ECAM Overview and Alerting Philosophy

From here the chapter enters its heart — the Flight Warning System (FWS) and ECAM. This is where Airbus cockpit philosophy is most concentrated: the aircraft not only shouts when a system misbehaves, it writes "what failed and what to do" on the screen in plain English. To understand it, lay three foundations first: what hardware it is made of, what alerting philosophy it follows, and what colours and levels it speaks in. This article lays those three; the following articles develop attention-getters, the E/WD, the SD, and the ECP.

1. The FWS — acquisition (SDAC) plus computation (FWC), transparent to a single failure

The AMM defines the FWS in one sentence and gives its two functions. Per AMM 31-50-00:

"The Central Warning System, called the Flight Warning System (FWS), is an avionics system which provides the crew with operational assistance for both normal (MEMO information) and abnormal configurations... The fully redundant architecture allows the FWS to be transparent to any single failure. The FWS performs two main functions: - data acquisition and concentration... Acquisition is shared between the System Data Acquisition Concentrator (SDAC) and the Flight Warning Computer (FWC) - warning computation (achieved in both FWCs)..."

Three points: (1) the two functions are acquisition + computation; (2) acquisition is shared between SDAC and FWC (red warnings acquired directly by the FWC, amber via the SDAC — see the overview); (3) warning computation is done in both FWCs — the source of "transparent to any single failure": one FWC or one SDAC failing is taken over by the other with no perceptible degradation (the MEL basis for "single FWC / single SDAC dispatchable" — see the MEL article). The FWS also does automatic altitude/decision-height callouts, speed increments and landing-distance factors. Its outputs are the MASTER WARN/CAUT lights, the text written on the E/WD and SD via the DMCs, and the aural warnings and synthetic voice through the loudspeakers via the Audio Management Unit.

2. The "lights out" philosophy and three-phase detection

The FWS is built on two basic principles. Per AMM 31-51-00:

"The two following principles have been adopted: - Cockpit "lights out" philosophy. In normal operation all the lights are off. The use of lights to indicate correct operation is limited to a minimum. - Detection sequence of an alert. The detection sequence is composed of three distinct phases: PHASE 1 Alert — Aural and visual attention getters; PHASE 2 Identification — Specific sound & general display (EWD); PHASE 3 Isolation — Detailed display (EWD and SD) and local caution/warning."

The lights-out philosophy means that in normal operation the cockpit is dark, and whatever lights up must be attended to — the opposite of an older cockpit's "a wall of green lights means normal". So the Airbus scanning maxim is "a dark light is good, a lit light demands a look". Three-phase detection is the framework for the whole alerting flow: first grab attention (light + sound) → tell you roughly what it is (specific sound + E/WD title) → give the detail and the drill (E/WD action lines + SD synoptic + local light). The following articles are, in order, the hardware of these three phases.

3. Six colours — the ECAM palette

ECAM speaks importance in colour, six defined. Per FCOM DSC-31-10:

"The ECAM display uses a color code that indicates the importance of the failure or the indication. RED: The configuration or failure requires immediate action. AMBER: The flight crew should be aware of the configuration or failure, but needs not take immediate action. GREEN: The item is operating normally. WHITE: These titles and remarks guide the flight crew as it executes various procedures. BLUE: These are actions to be carried out, or limitations. MAGENTA: These are particular messages that apply to particular pieces of equipment or situations (inhibition messages, for example)."

The two easiest to confuse are white vs blue: white = a title or guiding remark (telling you which procedure), blue = an action to be carried out, or a limitation (something for you to do). Mnemonic: "blue is what you act on, white is what you read". Red/amber/green descend in importance (immediate action / awareness / normal); magenta is reserved for "inhibition / special" edge information. This code runs through the E/WD, SD, PFD and ND — recognise it and a screen full of text acquires priority.

4. Three alert levels — the level sets the sound and the attention-getter

Alerts are classed in three levels by urgency, the single most important table in the article. Per AMM 31-51-00:

"LEVEL 3: warning — This corresponds to an emergency configuration. Corrective or palliative action must be taken immediately... associated with an aural alert (continuous repetitive chime or specific sound) and generally with a visual alert (MASTER WARN red flashing light)... LEVEL 2: caution — abnormal configuration... immediate crew awareness is required, but not immediate crew corrective action... generally associated with a general sound (single chime) and a steady visual alert (MASTER CAUT amber light). LEVEL 1: alert advisory — configuration requiring crew monitoring... These alerts do not trigger any "attention getters" (MASTER CAUT and sound), but the related messages are displayed in amber on the EWD."

