High-Temperature Sensor
Airflow Valve
The coolant high-temperature sensor (fig. 5-20,
The airflow valve (fig. 5-20, item A) is
item C), located in the coolant line, provides a ground
pneumatically modulated to limit, as necessary,
to the maintenance status display and recording system
conditioned air to the radar liquid cooling liquid-to-air
until coolant temperature rises above preset limits. The
heat exchanger. The ACS temperature/flow controller
loss of ground causes a weapon system fail code in the
supplies electrical power to the airflow valve torque
DDI.
motor, which opens or closes muscle pressure to the
airflow valve. The airflow valve is spring-loaded
Coolant Temperature Sensor
closed, and a built-in test is monitored by the ACS
temperature/flow controller. If the airflow valve fails,
The coolant temperature sensor (fig. 5-21, item B),
the ACS temperature/flow controller produces a signal
located in the coolant line, provides coolant tempera-
to produce a faulty maintenance code in the DDI.
ture reading to the ACS temperature/flow controller,
allowing the controller to modulate the airflow valve.
Ground Cooling Fan
Q5-27.
Describe the purpose of the F-18 aircraft
The ground cooling fan (fig. 5-19, item C) is
radar liquid cooling system.
electrically powered and supplies a flow of ambient air
Q5-28.
During ground operation, what component
for heat transfer from the liquid cooling heat exchanger
supplies cooling air for the heat exchanger?
during aircraft ground operations.
Q5-29.
Name the eight major components of the
Coolant System Filter
radar liquid cooling system.
Q5-30.
Describe the operation of the ground cooling
Coolant is filtered before passing through the radar
fan.
transmitter. When the replaceable filter element (fig.
5-21, item A) is contaminated, resulting differential
pressure will extend a manually reset indicator on the
FIRE-EXTINGUISHING SYSTEM
filter assembly, providing a visual contamination
LEARNING OBJECTIVES: Describe a
indication.
fire-extinguishing system and its components.
Identify an auxiliary power unit fire detection
Low-Pressure Sensor
and extinguishing system.
The low-pressure sensor (fig. 5-20, item B), located
in the coolant line, provides a ground to the
maintenance status display and recording system until
the coolant pressure falls below presets limits. The loss
of ground causes a weapon system fail code in the DDI.
Figure 5-20.--Radar liquid cooling system component locator.
Figure 5-21.--Radar liquid cooling system component locator.
5-18
