Electronic Flight Information System (EFIS) — Page 287, Lesson 289

Let's start with the two display modes, because they set the foundation for everything else on the EFIS — the Electronic Flight Information System. First, map mode. This is the mode you'll use most in normal flight. It shows the navigational information you've selected on the control panel, and it's heading orientated — meaning the top of the screen is always the aircraft's current heading, so the map rotates as you turn. You can see this in Figure 17.6, which shows the map mode with things like your waypoints — EDNOR, BANTU, ZAPPO — along with distances like 26.3 nm, altitudes like 12000, and the time, 1347z. All of that is the navigational information you've chosen to display. Now, plan mode. This is the planning and review mode. It's orientated to true north — so the top of the screen is always north, not your heading. The information displayed at the top of the screen is the same as in map mode, but the key difference is what you use it for. Plan mode lets you review the planned route using the FMC/CDU LEGS page — that's the Flight Management Computer and its Control Display Unit, and the LEGS page is where the route legs are listed. The display will be centred using this page, so you can step through your route leg by leg and see the whole plan laid out against true north. Now let's move to the EHSI colour coding — the EHSI is the Electronic Horizontal Situation Indicator, the main navigation display. The colour coding here is to the ICAO standard, which is also the standard adopted by EASA. And EASA's CS-25 — that's the Certification Specification for large aeroplanes — recommends this colour presentation. Let me walk you through the colour sets. First, the display features: - Warnings are Red. - Flight envelopes and system limits are also Red. - Cautions and abnormal sources are Amber/Yellow. - Earth — the ground on the display — is Tan/Brown. - Engaged modes are Green. - Sky is Cyan/Blue. - The ILS deviation pointer — the localiser and glideslope deviation indicator — is Magenta. - The flight director bar is Magenta/Green. Then there's Colour Set 1, which covers the specified display features: - Fixed reference symbols are White. - Current data and values are White. - Armed modes are White. - Selected data and values are Green. - Selected heading is Magenta. - Active route/flight plan is Magenta. And there's an important note about magenta: it's intended to be associated with those analogue parameters that constitute 'fly to' or 'keep centred' type information — so when you see magenta, think of something you're actively flying toward or keeping centred, like the selected heading or the active route. Finally, precipitation and turbulence have their own coding. Precipitation is coded by rainfall rate: - 0 to 1 mm/h — Black - 1 to 4 mm/h — Green - 4 to 12 mm/h — Amber/Yellow - 12 to 50 mm/h — Red - Above 50 mm/h — Magenta And turbulence is coded White or Magenta. So the whole colour scheme is designed so that at a glance, you know the state of the system — red for warnings and limits, amber for cautions, green for engaged or selected values, and magenta for the things you're actively flying to. That's the EFIS map and plan modes, and the EHSI colour coding.