AvBrief Lists Likely Four-Seat and Twin Candidates for S-LSA Certification Under FAA MOSAIC Rules
Why It MattersMOSAIC's opening of S-LSA certification to four-seat and twin designs widens the light end of the piston and diesel market, with Brazil's earlier version already shaping demand for the RV-10.
A commentary by Bernardo Malfitano in AvBrief.com's Experimental Aviator section examines which four-seat and twin-engine airplanes could be certified as special light-sport aircraft (S-LSA) under the FAA's MOSAIC rules. MOSAIC allows larger airplanes, with up to four seats and including twins, to be certified through compliance with ASTM standards. Single-engine models with clean stall speeds below 59 knots can be flown without a medical certificate. Brazil passed its own version of MOSAIC in 2022, and more than 40% of flying RV-10s are registered there.
Three four-seaters have already been certified through ASTM standards. The first certified four-seat S-LSA in Brazil was the Van's RV-10, certified by Flyer Indústria Aeronáutica together with Van's; since 2023 a factory-built certified RV-10 can be bought in Brazil and used commercially for instruction or rental. Flyer also certified the SMA 305-230, a 230-hp turbocharged diesel/Jet A engine, as an option, which the author says raises the RV-10's range and endurance by 20%. The Sling TSi, a four-seater with a maximum weight of 2,095 pounds, is also on the list.
Candidates not yet certified, whose makers are working toward it, include the Veloce ANG (up to 2,786 pounds, useful load over 1,400 pounds, claimed cruise of 170 to 180 knots with the 300-hp AeroVolare engine) and the Bushliner 1850 Cyclone (4,200-pound maximum gross weight, 2,000-pound useful load, 350 hp), which is currently offered as a factory-assisted amateur-built airplane in Washington state.
Among twins, which sport pilots cannot fly but which can be certified as S-LSA under MOSAIC, four designs all use the Rotax 916 iS: the Aero AT AT-6 (cruise estimated at about 160 knots; first flight recently made), the Alpi Aviation Alpi 800 Pioneer (unveiled at Aero Friedrichshafen 2026; kit in Europe and MOSAIC certification planned for the U.S.), the Sling Twin (kit and ready-to-fly; only computer-generated images released, prototype hoped for EAA AirVenture 2027; homebuilt variant may have up to six seats) and the Skytron, which has a V-tail and wing-top pusher engines.
