TM 55-1510-215-10
then automatically return to the clock display mode.
NOTE
During the display of the date, the clock annunciator will
be blanked from the display. If, when in the clock mode,
The flight time up to approach may
the DT/AV button is pressed continuously for two
be recorded just before the time is
seconds, the display will return from the date to the time
set to zero for the approach. Total
function. In this time mode the colon activity is altered
flight time, less approach time, will
and may read continuously or be blanked from the
then be available.
display. To return to the normal time mode with its colon
activity indication, press the DT/AV button again for two
(5) Timer operation.
seconds and the correct time mode will be restored. The
calendar function will automatically advance the date
1. Press the MODE button to position
correctly according to the four year perpetual calendar.
the annunciator above the word
One day must be added manually on February 29 of
TIMER.
every leap year.
The date advances correctly at
midnight each day. In the 12 hour time mode, AM or PM
2. Press the RST button so that the
indication is not provided. It is possible, in rare cases
time will read zero.
such as initial setup after a battery change, for the date
to change at 12 noon instead of 12 midnight. If this is
3. To start the timer counting, press
observed just add 12 hours to the time displayed using
the ST/SP button one time. The
the set methods previously described. A simple test can
timer will initially count in minutes
be made to determine that the clock is reading AM or
and seconds and the colon will blink
PM correctly. Set in 11:59 on the clock and note the
off for one-tenth second each
date. Activate the clock and wait one minute. If the date
second. After 59 minutes and 59
remains the same after the clock times to 12:00, the
seconds, the timer will change to
clock is reading noon and can now be set to the correct
count in hours and minutes up to a
AM or PM time.
maximum of 23 hours and 59
minutes.
During the hours and
(4) Timer. The timer may be used effectively
minutes count, the colon will
as a cumulative trip timer for single or multileg flights.
indicate counting activity by blinking
The timer is started from zero at the beginning of a flight.
off one second each ten seconds.
The time into the flight is continuously available by
The timer count may be stopped
selecting the timer mode. Returning to the clock mode
and held at a particular time by
will not disturb the operation of the timer. At the end of
pressing the ST/SP button. To add
the first flight leg, the ST/SP button is pressed while in
to the existing count, press the
the timer mode to hold the total flight time accumulated
ST/SP button again and the timer
so far. This will be retained in memory and will be
will continue counting up from the
available for view any time the timer mode is selected
previous total. To start a new count,
even when on the ground and shut down. At the
press the RST button and zero the
beginning of the next flight leg the previously
display. Press the ST/SP button to
accumulated flight time may be zeroed or maintained.
start a new count.
Pressing the ST/SP button will again start the counter,
either adding to the previous flight time or from zero, as
(6) Display test. Pressing both the SET and
desired. If the flight timer feature is not used, the timer
DT/AV buttons at the same time will result in a display
may be used for any short term timing function such as
test function.
All display segments, colon, and
ground and speed checks, timed turns or timed
annunciators will be activated. If the display test is done
approaches. For ground speed checks, the timer is
from the clock mode it will return to the time set mode. If
started at the beginning check point and then stopped at
the display test is done from timer mode, the display will
the final check point. The elapsed time is now held on
return to the timer mode in the set condition.
the display for ground speed calculation. For timed
approaches, the timer is previously set to zero. At the
c. Other Instruments.
final approach fix, the ST/SP button is activated and the
time shown on the display will be elapsed time into the
The instrument pressure gage is located on the
approach.
instrument panel (fig. 2-22).
2-70B Change 10
