Training Manual Table of Contents

A318/A319/A320/A321 EASA Part 66 Cat. B1B2

29 Hydraulic Power 29-11 Green Hydraulic System

Green Hydraulic System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Reservoir . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
29-00 General Reservoir Pressurization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
System Presentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Fire Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Engine Driven Pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Reservoirs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Ground Couplings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Fire Shut-Off Valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Pressure Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Engine Driven Pumps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Power Transfer Unit (PTU) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Electric Pumps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 High Pressure Manifold . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Hand Pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Leak Measurement Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Ram Air Turbine (RAT) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 HP Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Accumulators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Accumulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Power Transfer Unit (PTU) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Sampling Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Priority Valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Pressure Relief Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Hydraulic System Users . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Leak Measurement Manifold . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Green, Blue, Yellow Users . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Power Transfer Manifold . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Line Routing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Return Manifold . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Green Hydraulic System Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
29-10 Main Hydraulic Power Leakage Measurement Manifold . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
System Controls. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 High Pressure Manifold . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Engine 1 Pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Engine Driven Pump 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Ram Air Turbine (RAT) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 EDP 1 Case Drain Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Blue Electric Pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 EDP 1 Pressure Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Power Transfer Unit (PTU) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Engine Fire Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Engine 2 Pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Green Hydraulic Reservoir . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Yellow Electric Pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Reservoir . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Blue Pump Override . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Engine Driven Pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Leak Measurement Valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Ground Service Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

29-30 Indication 29-12 Blue Hydraulic System

Electrical Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Reservoir . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
System Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Reservoir Pressurization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Main System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Electric Pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Circuit Identification. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Blue Hydraulic System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Ram Air Turbine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

for training purposes only

Contents - I
 Training Manual Table of Contents
A318/A319/A320/A321 EASA Part 66 Cat. B1B2

Pressure Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Yellow Hydraulic System Electric Pump Protection . . . . . . . . . . . . . . . . . . 14

High Pressure Manifold. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Yellow Engine Driven Pump 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Blue Hydraulic System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 EDP 2 Case Drain Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Leak Measurement Manifold. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 EDP 2 Pressure Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Return Manifold. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Engine Fire Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Ground Couplings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Reservoir . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Blue Hydraulic System Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Return Manifold . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Leakage Measurement Manifold. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Yellow PTU-Manifold. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
High Pressure Manifold. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Yellow Brake Manifold. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Blue Electric Pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Yellow Ground Service Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Case Drain Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Blue Electric Pump Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 29-15 Maintenance Practices
Ram Air Turbine (RAT) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Hydraulic Reservoir Pressurizing System . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
RAT Actuator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Blue Hydraulic Reservoir . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Return Manifold. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Restrictor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Ground Service Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Pressure Reducing Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Ground Connector. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
29-13 Yellow Hydraulic System Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Reservoir. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Water Separator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Reservoir Pressurization. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Reservoir Check Valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Fire Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Pressure Gage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Engine Driven Pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Pressure Relief Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Ground Couplings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Manual Depressurization Valve. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Pressure Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Hydraulic Reservoir Filling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Power Transfer Unit (PTU) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Coupling Socket . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Electric Pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Restrictor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Hand Pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Hand Pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
High Pressure Manifold. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Filling Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Leak Measurement Manifold. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Reservoir Filling Selector Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
PTU Manifold . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Reservoir Quantity Indicator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Return Manifold. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Check Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Yellow Hydraulic System Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Hand Pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Leakage Measurement Manifold. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Seal Drain System Presentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
High Pressure Manifold. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Yellow Hydraulic System Electric Pump . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Forward System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Yellow Hydraulic System Electric Pump . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 AFT System. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

for training purposes only

Contents - II
 Training Manual Table of Contents
A318/A319/A320/A321 EASA Part 66 Cat. B1B2

Leakage Measurement System Presentation . . . . . . . . . . . . . . . . . . . . . . . 11 Flight Controls (F/CTL) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Instruments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Hydraulic System Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Landing Gear (L/G). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Full System Check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Component Check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 29-
29-20 Auxiliary Hydraulic Power
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

29-22 Ram Air Turbine (RAT)

General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
RAM Air Turbine A319/A321 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
RAT De-Icing Device . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
RAT Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Retraction Position . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Extension . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
RAM Air Turbine A320 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
RAT Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Retracted Position. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Extension . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Retraction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

29-23 Power Transfer System (PTU)

PTU General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
PTU Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Power Transfer Unit Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Power Transfer Unit (PTU) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Yellow PTU Manifold. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Green PTU Manifold . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Isolation Coupling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

29-99 CFDS
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Auto Flight System (AFS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

for training purposes only

Contents - III
 Training Manual Table of Contents
A318/A319/A320/A321 EASA Part 66 Cat. B1B2

for training purposes only

Contents - IV
 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -00

29 Hydraulic Power

for training purposes only

29-00-1
 Training Manual Hydraulic Power
A318/A319/A320/A321 29-00 General

29-00 General Engine Driven Pumps (EDPs) are located on the accessory gearbox of each en-
gine. They are of the variable displacement type.

System Presentation Electric Pumps

The blue system is pressurized by an electric pump.
General An electric pump allows the yellow system to be pressurized enabling ground op-
There are three independent hydraulic systems: Green, Blue and Yellow. erations when the engines are stopped.
Together they supply hydraulic power at 3000 psi (206 bar) to the main power us- Hand Pump
ers. The three systems are not hydraulic connected.
The hand pump is used to operate the cargo doors when electrical power is not
In normal operation, the green and yellow hydraulic systems are powered by En-
available.
gine Driven Pumps (EDPs), and the blue hydraulic system by an electric pump.
It is located on the yellow ground service panel.
Auxiliary power is provided by an electric pump in the yellow system.
A bidirectional Power Transfer Unit (PTU) enables the green system to be pow-
ered by the yellow system or vice versa, without fluid transfer.
A Ram Air Turbine (RAT) is provided in the blue system for emergency use.
A hand pump is provided in the yellow system for cargo door manual operation.

