To return INS to normal display modes,
momentarily set data selector to LUL
Designating fl-to destinations on TACAN.
Press waypoint change.
Insert new TO-FROM waypoints.
available from INS for display on
pilot's RMI and on pilot's and
copilot's HSI's as determined by
COURSE INDICATOR switches.
After NA V READY annunciator illuminates, place
mode selector to NA V.
Do not pull up on mode selector when
switching to NAV. Pulling causes
overshooting into the ATT position
which invalidates the alignment and
alignment must be restarted.
To fly selected course:
Pilot's COURSE INDICATOR switch INS.
Pilot's RMI select switch INS.
Horizontal situation indicators (pilot's and/or
copilot's HSI) Steer toward indicators.
CDU ALERT annunciator Monitor. Observe
illumination approximately 1.3 minutes before
reaching point for automatic leg switch.
Indicator flashes on and off after passing a
waypoint, if AUTO-MAN switch is in MAN.
Aided TACAN operation:
Mode selector NAV.
Data selector DSRTK/STS.
Key "4" Press. Observe right data display is
"000004" INSERT/ADVANCE pushbutton
annunciator is illuminated.
Observe right data display
is "1-XX4" and INSERT/ ADVANCE
pushbutton annunciator is extinguished.
Every 30 seconds, the INS will select
sequence for updating. To be eligible,
between 5 and 150 nm and channel
between I and 126.
(e) Data selector UL WY PT or UTM WY PT.
Keys "7" and "9" Press simultaneously.
Observe channel number of the TACAN
station being used for navigation flashes on
and off. Data displays indicate coordinates of
station selected via thumbwheel.
To monitor station selection Observe TO-
FROM data display. Observe only the
number of stations eligible for mixing will be
displayed. A "O" indicates that none of the 9
stations are eligible for selection.
Monitor INS UPDATE annunciator.
Mixing will not be annunciated if: (a)
TACAN control is inappropriately
set; (b) TACAN station data loaded in
error; (c) aircraft look-down angle is
ground distance is less than two times
the altitude. When 2 minutes elapse
without an update, the NO INS
UPDATE annunciator will illuminate.
To return INS display to normal Set data
selector to any position except WYPT or
(j) To monitor program of mix Set data selector
to DSRTK/STS. (Observe Accuracy Index
(AI) will decrement to "0".)
To insure favorable geometry during
the update process, the following
TACAN station criteria should be
Change 5 3-61