T-45C TS, ADV & IUT ENG-27/ENG-28
Engineering Review
(1) LP fuel pump: driven by external gearbox,
Sg 2, fr 57
pump maintains fuel pressure to HP fuel
LP Fuel Pump
pump, preventing HP fuel pump cavitation
Sg 2, fr 58
(2) Fuel-cooled oil cooler (FCOC): heat
Fuel Cooled Oil
exchanger unit transfers oil heat to fuel,
Cooler
reducing or eliminating fuel system icing
Sg 2, fr 59
(3) Filter: removes foreign matter from fuel
Filter
(4) HP fuel pump: driven by external gearbox,
Sg 2, fr 60
supplies HP fuel to fuel control unit (FCU)
HP Fuel Pump
and SIFCU
(5) FCU: fuel flow scheduling unit with
Sg 2, fr 61
acceleration control and altitude and
FCU
airspeed compensation
(a) Initial shot solenoid provides increased
fuel flow to increase engine surge
margin during engine acceleration
i)
Enabled when altitude decreases
through 7,700 +/- 500 feet
ii)
Disabled when altitude increases
through 9,500 +/- 300 feet
(b) Acceleration switch dampens throttle
Sg 2, fr 62
valve response for rapid throttle
Acceleration Switch
movements
(c) Servo pressure control maintains
Sg 2, fr 63
constant pressure drop across throttle
Servo Pressure Control
valve, compensating for changes in
airspeed and altitude
(d) Solenoid (fuel trim): trims basic fuel
Sg 2, fr 64
flow in response to engine control
Solenoid (Fuel Trim)
amplifier (ECA) inputs
(e) ACCEL caution light illuminates if
solenoid not in commanded position
(9-98) Original
Page 27-25
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