Cfalk From , joined Dec 1969, posts, RR: Reply 3, posted (11 years 11 months 2 weeks 4 days 3 hours ago) and read 553 times:
It IS 9V-SMK.
SA has 747-400s (pax versions) registered from 9V-SMA to 9V-SMZ inclusive, except for 9V-SMX, for some reason. They also have 9V-SPA to 9V-SPQ inclusive, except for SPK (crashed). SPP and SPQ have not been delivered yet.
For their 747-400 freighters, they have 9V-SFA to 9V-SFR, but is also missing one - SFN.
Ansett operates three 747-412's which is the designation for 747-400s built for Singapore Airlines. They might account for the missing planes, but I can't confirm that.