NORMAL PROCEDURES
VOLUME ADJUSTMENT
The volume control knob controls the volume or the threshold of the radio /
system / function displayed in the Audio Panel display.
The default selection for the display is HDPH (Headphone): rotating the VOL
control knob adjusts the volume of all audio signals simultaneously.
The display shows the label of the individual radio / system / function when it
is activated by pressing the corresponding round pushbutton on the Audio
Panel (pushbutton illuminates).
If the radio / system / function is already active and volume needs
readjustment, double click the corresponding round button to deselect and
reselect it.
When the VOL control knob remains untouched for more than 15 seconds,
the display automatically reverts to HDPH.
SELECTION OF COCKPIT / CABIN INTERCOMMUNICATION
Pushing the PILOT button on the cabin audio panel flashes the CAB button
annunciator light.
The CAB button on the pilot-side audio panel flashes and generates a single
tone that is sent through the PA system and to the cabin audio controller.
The acknowledgement of the cabin call by the cabin audio controller is
indicated as a fast flash on the CAB button. When the CAB button is flashing
fast, it establishes an audio connection between the cockpit ICS channel and
cabin audio controller. This is indicated by a steady lighting of the CAB
annunciator. The annunciator on the CAB button slowly flashes and a single
audio tone sounds in the pilots’ headset when a request for cabin ICS is
initiated by the cabin audio system.
When the pilot pushes the CAB button after a call from the cabin, it
establishes an audio connection between the cockpit and cabin. This is
indicated by a steady CAB light.
FAILURE INDICATIONS
Any of the components of the radio system that are not supplying valid data
to the MCDU or PFD are shown in amber and frequencies are replaced with
amber dashes.
NIM FAILURE
Failure of a NIM does not trigger any message in the CAS window. It can
only be recognized by the simultaneous loss of all the associated radios
indicated by amber labels and amber dashes replacing frequencies.
In this event, the on-side pilot only can control the radios in the affected
MRC by selecting the MCDU to BACKUP RADIO page.
The affected VHF COM radio can be used for transmission by the on-side
pilot only if the Audio Panel is set to BKUP.