Reservoirs
Each hydraulic system has its own reservoir.
It supplies hydraulic fluid to the system pumps, and is pneumatically pressurized.
The green reservoir is located in the main landing gear bay, the yellow reservoir
in the yellow hydraulic compartment and the blue reservoir above the blue ground
service panel.
All the reservoirs are filled from the green ground service panel.

Fire Shut-Off Valves

On the green and yellow systems, a fire shut-off valve is positioned upstream of
the engine driven pump to isolate the system.
They are operated by their respective engine fire pushbutton switches to isolate
the engine driven pump in case of engine fire.

Engine Driven Pumps

The green and yellow systems are each pressurized by a pump driven respective-
ly by engine 1 and engine 2.

for training purposes only

29-00-2
 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -00 General

Figure 1: Hydraulic Power System

NW Steering Emer Generator Flaps
Landing Gear Slats
Yaw Damper 1
Rudder Slats & Flaps
Flaps & WTB Yaw Damper 2
Slats L & R WTB Priority Rudder Priority Rudder Priority
P P P
Valve Valve Valve
Stabilizer Flaps L & R WTB Flaps L WTB
L Elevator Slats L & R WTB Stabilizer
L & R Spoiler 1 L & R Elevator R Elevator
L & R Aileron L & R Spoiler 3 L & R Spoiler 2
L & R Spoiler 5 L & R Aileron L & R Spoiler 4

Leak Measurement Leak Measurement Leak Measurement

Valve Valve Valve

Normal Brake Alternate Brake

Reverser Eng. 1 Reverser Eng. 2

S S
System System System
Accu Accu Accu
MP MP Cargo Doors

Power
Eng. 2
Transfer Elec
Pump
Eng. 1 Unit Pump
RAT M M
Pump

Eng. 2
Eng. 1 M Fire M
Fire Valve Hand
Valve
Pump

Green Reservoir Blue Reservoir Yellow Reservoir

for training purposes only

29-00-3
 Training Manual Hydraulic Power
A318/A319/A320/A321 29-00 General

Ram Air Turbine (RAT) Hydraulic System Users

A Ram Air Turbine extends automatically in the event of both engine and APU
generator failures and allows the blue hydraulic system to be pressurized. Green, Blue, Yellow Users
• RAT delivered pressure is 2500 psi (172 bars). The three independent hydraulic systems respectively supply the users indicated
• Automatic deployment is inhibited on ground. on the diagram.
• Manual operation from the cockpit is always possible. Between these systems, the users are shared in order to ensure the aircraft con-
The Ram Air turbine is located in the blue hydraulic compartment. trol, even if only one hydraulic system is inoperative.
RAT stowage is possible on ground only. On the blue hydraulic system, the Constant Speed Motor/ Generator (CSM/ G) is
used to provide aircraft electrical power in case of emergency.

Line Routing
Accumulators
The three systems are not hydraulically connected and where possible are kept
An accumulator, in each circuit helps to maintain a constant pressure during nor- apart to keep to a minimum the effect of engine or tire burst, or other damages.
mal operation by covering transient demands. There are no hydraulic pipes in the passenger cabin or flight compartment.
Power Transfer Unit (PTU)
A bidirectional Power Transfer Unit enables the green system to be powered by
the yellow system or vice versa, without fluid transfer.
The PTU is automatically activated when the differential pressure between the
green and yellow system is higher than 500 psi (34 bars). When the engines are
shut down, the PTU allows the green system to be pressurized using the yellow
electric pump. The PTU is inhibited during the first engine start and is automatical-
ly tested at second engine start.

Priority Valves
In the event of low hydraulic pressure, the priority valves maintain the operation of
essential systems by cutting off hydraulic power to heavy load users.

for training purposes only

29-00-4
 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -10 Main Hydraulic Power

29-10 Main Hydraulic Power

for training purposes only

29-10-1
 Training Manual Hydraulic Power
A318/A319/A320/A321 29-10 Main Hydraulic Power

System Controls Blue Pump Override

For maintenance purposes, the blue hydraulic circuit can be pressurized by press-
Engine 1 Pump ing the BLUE PUMP OVRD pushbutton on the maintenance overhead panel.
ENG 1 PUMP pushbutton controls the engine 1 hydraulic pump. On ground, the electric pump operates, provided the BLUE PUMP OVRD push-
In normal conditions the engine driven pump 1 pressurizes the green system. button has been pressed in and the ELEC PUMP pushbutton is set to AUTO.
When the pushbutton is set to OFF, the pump operates in the depressurized
mode. Leak Measurement Valves
A leak measurement valve is positioned in each circuit upstream of the primary
Ram Air Turbine (RAT) flight controls.
The RAT MAN ON guarded pushbutton permits Ram Air Turbine deployment at Used for the leakage measurement of each circuit, they are closed, by selecting
any time. OFF the leak measurement valve pushbutton switches on the maintenance over-
RAT deployment is automatic in case of failure of main generators (engines and head panel.
APU) in flight.

Blue Electric Pump

The blue ELEC PUMP pushbutton controls the blue electric pump.
With the BLUE ELEC PUMP pushbutton set to AUTO, the electric pump operates
from the moment the first engine is started until the last engine is shut-down.
When the pushbutton is set to OFF, the pump is de-energized.

Power Transfer Unit (PTU)

The PTU pushbutton controls the arming of the bidirectional Power Transfer Unit
automatic function.

Engine 2 Pump
ENG 2 PUMP pushbutton controls the engine 2 hydraulic pump.
In normal conditions the engine driven pump 2 pressurizes the yellow system.
When the pushbutton is set to OFF, the pump operates in the depressurized
mode.

