Anti-icing Air System. The anti-icing air system is
3. On - engine running at idle, disconnected from
supplied by bleed air injected into the gas turbine intakes
p r o g r a m m e d control, PT brake on, and stop not
upstream of the moisture separator/blow-in panels. A
commanded
manually operated anti-icing valve is located
4 . O n L i n e - engine running, connected to
downstream of each GTM bleed air regulating valve.
programmed control, PT brake off, and clutch engaged
The anti-icing valve position is monitored by the
computer in the SCU, which generates a status message
5. Cooldown - engine running at idle, disconnected
on the PDU. An ICING alarm indicator for each GTE is
from programmed control, and PT brake on
provided on the PACC propulsion mimic panel.
The SCU computer controls the GTE brakes, valve
HIGH-PRESSURE AIR SYSTEM. The HP air
alignment, cooling fan, and vent damper automatically
system provides compressed air at 3000 psig to air
to fulfill any legal engine state change requested by the
storage flasks of various sizes and special-purpose
operator.
functions. The HP air system is supplied by two HP air
The GTE emergency controls consist of three
compressors. This system is used as an alternate source
separate, but interrelated, categories: (1) emergency
of starting air for the SSGTGs and GTEs. It also supplies
stops, (2) automatic shutdowns, and (3) GTE fire
the 5-inch gun, torpedo tubes, helicopter services, and,
detection and control.
if necessary, the ship's service air system.
An operator can initiate an emergency stop, while a
GTE is in the ON or ON LINE state, by depressing the
GTE Control System
EMER STOP, PRI(RSV) HALON RLSE, or
MODULE VALVE CLOSE push button. Depressing a
HALON RLSE or MODULE VALVE CLOSE push
Control and monitoring of all four GTEs is available
button indirectly causes the SCU to send an emergency
from the PACC. However, normal control functions are
s t o p command to the IIEC. The SCU sends an
only available from either the PACC or appropriate SCU
emergency stop command to the IIEC in response to a
at anyone time. The following items of the GTE control
module Halon actuation alarm or loss of GTE fuel
system are discussed in this section:
manifold pressure.
1. Engine fan control
An IIEC automatic shutdown is indicated when the
2. Engine state logic
AUTO SHUT DOWN lamp on the PACC illuminates.
Each automatic shutdown causes the SCU computer to
3. Emergency controls
carry out an emergency stop in addition to the IIEC
The engine fan control computer program function
s h u t d o w n sequence. There are nine automatic
is always enabled. It automatically operates the module
shutdowns associated with the MCS system. GTE lube
cooling fan and damper in response to any one of the
oil supply pressure low, power turbine vibration high,
following three inputs: (1) GTE cooling air outlet
and power turbine overspeed shutdown are examples of
temperature transducer, (2) GTE start command, and (3)
a u t o m a t i c shutdowns. Five of the nine automatic
t h e Halon release command. The SCU computer
shutdowns are inhibited when BATTLE OVRD ON is
controls the GTE cooling fan and vent damper.
depressed. The five automatic shutdowns inhibited by
There are five possible engine states for a GTE.
battle override are as follows:
Each engine state is associated with a computer program
1. GTM fail to light off or flameout shutdown
function in the SCU computer. An engine state computer
program function senses the actual state of the GTE and
2. GTM lube oil supply-low pressure shutdown
allows an operator to start an engine state change. The
3. GTM power TIT high shutdown
push buttons that enable an engine state change are on
the gas turbine propulsion mimic of the PACC and SCU.
4. GTM gas generator vibration high
The five engine state logic computer program functions
5. GTM power turbine vibration high
are defined as follows:
The GTE fire detection system consists of three
1. Off - fuel off, power turbine (PT) brake on and
ultraviolet flame detectors in the module and a signal
disconnected from programmed control
conditioner located under the module. When a fire is
2. Motor - engine off before alignment of an air
detected, an alarm message appears on the PDU and a
system for motoring
MODULE FIRE lamp illuminates on the PACC and
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