AIRPLANE
OPERATIONS
MANUAL
FLIGHT
INSTRUMENTS
REVISION 38
2-17-30
Page
1
Code
01
AOM-145/1114
CHRONOMETER/CLOCK (TYPICAL)
The chronometer/clock provides the flight crew with Greenwich Mean
Time (GMT), local time (LOC), elapsed time (ET), chronological time
(CHR), DATE, and flight number. The instrument is powered by the
airplane’s electrical system and an internal battery. When the airplane
is deenergized, the displays are blanked, although the functions
continue to be updated in the memories with exception of the ET and
chronometer functions. Display may also blank when a failure exists in
the instrument.
CHRONOMETER/CLOCK CONTROLS AND INDICATORS
1 - CHRONOMETER BUTTON
− Successive pressings control start, stop, and reset of the
chronometer indicator and pointer providing the following:
− START: Replaces elapsed time by chronometer
indications, starting its counting.
− STOP: Freezes chronometer indicator and pointer.
− RESET: Returns the chronometer pointer to zero and
replaces chronometer indication by elapsed
time.
NOTE: A chronometer button is also provided on each control wheel.
2 - GMT, LOC, DATE, AND FLIGHT NUMBER INDICATOR
− Displays Greenwich Mean Time in the 24-hour format. A fixed
dot appears between the two-hour digits, above the GMT
inscription.
− Displays local time in the 24-hour format. A fixed dot appears
between the two minute digits, above the LOC inscription.
− Displays the date, alternating between month/day and year
every second.
− Displays the flight number from 0000 to 9999.
3 - CHRONOMETER POINTER
− Measures chronometer seconds over an analog scale.
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