Yellow Electric Pump

The yellow ELEC PUMP pushbutton controls the yellow electric pump.

for training purposes only

29-10-2
 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -10 Main Hydraulic Power

Figure 1: System Controls

for training purposes only

29-10-3
 Training Manual Hydraulic Power
A318/A319/A320/A321 29-10 Main Hydraulic Power

Figure 2: Hydraulic Control Panel

A B
B

 
           
   
 
      
    
A      
 
          

  
       
 
     
 
      
 
 
       
  
         
 
 

for training purposes only

29-10-4
 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -10 Main Hydraulic Power

Figure 3: Hydraulic Control Panel

A B
B



       
        
     
 
     
      
  


 
    
     
       
    
       

   

   
 
 
 
 
 
 
 

for training purposes only

29-10-5
 Training Manual Hydraulic Power
A318/A319/A320/A321 29-10 Main Hydraulic Power

SYSTEM OVERVIEW - PTU & RAT

for training purposes only

29-10-6
 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -30 Indication

29-30 Indication

for training purposes only

29-30-1
 Training Manual Hydraulic Power
A318/A319/A320/A321 29-30 Indication

Figure 1: ECAM Hydraulic Page



 

  


 

 
 

 

  











        
        


for training purposes only

29-30-2
 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -30 Indication

Figure 2: ECAM Hydraulic PAGE




 
  

 

 
  

 

 




 

 

 



 







 

         


for training purposes only

29-30-3
 Training Manual Hydraulic Power
A318/A319/A320/A321 29-30 Indication

Figure 3: Hydraulic Indications






 
 


   


  





 
 

 



 





for training purposes only

29-30-4
 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -30 Indication

Figure 4: ECAM Hydraulic Power System

for training purposes only

29-30-5
 Training Manual Hydraulic Power
A318/A319/A320/A321 29-30 Indication

Figure 5: Warnings and Cautions

   
 
      
   
      
 
   

 
    
   
   
  
   
 

           
    
    
 
   
   
    
  
   
     
     
 
  

 
 
 
  
Memo Display
   
    

  If ram air turbine is not fully stowed, RAT OUT message is displayed in green.


  Light becomes amber during flight phase 1 and 2.
 

  HYD PTU is displayed in green when PTU is running.
   
  

 
  
 
 
   
 
  


 
  
 


   
  


         

for training purposes only

29-30-6
 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -30 Indication

Electrical Supply
Figure 6:

BUS BAR AC DC
AC DC HOT
A/C SYS ESS ESS
ENG 1 DRIVEN PUMP CTL 
ENG 2 DRIVEN PUMP CTL 
ENG 1 FIRE SHUT OFF VALVE 
ENG 2 FIRE SHUT OFF VALVE 
 
Bl e ELEC PUMP
Blue
 
 
Yellow ELEC PUMP
 
Power Transfer Unit 

LEAK MEASUREMENT VALVES

 
RAT
 

 

for training purposes only

29-30-7
 Training Manual Hydraulic Power
A318/A319/A320/A321 29-30 Indication

System Description
Main System
Line Routing
Most of the components of the systems are in the three hydraulic compartments.
The Green system components are in the main landing gear compartment. The
Yellow system components are in the hydraulic compartment in the right belly fair-
ing. The Blue system components are in the hydraulic compartment in the left belly
fairing. The two hydraulic compartments (Blue and Yellow) are forward of the main
landing-gear compartment.
There are three ground service panels, one for each main system. The Blue and
Green ground service panels are in the left belly fairing. The Yellow ground service
panel is in the right belly fairing. All of the ground service panels are aft of the main
landing-gear compartment.
All of the ground service panels have self-sealing connectors for hydraulic power
supply on the ground. The ground service panel of the Green system has a hand
pump, filter and selector valve so that any of the reservoirs can be filled from it.
The ground service panel of the Yellow system has a hand pump and selector
valve. They give an alternate method to operate the cargo doors.
The ground service panel of the Blue system has the ram air turbine control panel.

for training purposes only

29-30-8
 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -30 Indication

Figure 7: Line Routing of Center Part

for training purposes only

29-30-9
 Training Manual Hydraulic Power
A318/A319/A320/A321 29-30 Indication

Figure 8: Line Routing of Forward Part Figure 9: Line Routing of Aft Part

for training purposes only

29-30-10
 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -30 Indication

Figure 10: Location of Hydraulic Components

for training purposes only

29-30-11
 Training Manual Hydraulic Power
A318/A319/A320/A321 29-30 Indication

Figure 11: Location of Hydraulic Components

for training purposes only

29-30-12
 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -30 Indication

Circuit Identification Each pipe is identified by a self-adhesive label, which indicates:

• the part number of the pipe
Pipes • the identification of the pipe as a hydraulic pipe, its function with black dots and
High pressure (HP) pipes which are not in fire zones are made of titanium alloy the direction of the fluid flow with yellow and blue fields
and are not painted. HP pipes in fire zones are made of stainless steel. Low pres- • an identification of the system compromising a color and a number 1, 2 or 3
sure (LP) pipes are made of light alloy and are painted for protection against cor- respectively indicating the green, blue or yellow system.
rosion. Flexilble pipes are used where it is necessary because there is vibration or
movement between components.
Figure 12: Pipeline and Component Identification

for training purposes only

29-30-13
 Training Manual Hydraulic Power
A318/A319/A320/A321 29-30 Indication

Connections
The manifolds have bobbin type connections for some components. The bobbins
are equipped with a square seal on the component side and an o-ring on the man-
ifold side.
Figure 13: Bobbin Type Connection

for training purposes only

29-30-14
 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -11 Green Hydraulic System

29-11 Green Hydraulic System

for training purposes only

29-11-1
 Training Manual Hydraulic Power
A318/A319/A320/A321 29-11 Green Hydraulic System

Green Hydraulic System Fire Valve

Most of the system components are installed in the main landing gear compart- The green system fire valve installed in the left hand wing, inboard of the pylon, is
ment. controlled by ENG 1 FIRE push-button.
When the valve closes it stops the supply of fluid to the Engine Driven Pump.
Reservoir
The reservoir is equipped with a direct reading gauge, a quantity indicator and a Engine Driven Pump
low level switch for ECAM indicating and warning. The Engine Driven Pump is attached to the accessory gearbox. A solenoid valve
Normal fill level: 14 l. (3.7 US gal) controlled by the ENG 1 PUMP push-button selects the pressurized or depressu-
rized mode.
Maximum gaugeable level: 18 l. (4.76 US gal)
The Engine Driven Pump cooling and lubricating flow passes through the case
Low level warning: 3.0 ± 0.4 l. (0.79 ± 0.1 US gal) drain filter installed in the return circuit.
Reservoir Pressurization Pump outlet pressure is 3000 psi (206 bar) at zero flow.
The reservoir is normally pressurized with air to prevent cavitation of the pumps. The Engine Driven Pump includes a blocking valve which isolates the pump from
the hydraulic system when the pump operates in the depressurized mode.
The reservoir is pressurized to 50 psi (3.43 bar) and is sealed to hold the pressure
when there is no air supply. Case drain filter clogging indication: 87 ± 8.7 psi (6 ± 0.6 bar).
The threshold of the low pressure switch is 22 psi (1.52bar).
Ground Couplings
The ground service panel consists of two connectors used to pressurize the green
hydraulic system from a ground cart, a selector valve, two connectors and a hand
pump used for hydraulic reservoir refilling.

