N766AS From , joined Dec 1969, posts, RR: Reply 1, posted (12 years 2 months 2 weeks 3 days 18 hours ago) and read 1015 times:
The flight crew must be certified to perform higher category approaches. And, yes, Cat III approaches have MUCH lower mins (right down to 0-0) than a Cat I. No, it doesn't stop at III... not really. It goes:
with CAT IIIc having zero-zero landing mins, and a requirement for specialized flight crew, instruments, and manditory autoland.
If you do a forum search, you can find a LOT more detailed explanation.