Can anyone here help explain how the fly-by-wire system works in simple terms?
Most have at least 2 electro/hydraulic systems.
One of manual input, a sensor reads the input, a valve opens, hydraulic power moves the flight control to the desired position, another sensor on the actuator validates the position of the flight control. A FCC (usually 2x redundant), Flight Control Computer monitors and control's this action, it is usually at least 4 times redundant for each axis of control.
The 2nd is similar but the input comes from an autopilot, Otto the Pilot usually resides within the FCC's.
Not all aircraft have flight protection in manual input mode and it can now be turned off on just about all aircraft.