T-45A UJPT, E2-C2, ADV & IUT Eng-13
Hydraulic Subsystems
a.
Sequence of normal main gear/door
Sg 1, fr 10
extension
Video: Landing Gear Sequence
NOTE: Extension and retraction
commence concurrently; however, all
three gear/door assemblies have their
own hydraulic actuators and do not
necessarily complete the extend/retract
cycle at exactly the same time
(although they are within a few
seconds of each other).
(1) Setting LDG GEAR UP/DN handle
to DN electrically initiates
operation of landing gear hydraulic
control valve
(2) Hydraulic pressure is directed to
open inner (main gear) doors (in
approximately 1 second)
(3) When inner (main gear) doors fully
open, gear uplocks are
hydraulically released, and
hydraulic extension actuator is
activated
(4) When fully extended, gear is
hydraulically and mechanically
downlocked by hydraulic downlock
actuator and springs acting on
lock links attached to side brace
(5) After gear is down and locked,
inner doors close and lock
hydraulically
NOTE: The trunnion, trailing arm,
and fixed strut doors remain open
because they are mechanically
attached to the gear.
(8-03) Original
Page 13-11
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