air flow. The ambient air temperature sensor
After the bleed air passes the anti-icing, air-
signal determines the magnitude of valve position
flow regulator valves, it becomes anti-icing air and
change that will accompany any given engine
is piped to the GTGS intakes. Anti-icing air
speed change. Following an engine speed change,
entry into a GTGS intake is made through an
the controller will again regulate the temperature
8-inch pipe. The hot anti-icing air flows into the
of the inlet air in the intake to 38°F. It does this
intake duct and mixes with the intake air. No
by comparing the bulk air temperature to the
manifolds or nozzles are used.
controller's 38°F fixed temperature reference.
Injection of hot anti-icing air into the GTE
The controller used to operate the anti-icing
intakes is accomplished through the U-shaped
valve for each GTGS intake combines and
compares one input signal (duct air temperature)
silencers inside each duct. The manifolds are
with the fixed temperature signals (38°F) to
constructed from 8-inch diameter pipe with
produce a torque motor control position signal.
1 1/4-inch holes drilled along the sides of each
The anti-icing valve used on a GTGS is the same
leg. Because of the larger cross-sectional area and
as that used on a GTM.
capacity of the propulsion intakes, manifolds
When the GTGS anti-icing temperature
must be used to mix the air thoroughly.
controller is enabled, it maintains the temperature
FFG Anti-Icing System
of the inlet air in the intake at 38°F. Again the
controller compares duct air temperature to the
In the FFG anti-icing air system (fig. 4-10),
38°F fixed temperature.
bleed air is taken from the common header and
Figure 4-10.--FFG anti-icing system.