TM 55-1520-240-23-7
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MISCELLANEOUS EQUIPMENT
(Continued)
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MASTER CAUTION PANEL
The master caution system provides an indication when
a sensor in any of 37 circuits (helicopters without 74 ),
or 41 circuits (helicopters with 74 ) detects the operating
condition or the abnormal condition which is being
monitored. The sensor circuit lights the associated
capsule in the master caution panel on the center
instrument panel. When any capsule on the caution
panel comes on, two MASTER CAUTION lights also
come on. The MASTER CAUTION lights are on the
pilot’s and copilot’s instrument panels. These lights
have an integral switch that turns off both CAUTION
lights when pressed but does not turn off the lighted
capsule. The capsule remains on as long as the fault
or the condition in the monitored circuit is present. All
lamps in the system can be operated at full brightness
(bright) or at a reduced brightness (dim). The system
also has a test circuit that lights all lamps in the system.
On helicopters with 17 and without 74 , an NVG filter
is stored on guides behind the instrument panel. When
required, the filter is pulled out and down to cover the
master caution panel. On helicopters with 74 , the NVG
filters are incorporated in the master caution panel light
capsules.
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