Figure 3-27. TACAN/DME Display Unit
tor switch is set to BOTH the PAGE pushbutton selector
switch will alternate the left and right lower displays
between bearing to station and station identifier.
(3) Mode selector switch.
(a) OFF. Turns system off/on.
(b) NAV 1. Selects information for display
from the TACAN/DME unit as selected by the # 1 VHF
navigation receiver or TACAN control unit, depending
upon whether either pilot has selected TACAN on EFIS
(c) NAV 2. Selects information for display
from the TACAN/DME unit as selected by the #2 VHF
(d) BOTH. Selects information for display
from the TACAN/DME unit as selected by both the # 1
and #2 VHF navigation receivers.
(1) Turn-on procedure.
BATTERY switch - ON.
AVIONICS MASTER POWER switch -
(display control panel, fig. 3-8) - Select TCN.
Mode selector switch (TACAN indicator,
fig. 3-27) - Select operating mode.
VOL control (TACAN control unit, fig. 3-
26) - Rotate clockwise from detent to
The TACAN/DME indicator will run a display segment
text and then scroll from right to left and display IND in
the upper left comer of the display and the software
version number in the upper right corner of the display for
approximately 3 seconds. TCN will be displayed in the
lower left corner and the software version will be
displayed on the lower right corner of the display for
approximately 3 seconds. After the three seconds SELF
TEST PASS or SELF TEST FAIL (with a fail message
number) will be displayed.
The fail message number indicates the circuit
which has failed. Always note the fail message
number prior to system shutdown
(2) TACAN air-to-ground navigation procedure.
After turn-on procedure proceed as follows:
X-Y mode selector switch (TACAN control
unit, fig. 3-26) - As required.