4.1 Communication Systems: Call, Interphone & Passenger Address

Three systems, three purposes

Candidates lose marks by treating cabin communication as a single system. It is three.

They are physically and logically separate, which is why a defective PA does not necessarily prevent an interphone call, and vice versa.

The call system and its indications

The call system communicates by chime and lamp. The pattern differs by source, and knowing the pattern is what allows a crew member to respond correctly without walking the cabin:

• Passenger call — single chime with a lamp illuminated over the row or in the master call light panel at the station.
• Lavatory call — chime with a distinct lavatory indication; increasingly important since a lavatory call may be the first sign of a smoke event or a passenger collapse.
• Crew-to-crew call — a chime and an indication showing the calling station.
• Flight deck to cabin — a distinct chime and indication so that cabin crew know the flight deck is calling, which is answered immediately.
• Emergency call — a repeated, distinctive alert with a red or flashing indication. It is answered without delay at the nearest station.

Reset discipline matters. A call lamp left illuminated masks the next call from that area, and a lavatory call that is reset without anyone checking the lavatory defeats the purpose of the system.

PA priority

Passenger address systems are priority-ordered. The usual order, from highest to lowest, is:

1. Flight deck announcements;
2. Cabin crew handsets;
3. Pre-recorded announcements (safety demonstration, service announcements);
4. Boarding music and entertainment audio.

Practically, this means a flight deck announcement will cut across a crew member mid-sentence, and a crew announcement will cut across the pre-recorded safety demonstration. In an emergency it also means the flight deck can command the cabin directly and instantly.

Where a PA is used for an emergency command — the evacuation order, the brace call, the instruction to sit down in turbulence — it must be loud, short, repeated and in plain language. Long sentences are lost.

Talking to the flight deck properly

An unstructured call wastes the flight crew's attention at the exact moment they have least to spare. Use a fixed structure:

Then stop talking and listen. The most common failure in real events is a crew member who reports continuously and never allows the flight deck to acknowledge or instruct.

For a planned emergency, the traffic runs the other way and uses the standard framework covered in the emergency procedures chapter, in which the pilot-in-command briefs the senior cabin crew member on the nature of the emergency, intentions, time available and any special instructions.

Sterile flight deck

During critical phases of flight — normally taxi, take-off, climb below a defined level, descent below that level, approach and landing — the flight deck is sterile. Cabin crew do not call the flight deck except for matters affecting the safety of the flight. What qualifies is straightforward: fire or smoke, a suspected security threat, a serious medical emergency, structural damage or anything the crew member believes affects the safe conduct of the flight. What does not qualify is a service question, a catering shortfall or a passenger complaint.

Never let the sterile rule stop a safety call. If it is safety, call.

When the system fails

Nig. CARs Part 9 requires that each AOC holder have an approved means by which the cabin crew can notify the flight crew. If the primary interphone fails, the operator's procedures will prescribe an alternative, which typically includes:

• Using another station's handset, since failures are frequently local to one handset;
• The PA as an attention-getter, using an agreed form of words;
• Pre-briefed knock codes on the flight deck door;
• Hand signals through the door viewer or observation panel where fitted;
• Sending a crew member forward, subject to flight deck security procedures.

Whatever the method, it must be the one in the operator's manual and briefed before departure, not improvised in the event. Communication failures are always reported to the flight deck at the first opportunity and entered in the technical log, because an aircraft with no means of cabin-to-flight-deck notification may not be dispatchable under the MEL.