA has accepted or approved; on July 16, 2026 it accepted four ASTM integration standards for that purpose.

Test standards. A follow-up rule, published and effective September 14, 2026, incorporates three updated sport pilot practical test standards. Its compliance date, October 14, 2026, is still upcoming.

Which date applies?

The FAA’s overview gives October 22, 2025 for sport pilot certification, light-sport repairman certification and maintenance of light-sport aircraft, and July 24, 2026 for certification of light-sport aircraft. As of October 12, 2026, both have passed. The Federal Register explains the gap: provisions that depend on new consensus standards or new procedures for operating limitations got 365 days after publication, the rest 90. The rule’s DATES section lists which instructions fall on each date.

Keep publication, effective and compliance dates apart, and remember that a page’s “Last updated” date shows only that it was edited: the FAA’s light-sport standards page shows October 6, 2026, yet its standards were accepted by the July 16, 2026 notice.

A hypothetical example

Imagine you ordered a light-sport kit and wonder whether the new rules cover it. The rule ties kit-built requirements to your purchase date compared with the applicable effective date, and which date applies depends on the provision.

This illustrates why the DATES section matters more than a headline date. Still to verify: your purchase date, which provisions bear on your kit, and the manufacturer’s paperwork. It does not decide whether any real kit is covered.

Where to go next

• Sport pilots: aircraft eligibility versus aircraft certification, night flying, retractable gear and propeller endorsements, and the October 14, 2026 practical-test date
• Owners and builders: light-sport repairmen and E-AB condition inspections, kit-built E-AB versus light-sport kit, and safety directives and airworthiness directives
• Manufacturers and buyers: the statement of compliance and the consensus standards directory
• Not sure it is even an aircraft? Ultralight vehicles under Part 103

FAA guidance is still arriving. As of October 10, 2026, the FAA’s MOSAIC overview listed an FAQ for pilots, an FAQ for Part 91 operations and AC 90-121 as “coming soon,” and its record for AC 90-121 showed Inactive with no content available. Check the FAA pages for current status.

Implementation timeline

As of October 12, 2026. Kind says what sort of date a row is: publication, effective, compliance, or an FAA guidance or standards action.