Now, here's the problem the system is designed to solve — Page 434, Lesson 535

I want to walk you through the Flight Warning System — this is the nervous system of the aircraft, the part that tells you something is wrong before it becomes a problem. Let's start with the big picture. The purpose of the Flight Warning System, which we abbreviate as FWS, is to produce cautions and warnings for the crew. Its job is to increase your situation awareness and to give you suitable indications of the action necessary to avoid impending danger. So it's not just about telling you something is wrong — it's about telling you what to do about it, in time to avoid the danger. Now, here's the problem the system is designed to solve. Modern aircraft have a proliferation of warning systems — lots of them, from many different sources. If all of them went off at once, the crew could be confused by the multiplicity of warnings. So it's necessary to install an integrated flight warning system — one that prioritizes the warnings. By producing warnings relevant to a particular stage of flight and inhibiting other warnings, the system enables the crew to respond to the warning posing the most immediate threat to safety. That word "inhibiting" is key — the system actively suppresses warnings that aren't relevant right now, so you're not distracted by something that doesn't matter at this moment. Now let's look at the levels of alerts. The alerting and warning system produces three levels. First, Warnings, or Level A alerts. These require immediate crew action. Warnings must attract the pilot's attention in sufficient time for appropriate action to be taken. This is the highest priority — you act now. Second, Cautions, or Level B alerts. These require immediate crew alertness and subsequent crew action. Notice the difference — with a caution, you need to be alert immediately, but the action comes subsequently, after you've assessed the situation. It's not the same urgency as a warning. Third, Advisories, or Level C alerts. These require crew alertness only. No immediate action — just be aware. Now, how are these presented to you? The alerting and warning messages are presented to the crew in three forms: visual, aural — that's sound — and sensory, which is tactile, meaning touch. So you can see it, hear it, or feel it. Let's focus on the visual form, because that's where the colour coding comes in. The level of alert is indicated by colours. Warnings are presented in red. Cautions are shown in amber or yellow. Advisories are any colour except red or green — and on EICAS panels, which are the Engine Indication and Crew Alerting System displays, advisories are also amber. So red is the top priority, amber or yellow is the middle, and advisories are everything else, with that EICAS exception. These visual indications can be presented in two different forms. The first is electronic screens — alerts and warnings appear in coloured text or symbols on various electronic screens: flight, navigation, engine, and aircraft system displays. The second form is lights or flags. Red lights or reflective flags signify warnings and require remedial action if flight is to continue. An amber light or flag is used to indicate that a system or equipment is approaching a limit of normal function, and that corrective action is necessary to prevent further deterioration and consequent failure. So the amber light is your early warning — something is heading toward failure, and you need to correct it before it actually fails. Finally, there's one more piece of hardware you need to know about. Master warning and caution lights are normally provided, and they're located near the centre of scan in front of each pilot. That means they're positioned right in your normal field of view, so you can't miss them — they're the big, obvious lights that grab your attention when a warning or caution occurs. Let me show you what this looks like in practice. So to tie it all together: the FWS takes all the warnings from across the aircraft, prioritizes them by level — warning, caution, advisory — presents them visually with colour coding, plus aural and tactile cues, and puts the master lights right in your line of sight. The whole design is about one thing: making sure you respond to the most immediate threat, without being overwhelmed by everything else that's happening.