Redundancy in signal sources to autopilots means both FMGCs feed AP1 and AP2. The flight guidance commands that steer the aircraft come from the FMGCs, and in a dual autopilot setup these data streams are provided to both autopilots, allowing either AP to use guidance from either FMGC. This setup lets the system continue to provide valid commands if one FMGC or its path fails, and it also allows cross-checking between the two sources for consistency. Feeding only one FMGC would create a single point of failure, and there will still be FMGC input to the autopilots under normal operation.

In this scenario, the key idea is how the A320 determines the speed the autothrust should aim for. There are two ways: the flight management system can manage the speed automatically along the flight plan, or the pilot can manually set a speed using the speed selector, which becomes the target the auto-thrust tries to hold. Since the frame shows the pilot has chosen a specific speed value on the FCU, the target airspeed is the selected speed. The other terms describe different ways the system might determine speed (managed by the FMS, a computed value, or a reference metric), but they are not the manually chosen target being displayed here.

The main idea here is that some engine health indicators are kept visible across different ECAM views so you can monitor key values without switching screens. Engine oil quantity is displayed on both the ECAM ENGINE page and the ECAM cruise page because oil level is a critical metric for engine lubrication and safety, and you want quick, constant visibility of it no matter which page you’re looking at. On the engine page you’re focused on the engine’s health and performance, so you’ll see oil-related data there, including the quantity, to gauge how much oil remains and to spot any unusual changes. When you switch to the cruise page, the system overview shifts to a broader status of critical systems during cruise flight, and engine oil quantity is still shown so you can confirm the oil level is within limits without toggling back to the engine-specific view. This continuity helps you assess overall engine condition during different flight phases. The other parameters listed don’t share that same cross-page visibility. For example, many engine-specific indicators like N2 speed or oil pressure are primarily shown on the engine page, while fuel quantity is presented in the cruise/overall fuel pages rather than as a per-engine oil value.

Passenger address calls come from the Audio Control Panel. The ACP is the cockpit/cabin audio hub: it lets you select the PA function, choose the microphone source, adjust volume, and route announcements to the cabin (and to specific zones if equipped). The other panels are for data management (MCDU), autopilot/flight guidance (FCU), or navigation display (ND) and do not provide PA capabilities. So, to address passengers, you use the Audio Control Panel.