it to the masker emitter rings outside the ship's hull or
preventive maintenance reduces the chance of failure of
to the gas turbine start/motor air system. The masker air
both the fuel heater and the controller. You must connect
any malfunctions to the heater controller immediately
system consists of cutout valves, coolers, falters, transfer
valves, regulating valves, piping, and emitter rings.
to maintain the desired fuel quality to the GTEs. Make
sure you follow the proper electrical safety precautions
GAS TURBINE START/MOTOR AIR
w h e n performing maintenance on the fuel heater
SYSTEM
controller.
TROUBLESHOOTING.-- If you are called upon
The gas turbine start/motor air system receives both
to troubleshoot the heater controller, make sure you
hot bleed air from the collection and distribution system
follow the procedures listed in the technical manual. You
and cool bleed air from the masker air system. This
must have a thorough knowledge of solid-state devices
system distributes bleed air to both the propulsion and
to troubleshoot this unit effectively. Faults in the heater
the electrical GTEs for starting and motoring. The
c o n t r o l l e r can be caused by short circuits, open
components of this system consist of cutout valves,
c o m p o n e n t s , or grounds. Since the controller is
m i x i n g valves, filters, regulating valves, and
c o m p l e t e l y solid-state, there is a chance that the
distribution piping.
components can fail from excessive heat. The heater
controller is equipped with heat sinks to help reduce the
PRAIRIE AIR SYSTEM
heat buildup inside the controller. Your job as a GSE will
be to locate and repair all faults that occur to the fuel
The prairie air system receives hot bleed air from
heater controller.
the collection and distribution system. It then cools the
bleed air and distributes it through the propeller shaft to
t h e leading edges of the propeller blades. The
BLEED AIR SYSTEM
components of the prairie air system include coolers,
There are five systems (four on the FFG-7 class
cutout valves, and distribution piping.
ships) that make up the ship's bleed air system. These
systems include the following:
GAS TURBINE ANTI-ICING SYSTEM
Bleed air collection and distribution system
The gas turbine anti-icing system receives hot bleed
Masker air system
air from the collection and distribution system. The
system then distributes bleed air to the propulsion and
Gas turbine start/motor air system (not on the
electrical GTE intakes to prevent the formation of ice.
FFG-7 class ships)
The components of this system consist of manual
butterfly regulating valves and distribution piping. The
Prairie air system
gas turbine anti-icing system is not used to remove ice
Gas turbine anti-icing system
because engine damage may result from ice ingestion.
In the following paragraphs, we will give you a brief
OPERATION
description of each of these systems.
The bleed air system on board gas turbine-powered
BLEED AIR COLLECTION AND
ships is normally operated and monitored by the ECSS,
DISTRIBUTION SYSTEM
PCS, or the MCS. On the DD-963, DDG-993, and
CG-47 class ships, the bleed air system controls and
The bleed air collection and distribution system
indicators are located on the PACC and the PLCC. On
collects compressed air extracted from the compressors
the FFG-7 class ships, the bleed air system controls and
of all operating GTEs and delivers it to the other
indicators are located on the PCC and the auxiliary
systems. This system consists of regulating valves,
control console (ACC). On the DDG-51 class ships, the
isolation valves, piping, a main header, and relief valves.
bleed air system controls and indicators are located on
the PACC and the SCU.
MASKER AIR SYSTEM
The valves for the bleed air system are controlled
The masker air system receives hot compressed
and monitored from the control consoles. The consoles
bleed air from the bleed air collection and distribution
provide for the opening and closing of the bleed air
system. This system cools the bleed air and distributes
valves. Some valves, such as the anti-icing valves, are
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