Cockpit Security — Door Surveillance and Alerting

After 9/11 cockpit security became part of the communications chapter — the AMM names it the Anti-Hijack System. It gives the crew two capabilities:

to see: the CDSS (Cockpit Door Surveillance System) — see who is at the door before opening it;
to alert: two-way cockpit alerting — the cabin can discreetly tell the cockpit of a threat (e.g. an intrusion attempt), and the cockpit can tell the cabin.

A boundary to draw: this chapter covers "seeing" (the cameras) and "alerting", not "locking" (the cockpit door lock itself) — the lock and entry-request keypad belong to ATA-52.

1. Architecture

CDSS door surveillance (anti-hijack, "see"):
   camera 1 (above door, views the door front)──┐
   camera 2 (ceiling, right door-1 area)─────────┼─▶ system controller (avionics bay)─▶ pedestal system display
   camera 3 (ceiling, left door-1 area)──────────┘    (115 V AC via CKPT DOOR VIDEO pb)
   controls: CKPT DOOR VIDEO pb (overhead, on/off) · CAM SEL (camera 1 vs 2+3) · CKPT ENTRY rotary

Cockpit alerting (two-way, "alert"):
   cabin → cockpit:  attendant-area pb held ≥1 s ──▶ continuous cockpit buzzer + CAB ALERT red
   cockpit → cabin:  two cockpit pushbuttons ──via CIDS──▶ buzzer + alert lights at each attendant station

2. CDSS door surveillance — see who is there before opening

The CDSS's purpose in one line. Per AMM 23-72-00:

The CDSS uses cameras and a system controller to monitor the cockpit entrance and the left and right door 1 areas. The CDSS images are shown on the system display in the cockpit. This lets the flight crew identify persons before they get access to the cockpit.

The three cameras (AMM §3): camera 1 above the door views the door front, shown full-screen; cameras 2/3 in the ceilings of the right and left door-1 areas, shown split-screen. In the configuration covered here the image appears on the centre-pedestal system display (via 31-67, ATA-31), not a dedicated LCD.

The controls: the CKPT DOOR VIDEO pb (overhead) turns the whole CDSS on/off (white OFF legend lit when off) and also gates the 115 V AC to the system controller, which then supplies the cameras; the CAM SEL pb switches between camera 1 and cameras 2+3; and the CKPT ENTRY rotary. Per AMM 23-72-00:

When set to the CKPT ENTRY position it gives a signal to the data management computers and to the system controller. If the white OFF legend in the CKPT DOOR VIDEO pushbutton switch (17RA) is off (the CDSS is on), the images from camera 1 are shown on the system display.

[!note]- CDSS in one line: the cockpit door's video peephole Someone requests cockpit entry (rings the entry-request keypad, ATA-52) → the crew use the CDSS to see who is at the door (camera 1's door-front image) → they open only when satisfied there is no threat. The CKPT ENTRY rotary ties the "view the image" step into the entry-request flow. The CDSS only sees; the actual unlock/door logic is ATA-52.

3. Cabin-to-cockpit alert — reporting a threat discreetly

If a threat appears in the cabin (e.g. an attempted intrusion), the cabin crew need a way to alert without alarming the aggressor. Per FCOM DSC-23-40-20:

This function enables the cabin crew to rapidly and discretely alert pilots of any threat in the cabin, such as cockpit intrusion. The cabin crew activates the alert by pressing one of the pushbuttons located in each attendant's area for a minimum of one second. When the alert has been activated by the cabin crew, the buzzer sounds continuously in the cockpit, and the cockpit's center pedestal CAB ALERT pushbutton comes on.

The cockpit response and its cancel. Per FCOM DSC-23-40-20:

(1) CAB ALERT pushbutton — ALERT light : This light comes on red, and a buzzer sounds in the cockpit, when an alert has been initiated from the cabin. Off : When the cockpit crew pushes the ALERT pushbutton, the buzzer stops and the red ALERT light goes off.

[!warning]- Why "discretely" is the key word The key word is discrete: the cabin presses an unobtrusive button (no shout, no obvious action), and the cockpit gets a continuous buzzer and red light — the aggressor does not know an alert has been raised. Unlike a routine cabin call (article 7's ATT one/three), which is "answer the interphone", this is "security alert, do not signal it". It requires a press held ≥1 s to guard against inadvertent activation.

4. Cockpit-to-cabin alert

The reverse path lets the cockpit tell the cabin of a threat. Per FCOM DSC-23-40-20:

This function enables the flight crew to inform the cabin crew, via the CIDS network, of any threat in the cockpit. The flight crew activates this alert by pressing one of the two pushbuttons installed in the cockpit. [...] The alert buzzer sounds in the cabin, and the alert lights come on, in each cabin crew station.

It travels over the CIDS network of article 7 — which is why cabin communication (CIDS) and security alerting share the communications chapter: the alert reuses the CIDS cabin data buses.

Self-test

[!note]- Q1. What do the three CDSS cameras view, which is full-screen versus split, and where is the image shown here? Camera 1 (above the door) views the door front, full-screen; cameras 2/3 (right/left door-1 ceilings) split-screen. In this configuration the image is on the centre-pedestal system display.

[!note]- Q2. What do the CKPT DOOR VIDEO pb, CAM SEL and CKPT ENTRY rotary each do? CKPT DOOR VIDEO turns the CDSS on/off (and gates camera power); CAM SEL switches between camera 1 and cameras 2+3; CKPT ENTRY signals the data-management computers/system controller and, with the CDSS on, shows camera 1.

[!note]- Q3. How does the cabin discreetly alert the cockpit, why the ≥1 s hold and the emphasis on discretion, and how is it cleared? Press an attendant-area button ≥1 s → continuous cockpit buzzer + red CAB ALERT; the aggressor is not signalled. The hold guards against inadvertent activation; cleared by pressing the ALERT pushbutton.

[!note]- Q4. Over what network does the cockpit-to-cabin alert travel, and why does that put it in this chapter? Over the CIDS network; the alert reuses the cabin data buses, so it sits in the communications chapter.

Key takeaways

Point	Detail
Security = see + alert	CDSS cameras (see) + two-way alerting (alert); the lock is ATA-52
CDSS	3 cameras (1 front full-screen, 2/3 split); pedestal system display; CKPT DOOR VIDEO / CAM SEL / CKPT ENTRY
Cabin→cockpit	Discreet press ≥1 s → continuous buzzer + red CAB ALERT; aggressor not signalled
Cockpit→cabin	Two pushbuttons → buzzer + lights at each attendant station, over the CIDS

References

FCOM DSC-23-40-20 — cabin-to-cockpit discreet alert (≥1 s, continuous buzzer, CAB ALERT red); cockpit-to-cabin alert (via CIDS).
AMM 23-72-00 — CDSS anti-hijack; three cameras; system display; CKPT DOOR VIDEO / CAM SEL / CKPT ENTRY.

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.