T-45A UJPT, E2-C2, ADV, & IUT Eng-09
Hydraulic System
(2) Provides backup supply of hydrau-
lic pressure for flight controls
during operation of the RAT
(3) Compensates for pressure fluctua-
tions of the RAT
(4) Provides pressure to keep the RAT
extended
d.
Physical
(1) Includes a pressure regulating
valve (cutout) and a cylinder with a
free-floating piston that separates
fluid from nitrogen
(2) Regulator valve cycles pressure
between 2,500 and 3,000 psi,
because the RAT is a fixed dis-
placement pump whose output
pressure is not internally regulated
(3) Pressurized with nitrogen
3.
Emergency package assembly
Overlay 3
Emergency Package Assembly
a.
Functional: automatically deploys the
RAT and directs Emergency Hydraulic
System pressure to flight controls when
HYD 2 pressure below 1,500 psi
b.
Physical: thermal relief valve, spool
valve, solenoid valve, restrictor
NOTE: The emergency package
Sg 4, fr 3
assembly isolates the HYD 2 EDP from
HYD 2 RESET
the system when the RAT is deployed
(does not put the HYD 2 EDP pump in
bypass). To regain HYD 2 EDP
pressure (and stow the RAT), the HYD
2 RESET button must be pressed.
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