B757 200RR Hydraulics

757 Operations Manual

Hydraulics

Chapter 13

Table of Contents

Section 0

13.0 Hydraulics-Table of Contents

Controls and Indicators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.10.1

Hydraulic Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.10.1 Status Display Display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.10.2 Miscellaneous Hydraulic System Controls . . . . . . . . . . . . . . . . 13.10.3 Power Transfer Transfer Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.10.3 Ram Air Turbine Turbine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.10.3 System Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.20.1

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.20.1 Hydraulic Systems Systems Schematic . . . . . . . . . . . . . . . . . . . . . . . 13.20.2 Left Hydraulic System

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.20.3

Fluid Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.20.3 Engine–driven Pump Pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.20.3 Electric Motor–driven Motor–driven Pumps . . . . . . . . . . . . . . . . . . . . . . . . 13.20.3 Power Transfer Transfer Unit (PTU) (PTU) . . . . . . . . . . . . . . . . . . . . . . . . . . 13.20.4 System Pressure Pressure Indications . . . . . . . . . . . . . . . . . . . . . . . . . 13.20.4 Right Hydraulic System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.20.4 Fluid Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.20.4 Engine–driven Pump Pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.20.4 Electric Motor–driven Motor–driven Pump . . . . . . . . . . . . . . . . . . . . . . . . 13.20.5 System Pressure Pressure Indications . . . . . . . . . . . . . . . . . . . . . . . . . 13.20.5 Reserve Brakes System System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.20.5 Center Hydraulic System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.20.5 Fluid Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.20.5 Electric Motor–driven Motor–driven Pump . . . . . . . . . . . . . . . . . . . . . . . . 13.20.5 System Pressure Pressure Indications . . . . . . . . . . . . . . . . . . . . . . . . . 13.20.5 Ram Air Turbine Turbine (RAT) (RAT) Pump . . . . . . . . . . . . . . . . . . . . . . . . . . 13.20.6 EICAS Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.30.1

Hydraulics EICAS Messages . . . . . . . . . . . . . . . . . . . . . . . . . . 13.30.1 Copyright © The Boeing Company. Company. See title page for details.

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Hydraulics Table of Contents


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Copyright © The Boeing Company. See title page for details.

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Hydraulics

Chapter 13

Controls and Indicators

Section 10

13.10 Hydraulics-Controls and Indicators

Hydraulic Panel

1

SYS PRESS

SYS PRESS

SYS PRESS

2

RSVR

RSVR

RSVR

HYD PUMPS L ENG

C 1 - ELEC -2

R ENG

3

ON

ON

ON

ON

4

PRESS

PRESS

PRESS

PRESS

OVHT

OVHT

OVHT

OVHT

ELEC

ELEC 5

6

ON

ON

PRESS

PRESS

OVHT

OVHT

OVERHEAD PANEL

1

System Pressure (SYS PRESS) Lights

Illuminated (amber) – system pressure is low. 2

Reservoir Low Quantity (RSVR) Lights

Illuminated (amber) –reservoir quantity is low, or reservoir pressure is low. 3

Left/Right Engine (L/R ENG) Pump Switches

ON – the engine–driven hydraulic pump pressurizes when engine rotates. Off (ON not visible) – the engine–driven hydraulic pump is turned off and depressurized. 4

Pump Pressure (PRESS) Lights

Illuminated (amber) – pump output pressure is low.


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Hydraulics Controls and Indicators

757 Operations Manual 5

Left/Right and Center 1/2 Electric (L/R ELEC and C1/2 ELEC) Pump Switches

ON – the electric motor–driven pump pressurizes the left, center or right hydraulic system. Off (ON not visible) – the electric motor–driven hydraulic pump is turned off and depressurized. 6

Pump Overheat (OVHT) Lights

Illuminated (amber) – pump temperature is high.

Status Display

1

HYD QTY

2

HYD PRESS

L

C

R

.75 RF 3010

1.00 2980

1.00 3000

STATUS DISPLAY

1

Hydraulic Fluid Quantities (HYD QTY)

• displays system reservoir quantity (1.00 is the normal service level) • RF (magenta) – displayed when the reservoir requires refilling 2

Hydraulic System Pressures (HYD PRESS)

Displays hydraulic pressure in pounds per square inch of the pump with the highest pressure.


