Attention-Getters and Aural Alerts

The overview of ECAM philosophy described three-phase detection; the first phase is attention — grabbing you with light and sound before you ever look at a screen. This article is that phase: how the two master lights work, how the whole aural catalogue is classed, what the synthetic voices say, and one often-overlooked rule — two different sounds cannot play at once. This is the cockpit's ears and peripheral vision, and drilling it lets you know, from a sound alone, roughly what happened and whether to act at once.

1. The two master lights — red flashing vs amber steady, spring-loaded

The lights' action difference was noted in the previous article; here is their function as spring-loaded pushbuttons. Per AMM 31-51-00:

"They are of the spring-loaded pushbutton switch type. The MASTER WARN lights flash for most of the level 3 warnings... The MASTER CAUT steady lights come on for the level 2 alerts, and are accompanied by an aural caution signal (single chime). If the light is pushed when active, both visual and aural "attention getters" are reset... The "attention getters" (lights and sounds) are not activated by level 1 alert."

So the two lights are both indicator and button: press once = extinguish + stop the corresponding level's aural. But some red warnings are the exception. Per AMM 31-51-00:

"When the MASTER WARN light is pushed, the MASTER WARN light goes off and the aural warnings for the level 3 warnings present are cleared one after the other, except for the warnings whose audio signal cannot be cancelled."

A few red warnings will not silence when the light is pressed — typically overspeed and landing-gear-not-down — their audio is designed "not cancellable", forcing you to fix rather than mute. This is the mirror image of the altitude alert (whose C chord is cancellable): same medium, sound, but some can be pressed off and some cannot, by urgency. After each cancel there is one second of silence.

2. Three aural classes — general attention / instinctive / synthetic voice

The AMM classes the loudspeaker sounds in three, the skeleton for the whole catalogue. Per AMM 31-51-00:

"The two cockpit loudspeakers provide the crew with the following aural alerts: - General sounds to draw attention: . A Single Chime (SC) which accompanies the cautions . A Continuous Repetitive Chime (CRC) which accompanies most of the warnings. - Specific sounds for instinctive reactions: . Cavalry charge for AP disconnect . Triple click for landing capability change . Hybrid audio (cricket. stall) for stall warning . Buzzer for calls and SELCAL . "C" chord for altitude alert. - Synthetic voices..."

The second class — "specific sounds for instinctive reactions" — is the essence: each sound is dedicated to one event, so that without looking you reflexively know what happened.

This is the pilot's "auditory dictionary", to be drilled to reflex — especially cavalry charge = AP off, the classic instant answer.

3. The synthetic voices — callouts, the RETARD family, priority and dual input

The third class is a long list, selected by the FWC from a standard set per aircraft wiring. Per AMM 31-53-00:

"- Altitude call outs (synthetic voice)... "Two thousand five hundred"..."Five hundred""Four hundred"..."Fifty""Forty""Thirty""Twenty""Ten""Five". The FWC is capable of announcing intermediate altitudes... - Voice identification for warnings: "HUNDRED ABOVE""MINIMUM""TWENTY RETARD""TEN RETARD""RETARD""CONTINUOUS RETARD""DUAL RETARD""RUNWAY TOO SHORT""BRAKE MAX BRAKING""SET MAX REVERSE""KEEP MAX REVERSE""WINDSHEAR"(×3)"SPEED"(×3)"PRIORITY LEFT""PRIORITY RIGHT""V ONE""STALL-CRICKET""PITCH-PITCH""DUAL INPUT"."

A few groups to sort out:

• Callouts — from "two thousand five hundred" down to "five", the FWC's work (rounded to the nearest ten between 400 and 100 ft, to the foot below 100).
• RETARD family — RETARD, CONTINUOUS RETARD, TEN/TWENTY RETARD, DUAL RETARD — prompting thrust to idle on landing / autoland.
• Stick priority — PRIORITY LEFT/RIGHT (one sidestick taken over), DUAL INPUT (both sidesticks moved) — a flight-control instinctive prompt, telling you at once "who is moving the stick / both are".
• SPEED SPEED SPEED — sounded when current thrust cannot recover the required flight state by pitch alone: an energy warning.

