HYD PRESS SYS C

Condition: The center hydraulic system pressure is low. Objective: To restore system pressure and configure for landing using alternate systems, if needed.

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Decision Flowchart

flowchart TD
    A["HYD PRESS SYS C"] --> B["Step 1: C1 or C2 AIR DEMAND<br/>pump selector — ON"]
    B --> C{"HYD PRESS SYS C<br/>message status?"}
    C -->|Message blanks| D["■ ■ ■ ■<br/>Checklist complete"]
    C -->|Message stays| E["Step 3: C2 ELEC PRIMARY pump — Off"]
    E --> F["Step 4: C1 & C2 AIR DEMAND selectors — OFF"]
    F --> G["Step 5: GND PROX FLAP OVRD — OVRD"]
    G --> H["Step 6: Do NOT accomplish:<br/>Auto Speedbrake, Spoilers"]

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Checklist

• Step 1: C1 or C2 AIR DEMAND pump selector … ON
• Step 2: Choose one:

HYD PRESS SYS C message blanks	HYD PRESS SYS C message stays shown
■ ■ ■ ■ (Checklist complete)	→ Go to Step 3

• Step 3: C2 ELEC PRIMARY pump switch … Off
• Step 4: C1 and C2 AIR DEMAND pump selectors … OFF
• Step 5: GND PROX FLAP OVRD switch … OVRD
• Step 6: Do not accomplish: AUTO SPEEDBRAKE, SPOILERS

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Inoperative Items (Center System Loss)

WARNING

Center Hydraulic System Loss 시 사용 불가 항목:

• Primary flap and slat operation → Plan more time for slower flap/slat (alternate operation)
• Main landing gear hydraulic operation → Alternate gear extension 필요
• Main gear steering → Inoperative
• Auto speedbrake → Inoperative
• Spoilers → Reduced effectiveness

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Related HYD Checklists

EICAS Message	Condition	Section
HYD AUTO CONTROL C	Auto control of center demand pumps fails	13.1
HYD OVERHEAT PRI C1, C2	Pump temperature high	13.2
HYD PRESS DEM C1, C2	Demand pump output pressure low	13.4
HYD PRESS PRI C1, C2	Primary pump pressure low	13.4
HYD PRESS PRI L	Left primary pump pressure low (L thrust reverser may be inop)	13.4
HYD PRESS PRI R	Right primary pump pressure low (R reverser, autobrake, normal brakes may be inop)	13.5

Cross-References