Chapter 5: Communications

Question 1

Describe the cockpit indications of an incoming cabin or ground call.

Answer 1

Blue CALL light (Located on forward overhead panel)

Illuminated – call to flight deck by attendant or ground crew. Accompanied by single high tonechime.

Question 2

Explain the meaning of an illuminated Offside Tuning Light on the Radio Tuning Panel.

Answer 2

Offside Tuning Light Illuminated (white)

• The radio normally associated with this panel is being tuned by another radio tuning panel, or
• The radio tuning panel is being used to tune a radio not normally associated with this radio tuning panel.

Question 3

Explain how to activate and deactivate the Oxygen Mask Microphone.

Answer 3

The oxygen mask microphone is enabled and the boom microphone is disabled when the right oxygen mask panel door is open.
The oxygen mask microphone is disabled and the boom microphone is enabled when the right oxygen mask panel door is closed and the TEST/RESET switch is pushed.

Question 4

Describe the Flight Interphone, Service (Attendant) Interphone, and Passenger Address Systems.

Answer 4

Flight Interphone System:

• The flight interphone system is an independent communication network. Its primary purpose is to provide private communication between flight deck crewmembers without intrusion from the service interphone system. The ground crew may also use the flight interphone through a jack at the external power receptacle.Service (Attendant) Interphone System:
• The service interphone system provides intercommunication between the flight deck, Flight Attendants, and ground personnel.Passenger Address System:
• The passenger address (PA) system allows flight deck crewmembers and flight attendants to make announcements to the passengers. The PA system use is prioritized. Flight deck announcements have first priority and override all others.

Question 5

Describe the Operation of the Audio Control Panel (ACP).

Answer 5

Transmitter Selector (MIC SELECTOR) Switch –
- Illuminated - related switch is active.
- Only one switch may be selected at a time; pushing a second
switch deselects first switch.
- Reception is possible over the selected system regardless of
whether the related receiver switch is on.
SELCAL Light – (a “C” in bottom of Transmitter selector)
- Illuminated – Accompanied by chime, alerts crew,
communication is desired on indicated communication radio.
- Will automatically reset when microphone is keyed, control
wheel MIC switch is pressed or R/T-I/C switch is positioned to
R/T.
Receiver Switches –
- Illuminated (white) – Related switch is active.
- Multiple switches may be selected.
Alternate-Normal (ALT-NORM) Switch –
- NORM (Normal) – ACP operates normally.
- ALT (Alternate) – ACP operates in degraded mode.

Question 6

Describe the Degraded Audio System operation.

Answer 6

Audio system operation can be switched to a degraded mode by placing the ALT/NORM switch to ALT. In this mode, the ACP at that station is inoperative and the crewmember can only communicate on one radio.
The radio available at each crewmember
station is:
Captain VHF-1
First Officer VHF-2
Observer VHF-1
Note: The mask and boom microphones can be used for transmission on the usable radio. The hand microphone is not usable in the degraded mode of operation. An audio system operating in the degraded mode cannot access the passenger address system through the audio control panel.

Question 7

Explain the function of the SERVICE INTERPHONE Switch.

Answer 7

OFF – external jacks are deactivated. Communication between the flight deck and flight attendants is still possible.
ON – adds external jacks to service interphone system.