A320 ECAM System Display Pages

The system display (SD) is the lower of the two ECAM screens in the center of the A320's instrument panel. The engine/warning display above it tells the crew what has happened and what to do; the SD shows the system concerned as a synoptic page, a simplified diagram of its pumps, valves, buses and sensors with their values. Most of the time the crew do not choose the page: the ECAM selects the one that suits the flight phase, replaces it when a failure or a drifting parameter needs attention, and gives it back afterward.

Each page has its own symbols and thresholds, which is why the SD fills so many type rating questions. The alerts, the color code and the flight warning computers are covered in A320 ECAM and warning system, the screens and their switching in A320 EIS displays and EFIS controls.

The system display and its permanent data

The display management computers draw the pages from data supplied by the two system data acquisition concentrators. DMC 1 normally drives both ECAM screens, and DMC 2 takes over automatically if it fails. The SD shows one of twelve system pages, ENGINE, BLEED, CAB PRESS, ELEC, HYD, FUEL, APU, COND, DOOR/OXY, WHEEL, F/CTL and CRUISE, or in their place the STATUS page.

All pages share one visual language. Normal values are green. Amber marks a value outside its normal range or a valve that disagrees with its selection, and a few values, such as cabin altitude and APU speed, turn red at a limit. Amber crosses (XX) replace a value that is not available, and amber dashes over its last digits show degraded accuracy. Valves are drawn in line with the flow path when open and cross line when closed. A green value that pulses is an advisory: the parameter has drifted out of its normal range, and it pulses for as long as it stays outside it.

Along the bottom of every page runs the SD permanent data strip:

Automatic page calling by flight phase

The ECAM chooses the page in one of four operating modes: normal, the page that suits the flight phase; failure, the page of the system affected by a warning or caution; advisory, the page of a drifting parameter, with the value pulsing; and manual, the page the crew select. A failure or advisory page replaces a page the crew have called. Advisories are inhibited in some flight phases.

The phases are the ten flight phases of the flight warning computers (FWC), defined independently of the FMGC's. Phases 1 and 2 are on the ground before takeoff power is set; 3, 4 and 5 cover the takeoff, under the T.O INHIBIT memo; 6 spans the flight between takeoff and landing; 7 and 8 cover the landing, under LDG INHIBIT; and 9 and 10 are on the ground again. The phase decides more than the page:

Other pages are called by events. The ENGINE page appears when a start sequence begins or CRANK is selected, and goes 10 seconds after the start once the ENG MODE selector is back at NORM. The APU page appears when the APU MASTER SW is set ON, with ground power or a main generator supplying the aircraft, and goes once the APU has run above 95 % for 10 seconds. A crew oxygen pressure below 800 psi calls the DOOR/OXY page, an emergency generator test on the ground the ELEC page. When a procedure is complete, pressing CLR returns the SD to the flight phase page.

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ENG, BLEED, CAB PRESS and COND pages

The ENGINE page complements the E/WD, which permanently shows N1 (and EPR, the thrust parameter of V2500 engines), EGT, N2 and fuel flow. For each engine it gives the fuel used, the oil quantity, pressure and temperature and the N1 and N2 vibration; during a start it adds the start valve, ignition and bleed pressure. Nacelle temperatures appear when one exceeds 240 °C.

The BLEED page draws the pneumatic system from the engines to the packs. An engine's number turns amber when its N2 is below idle, and the crossbleed valve in transit is amber, never green. For each pack it shows the outlet temperature, amber above 90 °C, the compressor outlet temperature, amber above 260 °C, the bypass valve as H (hot, open) or C (cold, closed) and the pack flow, which may read up to 30 % low and turns amber when the pack valve is closed.

The CAB PRESS page shows the landing elevation, AUTO or MAN according to the LDG ELEV selector, the differential pressure (ΔP), the cabin vertical speed and altitude, the outflow and safety valves, the active system (SYS 1, SYS 2 or MAN), the packs and the avionics ventilation:

A landing elevation set by hand is read on this page, because the scale of the knob is only indicative.

The COND page shows the cabin zones with their duct temperatures, green and amber at 80 °C (176 °F). Each trim air valve is a green arrow, replaced by amber crosses if the valve fails, and a failed recirculation fan shows FAN in amber. A cargo section gives the cargo duct temperature and isolation valves.

ELEC, HYD, FUEL and APU pages

The ELEC page shows the sources, contactors and buses. Its limits repeat. AC sources, from the generators to external power and the static inverter, turn amber below 110 V or above 120 V, and the generators and external power below 390 Hz or above 410 Hz; batteries and transformer rectifiers turn amber below 25 V or above 31 V. A generator's legend goes amber when any of its load (amber above 100 %), voltage or frequency is amber, a transformer rectifier's only when both its voltage and its current (amber at 5 A or less) are. Battery discharge above 5 A is amber. The IDG oil outlet temperature pulses as an advisory above 147 °C; above 180 °C, with low oil pressure or with the IDG disconnected, the IDG legend is amber.

The HYD page shows the green, blue and yellow systems side by side. A system's label is white and its triangle green above 1,450 psi; below that both turn amber, as does the pressure figure. The reservoir quantity is green, amber at low level. An engine pump is drawn in line green when on with normal pressure, LO in amber when on with low pressure, and cross line amber when switched off. The yellow electric pump is white when off and green when on. The PTU symbol is green in AUTO, with arrows showing which system it supplies, and amber with its pushbutton OFF; the RAT is a white triangle when stowed and green once extended.

