AIRPLANE
OPERATIONS
MANUAL
NAVIGATION AND
COMMUNICATION
MARCH 30, 2001
2-18-22
Page
1
Code
01
THIRD VHF COMMUNICATIONS SYSTEM
The airplane may be equipped with a third VHF Communications
System. All functions of the Collins VHF-22A System are controlled by
the CTL-22 VHF Control Panel located at the main panel.
The Avionics Master DC Bus 1 supplies the third VHF
Communications System with a protective 5A circuit breaker.
THIRD VHF COM CONTROLS AND INDICATORS
1 - ACTIVE FREQUENCY DISPLAY
− Displays the active frequency (frequency to which the equipment
is tuned) and diagnostics messages.
2 - XFR/MEM SWITCH
− This is a 3-position, spring-loaded toggle switch.
− When held to the XFR position, the preset frequency is
transferred up to the active display and the equipment retunes.
The previously active frequency becomes the new preset
frequency and is displayed in the lower window.
− When held to the MEM position, one of the six stacked memory
frequencies is loaded into the preset display.
− Successive pushes cycle the six memory frequencies through
the display.
3 - FREQUENCY SELECT KNOBS
− Two concentric knobs control the preset or active frequency
displays.
− The large knob changes the digits to the left of the decimal point
in 1 MHz steps.
− The smaller knob changes the digits to the right of the decimal
point in 0.005 MHz steps.
− Numbers roll over at the upper and lower frequency limits.
To Next Page
