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. This action allows only the
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. Distance and bearing
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.
Since the TACAN ground system does not
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. Allows display of
nautical miles, groundspeed, and time-to-station.
Refer to Figure 3B-15.
1. NM (Nautical Miles)
2. KT (Knot)
3. MIN (Minutes)
Figure 3B-15. DME Slave Indicator
(1) NM . Displays nautical miles to the
(2) KT. Displays aircraft groundspeed.
(3) MIN. Displays time-to-station.
brightness control of the display.
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
3. Frequency selector Select desired
frequency, and press the mode button
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. Search time is usually
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.
5. VOL control As required.
6. DME HOLD switch As required.
(2) Shutdown Procedure. OFF/VOL switch
For information on the Global Positioning
System, refer to Chapter 3, Paragraph 3-7.