Hydraulic Control Panel is part of Overhead panel

Engine Pump Switch #

ON – When a ENG PUMP switch is selected to ON, selection is indicated when all lights are extinguished, enabling the engine-driven pumps to pressurize the hydraulic system when the engine is running.

OFF – When a ENG PUMP switch is selected to OFF, the engine-driven pump is depressurized, and the OFF light illuminates white.

FAULT – The ENG PUMP FAULT light illuminates amber when:

• Reservoir low level
• Reservoir overheat
• Reservoir low air pressure
• Reservoir low pressure (inhibited on the ground with engine stopped)

The ENG PUMP FAULT FAULT light extinguishes when the ENG PUMP switch is selected OFF (except during an overheat, when the light remains illuminated as long as the overheat is present).

RAT Man On Switch #

Ram Air Turbine Manual On Switch

RAT MAN ON Switch – When pushed, the ram air turbine extends. The RAT is located on the left bottom side of the fuselage.

The RAT can be deployed for emergency use to pressurize the blue hydraulic system. The RAT can only be stowed on the ground.

The RAT will also extend by depressing the RAT MAN ON switch, located on the hydraulic control panel: however, this switch is dedicated to pressurizing the blue hydraulic system only and does not provide emergency electrical power.

Blue Electric Pump Switch #

AUTO – The ELEC PUMP operates, if AC power is available when in flight or on the ground, if one engine is running

OFF – When the BLUE ELEC PUMP switch is selected to OFF, the electric-driven pump is de-energize and the OFF light illuminates white.

FAULT – The BLUE ELEC PUMP FAULT light illuminates amber for a Blue hydraulic system:

• Reservoir low level
• Reservoir overheat
• Reservoir low air pressure
• Pump low pressure (inhibited on the ground when engines are stopped)
• Pump overheat

The BLUE ELEC PUMP FAULT light extinguishes when the BLUE ELEC PUMP switch is selected OFF (except during an overheat, when the light remains illuminated as long as the overheat is present).

Power Transfer Unit Switch #

AUTO – The reversible motor pump is armed when both yellow and green electro-hydraulic valves are open. The PTU runs automatically when the differential pressure between the green and yellow systems is more than 500 PSI (except when inhibited). The PTU is inhibited when:

• The PARK BRK is ON and only one ENG MASTER switch is ON
• The nose wheel steering disconnect pin is installed and only one ENG MASTER switch is ON
• The PTU switch is OFF
• The cargo doors are being operated (inhibition continues for approximately 40 sec)

FAULT – The PTU FAULT light illuminates amber when the green or yellow reservoir is:

• Low level
• Overheat
• Low air pressure

The PTU FAULT light extinguishes when the PTU switch switch is selected OFF (except during an overheat, when the light remains illuminated as long as the overheat is present).

OFF – When OFF is selected, then both green and yellow PTU electro-hydraulic valves are energized and closed, and hydraulic power transfer stops.

Yellow Electric Pump Switch #

ON – The YELLOW ELEC PUMP is energized when selected ON, selection is indicated when a blue color boxed ON light is illuminated. If electrical power is removed, the pump remains de-energized at the next electrical power application.

OFF – When the YELLOW ELEC PUMP switch is selected to OFF, selection is indicated when no lights are illuminated and the electric-driven pump is de-energized. It is automatically energized when the forward or aft cargo door lever is operated. During cargo door operation, all other yellow system users are inhibited except for the No. 2 engine thrust reverser and yellow system braking (alternate brakes, parking brake, and brake accumulator).

FAULT – The YELLOW PUMP FAULT light illuminates amber when:

• Reservoir low level
• Reservoir overheat
• Reservoir low air pressure
• Pump low pressure
• Pump overheat

The YELLOW ELEC PUMP FAULT light extinguishes when the YELLOW ELEC PUMP switch is selected to OFF (except during an overheat, when the light remains illuminated as long as the overheat is present).

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