TM 1-1520-238-T-6
9–8
9–1.
EQUIPMENT CHARACTERISTICS, CAPABILITIES, AND FEATURES
9–1
(15) Caution/Warning.
(a) The pilot and CPG caution/warning system accepts discrete fault signals and alerts the pilot and
CPG to hazardous conditions by lighting caution and/or warning indicators in the instrument panel. When a fault
signal is received, the caution or warning indicator is lighted and flashes at 2 Hz while the MASTER CAUTION
indicator on the master caution/warning panel simultaneously flashes at 5 Hz. Pressing the MASTER CAUTION
indicator acknowledges the fault and turns the MASTER CAUTION indicator off which causes the caution or
warning indicator to remain steady–on. When the fault condition is removed, the indicator turns off.
(b) The audio warning system provides audible hazard warning signals to the pilot and CPG headsets.
Audio warning signals are generated when the following conditions occur:
Engine out.
Rotor low.
Stabilator failure.
(16) Squat Switch System.
The squat switch, a magnetic proximity switch located in the left–hand
forward avionics bay (FAB), is mounted to the airframe and the target is mounted on the main landing gear (MLG).
When the helicopter is on the ground the switch acts as a safety device for some systems while enabling fault
detection capabilities for other systems.
9–2.
LOCATION AND DESCRIPTION OF MAJOR COMPONENTS
9–2
a. AC Electrical Power Generation System.
The ac electrical power generation system (fig. 9–1)
consists of two identical ac generators, two generator control units (GCUs), and two ac contactors.
(1) AC Generators 1 and 2.
Two ac generators, located in the main transmission bay, are mounted on
and driven by the accessory section of the main transmission. Each ac generator is capable of producing all ac
electrical power required by the aircraft. Two quick disconnect receptacles and four terminal studs are mounted on
each generator for power and control connections. Each ac generator is self–excited, brushless, air–cooled with
pre–lubricated bearings and is rated at 115/200 VAC, 400 Hz 35 KVA. Each ac generator weighs approximately
45 lbs.
b. GCUs 1 and 2.
Two GCUs, located in the electrical power distribution box, control and protect the ac
generators. Each GCU is a solid state LRU with a single quick disconnect receptacle which consists of five major
circuits, two printed wiring boards, three hermetically sealed relays, and a base assembly enclosed in a metal
case.
c. Generator Contactors K1 and K2.
Two generator contactors, located behind the pilot in the electrical
power distribution box, control connections between the ac generators and ac buses 1 and 2. Each generator
contactor is a solid state LRU with nine terminal studs and one quick disconnect receptacle on the front face for
power and control connections.
