Beechcraft C-12C Operator And Technical Reference Manual page 315

display brightness to compensate for changes in the
ambient light level.
Pilot selection of #2 NAV to tune the TACAN will
remove the TACAN derived steering information from
the #1 HSI display.
steering information obtained from the #1 NAV/TAC
control to be displayed on the #1 HSI display. Pilot
selection of #1 NAV/TAC DME HOLD will also remove
the steering information from the #1 HSI display.
A DME HOLD push switch located on the pilot's
instrument panel is utilized to select DME-HOLD mode
of operation. A DME/TAC source selector switch,
located on the pilot's audio control panel, permits
selection of DME or TACAN mode of operation. With
the switch in the TACAN mode, bearing information is
derived from the TACAN signal of the TACAN station.
The KTU-709 system is now serving as a navigation
receiver as well as a DME.
information will be displayed on the pilot's HSI along
with a display of range/ groundspeed/time-to-station
data on the DME slave indicator.
CAUTION
Since the TACAN ground system does not
provide guidance
Landing System (ILS) approaches, any ILS
approach must be flown in the VOR/ILS
mode, using the TACAN for DME only.
b. DME Slave Indicator.
nautical miles, groundspeed, and time-to-station.
Refer to Figure 3B-15.
1. NM (Nautical Miles)
2. KT (Knot)
3. MIN (Minutes)
4. Photocell
Figure 3B-15. DME Slave Indicator
This action allows only the
Distance and bearing
during Instrument
Allows display of
(1) NM. Displays nautical miles to the
station.
(2) KT. Displays aircraft groundspeed.
(3) MIN. Displays time-to-station.
(4) Photocell.
brightness control of the display.
c. Operation.
CAUTION
Power to the KTU-709 TACAN system
should be turned on only after engine start-
up. This procedure will increase the
reliability of the solid state circuitry.
(1) Operating Procedure.
1. OFF/VOL control – Turn clockwise.
2. DME/TAC source selector switch – As
required.
3. Frequency selector – Select desired
frequency, and press the mode button
as required.
Prior to station lock-on, dashes will appear
in the window of the KDI-773 DME slave
control indicator, as the system searches
for the station.
about one second. Once the system has
locked on, the distance read-out will
appear, followed quickly by groundspeed
and time-to-station computations.
4. DME/TACAN audio switch – On.
Verify station.
5. VOL control – As required.
6. DME HOLD switch – As required.
(2) Shutdown Procedure. OFF/VOL switch –
OFF.
3B-24. GLOBAL
(KLN 90B).
For information on the Global Positioning
System, refer to Chapter 3, Paragraph 3-7.
TM 1-1510-218-10
Allows for automatic
NOTE
Search time is usually
POSITIONING SYSTEM
3B-25