OPERATIONS MANUAL

Communications
Cockpit Voice Recorder:
Monitor
Indicates test
values.
Test switch
Push (momentary action)
Test is in progress
as long as switch is
pressed.
Test procedure
The following four recorder channels are tested:
area microphone, captain’s audio, first officer’s
audio, observer’s audio. A 600 Hz test tone
passes through the first channel for 1 second,
then through the next for 1 second, and so on.
After the last channel test, it restarts with the
first channel. During a successful test, the needle
on the monitor stays within the green band. A
deviation into the red band indicates a failed
channel. The test starts after a delay of 3 seconds,
during which the needle indicates zero.
(In the simulator, the voice recorder does not
actually record; and the test and erase functions
are a simulation only.)
Erase switch
Push (momentary action)
Erases voice recordings
when switch is pressed
for at least 2 seconds, and
aircraft is on ground, and
system is powered, and
parking brake is set.
Headset jack
May be used to plug in a headset
to monitor audio or the test tone
(in the simulator not applicable).
Area microphone
Picks up ambient sounds on the
flight deck such as conversations
and aural alerts. These sounds
are routed to one of the voice
recorder channels.
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