GENERAL ... GROUND COUPLINGS

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 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -11 Green Hydraulic System

Figure 1: Green Hydraulic System

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 Training Manual Hydraulic Power
A318/A319/A320/A321 29-11 Green Hydraulic System

Pressure Switch It also makes a supply of fluid available in case of any demand.
The pressure switch monitors the Engine Driven Pump outlet pressure for ECAM The accumulator is precharged with nitrogen to 1885 psi (130 bar) at 20°C. It holds
indications. 0.18 liter (0.047 US gal) of usable fluid when it is full.
The threshold of pressure switch is 1740 psi (120 bar).
Sampling Valve
A check valve downstream of the pump stops the fluid flow to the pump if the
A sampling valve is provided on the HP manifold.
system is pressurized by the Power Transfer Unit (PTU).

Power Transfer Unit (PTU) Pressure Relief Valve

The system relief valve connects the high pressure circuit to the return circuit in
The Power Transfer Unit will run automatically when the differential pressure be-
case of overpressure.
tween the green and yellow circuits is greater than 500 psi (34. 5 bar).
The relief valve opens at 3436 psi (237 bar) and closes at 3190 psi (220 bar).
The PTU is inhibited during the first engine start and cargo door operation.

High Pressure Manifold

Pressure Switches
The signals from both pressure switches are sent to the Flight Control Computers,
to the Braking Steering Control Unit, to the ECAM and to the Flight Augmentation
Computer.
The threshold of the pressure switches is 1450 psi (99.5 bar).

Pressure Transducer
The pressure transducer provides data for pressure indication on the ECAM and
sends information to ELAC 1 and 2.

Leak Measurement Valve

The leak Measurement valve isolates the flight controls when the guarded LEAK
MEASUREMENT VALVES pushbutton on the maintenance panel is set to OFF.

HP Filter
The high pressure filter is equipped with a clogging indicator.
The clogging indicator operates when the differential pressure is higher than 87 ±
8.7 psi (6 ± 0.6 bar).

Accumulator
The accumulator acts as a damper for small changes.

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 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -11 Green Hydraulic System

Figure 2: Green Hydraulic System

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 Training Manual Hydraulic Power
A318/A319/A320/A321 29-11 Green Hydraulic System

Leak Measurement Manifold

The leak measurement valve block supplies the flight controls of the right hand
wing, left hand wing and tail section via three outputs.
Operating a spool valve allows the associated section to be supplied for leak
measurement test.

Power Transfer Manifold

Normal Braking Selector Valve
The normal braking selector valve cuts-off the hydraulic supply to the normal
brakes.

Solenoid Valve
The solenoid valve installed in the Power Transfer Unit supply line stops the Pow-
er Transfer Unit operation.

Priority Valve
The priority valve makes sure that all available hydraulic pressure is sent to the
primary flight controls if pressure in the system is reduced. The priority valve clos-
es at 127 bar (1841.9787 psi) to 130 bar (1885.4901 psi) and opens at 135 bar
(1958.0089 psi) to 140 bar (2030.5278 psi). The system priority valve is installed
on the PTU manifold.

Return Manifold
The return manifold comprises:
• one return filter equipped with a clogging indicator.
• one temperature transmitter which consists of one temperature switch and two
temperature transducers.
The bypass device operates when the pressure differential across the filter ele-
ment is more than 4.0 +0.4 - 0.4 bar (58 +6 -6 psi. It allows fluid to go from the inlet
to the outlet without filtration.
Temperature switch and temperature transducers send data to the ECAM for
warnings.
The filter has a filtration rating of 3 microns.

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 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -11 Green Hydraulic System

Figure 3: Green Hydraulic System

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 Training Manual Hydraulic Power
A318/A319/A320/A321 29-11 Green Hydraulic System

Green Hydraulic System Components

Leakage Measurement Manifold
The ground leakage measurement manifolds of the three hydraulic systems are
identical. The 2-way spool valves are manually opened for ground maintenance
tasks only. (leak measurement test)
Figure 4: Leakage Measurement Manifold

A

A

B

  B 






 





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 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -11 Green Hydraulic System

High Pressure Manifold HP Filter

The HP manifold has ports which connect it to the other parts: The filter element is of the replaceable type. It cannot be cleaned.
• A system pressure inlet from pumps and ground supply. The filter also includes a clogging indicator which has to be reset manually after
• Two outlets to the Leak Measurement System Manifold. replacement of the filter element.
• One outlet and one inlet to the PTU manifold. An anti-spill device is also included in the filter in order to prevent any hydraulic
• One connection to the accumulator/ cargo doors selector valve/ brake mani- fluid flow when the filter element and the bowl are removed.
fold. The HP filter has a filtration rating of 15 microns.
Figure 5: HP Manifold Components



  



 



 






 






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 Training Manual Hydraulic Power
A318/A319/A320/A321 29-11 Green Hydraulic System

Pressure Transducer Figure 6: HP Manifold Components

The pressure transducer measures the system pressure and sends signals to the
SDAC for ECAM display and to ELAC 1/ 2 for Flight Control System.

Fluid Sampling Valve

The sampling valve makes it possible to take samples of fluid for analysis with the
system at full pressure.

The end cap provided with a slot is used as a tool to open the valve.

