Suppose the pilot or pilots of a plane become incapacitated for whatever reason. At the moment, there is nothing that can be done from the outside to stop it other than to shoot it down (am I right?).
Would it in theory be possible that planes have a 'safe landing' program built in that, at a signal from the ground takes over control? It then does everything necessary to land correctly and automatically at a nearby airport.
I realise I am making a lot of assumptions here. My main question is not about the logistics of what would have to happen on the ground, nor is it about whether a new generation of terrorists could hack into such a system for their own purposes. It is about how easily current autopilots could be adapted to have a 'land safely' option. What modifications would the manufacturers have to install within the plane itself that would make this possible?
Is it true that currently, the only way to control a runaway aircraft is to shoot it down?
In theory could an existing autopilot have a simple interface that is retrofitted such that a single signal from the ground sets it in 'return to base' mode and produces a safe landing?