EAA contacted me a couple of weeks back, asking me to go through the registry and estimate how many aircraft will qualify under MOSAIC.
Out of about 144,000 Standard category, single-engined, recip-powered aircraft in the US, roughly half (77,100) will be able to be flown by pilots operating under Sport Pilot rules. However, that 77K aircraft does include about 14,000 aircraft that meet the current Light Sport rules.
The biggest item that disqualify many aircraft is the 54-knot clean stall limit. Sure, twins and turboprops will be *allowed* under MOSAIC, but few (if any) meet the 54 knot limit. The situation with the Cessna 182 is an example. Early 182s meet the limit, but as of the 182E, they raised the gross weight and hence the stall speed rose to 56 knots. Retractable gear is allowed, but few meet the MOSAIC limit stall-speed limit. And a quarter of them are single-seaters (Mooney Mites).
The other bugaboo is seating capacity. MOSAIC is limited to four seats, but there are a number of older designs certified to fly with an additional seat in the baggage compartment ("child's seat"). The way the proposed rules are written, though, pilots flying MOSAIC-qualified aircraft under Sport Pilot can still carry only one passenger.
It's harder to estimate the EAB aircraft that will qualify, but a rough guess is about 45% of the ~28,000 fleet. Each homebuilt is technically a unique aircraft, and won't have formal CAS determination of clean stall speed. The FAA released a list of Standard-Category aircraft that qualified as Light Sport; they never did the same for homebuilts and left it to the individual owners. I anticipate the same for MOSAIC.
This is all based on the current version of the MOSAIC NPRM. It's possible that the limits may change, a number of folks (including myself) submitted comments about how most RVs will be excluded with the 54-knot limit.
One thing interesting in the NPRM is that the FAA is proposing to reduce the confusion factor between aircraft certified Light Sport and the ability to fly non-Light-Sport-Certified aircraft under Sport Pilot. They're removing the "Light Sport Aircraft" definition from Part 1. Instead, Part 21 will define the requirements for a Special or Experimental Light Sport Aircraft, and Part 61 will define Sport Pilot and the requirement for planes that are allowed to be flown.
Ron Wanttaja