T-45A UJPT, E2-C2, ADV, & IUT Eng-09
Hydraulic System
C.
Emergency hydraulic system: RAT 1.4.8.7
Sg 4, fr 4 (4 overlays)
WARNING
CAUTION
HYDFAIL
RATEXTEND LIGHT
LIGHT
1.
Deployment
CAUTION
CAUTION
HYD1PRESS LIGHT
HYD2PRESS
LIGHT
MICRO
SWITCH
RESERVOIR
RESERVOIR
FCACCUM
FCACCUM
EDP
EDP
LAIL
PRIORITY
RAM
a.
Falling pressure in HYD 2 is sensed by
VALVE
AIR
H
RAIL
Y
TURBINE
EMERGENCY
D
BYPASS
PACKAGE
RESET 2
HAND
VALVE
ASSEMBLY
PUMP
STAB
the emergency package assembly
SPDBRK
SLATS
LGEAR
NWS
FLAPS
LBAR
HOOK
b.
Emergency package assembly directs
HYD 1 PRESSURE
MECHANICAL
HYD 2 PRESSURE
WHLBRKS
CHECK VALVE
PRESSURIZED WITH
FLAPEMERGENCY
RAT EXTENDED
SELECTOR/PRIORITY
AND GATE
VALVE
ELECTRICAL
RAT accumulator pressure to RAT
HYDRAULIC SYSTEM BLOCK
actuator, raising RAT into airstream
DIAGRAM
2.
Operation
Overlay 1
RAT Actuator/RAT
a.
RAT output regulated by cutout
(1) Cutout shuts off RAT output at
rising pressure of 3,000 psi
(2) Cutout connects output of RAT at
falling pressure of 2,500 psi
b.
RAT charges accumulator
Overlay 2
RAT Actuator
c.
Supplies HYD 2 flight control services
through emergency package assembly
3.
If HYD 2 EDP is producing more than 1,800
Overlay 3
psi, and engine rpm is equal to or greater
HYD 2 RESET Button
than 45%, HYD 2 RESET button can be
used to retract RAT
NOTE: The only indication of whether or
not the HYD 2 EDP is producing adequate
pressure to stow the RAT is the HYD 2
caution light extinguishing at approximately
2,000 EDP psi.
4.
Normal engine shutdown
Overlay 4
RAT Shutdown
a.
RAT will extend when HYD 2 pressure
drops below 1,500 psi
(8-03) Original
Page 9-29
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