Nail the table:

The single most-tested point: a level-1 advisory has no attention-getter — no sound, no light, just an amber line on the E/WD. Because level 1 is "loss of redundancy / degradation" that does not affect safety and only needs awareness, it does not interrupt you. So with no sound and no light but a new amber line on the E/WD, that is a level-1 advisory — it must be caught by scanning; it will not shout. This is what new students miss: "no sound, no light" does not mean "nothing". The three levels are strictly prioritised — 3 over 2 over 1, the latest of a level over earlier — managed by the FWC monitor.

5. Independent, primary, secondary failures — one root, a cascade

The FWS classes failures in three, needed to read the E/WD boxes and stars. Per AMM 31-51-00:

"(a) Independent failure — This is a failure which affects an isolated item of equipment or system without affecting the other items... (b) Primary failure — This is a failure of an item of equipment or system which causes the loss of other items of equipment on which it depends. This configuration constitutes a cascade of failures which all originate from the same primary failure. (c) Secondary failure — This is the loss of an item of equipment or system which results from a primary failure. This apparent failure could, in some cases, disappear after corrective crew action."

The relation is "one root, a cascade": the primary failure is the root (e.g. green hydraulic), the secondary failures are what it drags down (e.g. a surface actuator that depends on green); an independent failure stands alone. The E/WD boxes the primary title and stars the secondary. The significance for the drill: you act on the root (primary); the secondaries often clear themselves once the root is handled — which is why the ECAM procedure gives the primary first and reveals the secondaries only as you press CLR.

6. Four operating modes and "as needed"

ECAM's chief advantage is "as needed" — it shows what you should see only when you should. Per FCOM DSC-31-10:

"One of the main advantages of the ECAM is that it displays applicable information to the flight crew, on an "as needed" basis. • Normal Mode: Automatically displays systems and memos, in accordance with the flight phase. • Failure Mode: Automatically displays the appropriate emergency/abnormal procedures, in addition to their associated system synoptic. • Advisory Mode: Automatically displays the appropriate system synoptic, associated with a drifting parameter. • Manual Mode: Enables the flight crew to manually select any system synoptic via the ECP."

The essence is "who decides which SD page shows": normal by flight phase, failure by fault, advisory by a drifting parameter, manual by your hand — with a priority (manual > failure > advisory > flight phase, developed in the SD article). The advisory mode deserves note: a parameter drifting out of normal range but not yet at warning level makes ECAM auto-call that synoptic with the parameter pulsing green — "not failed yet, but take a look" — the FWS's early-warning goodwill.

7. Takeoff/landing inhibition — fewer interruptions in high-workload phases

A final philosophy: inhibit most alerts in critical phases. Per FCOM DSC-31-10:

"Most warnings and cautions are inhibited during critical phases of flight (T/O INHIBIT – LDG INHIBIT), because most system failures will not affect the aircraft's ability to continue a takeoff or landing."

The logic is "your hands are fullest now, and most failures do not affect your ability to continue, so do not bother you yet" — non-critical alerts are held until after the takeoff/landing phase. The FWS filters this across ten flight phases (phase numbers for T.O/LDG INHIBIT are developed in the E/WD article). The RCL button can temporarily suppress the inhibition to reveal held alerts.

Self-test

[!note]- Q1. What are the FWS's two functions, who shares acquisition, and what does "transparent to a single failure" mean? Acquisition and computation. Acquisition is shared by SDAC and FWC; computation is in both FWCs. Single-failure transparency: one FWC or SDAC failing is taken over by the other with no perceptible degradation.

[!note]- Q2. State the lights-out philosophy in a line, and the three detection phases. A dark light is good, a lit light demands a look. Phases: Alert (attention-getters) → Identification (specific sound + E/WD) → Isolation (detailed E/WD/SD + local light).

[!note]- Q3. Which alert level has no attention-getter, and how is it found? Level 1 advisory — no sound, no light, only an amber line on the E/WD. It must be caught by scanning.

[!note]- Q4. How are independent / primary / secondary failures distinguished, and which do you act on? Independent stands alone; primary is the root of a cascade; secondary results from a primary. Act on the primary; secondaries often clear themselves.

[!note]- Q5. In white vs blue, which is an action? Blue is the action (or limitation) to carry out; white is a title/guiding remark.

Key takeaways

References

• FCOM DSC-31-10 — six colours, priority, four operating modes, as-needed display, takeoff/landing inhibition.
• AMM 31-50-00 — FWS definition, SDAC+FWC split, full redundancy.
• AMM 31-51-00 — lights-out philosophy, three-phase detection, three alert levels, independent/primary/secondary failures, flight-phase inhibition.

Independent study material, not an Airbus publication and not endorsed by the manufacturer. Always defer to the current operator FCOM, FCTM, and QRH for operational use.