HYDRAULIC

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ENG PUMP SHUTOFF BUTTON

PUSH IN: Closes the hydraulic shutoff valve (SOV), isolating the respective engine driven pump (EDP) from the associated hydraulic system.

PUSH OUT: Normal position.

ELECTRIC HYDRAULIC PUMP SELECTOR KNOB

OFF: Turns the respective pump off.

AUTO: Back-up for the respective EDP.

In flight: Activates in case of

• EDP or engine fail, or

• Flaps selected > 0.

On ground: Activates in case of flaps selected >0, and

• TL set to takeoff thrust, or

• Groundspeed > 50 kts.

ON: Pump operates continuously, overriding system logic.

Note: ELEC PUMP 2 in AUTO: If engine 1 running and parking brake released pump turns on (Single engine taxi logic).

PTU (POWER TRANSFER UNIT) KNOB

OFF: PTU is turned off.

AUTO: Allows the PTU to operate automatically, according to hydraulic system logic.

ON: Operates continuously, overriding system logic.

HYDRAULIC SYSTEM 3 SELECTOR KNOBS

OFF: Turns the respective electrical pump off.

ON: Turns the respective electrical pump on. 3B overrides system logic.

AUTO (3B): Turns 3B on automatically if AC Electric Pump 3A fails.

The PTU does not work on the ground.

Note: HYDRAULIC SYSTEM 3A pump is powered by the AC ESS BUS (Electrical Emergency).