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KMA 29 Audio Panel Pilot’s Guide
Audio Panel Operation
AUDIO PANEL OPERATION
The audio panel receives audio from remote radio units, decodes the
audio, controls the gain (volume) and routing of the various channels,
filters audio signals, and output the audio to various speakers and head-
phones. It controls microphone inputs to various radios, intercom and
passenger address systems. Amplifiers are included for driving head-
phones and speakers.
The audio panel also has inputs for intercom, crew annunciator, crew
communication, hot microphones and full time emergency warning
inputs from aircraft systems.
COM MICROPHONE OPERATION
When a microphone selector button is selected and PTT switch is
enabled, the pilot’s or copilot’s microphone signal is routed to that
radio’s microphone input. Pressing the MIC selector button to enable a
particular COM also causes the audio for that particular COM to be
Above each microphone input selector button are left and right arrow
LEDs that show the status of the respective COM transceiver. The left
arrow is lit when that particular COM transceiver is assigned to the pilot.
The right arrow is lit when that particular COM transceiver is assigned to
the copilot. Only one COM microphone output can be active for the pilot
or copilot at a time with two exceptions. The two exceptions are Split
Mode and Telephone Mode (or Duplex Mode) operation. Refer to Split
Mode Operation and Telephone Mode Operation in this Pilot’s Guide for
When switching between COMs, such as from COM 1 to COM 2 (while
COM 2 AUDIO has been selected), COM 1 audio will continue to be
heard. This eliminates the need for the pilot to switch the COM 1 audio
back on, if desired.
When switching from COM 1 to COM 2 (while COM 2 AUDIO has not
been selected), COM 1 audio is switched off. This means that switching
the COMs does not affect the selection of the COM receiver audio.
The audio panel gives priority to the pilot’s PTT switch. If the copilot is
transmitting and the pilot presses the PTT switch, the pilot’s microphone
is heard over the selected COM transmitter.