The FUEL page shows the tanks, pumps, valves and transfers, the fuel used by each engine and the total fuel flow. A wing pump is in line green with normal pressure, LO in amber with low pressure and cross line amber when off, while a center pump stopped automatically, as intended, is cross line green. A boxed amber quantity cannot be used: the outer tank when both its transfer valves fail to open, the center tank when both its pumps are failed or off. Advisories in phases 2 and 6 flag fuel above 45 °C in an inner cell or 55 °C in an outer cell, below −40 °C, or more than 1,500 kg (3,300 lb) between the wings. Dashes over the last two digits of the fuel on board on the E/WD send the crew to this page to find the degraded tank.

The APU page shows APU speed (N) and EGT, the bleed valve and pressure, and the APU generator. AVAIL appears in green above 95 %. N turns amber at 102 % and red at 107 %, which shuts the APU down; EGT turns amber 33 °C below EGT MAX and red at EGT MAX, when the automatic shutdown begins. FUEL LO PR appears in amber when the APU fuel pressure is low, and FLAP OPEN, green while the air intake flap is open, becomes an advisory if the flap has not closed 3 minutes after the MASTER SW is switched off.

DOOR/OXY, WHEEL and F/CTL pages

The DOOR/OXY page draws the fuselage with its doors and the crew oxygen system. A door closed and locked is a green outlined square, a door not locked is amber, and SLIDE appears in white beside a door whose slide is armed. A door not closed gives a caution that calls this page. The crew oxygen pressure is green at 800 psi or more, pulses green below 800 psi, which also calls the page, and is amber below 400 psi; on the ground an amber half frame below 1,500 psi calls for a check against the minimum. In phases 5, 6 and 7 the page also shows the cabin vertical speed.

The WHEEL page combines landing gear, brakes and steering. Each gear has two triangles, one from each landing gear control and interface unit (LGCIU): green when downlocked, red in transit, absent when uplocked, and amber crosses if that LGCIU has failed. L/G CTL in amber means that the gear disagrees with the lever and is not moving to it. Brake temperatures are green; a green arc marks the hottest wheel above 100 °C, the cue for the brake fans where fitted, and turns amber above 300 °C with a caution. AUTO BRK shows in green with the armed mode, LO, MED or MAX, flashes for 10 seconds after the autobrake disengages and turns amber on failure. The NORM BRK, ALTN BRK and ANTI SKID legends appear only when braking is degraded or in alternate mode, and N/W STEERING in amber when steering is lost. In normal braking no brake pressure is shown anywhere in the cockpit.

The F/CTL page shows the control surfaces, the flight control computers and the hydraulic supply. A spoiler deflected more than 2.5° is a green triangle, a retracted one a green line and a failed one amber. Aileron and elevator indexes are green on white scales and turn amber when their actuators are lost; the rudder turns amber only when all three hydraulic systems are low. Pitch trim figures are green and the rudder trim blue. ELAC and SEC numbers are green in gray boxes and turn amber when a computer fails or is switched off. During the taxi flight control check the pilot monitoring watches this page and calls "full up, full down, neutral" and "full left, full right, neutral".

CRUISE and STATUS pages

The CRUISE page is the only system page without a key on the ECAM control panel. The crew can never select it; it appears only through the flight phase logic. Unlike the others it covers no single system: in the picture below it shows each engine's fuel used, oil quantity and vibration, then the cabin's landing elevation, vertical speed and altitude.

The STATUS page is a list rather than a diagram: the aircraft's operational summary after a failure, in a fixed order and color code. Limitations come first in blue, then approach procedures, procedures in blue, information in green, canceled cautions in white, inoperative systems in amber and maintenance status in white. When it is not empty it appears by itself as the crew clear the last alert, and again when CONF 1 is selected for the approach. While it holds more than canceled cautions or maintenance status, an STS reminder stays on the E/WD. Maintenance status appears only on the ground, before engine start or after shutdown. Pressing STS calls the page; an empty one shows NORMAL for 3 seconds.

Manual page selection on the ECP

The ECAM control panel (ECP) on the pedestal carries a key for every system page except CRUISE, the STS key and an OFF/BRT knob for each screen. Pressing a key calls its page and lights the key; pressing it again returns the SD to the flight phase or warning page. A key also lights when an advisory concerns its system. Holding ALL shows every page in turn at 3-second intervals, and releasing it keeps the page on view. During the preliminary cockpit preparation the crew press HYD, ENG and DOOR to check the hydraulic levels, engine oil and oxygen pressure.

If the ECP fails, CLR, RCL, STS, EMER CANC and ALL keep working, because they are wired directly to the flight warning and display management computers, so ALL becomes the way to reach a page. If the upper screen fails or is switched off, the E/WD moves to the lower one. A system page can then be shown there by holding its key for up to 3 minutes, or sent to a navigation display with the ECAM/ND XFR selector, and an advisory appears as a message on the E/WD while its key flashes.

Library articles are written for study and exam preparation. They do not replace your aircraft's approved documentation, your operator's procedures or the regulations themselves.