>If your technology detected a new Alien at the controls in flight - as happened in 9/11, or even an approved 15 yr old visitor - what would technology do ? Freeze the controls and shut down the engines ?<
NO
If There was a major deviation from the flight planned route in the FMS it would require a code to be entered to disengage the autopilot ie the autopilot would lock onto the existing route. In that mode the normal autopilot disengage would not operate! Who would fly it anyway if the crew were not in the front end
?
Who knows in the future it may be quite possible for the aircraft to be controlled from the ground as in existing unmanned aircraft.
But frankly with the existing way anyone determined enough could gain access! All they would have to do is to wait for one of the crew to visit the toilets position themselves by the toilet as a waiting passeneger and push their way in as the Captain/First officer re entered the cockpit.
You either isolate the crew completely ie NO toilet access, No cabin crew access, No coaxing out of the cockpit with aircraft problems or passenger problems or the whole existing system is a public relations exercise with little practical anti terrorism purpose.
Pace