I was picking random numbers to try and spell out that cruising speed isn’t a huge safety risk, but landing speed is. Notice that the slow speed (55 kts) I picked is legal under MOSAIC but the higher unsafe speed (80 kts) isn’t legal, and this illustrates that the FAA kept a fairly sane stall speed limit.
The fact that the stall speed limitation closely matches the existing limits for light singles shows where the FAA draws the safety lines. Although MOSAIC apparently allows twins, they keep the stall speed limitation at a sane number.
The only thing I don’t fully understand is them differentiating between 59 kts for a sport pilot, and 61 kts for a light sport aircraft. It feels a little arbitrary to draw those lines differently.
> The only thing I don’t fully understand is them differentiating between 59 kts for a sport pilot, and 61 kts for a light sport aircraft. It feels a little arbitrary to draw those lines differently.
The NPRM document explains it somewhere around page 200. It’s important to note that it’s 59 knots CAS clean vs 61 knots CAS dirty.
The argument seems to be that a sport pilot is operating with less training and less oversight and so if something goes wrong and they can’t get the aircraft fully configured for landing they’ll still be able to operate and touch down at 59 vs whatever the clean stall speed would be for an aircraft with a dirty stall speed of 61 knots. That margin could be fairly large (10 knots or more) and the difference in energy between 59 and 71 knots is massive.
The fact that the stall speed limitation closely matches the existing limits for light singles shows where the FAA draws the safety lines. Although MOSAIC apparently allows twins, they keep the stall speed limitation at a sane number.
The only thing I don’t fully understand is them differentiating between 59 kts for a sport pilot, and 61 kts for a light sport aircraft. It feels a little arbitrary to draw those lines differently.