(I lost my reply on a copy-paste / expired link, let's try again)
Sensors 'broadcast' the information across the systems in a very simple way (electronic but not hackable). Everyone get its data directly from sensors.
The FMC is like a pilot without hands. It is a client of the flight control system (another computer) like the pilot itself. When the pilot connects it (this is physically controlled) it can change the parameters of the AP, but it stills not controlling the airplane.
Hypothesis (this is wild): you physically get to the FMC and hack it. The only thing you will be able to do is to change the route (only if) it is engaged. But under a class A/B airspace, this will be immediately be noticed by air controllers that will notify the pilots. Anyway, the pilot should notice it right away. The FMC functionality is very restricted, really.
Sensors 'broadcast' the information across the systems in a very simple way (electronic but not hackable). Everyone get its data directly from sensors.
The FMC is like a pilot without hands. It is a client of the flight control system (another computer) like the pilot itself. When the pilot connects it (this is physically controlled) it can change the parameters of the AP, but it stills not controlling the airplane.
Hypothesis (this is wild): you physically get to the FMC and hack it. The only thing you will be able to do is to change the route (only if) it is engaged. But under a class A/B airspace, this will be immediately be noticed by air controllers that will notify the pilots. Anyway, the pilot should notice it right away. The FMC functionality is very restricted, really.