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Composed of...
- Four independent systems:
- 1. First-stage hydraulic system (flight controls with T/R shut off)
- 2. Second-stage hydraulic system (flight controls and utility hyd sys)
- 3. Wheel brake system (and parking brake)
- 4. Rotor brake system
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Utility Hyd Sys
- On 2nd stage hydraulic module:
- 1. Landing gear components (extension and retraction)
- 2. Priority valve - senses loss in system pressure >2,250PSI, and closes to give priority to M/R and T/R servos
- 3. Pedal damper/yaw trim actuator
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Servo Switches
- On each Pilot and CPilot coll
- If Pilot switched a servo off, only that switch can be used to switch on again
- Switches connected to Ess Bus, 2 CBs
- Fail-On system
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Pressure Indications (stages 1 and 2)
- Normal is 3,000PSI (available by
 10%NR) - SERVO SYS caution light if drops below 1,600PSI
- Gage on Engine page (IIDS) is slider only, no numbers
- Little Red Buttons on both pressure and return filters (4 total)
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Filters (stages 1 and 2)
- Each stage: output line filter (nonbypass), and return bypass filter
- Line filter LRB pops at 7010psi differential
- Return filter LRB pops at 10010psi differential
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T/R Servo Shutoff Valve
- On the 1st stage hydraulic pressure line only
- If fluid level switch activates, the solenoid shutoff valve blocks flow to #1 T/R servo (#1 SERVO SYSTEM caution on)
- Even if 2nd stage hyd loses pressure too, 1st stage will supply pressure to M/R servos
- (#1 SVO SHUTOFF CB on Ess Bus)
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