Details matter
Examining the oddities in the MOSAIC rule
The Modernization of Special Airworthiness Certification (MOSAIC) final rule is here, and it will have a substantial impact on the design and production of light sport aircraft and the privileges afforded to sport pilots. The rule itself is no light reading, consuming 189 pages of the Federal Register, and there is a corresponding complexity to the changes implemented by the FAA. It’s worth reviewing the details despite the large amount of coverage the rule has received over the past few months. As the rules pertaining to sport pilots become effective October 22, 2025, let’s focus on some of the oddities that apply.
For the most part, MOSAIC provides greater access to aircraft that sport pilots can fly and expands the limitations of light sport aircraft. But the FAA severed the direct connection between sport pilot privileges and light sport aircraft. At some point after July 24, 2026 (the effective date of the new rules applicable to certification of light sport category aircraft), there will be light sport aircraft that no sport pilot can legally operate. This is because the new design criteria for light sport aircraft are broader than the limitations on aircraft a sport pilot can fly. For example, sport pilots are limited to operating airplanes with a “clean” stall speed (VS1) of 59 knots calibrated airspeed since their original certification under new FAR 61.316(a)(1) while light sport category airplanes can have a “dirty” stall speed (VSO) of 61 knots calibrated airspeed under new FAR 22.100(a)(3).
Sport pilots can now fly more aircraft, including many legacy aircraft holding standard category airworthiness certificates like four-seat airplanes. But many older aircraft do not have published clean stall speeds at maximum certified takeoff weight and the most critical center of gravity expressed in calibrated airspeed. Fortunately, the FAA indicates that Advisory Circular 90-89C may be used to determine calibrated airspeed, but this provides little help to those aircraft with modifications affecting stall speed since the point of calculation for the stall speed is the aircraft’s original certification. To be clear, in order to be flown by sport pilots, an airplane must have been originally certified with a VS1 of 59 knots calibrated airspeed or less (and meet the remaining requirements of FAR 61.316).
Perhaps one of the most significant changes to the sport pilot scheme is the requirement to take a practical test meeting the requirements of FAR 61.307(b) if adding an airplane single-engine land or sea, or a rotorcraft-helicopter privilege. Before the rule, any sport pilot could add any available category and class privilege to their repertoire by passing a proficiency check from an authorized instructor. As the reason for the change, FAA noted that the increased complexity of available airplanes and helicopters born by the rule necessitates a practical test over a proficiency check.
As for rotorcraft, sport pilots can now operate both gyroplanes and helicopters. However, helicopters are limited to a special type of aircraft certified as light sport aircraft with “simplified flight controls” developed under a consensus standard. The privilege will be limited to a specific make and model and require further proficiency checks and endorsements for each additional make and model privilege sought under revised FAR 61.31. It should also be noted that much of the training and experience logged in an aircraft with simplified flight controls will not count toward the aeronautical experience requirements of private, commercial, or airline transport pilot certificates under new FAR 61.9.
With additional training and an endorsement required by FAR 61.329 for each category and class privilege sought, sport pilots can now fly at night but only if the pilot has a valid Part 67 airman medical certificate or is flying under the BasicMed rules (which notably require a pilot to have previously held an airman medical certificate). Those airmen exercising sport pilot privileges because of concerns about their medical eligibility will want to be cautious, as the general medical framework for sport pilots remains mostly unchanged under FAR 61.303(b). A sport pilot is not eligible to exercise their privileges if their most recent application was denied or most recent medical certificate was suspended or revoked.
Sport pilots can now operate aircraft with retractable landing gear and airplanes with a manual controllable pitch propeller upon obtaining the training and endorsements required under FAR 61.331. The training and endorsement can either be from an authorized instructor certifying proficiency in such an aircraft or as a traditional complex aircraft endorsement under FAR 61.31(e). Ground adjustable or automatically adjusting propellers require no special training.
MOSAIC is a landmark regulation and an altogether positive development. But, the devil is in the details and should not be overlooked. 
Related Articles
