T-45A UJPT, E2-C2, ADV, & IUT Eng-09
Hydraulic System
c.
Regardless of RAT status, HYD 1 is
providing primary power for the flight
controls
F.
HYD 2 operational characteristics summary
1.4.8.2.1
HYD 2 is an independent hydraulic system used
to power the flight controls. The Emergency
Hydraulic System provides HYD 2 redundancy
when HYD 2 EDP pressure falls to
approximately 1,500 psi, regardless of the HYD
1 status
WARNING: Sustained high-frequency, high
amplitude control inputs during flight with
RAT only hydraulic pressure could result in
loss of aircraft control. Ejection outside the
safe ejection envelope may occur if control
is lost during a landing attempt.
IV. Emergency hydraulic system:
Sg 4, fr 1
Lesson Organization
A.
Description: the emergency hydraulic system
acts as a backup to the HYD 2 system, by
deploying the RAT when HYD 2 pressure falls
below acceptable levels. The RAT
automatically extends whenever HYD 2 EDP
pressure falls below 1,500 psi. Since the RAT
is a fixed displacement pump, emergency
hydraulic pressure will fluctuate between 2,500
and 3,000 psi displayed on the HYD 2 gauge,
Sg 4, fr 2 (3 overlays)
whenever the RAT is in operation
WARNING
CAUTION
HYDFAIL
RATEXTEND LIGHT
LIGHT
CAUTION
CAUTION
HYD1PRESS LIGHT
HYD2PRESS
LIGHT
MICRO
SWITCH
RESERVOIR
RESERVOIR
FCACCUM
FCACCUM
B.
Emergency hydraulic system components
EDP
EDP
LAIL
PRIORITY
RAM
VALVE
AIR
H
1.4.8.6
RAIL
Y
TURBINE
EMERGENCY
D
BYPASS
PACKAGE
RESET 2
HAND
VALVE
ASSEMBLY
PUMP
STAB
1.
RAT
SLATS
LGEAR
NWS
SPDBRK
FLAPS
LBAR
HOOK
HYD 1PRESSURE
MECHANICAL
HYD 2PRESSURE
WHLBRKS
CHECKVALVE
PRESSURIZEDWITH
FLAPEMERGENCY
RAT EXTENDED
SELECTOR/PRIORITY
ANDGATE
VALVE
ELECTRICAL
a.
Location: RAT bay, aft fuselage
HYDRAULIC SYSTEM BLOCK
behind gravity filler cap, forward of tail
DIAGRAM
section
Overlay 1
Ram Air Turbine (RAT)
Page 9-26
(8-03) Original
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