Pressure Relief Valve 

The pressure relief valve protects the system from overpressure. It opens at 237 
bar (3436 psi) and closes at 220 bar (3190 psi).
 
Leakage Solenoid Valve
The leakage solenoid valve controls the fluid flow to the leakage measurement 
system manifold. It is normally open. During ground operation of the system, the 
valve is closed to connect the HP outlet port to the return circuit and thus shuts the
HP inlet port. 
Pressure Switches

The two pressure switches monitor the system pressure, and send a signal at both
low and high pressure. 
The pressure switch 1151GN sends information to the FWC, the flight control sys-
tem and the auto flight system.
The pressure switch 10CE-2 sends information to the flight control system only.

Accumulator
The accumulator is of the cylindrical type with an internal bladder. The metal body
has an outer layer of kevlar to make it stronger. The accumulator is precharged 
with nitrogen to 130bar (1885psi) at 20°C.
The accumulator has a total volume of 1 l (0.26 US gal) and the gas precharge
pressure is 130 bar (1885 psi). It holds 0.18 l (0.0475 US gal) of useable fluid when
it is full (at 3000 psi (206 bar)). A gas charging valve and a direct reading pressure
gage are installed on the accumulator.

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 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -11 Green Hydraulic System

Engine Driven Pump 1 EDP 1 Case Drain Filter

The Engine Driven Pump (EDP), which is of the variable displacement type, is at- The filter is equipped with a pop-out clogging indicator. It operates when the dif-
tached to the accessory gearbox on the bottom of the engine via keyhole slots and ferential pressure across the filter is 87 ± 8.7 psi (6 ± 0.6 bar). There is no bypass
installation bolts. The suction line has a quick disconnect self-sealing coupling to device if the filter element is clogged.
facilitate pump removal/ installation. The filtration rating is 15 microns.
Figure 7: Engine Driven Pump/Case Drain Filter

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 Training Manual Hydraulic Power
A318/A319/A320/A321 29-11 Green Hydraulic System

EDP 1 Pressure Switch

The switch monitors the output pressure of the engine driven pump. It sends a low
pressure signal at 1740 ± 72.5 psi (120 ± 5 bar pressure decreasing) and stops
the signal when the pressure reaches 2200 psi (152 bar pressure increasing).

Engine Fire Valve

The fire valve, which is of the ball valve type is installed in the LH wing between
the rear spar and the false rear spar inboard of the pylon. The electric motor is a
28 VDC type motor. An indicator, visible through a window provided in the valve
housing, shows the valve position (open or shut).
Figure 8: Engine Fire Valve

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 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -11 Green Hydraulic System

Green Hydraulic Reservoir

Reservoir
The reservoir is made of two moulded light alloy sections welded together. The top
of the reservoir has a manifold for the components of the air pressurization sys-
tem. The reservoir is divided into two parts. The lower part is always full. A transfer
tube enables hydraulic fluid exchange with the upper part which constitutes the flu-
id reserve.
Figure 9: Green Hydraulic Reservoir Location

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 Training Manual Hydraulic Power
A318/A319/A320/A321 29-11 Green Hydraulic System

Engine Driven Pump

General Description
There are two different types of EDP which are permitted. ABEX make one type,
VICKERS the other. The two types are completely interchangeable. They give
equivalent supplies of hydraulic power and their mechanical and electrical con-
nections are the same.
The engine-driven pump (EDP) is attached to the accessory gearbox on the bot-
tom of the engine. A splined quill drive connects the gearbox to the input shaft of
the pump. The quill drive is made to shear if the pump can not turn. The attach-
ment flange of the pump has keyhole slots where the installation bolts are.
The suction line connection has a quick-release self-sealing coupling. Together,
they make it possible to replace the pump quickly.
The pump is of the variable-displacement type. The rotating assembly turns all of
the time that the engine operates.
The pump has nine pistons which are connected to a moveable yoke plate. When
the angle of the yoke plate changes, the strooke of the pistons changes and the
output of the pump is increased or decreased. The compensator valve supplies
servo pressure to the actuator piston, which controls the angle of the yoke.
A solenoid valve (controlled from the flight compartment) makes it possible to
change the operation of the pump so that it does not supply pressure to the system
(depressurized mode). The EDP includes a blocking valve which isolates the
pump from the hydraulic system when the pump operates in the depressurized
mode. In the depressurized mode the outlet of the pump is connected internally
directly to the inlet of the pump.
The pump then operates with an internal pressure of approximately 1000 psi (70
bar), with zero flow. This is the pressure necessary on the actuator piston to re-
duce the angle of the yoke to near zero when the outlet and control pressures are
balanced.
A case pressure relief valve connects the fluid in the EDP case to the inlet of the
pump if the pressure of the fluid in the case is too high (for example if the case
drain pipe is blocked). A pump inlet boost impeller is included in the EDP which
increases the pressure of the fluid at the inlet of the pump. This makes certain that
the chambers of the pump get a sufficent supply of fluid at all conditions of opera-
tion.

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 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -11 Green Hydraulic System

Figure 10: Engine Driven Pump - Schematic

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29-11-15
 Training Manual Hydraulic Power
A318/A319/A320/A321 29-11 Green Hydraulic System

Figure 11: Green Hydr. Syst. Electronical Power Supply and Monitoring

            
                 
    
   
   
    
       
    
   
        
          
         
       
     
            
         
  
      
  

 
 

    
  

  

                  
 
               
     
            
            

                
 
          
     
  
  
       
 
     


             
   

 
                
          
                 
         
  

          

                                                       
  
  
                                                        
    
                                                           
  
                             
                                   
                            
                                 
  
  
    
         
    
         
        
             

          
       
                       
       
        
             
  
  
  
         
     
   
            
              
                  
           
   
        

for training purposes only

29-11-16
 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -11 Green Hydraulic System

Drain Valve Figure 13: Reservoir

A hollow type drain valve is installed at the bottom of the reservoir. The valve is
opened by turning (counter-clockwise) and pushing the bushing/valve pin assem-
bly. Then the bushing is rotated clockwise to lock the valve in the open position.

