T-45C TS, ADV & IUT ENG-27/ENG-28
Engineering Review
(c)
After pressure has dropped 1500
+/- 100 psi, RAT will deploy and the
RAT caution light will illuminate
d.
If pressure drop due to fluid loss, pressure
may temporarily rise and cycle after RAT
extends but then will continue to drop
NOTE: The HYD 1 & 2 caution lights
indicate EDP pressure only. Since the
EDP is the sole source of hydraulic
pressure in the HYD 1 system, the HYD 1
gauge normally reflects the serviceability
of the pump. The only exception to this
would be loss of pressure due to hydraulic
fluid leakage. The HYD 2 gauge shows
system pressure resulting from either the
HYD 2 EDP or the Emergency Hydraulic
System. Neither the pump or the RAT will
maintain HYD 2 pressure if a system leak
depletes HYD 2 system reservoir. Should
HYD 2 fluid depletion result in less than
700 psi system pressure, spring tension
will cause the RAT to automatically
retract, however, in-flight aerodynamic
loading may prevent retraction.
c.
Effects on flight safety
(1) HYD 2 or Emergency Hydraulic System
maintains hydraulic pressure for flight
controls if HYD 1 fails
(2) HYD 1 maintains pressure for flight controls
if HYD 2 fails
(3) If pressure loss is in HYD 1, normal
operation is lost for landing gear, brakes,
flaps, slats, hook, speed brakes, nose
wheel steering (NWS), and launch bar
NOTE: Proper use of emergency backup
systems for these services is covered in
NATOPS and is the subject of future
lessons.
(9-98) Original
Page 27-66
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