FAR23 sets the certification standard for aircraft up to 12,500 lbs MTOW.
Aircraft above 12,500 lbs must meet FAR25
SFAR41 allows aircraft up to 13,500 lb to meets only FAR23.
The Lear 23 for example was designed as an FAR23 aircraft and had an MTOW of 12,500 lb. With an aircraft, crew, passengers and bagage you were at 12,500 before you put in any fuel !!
Hence SFAR 41
In UK you can request a category of C.of A. i.e private, cargo passenger etc depending on what you plan to use the aircraft for.
Under FAA the C. of A category is indicated on the TCDS ( Type Certificate Data sheet). Below 12,500 is Normal and above 12,500 is a Transport Category
Thus if you buy your Grannie a B747 for personal use it will be a transport Category C.of A.
