MOSAIC on the Horizon

The “official” proposal package, if you will, was submitted to the FAA over the summer with the expectation that we’ll see a final rule sometime in summer 2025. If you know how rulemaking happens in aviation, doesn’t that seem backward? Isn’t the FAA in the rulemaking business? This is actually a bit different. MOSAIC is a two-sided project, a collaborative effort with the industry, not just FAA officials making up rules that aviation will later study. This is unusual because, historically, the FAA prepares the rules on its own, with some measure of industry or member organization input. Usually well into the process with the new rules created, officials issue a proposal and call for comments from the public. These comments are reviewed, and following a “quiet period” the rule writers finalize the regulation, and the industry and pilot communities see the final language.

Not this time. This time the proposed rules package submitted to the FAA in 2024 was driven by the stakeholders in GA rather than the legislating body. Because current-day LSA and the coming MOSAIC LSA gain FAA approval through a process called industry consensus standards, the aviation agency had to inform ASTM (formerly known as the American Society for Testing and Materials) committee members what rule writers had in mind long before the rule was released.

Members of ASTM’s F37 standards committee—composed equally of industry participants and regular users—were tasked with drafting aircraft approval standards and subsequently building support through ballot votes from more than 200 people serving on the committee. In order to prepare these standards and have them ready when MOSAIC is released, committee members had to be told many details about what the FAA was considering. This has been going on for years, and it has given the industry unusual access to the agency’s thinking. While the FAA sends representatives to serve on the F37 LSA committee, the entire agency gets only a single ballot vote, just like every other individual participating.

The trouble is this openness only applies to the aircraft approval, and not to the regulations governing pilot certification or operating limitations. The FAA kept that as an inside job. This makes sense when you understand that MOSAIC has two components—the airplane and the pilot. 

The airplane side of the regulation I have described as the FAA’s “Christmas in July (2023)” gift to the flying community. Those of us interacting with the FAA for years feel we got everything we requested in terms of expanding LSA capabilities, including abandoning a specific maximum gross weight (currently 1,320 pounds for landplanes) and permitting higher speeds, slightly more complex aircraft systems, and more seats. The FAA, in the interest of safety, wanted to find an “equivalent level of safety” with existing LSAs, which have had a good accident record, so the key parameter is now clean stall speed. The proposal floated by the FAA has stall speeds capped at 54 knots calibrated airspeed in the clean (or no-flaps) configuration. Industry has pushed back, asking for higher limits, ranging from 57 to 63 knots. We’ll see where the FAA lands on that one.

A few key features of the airplane side of MOSAIC. Top speed grows dramatically from 120 knots to 250, and propulsion systems have expanded beyond the LSA mandate of a single reciprocating engine; now we can consider electrics and other forms of propulsion. No longer would LSAs be limited to fixed-pitch props or fixed landing gear.

While we have a good blueprint for the airplane side of MOSAIC, we don’t know nearly as much about what will be required of pilots. For example, what is required for a sport pilot to fly a MOSAIC LSA at night? If a MOSAIC LSA has four seats (as proposed), can a sport pilot fill them all? (The initial proposal had the sport pilot limited to one passenger regardless of the number of seats.) Similarly, mechanics of light sport aircraft see changes coming, and they also have questions. There’s an avenue to give sport pilots access to aircraft with retractable landing gear and adjustable props with endorsements. 

What we do know is that MOSAIC will look a lot like LSA from the medical side of things—that is, you won’t need one as long as you have a valid state-issued driver’s license and if you previously held an FAA medical that it was not suspended or revoked. This applies to day/VFR flight and it’s expected that to fly at night will require either an FAA medical or BasicMed. It’s likely that sport pilots under MOSAIC will still be limited to flying no higher than 10,000 feet msl or 2,000 feet agl, as is currently the rule under LSA.

However MOSAIC looks when it finally emerges, aviators are only months away from gaining exciting options. Aircraft designers and producers—with good awareness of what will be permitted—have been working hard for years. Some will bring brand-new designs to market. Others will offer existing LSA designs upsized to expanded MOSAIC parameters. Many present LSAs were created to work in countries where larger, faster aircraft were already allowed, so they have less new design work to do. Sometimes these LSA are called “MOSAIC-ready.”

Finally, there’s something else to consider. While pilots await new aircraft flying under MOSAIC permissions, the current LSAs are themselves good airplanes. They’re understood, and they’re proven. For many recreational pilots, a current-spec LSA is all they need. Importantly, they’ll continue to be considerably more affordable, and many pilots will be pleased about that.

In case this column’s title, The Light Stuff, sounds vaguely familiar, your memory is good. Recalling The Right Stuff Hollywood astronaut movie from 1983, my Light Stuff column ran for 14 years in KITPLANES, another of the Firecrown aviation brands. I’m happy to bring my perspective on the LSA and, soon to come, MOSAIC categories to the readers of Plane & Pilot.