Chapter 15

Communications

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SYSTEM DESCRIPTION

GENERAL

The aircraft communications system includes two VHF radios, flight interphone, and passenger address.

 

AUDIO SELECTORS

 

Audio selector control panels are at each pilots station. The audio select switches can monitor as many communication and navigation radios as desired. To transmit on any audio receiver panel, select the desired microphone select switches at the top of the panel.

 

AUDIO SELECT SWITCHES

 

On GLASS & COMBO panels the audio select switches are round knobs. Push the switch to select a radio and turn the switch to adjust the volume (volume not simulated). On the STEAM panel the select switches are toggle switches. Any number of radios can be monitored simultaneously.

 

AUDIO SELECTOR PANEL FAILURES

 

On GLASS & COMBO aircraft if the radio panel internal amplifier fails, an alternate amplifier may be selected with the NORM/ALT switch. 

 

 

VHF COMMUNICATIONS SYSTEM

 

There are two VFH communications radio systems. Frequencies are selected at the VHF COMM control heads on the radio pedestal. Each control head has two frequency selectors and a transfer switch to select the active frequency. 

 

VHF-900 SERIES TRANSCEIVER

 

These radio control panels operate the same as the standard radios except the digital readout has been replaced with a gray LED display. These radios are only on the GLASS panel. 

 

 

FLIGHT INTERPHONE

 

The flight interphone system allows communication between cockpit and the cabin. 

 

 

CALL SYSTEM

 

The call system consists of call lights, aural signals, and call switches. A pushbutton on the overhead panel will send a aural tone through the cabin. 

 

 

PASSENGER ADDRESS

 

Pressing the PA switchlight on the overhead panel activates the PA system and allows the cockpit crew to make an announcement in the cabin. Pressing the switch again turns the system off.

 

 

Communications

 

CONTROLS AND INDICATORS

 

 

LOCATION: Audio Panel

 

MICROPHONE SELECT SWITCHES

 

Connects microphone to selected radio. Switches are lighted when on. Only one mic can be selected at one time.

 

AUDIO SELECT SWITCHES

 

Click to turn on and off. GLASS switches are lighted when ON.

 

NORM/ALT AMPLIFIER SWITCH

 

Selects either the normal or alternate amplifier to the radio system.

 

 

 

LOCATION: Radio Pedestal Panel

 

FREQUENCY LIGHTS

 

Indicates operating frequency selected.

 

FREQUENCY SELECTORS

 

Changes the standby frequency.

 

FREQUENCY SELECTOR TRANSFER SWITCH

 

Selects operating frequency.

 

COMMUNICATION TEST SWITCH

 

Deactivates automatic squelch.

 

 

 

LOCATION: Overhead Panel

 

PA SWITCH

 

Pressing the PA switchlight on the overhead panel activates the PA system and allows the cockpit crew to make an announcement in the cabin. Pressing the switch again turns the system off.

 

PILOT ATTENDANT CALL

 

Push to call cabin attendants. Actuates chime in the cabin.

 

ATTND CALLING SWITCH/LIGHT

 

Light tests only.