T-45A UJPT, E2-C2, ADV, & IUT Eng-09
Hydraulic System
PROGRESS CHECK
Question 1 -- 1.4.8.3.1
What is the function of the emergency hydraulic
system and when does it activate?
ANSWER: The emergency hydraulic system acts as a
backup to the HYD 2 EDP. If the HYD 2 EDP is unable
to maintain sufficient pressure for any reason and HYD
2 EDP pressure falls below 1,500 psi, the RAT will
deploy and provide emergency hydraulic power to the
HYD 2 side of the flight controls.
Question 2 -- 1.4.8.2.1, 1.4.8.3
What information do the HYD 1, HYD 2, and BRAKE
pressure gauges provide and what should they
display when the hydraulic system is functioning
normally?
ANSWER:
1. HYD 1 indicates HYD 1 system pressure as
provided by the HYD 1 EDP. If HYD 1 is
functioning normally, it should indicate 3,000 psi.
2. HYD 2 indicates HYD 2 system pressure as
provided by the HYD 2 EDP or the Emergency
Hydraulic System. If HYD 2 EDP is functioning
normally, it should indicate 3,000 psi. If the
emergency hydraulic system is functioning
normally, it should fluctuate between 2,500 and
3,000 psi.
3. BRAKE indicates the nitrogen preload pressure in
the wheel brake/emergency flap accumulator. If
the accumulator is functioning normally, it should
indicate 3,000 psi when HYD 1 is operating and
approximately 2,800 psi when the engine is shut
down.
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