GNC 420(A) Pilot’s Guide and Reference
1-9
SECTION 1
INTRODUCTION
190-00140-20 Rev. K
Selecting COM Frequencies
While the GNC 420 is acquiring a position, take a
minute to dial in the active and standby frequencies to
be used for the rst phase of the ight. The GNC 420’s
display (Figure 1-12) is divided into separate windows
(or screen areas), including a COM Window, data eld
(distance), and the GPS Window (the right side of the
display).
Figure 1-12 Standby Frequency 135.325 MHz
COM Window
GPS Window
Active Frequency
Standby Frequency
Data Field
Changing the standby communication
frequency:
Turn the large left knob to select the MHz,
and the small left knob to select the kHz of
the desired frequency.
Placing the standby communication
frequency in the active field:
Press the COM Flip-flop Key (Figure 1-13).
Figure 1-13 Active Frequency 135.325 MHz
After entering the active frequency, follow the preceding
steps to enter the standby frequency.