Low Level Switch

The low level switch is a float operated switch which includes a relay and a magnet
which keeps the contacts open when the float is high. A metal shroud around the
float operates as a damper for small changes in the fluid level.
Figure 12: Low Level Switch

for training purposes only

29-11-17
 Training Manual Hydraulic Power
A318/A319/A320/A321 29-11 Green Hydraulic System

Air Pressure Gage Figure 14: Reservoir Components

The reservoir pressure gage displays the air pressure in a range of 0-75 psi (0-5
bar).

Air Pressure Switch

The air pressure switch closes when the pressure decreases to 22 ± 1.5 psi (1.5
± 0.1 bar). The contacts open when the pressure increases to 25 psi (1.7 bar).

Air Relief Valve

The air relief valve relieves pressure to the atmosphere in the event of a system
overpressurization (77 psi/ 5.3 bar).

Level Transmitter
The level transmitter permits:
• Direct reading of the hydraulic fluid level.
• Transmission of the level indication to the cockpit.
It includes an arm fitted with a float which drives a gear train on a magnetic cou-
pling. The synchro transmitter shaft supports a pointer to permit direct reading of
the fluid level.

for training purposes only

29-11-18
 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -11 Green Hydraulic System

Return Manifold Temperature Transmitter

The LP return manifold is the connection point for return lines from different parts The temperature transmitter connected to the SDAC comprises:
of the LP system. • a temperature switch which operates at 95 ± 2.2°C (203 ± 4°F).
The LP filter and a temperature transmitter are directly connected to the manifold. • two temperature transmitters which measure fluid temperature between -55°C
(+ 131°F) and 120°C (248°F).
LP Return Filter
The LP RETURN filter has a filtration rating of 3 microns. The bypass device al-
lows fluid to go from the inlet to the outlet without filtration.
Figure 15: Return Manifold

LEAK MEASUREMENT MANIFOLD ... RETURN MANIFOLD

for training purposes only

29-11-19
 Training Manual Hydraulic Power
A318/A319/A320/A321 29-11 Green Hydraulic System

Ground Service Panel Figure 16: Ground Service Panel

Ground Test Connectors

The delivery ground connector (1008GM) and suction ground connector
(1006GM) are of the self-sealing type.

Reservoir Depressurization Valve

The reservoir depressurization valve is a manually operated 2-way valve. It is nor-
mally closed by spring force. It opens by turning the cap assembly or by connect-
ing the ground depressurization coupling.

Reservoir Quantity Indicator

RESERVOIR
The indicator has three coloured scales, one for each reservoir. Three lights: two FILL SYSTEM
Light Emitting Diodes (LEDs) for green and yellow, and filament lamp for blue, in- WITH HAND
dicate which system the indicator is set to. PUMP FILL VALVE

Reservoir Filling Selector

The reservoir filling selector valve assembly has two main parts:
• the hydraulic selector unit which controls the flow of fluid to the reservoirs.
• the electrical switch unit which controls the electrical supply to the quantity in-
dicator.

Filling Filter
The mechanical clogging indicator of the HP filling filter has a thermal lock which
inhibits its operation when the fluid temperature decreases to 0°C (32°F).
The thermal lock releases when the fluid temperature increases to 30°C (86°F).

Filling Hand Pump

The Hand Pump is a two stroke type pump and supplies 40 ml per stroke at a low
pressure or 10 ml per stroke at a high pressure. It is interchangeable with that of
the yellow system.
The hand pump includes a manually operated filling valve which is also used as a
flexible hose connector.

Reservoir Filling Connector

The reservoir filling connector is half of a self-sealing quick-disconnect coupling.
The filling valve also incorporates a filter and a check valve.

for training purposes only

29-11-20
 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -11 Green Hydraulic System

HP MANIFOLD - PRESSURE SWITCHES ... PRESSURE RELIEF VALVE

for training purposes only

29-11-21
 Training Manual Hydraulic Power
A318/A319/A320/A321 29-11 Green Hydraulic System

Figure 17: Green Hydraulic System    

  

   

   

 
  
 



 
 






 











  
 











 




   


  
 
  

 
  

 

  





 




  


 




 
 

for training purposes only

29-11-22
 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -12 Blue Hydraulic System

29-12 Blue Hydraulic System

for training purposes only

29-12-1
 Training Manual Hydraulic Power
A318/A319/A320/A321 29-12 Blue Hydraulic System

Most of the system components are installed in the blue hydraulic compartment
located in the left hand belly fairing, forward of the main landing gear compart-
ment.

Reservoir
The reservoir is equipped with a direct reading gauge, a quantity indicator and a
low level switch for ECAM indicating and warning.
Normal fill level: 6l (1.58 US gal)
Maximum gaugeable level: 8l (2.11 US gal)
Low level warning: between 2.0 and 2.3l (0.52 and 0.6 US gal).

Reservoir Pressurization
The reservoir is normally pressurized with air to prevent pump cavitation.
The reservoir is pressurized to 50 psi (3.43 bar) and is sealed to hold the pressure
when there is no air supply.
The threshold of the air pressure switch is 22 psi (1.52 bar).

Electric Pump
With the ELEC PUMP pushbutton set to AUTO, the blue electric pump will run, if
one engine is running, or BLUE PUMP OVRD pushbutton is set to ON, or Nose
Landing Gear is not compressed and AC power is available from APU. With the
last condition, at touch down a time delay relay maintains the pump operation for
two minutes after nose landing gear compression.
The pump outlet pressure is 3000 psi (206 bar) at zero flow.
A temperature switch sends a signal to the ECAM if the pump body temperature
exceeds 165°C.
The electric pump cooling and lubricating flow passes through the case drain filter
installed in the return circuit.

for training purposes only

29-12-2
 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -12 Blue Hydraulic System

Figure 1: Blue Hydraulic System

Pulsation
Damper

TEMP. TRANSMITTER

for training purposes only

29-12-3
 Training Manual Hydraulic Power
A318/A319/A320/A321 29-12 Blue Hydraulic System

Blue Hydraulic System Priority Valve

The priority valve makes sure that all available hydraulic pressure is sent to the
Ram Air Turbine primary flight controls if pressure in the system is reduced.
The Ram Air Turbine is deployed automatically in flight if the electrical power is Pressure Relief Valve
lost, or manually by using either of the guarded pushbuttons.
The pressure relief valve connects the high pressure circuit to the return circuit in
Pressure Switch case of over pressure.
The pressure switch monitors the electric pump pressure for ECAM indications. The relief valve opens at 3436 psi (237 bar) and closes at 3190 psi (220 bar).
The threshold of the pressure switch is 1450 psi (99.5 bar). Sampling Valve
A check valve stops the flow of fluid to the electric pump if the system is pressu- A sampling valve is provided on the HP Manifold.
rized by the Ram Air Turbine (RAT).

