A long time ago when training at LATCC, my trainer asked a just airborne, Hong Kong bound, BA 747 if his fancy new FMS could work out a heading for the checker board at kai tak. Some time later the pilot came back with a heading so we locked him on it, co-ordinated with maastrict and sent him on his way. Always wondered if he managed to stay locked on all the way and just how accurate it would have been.