IFPS man - I agree with your suggestion, quite possible.
Also, I remember attending a talk a couple of years ago by a guy representing a major manufacturer (unfortunately can't remember) who described a safety system using a GPS-referenced global terrain map, detailed right down to building level, which would prevent an a/c being flown into any obstacle (in questions he said it could even have prevented the 9/11 scenario). Wish I could remember the company and name of the system - does anyone else know about this?