High Pressure Manifold

Pressure Switches
The signals from both pressure switches are sent to the ECAM system and to the
Flight Control Computers.
The threshold of the pressure switches is 1450 psi (99.5 bar).

Pressure Transducer
The pressure transducer provides data for pressure indication on the ECAM and
sends information to ELAC 1 and 2.

Leak Measurement Valve

The leak measurement valve isolates the flight controls when the guarded LEAK
MEASUREMENT VALVES pushbutton on the maintenance panel is set to OFF.

HP Filter
The high pressure filter is equipped with a clogging indicator.
The clogging indicator operates when the differential pressure is higher than 87 ±
8.7 psi (6 ± 0.6 bar).

Accumulator
The accumulator acts as a damper for small changes. It also makes a supply of
fluid available in case of any demand. The accumulator is precharged with nitro-
gen to 1885 psi (130 bar) at 20°C. It holds 0.18l (0 047 USgal) of useable fluid
when it is full.

for training purposes only

29-12-4
 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -12 Blue Hydraulic System

Figure 2: Blue Hydraulic System

Pulsation
Damper

for training purposes only

29-12-5
 Training Manual Hydraulic Power
A318/A319/A320/A321 29-12 Blue Hydraulic System

Blue Hydraulic System Return Manifold

The return manifold comprises:
Leak Measurement Manifold The bypass operates when the differential pressure across the filter is more than
The leak measurement valve block supplies the flight controls of the right hand 58 ± 6 psi (4 ± 0.4 bar). Temperature switch and probes send data to the ECAM
wing, left hand wing and tail section via three outputs. for indication and warnings.
Operating a spool valve allows the associated section of the flight controls to be The LP filter is functionally the same as the LP filter installed in the green hydraulic
supplied for leak measurement test. system. The only differences are in its size and the configuration of the filter head.

Ground Couplings
On ground it is possible to pressurize the blue hydraulic system from a ground
power unit.

LEAK MEASUREMENT MANIFOLD & RETURN MANIFOLD

for training purposes only

29-12-6
 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -12 Blue Hydraulic System

Figure 3: Blue Hydraulic System

Pulsation
Damper

for training purposes only

29-12-7
 Training Manual Hydraulic Power
A318/A319/A320/A321 29-12 Blue Hydraulic System

Figure 4: Blue Electric Hydraulic Pump Control

for training purposes only

29-12-8
 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -12 Blue Hydraulic System

Blue Hydraulic System Components The ground leakage measurement manifolds of the three hydraulic systems are
identical.
Leakage Measurement Manifold The 2-way spool valves are manually opened for ground maintenance tasks only.
The supply of all the consumers other than the slat motor and the CSM/ G goes
through the leakage measurement manifold.
Figure 5: Leakage Measurement Manifold















for training purposes only

29-12-9
 Training Manual Hydraulic Power
A318/A319/A320/A321 29-12 Blue Hydraulic System

High Pressure Manifold

The supply of most of the consumers goes through the HP manifold.
The HP manifold is installed in the blue hydraulic compartment.
Figure 6: HP Manifold

MANIFOLD

FLUID SAMPLING VALVE HIGH PRESSURE MANIFOLD

for training purposes only

29-12-10
 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -12 Blue Hydraulic System

Priority Valve An anti-spill device is also included in the filter in order to prevent any hydraulic
The priority valve ensures sure that all available hydraulic pressure is sent to the fluid flow when the filter element and the bowl are removed.
primary flight controls if the pressure in the system is reduced.
Accumulator
Fluid Sampling Valve The accumulator is of the cylindrical type with an internal bladder.
The sampling valve makes it possible to take samples of fluid for analysis with the The metal body has an outer layer of kevlar to make it stronger.
system at full pressure. The accumulator is precharged with nitrogen to 1885 psi (130 bar) at 20°C.
The end cap provided with a slot is used as a tool to open the valve. The bladder is made of rubber and isolates the nitrogen gas from the hydraulic flu-
id. It holds 1 liter (0,26 US gal) of usable fluid when it is full.
Leakage Solenoid Valve
The leakage solenoid valve controls the flow of the fluid to the leakage measure-
ment system manifold. It is normally open.
During ground operation of the system, the solenoid valve can be operated from
the maintenance panel 50VU in the flight compartment, to isolate the primary flight
users. In this case, the valve is closed to connect the HP outlet port to the return
port and shut the HP inlet port.

Pressure Relief Valve

The pressure relief valve protects the system from overpressure.
It opens at 3436 psi (237 bar) and closes at 3190 psi (220 bar).

Pressure Switches
Two pressure switches send a low pressure signal at 1450 ± 72.5 psi (95 ± 5 bar)
(pressure decreasing) and send a high pressure signal at 1750 psi (120 bar) (pres-
sure increasing). The pressure switch 2151GN sends information to the FWC and
the Flight Control System. The pressure switch 10CE- 1 sends information to the
Flight Control System only.

Pressure Transducer
The pressure transducer measures the system pressure and sends signals to the
ELAC 1/ 2 for Flight Control System and to the SDAC for ECAM display. The trans-
ducer is a sealed unit.