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Miscellaneous Hydraulic System Controls Power Transfer Unit PTU ON 1

OFF ACCESSORY PANEL

1

Power Transfer Unit (PTU) Switch

ON – PTU operates if right engine operating. OFF – PTU operates only when automatically activated.

Ram Air Turbine RAM AIR TURB 1 2

PRESS

3

UNLKD

OVERHEAD PANEL

1

RAM AIR Turbine (TURB) Switch

Push – deploys the RAT. 2

Ram Air Turbine Pressure (PRESS) Light

Illuminated (green) – • the RAT is deployed • the RAT is producing hydraulic pressure 3

Ram Air Turbine Unlocked (UNLKD) Light

Illuminated (amber) – the RAT is not stowed and locked.


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Hydraulics

Chapter 13

System Description

Section 20

13.20 Hydraulics-System Description

Introduction

The airplane has three independent hydraulic systems: left, right, and center. The hydraulic systems power the: • • • • • • • •

flight controls leading edge slats trailing edge flaps landing gear wheel brakes nose wheel steering thrust reversers autopilot servos

Flight control system components are distributed so that any one hydraulic system can provide adequate airplane controllability. Hydraulic fluid is supplied to each hydraulic pump from the associated system reservoir. The reservoirs are pressurized by the bleed air system.


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Hydraulics System Description


Hydraulic Systems Schematic HYD PUMPS L ENG

RAM AIR TURB R ENG

C 1 - ELEC - 2

PRESS ON

ON

ON

ON

PRESS

PRESS

PRESS

PRESS

OVHT

OVHT

OVHT

OVHT

UNLKD

ELEC

ELEC

RESERVE BRAKES

ON

ON ON

PRESS

PRESS

OVHT

OVHT

LND GEAR

NOSE WHEEL STEERING

SLATS POWER TRANS

FLAPS

UNIT (PTU) R REV

L REV ALTN BRAKES

FLT CTRL

FLT CTRL

NORM BRKS

FLT CTRL

ISLN

L ENG

R ENG

L ELEC

ELEC C1

DISCH

ELEC C2

R RAT

ELEC

2

1

L E F T

SOV

SOV

LEFT

CENTER

RESERVOIR

RESERVOIR

Pump ISLN

Isolation valve

RIGHT

RESERVOIR SOV

Shutoff valve


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Left Hydraulic System The left hydraulic system powers: • • • • • •

flight controls flaps and slats landing gear alternate brakes nose wheel steering left engine thrust reverser

The system consists of a reservoir, engine–driven pump, electric motor–driven pump, and a power transfer unit (PTU) pump.

Fluid Supply Hydraulic fluid is supplied to each hydraulic pump from a reservoir. The reservoir is pressurized by the bleed air system. A quantity measuring system provides information to the EICAS status display. RF displays when a reservoir requires refilling prior to dispatch. The RSVR light illuminates and the EICAS advisory message L HYD QTY displays when the reservoir quantity is low. The RSVR light also illuminates and the EICAS advisory message L HYD RSVR PRESS displays when the reservoir air pressure is low. The reservoir maintains reserve hydraulic fluid for use by the PTU in the event of a left system hydraulic leak. Fluid for the engine–driven pump flows through a shutoff valve controlled by the engine fire switch. Pulling the fire switch shuts off the flow of fluid to the engine pump and depressurizes the pump.

Engine–driven Pump The primary hydraulic system pump is an engine–driven pump. The pump PRESS light illuminates and the EICAS advisory message L HYD ENG PUMP displays when the pump output pressure is low. The pump OVHT light illuminates and the EICAS advisory message L ENG HYD OVHT displays when the pump temperature is high.

Electric Motor–driven Pumps An electric motor–driven pump provides additional hydraulic power. The pump PRESS light illuminates and the EICAS advisory message L HYD ELEC PUMP displays when the pump output pressure is low. The pump OVHT light illuminates and the EICAS advisory message L ELEC HYD OVHT displays when the pump temperature is high.


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Power Transfer Unit (PTU) The PTU is a hydraulic motor pump which transfers hydraulic power from the right system to the left system. The PTU is automatically activated if the left engine fails or the left engine–driven pump pressure is low. When activated, the PTU supplements the left hydraulic system electric motor–driven pump to operate the following: • flaps and slats • landing gear • nose wheel steering PTU operation is inhibited if the right engine is not operating.

