Typical Electronic/Digital Aircraft Systems
Flight deck systems
The flight management system holds the navigation database, flight plan and performance data and supplies guidance to the autopilot and autothrottle. Air data computers and inertial reference units feed the electronic flight instrument system and the flight director. EICAS/ECAM presents engine and system data and generates crew alerts. Fly-by-wire replaces mechanical linkage with computers, sensors and hydraulic or electromechanical actuators, with several redundant lanes and reversion modes; FADEC performs the same role for engines.
Supporting systems
Traffic alert and collision avoidance, enhanced ground proximity warning, weather radar, radio altimeter, GNSS and ADS-B feed or draw from the same data buses. Built-in test equipment and a central maintenance system record faults for maintenance, and datalink (ACARS, SATCOM) exchanges messages with the ground.
Traps
Confusing which unit owns a function: the FMS does not drive control surfaces, the autopilot does not compute the flight plan, and BITE reports a fault but does not fix it. Questions also test degradation: after two failures a system may still be usable with reduced capability, so read the stated failure state carefully.
Rule of thumb
Learn each system by its inputs, its processing and its outputs, and by what happens when it fails. If a question asks for the correct crew or maintenance response, choose the one that matches the reported level of degradation rather than assuming total loss.