The triggering of these voices is spread across chapters (stall → ATA-27, windshear → ATA-22/34, RETARD → ATA-22), but "they are all voiced by the FWC's AUDIO board" is ATA-31's ownership.

4. The FWC AUDIO board and mutual exclusion — two sounds cannot play at once

An important, easily-overlooked rule: sounds queue. The FWC's AUDIO board generates all sounds and voices, with mutual exclusion between the two FWCs. Per AMM 31-53-00:

"On each audio discrete output board of both FWCs, a mutual exclusion function defines the priority to generate the sounds (audio signal or synthetic voice) between both FWCs... The audio signals and synthetic voice are sent to the same analog output controlled by the CPU which can reduce the sound by 6 dB."

And the concurrency rule (mentioned in the philosophy article). Per AMM 31-51-00:

"Two different sounds cannot be broadcasted at the same time and two different synthetic voices cannot be broadcasted at the same time. But one sound and one synthetic voice can be broadcasted together... The single chimes (SC) are limited to 1 within two seconds."

Fix the concurrency law: (1) two sounds cannot coincide, (2) two voices cannot coincide, (3) but one sound + one voice can. Why? Sounds are told apart by timbre, voices by content — two timbres overlaid are indistinguishable, two sentences overlaid unintelligible, but "one alert tone + one sentence" the ear can separate. So you may hear CRC (tone) and "STALL" (voice) together, but never two different chimes at once. This is why, with multiple failures, the sounds come one after another rather than in a pile.

5. Cancellation logic — press the light / EMER CANC, and the ones that will not clear

The cancellation paths, summarised (echoing the ECP article):

• Press the MASTER light — extinguish + stop the corresponding level's aural (§1), except the non-cancellable audio of overspeed/stall etc.
• EMER CANC (on the ECP) — a level-2 caution: display, audio and light all cancelled (rest of flight); a level-3 warning: only audio and light, not the warning display itself.
• The condition clears — sound and light stop by themselves.

One discipline: EMER CANC on a red warning silences and un-lights but does not remove the red text — it is for suppressing spurious cautions, not for "out of sight, out of mind" (developed in the operation article).

Self-test

[!note]- Q1. What is the action difference of the two master lights, what does pressing one do, and which red warnings will not silence? MASTER WARN flashes red (L3), MASTER CAUT steady amber (L2). Pressing extinguishes the light and stops the corresponding aural — except non-cancellable audio (overspeed, gear-not-down).

[!note]- Q2. Name the three aural classes and the meaning of cavalry charge / triple click / cricket / buzzer / C chord. General attention (SC, CRC); specific instinctive (cavalry charge = AP off, triple click = landing-capability/mode change, cricket = stall, buzzer = call/SELCAL, C chord = altitude); synthetic voices.

[!note]- Q3. Can two different sounds coincide? Two voices? One sound and one voice? Why? No / no / yes. Sounds are told apart by timbre, voices by content — two of either overlaid become indistinguishable, but one of each is separable.

[!note]- Q4. What do PRIORITY LEFT/RIGHT and DUAL INPUT mean? A sidestick has been taken over (priority), and both sidesticks are being moved (dual input).

[!note]- Q5. What does EMER CANC cancel on a level-3 warning, and what does it not? It cancels the audio and the MASTER light, but not the red text on the screen.

Key takeaways

References

• FCOM DSC-31-10-A — audio indicator table (meaning, duration, cancellation).
• AMM 31-51-00 — the two master lights, aural classes, concurrency law, cancellation.
• AMM 31-53-00 — FWC AUDIO board, the full sound and synthetic-voice list, mutual exclusion, -6 dB.

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.