Beechcraft C-12C Operator And Technical Reference Manual page 393

HEADING SWITCH
SELECTION
All on Compass 1
All on Compass 2
Normal
3C-21. NAVIGATION RECEIVERS (KNR-634A).
a. Description. Two VOR localizer / glideslope/
marker beacon navigation receivers (KNR634A
KNR-634 T2 ) and a TACAN/DME unit (KTU-709) are
controlled by two control units (KFS-579A and KFS-
564A) mounted in the instrument panel.
The NAV receivers receive and interpret VOR
range and LOC signals in the frequency range of
108.00 to 117.95 MHz, glideslope signals in the
frequency range of 329.15 to 335.00 MHz, and 75 Hz
marker beacon signals. In addition, the KFS-579A #1
NAV/TAC control tunes the KTU-709 TACAN/DME
system to all 252 TACAN channels.
receivers are powered through two 2-ampere circuit
breakers, placarded NAV #1 and #2, located on the
overhead circuit breaker panel, Figure 2-16.
b. NAV/TAC Control
Controls, Indicators, and Functions.
Figure 3C-17.
(1) Frequency Display. Liquid crystal digital
readouts provide a continuous display of both the
active frequency, or TACAN channel, and standby
frequency or TACAN channel (bottom line, placarded
SBY) when the system is in the frequency mode.
Display brightness is controlled by a switch, placarded
VHF / NAV / ADF, located right of the altitude alert on
the instrument panel.
(2) Frequency
frequency transfer switch is a momentary push-button
switch, placarded with a two-headed vertical arrow,
located to the right of the digital display.
Table 3C-11. Heading Reference Indicator Values
ACTIVE FREE / SLAVE
SWITCH
Pilot
Copilot
On-side
The NAV
Unit (KFS-579A)
Refer to
Transfer Switch.
FREE / SLAVE
SELECTION
Free
Slave
Free
Slave
Free
Slave
T1 ,
1. Frequency Display
2. Frequency Transfer Switch
3. Tuning Knobs
4. MODE Switch
5. OFF / VOL / PUSH TST Control
Figure 3C-17. NAV/TAC Control Unit (KFS-579A)
(a) Standby Entry Mode. Pressing the
frequency transfer switch with the unit in the standby
entry mode causes the frequency or TACAN channel
displayed in the active (upper) digital display to
The
interchange with the frequency or TACAN channel
shown in the lower (standby) digital display.
(b) Active Entry Mode. While the unit is
in the standby entry mode, pressing the transfer switch
for longer than 2 seconds will cause the unit to enter
the active entry mode. While in the active entry mode,
momentarily pressing the transfer switch will return the
unit to the standby entry mode.
TM 1-1510-218-10
HEADING REFERENCE
INDICATOR DISPLAYED
DG1 (amber)
MAG1 (amber)
DG2 (amber)
MAG2 (amber)
DG (white)
Blank
3C-39