INDEPENDENT INSTRUMENTSThe followin

INDEPENDENT INSTRUMENTS
The following independent instruments are installed in the AW139 cockpit:
• Two Chronometers (Clocks) and one Magnetic Compass
CHRONOMETER (CLOCK)
Two independent digital chronometers are installed on the instrument panel,
one in front of each pilot.
The chronometer provides the following functions:
• Local Time (LT) clock, in 12-hour format
• Universal Time Coordinate (UTC) clock, in 24-hour format
• Flight Time (FLIGHT) counter, up to 99 hours, 59 minutes and 59
seconds
• Stop Watch (SW) counter, 99 hours, 59 minutes and 59 seconds
• Down Counter (DC), which counts down from a maximum of 99 hours,
59 minutes and 59 seconds
The chronometer is provided with three pushbutton switches and a liquid
crystal display (LCD) with six numerals and annunciators to indicate the
display mode.
The operating power for the pilot chronometer is fed from the ESS 2 bus via
the CLOCK PLT circuit breaker.
The operating power for the copilot chronometer is fed from the MAIN 1 bus
via the CLOCK CPLT circuit breaker.
An internally mounted AAA-size alkaline battery in each chronometer keeps
the watch alive when the aircraft power is removed.
OPERATION
The clock is kept up-to-date also when the helicopter is not powered by the
internal alkaline battery, but the display only operates when power is
supplied by the relevant bus bar.
When activated, counters (FLIGHT, SW, DC) keep counting even if a
different display mode is selected.
The Flight Time counter (FLIGHT) is controlled by the WOW microswitch: it
automatically starts counting up at lift off and stops counting at touchdown.
Flight Time is continuously summed up until it is manually reset by holding
the ST/SP button while in FLIGHT mode.
CHRONOMETER – CONTROLS AND INDICATORS
1 RST or SET pushbutton
• Pressed in LT mode ........... Enters Local Time clock setting
mode
• Pressed in UTC mode ........ Enters Universal Time
Coordinate clock setting mode
• Pressed in FLIGHT mode .. No effect
• Pressed in SW mode ......... Resets the stopwatch
• Pressed in DC mode .......... 1st press: Resets the Down
Counter
2nd press: Enters Down
Counter setting mode
2 MODE pushbutton
• Pressed .............. Selects the display mode toggling
between LT, UTC, FLIGHT, SW, DC
3 ST/SP or ADV pushbutton
• Pressed in LT or UTC clock
setting mode ...........................
Advances the hour or the
minute or resets the seconds
• Pressed in FLIGHT mode ....... Resets the Flight Time
counter
• Pressed in SW or DC mode .... Starts or stops the counter
4 LCD display
5 Annunciators
• Displayed one at a time, show the current mode of the
chronometer