Northern Airborne Technology AA95-766 - Manual (Page 34)

AA95-766 Single Channel Audio Controller Manual SM95-766 Rev. 2.00
3.4
Emergency Operation
When the red mode switch is set to the ISO/EMR position, the pilot is removed from the
ICS bus and connected directly to the selected radios. This mode should be selected in
the event of a box fault or power failure.
In the ISO/EMR mode, all functions are retained by the pilot, except ICS and possibly
boom mic operation. If the box or airframe fault prevents the TX annunciator from
lighting during transmit (indicating a failure in the mic keying circuit), then the hand mic
should be used. A power fault of any kind will prevent the TX annunciator from lighting,
giving an immediate indication of failure. If ICS audio is still available, then the power to
the controller has not failed, and loss of the TX light indicates TX switch failure.
In the ISO/EMR mode, all switches work exactly as they do during NORMAL operation,
except for the RX and ICS volume controls, which have no effect.
The ISO/EMR function should be tested prior to flight to ensure proper operation, and
allow the radio levels to be set adequately for emergency operation.
Any selected receive audio is switched to the primary user (pilot) in the ‘emergency’
mode, but not to any passengers in the system. Audio level will be lower than in
NORMAL operation because the signals are obtained directly from the radios, bypassing
the electronics in the controller. This is provided for failure situations that make operation
impossible in the NORMAL mode (i.e. loss of power or amplifier failure, etc.)
3.5 Direct Audio
Direct Audio is an audio signal from an existing warning system that is connected
‘directly’ into the audio system, and is not front-panel selectable. The Direct Audio
signal is an amplified input, and can be adjusted at the time of installation (see section
2.3.4.2).
End of Section 3
Page 3-4 Dec 6, 2004
ENG-FORM: 806-0106.DOT
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