T-45C TS, ADV & IUT ENG-10
Hydraulic System Malfunctions
c.
After pressure has dropped below 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.
4.
Loss of fluid in both systems would render aircraft unflyable
IV. HYD 1 and HYD 2 hydraulic pump failure
Fig 1: Hydraulic
A. Indications
System
1.
HYD 1
a.
Low pressure or rapid pressure loss, as indicated by HYD 1
pressure gauge
b.
Possible noise and vibration associated with deteriorating pump
c.
CWS and auditory cautions noted (pressure below 600
+ 50 psi)
(9-98) Original
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