Boeing has received a US patent for a system that, once activated, removes all control from pilots to automatically return a commercial airliner to a predetermined landing location.
The "uninterruptible" autopilot would be activated - either by pilots, by on-board sensors, or remotely via VHF or satellite links by government agencies such as the CIA - if terrorists were to attempt to gain control of a flightdeck. Boeing believes that current preventative measures are less than foolproof - pilots can decide to open the lockable, bullet-proof cockpit doors and federal air marshals can be overpowered and de-armed.
According to the patent, which appears to be issued to Boeing's Phantom Works research organisation, the airframer is proposing a system whereby an on-board processor, once activated, disallows pilot inputs and prevents anyone on board from interrupting an emergency landing plan that can be predefined or radioed to the aircraft by airline or government controllers and carried out by the aircraft's guidance and control system. The system has its own power supply.
Boeing envisages several activation methods: manual switches force sensors on the cockpit door that would trip the anti-terror mode if a minimum force threshold were crossed and a remote link whereby the aircraft would be monitored on the ground and the automatic control mode remotely activated "once it is determined that the security of the air vehicle is in jeopardy".