Originally Posted by
sandos
Ok, so lets go with this scenario. For example, spoofing GPS is clearly possible since even Wikipedia lists several suspected and/or confirmed events. But the airplane has an IRU, and that I'm almost 100% certain is hack-proof! What happens if that and GPS deviates? I'm not even a pilot so I have no idea.
The FMS monitors the GPS, and takes it out of the loop if it deviates too much.