Originally Posted by
tdracer
Any competent crew should be able to detect if the aircraft isn't going where they want and take corrective action
To pick one simple example: If the selected track and altitude were 045 and FL390, and *all* of the displays were all showing data consistent with that, including updated GPS positions, etc. but the airplane was actually tracking 065 at FL300, how quickly do you think a crew would notice? My bet is on "never".