System Pressure Indications The SYS PRESS light illuminates and the EICAS caution message L HYD SYS PRESS displays when the hydraulic system pressure is low. Hydraulic system pressure displays on the EICAS status page. When the engine–driven and electric motor–driven pumps are inoperative, the EICAS status page displays the PTU output pressure.

Right Hydraulic System The right hydraulic system is similar to the left system. The right system powers: • • • • •

flight controls normal brakes reserve brakes right engine thrust reverser power transfer unit (PTU)

The system consists of a reservoir, engine–driven pump, and an electric motor–driven pump.

Fluid Supply The right reservoir is similar to the left system. The associated EICAS messages for low reservoir quantity or low reservoir air pressure are R HYD QTY and R HYD RSVR PRESS. The reservoir maintains a reserve hydraulic fluid for use by the reserve brakes in the event of a right system hydraulic leak.

Engine–driven Pump The right engine–driven pump is identical to the left system. The associated EICAS messages for low pump output pressure or high pump temperature are R HYD ENG PUMP and R ENG HYD OVHT. Copyright © The Boeing Company. See title page for details.

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Electric Motor–driven Pump The right electric motor–driven pump is identical to the left system. The associated EICAS messages for low pump output pressure or high pump temperature are R HYD ELEC PUMP and R ELEC HYD OVHT.

System Pressure Indications The right system pressure indications are similar to the left system. The associated message for low system pressure is R HYD SYS PRESS.

Reserve Brakes System Pushing the RESERVE BRAKES switch configures the hydraulic system to use the reservoir’s reserve fluid, activates the electric motor–driven pump regardless of the pump switch position and isolates the pump output power to only the normal brakes.

Center Hydraulic System The center system powers only flight controls. The system consists of a reservoir, two electric motor–driven pumps, and a ram air turbine (RAT) pump.

Fluid Supply The center reservoir is similar to the left system. The associated EICAS messages for low reservoir quantity or low reservoir air pressure are C HYD QTY and C HYD RSVR PRESS. The reservoir maintains reserve hydraulic fluid for use by the ram air turbine in the event of a center system hydraulic leak.

Electric Motor–driven Pump The two center electric motor–driven pumps are similar to the left system pump. The C2 pump may be load shed automatically to reduce electrical loads. The associated EICAS messages for low pump output pressure or high pump temperature are C HYD ELEC 1, C HYD ELEC 2, C HYD 1 OVHT, and C HYD 2 OVHT.

System Pressure Indications The center system pressure indications are similar to the left system. The associated message for low system pressure is C HYD SYS PRESS.


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Ram Air Turbine (RAT) Pump The RAT, when deployed provides hydraulic power to the flight controls portion of the center hydraulic system. The RAT provides adequate hydraulic power at speeds above 130 knots. In flight, the RAT deploys automatically when both engines fail. The RAT can be deployed manually by pushing the RAM AIR TURB switch. The UNLKD light illuminates and the EICAS advisory message RAT UNLOCKED displays when the RAT is not stowed and locked. When the RAT is producing pressure the ram air turbine PRESS light illuminates. Once deployed, the RAT cannot be stowed in flight.


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Hydraulics

Chapter 13

EICAS Messages

Section 30

13.30 Hydraulics-EICAS Messages

Hydraulics EICAS Messages The following EICAS messages can be displayed. Message

Level

Light

Aural

Condition

L ELEC HYD OVHT

Advisory

OVHT

Pump temperature is high.

Advisory

PRESS

Pump output pressure is low.

Advisory

RSVR

Hydraulic quantity is low.

Advisory

RSVR

Reservoir air pressure is low.

Caution

SYS PRESS

Advisory

UNLKD

R ELEC HYD OVHT L ENG HYD OVHT R ENG HYD OVHT C HYD 1 OVHT C HYD 2 OVHT L HYD ELEC PUMP R HYD ELEC PUMP L HYD ENG PUMP R HYD ENG PUMP C HYD ELEC 1 C HYD ELEC 2 C HYD QTY L HYD QTY R HYD QTY C HYD RSVR PRESS L HYD RSVR PRESS R HYD RSVR PRESS C HYD SYS PRESS L HYD SYS PRESS

Beeper

Hydraulic system pressure is low.

R HYD SYS PRESS RAT UNLOCKED

The ram air turbine is not stowed and locked.


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Hydraulics EICAS Messages


Intentionally Blank


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B757 200RR Hydraulics

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