HP Filter HIGH PRESSURE MANIFOLD & ACCUMULATOR

The filter element is of the replaceable type. It cannot be cleaned. The filter also
includes a clogging indicator which has to be reset manually after replacement of
the filter element.

for training purposes only

29-12-11
 Training Manual Hydraulic Power
A318/A319/A320/A321 29-12 Blue Hydraulic System

Blue Electric Pump Pulsation Damper

The electric pump of the blue hydraulic system is installed in the blue hydraulic The pulsation damper, which is a metal sphere, is installed in the pump outlet line
compartment. It is interchangeable with the yellow electric pump. to remove pulses from the HP flow.
The electric pump is installed in the blue hydraulic compartment. The electric Figure 7: HP Manifold
pump assembly includes:
• an electric motor,
• a pump inlet impeller,
• a hydraulic pump.
The electric motor is a conventional induction motor. It operates with a three-
phase electric supply of 115 V AC, 400 Hz. It has an air blower assembly to keep
the outer frame of the motor cool. In additional, there is a gerotor-type hydraulic
pump which supplies a flow of hydraulic fluid to the electric motor. The fluid goes
through the hollow drive shaft of the motor and keeps the shaft and bearing area
cool. BLUE ELECTRIC
PUMP
There is a temperature switch in the electric motor. If the temperature of the motor PULSATION
increases to 162 deg. C (503 deg. F) the switch operates and sends signals to the DAMPER
ECAM and to the overhead panel.
The inlet impeller is in the inlet to the hydraulic pump. It turns together with the
pump assembly. The impeller improves the flow of fluid to the inlet port of the cyl- ACCUMULATOR
inder barrels. This makes it possible for the pump to operate more efficiently with
a low inlet pressure.
The hydraulic pump is of the variable-displacement inline type with seven pistons.
A moveable hangar controls the stroke of the pistons and thus the displacement
of the pump. The hangar moves in response to changes in the system pressure.

Low Pressure Switch

The pressure switch is installed downstream of the electric pump to monitor the
output pressure. It sends a signal to the ECAM and a local warning to display the
blue pump low pressure warning.

Case Drain Filter

The case drain filter is equipped with a pop-out clogging indicator. It operates
when the differential pressure across the filter is 87 ± 8.7psi (6 ± 0.6 bar).
There is no by-pass device if the filter element is clogged. The filtration rating is
15 microns. LOW PRESSURE CASE DRAIN
SWITCH FILTER

for training purposes only

29-12-12
 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -12 Blue Hydraulic System

Figure 8: Blue Electric Pump

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A318/A319/A320/A321 29-12 Blue Hydraulic System

Blue Electric Pump Protection Figure 10: Phase Unbalance Detector

A current transformer and a phase unbalance detector provide protection if there
is a fault in the electric pump motor or in the supply. The current transformer com-
pares the flow of current in each phase of the AC motor supply.
If a difference is detected, the current transformer sends a signal to the phase un-
balance detector which stops the pump motor.
A test pushbutton is provided on the phase unbalance detector to simulate current
transformer operation.
An indicator light comes on to show that both units have operated correctly.
Figure 9: Current Transformator

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A318/A319/A320/A321 29 -12 Blue Hydraulic System

Ram Air Turbine (RAT) Figure 11: RAM Air Turbine

The purpose of the rat is to pressurizethe blue hydraulic system in case of hydrau-
lic system pressure loss.
Beside the normal hydraulic pressure userssupply, the pressure is also able to op-
erate an emergency generator (CSM/G).
The RAT is installed in the LH belly fairing. It is extended into the airflow by an ac-
tuator. RAT retraction is only possible when the aircraft is on ground.
The RAT is a constant speed unit.
The RAT is extended and locked in position by means of a RAT actuator.

Manufacturer: RAT for A319/ A321 is Sunstrand USA

RAT for A320 is Dowty England

RAT Actuator
The RAT actuator is installed between the aircraft structure and the RAT leg as-
sembly. It is used for RAT extension and retraction. It is extended by spring force
and retracted by hydraulic power. The jack is mechanically locked in both the ex-
tended and retracted positions. RAT extension is controlled by two solenoids lo-
cated at the top of the actuator. A ground retraction module controls the retraction
of the actuator.

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Blue Hydraulic Reservoir Figure 12: Blue Hydraulic Reservoir

The inside of the reservoir includes baffles which give a supply of fluid under neg-
ative "g" conditions.
The baffles also form an anti-emulsion device which limits the emulsion when
there is a large return flow.

Air Pressure Gage

The reservoir pressure gage displays the air pressure in a range of 0-75 psi (0-
5.15 bar).

Air Pressure Switch

The air pressure switch closes when the pressure decreases to 22 psi (1.5 bar).
The contact opens when the pressure increases to 25 psi (1.7 bar).
An additional pressure switch is installed only on A320 aircraft using dowty ram air
turbine (RAT) sends a discrete signal to the SDAC. If the air pressure in the blue
reservoir decreases to 30 psig or 45 psia, the pressure switch gives a signal in
flight (flight phases 5, 6 and 7) which is then memorized only and displayed after
landing (flight phases 8, 9 and 10).

Air Relief Valve

The air relief valve relieves pressure to the atmosphere in the event of a system
overpressurization (77 psi - 5.3 bar).

Low Level Switch

The low level switch is a float operated switch which includes a relay and a magnet
which keeps the contacts open when the float is high. A metal shroud around the
float operates as a damper.

Level Transmitter
It gives a visual indication and sends a signal to the SDAC and to the reservoir
quantity indicator on the green ground service panel for fluid content indication.

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Return Manifold Figure 13: Return Manifold, Return Filter and Temp. Transmitter

Filter
The LP return filter has a filtration rating of 3 microns.
The bypass device allows fluid to go from the inlet to the outlet without filtration.

Temperature Transmitter
The temperature transmitter connected to the SDAC comprises:
• a temperature switch which operates at 95 ± 2°C (203 ± 4°F)
• two temperature transmitters which measure fluid temperature between - 55°C
(+ 131°F) and 120°C (248°F).

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Ground Service Panel Reservoir Drain Valve

A hollow type drain valve is installed on the service panel. The valve is opened by
Reservoir Depressurization Valve turning (counter-clockwise) and pushing the bushing/ valve pin assembly. Then,
The reservoir depressurization valve is a manually operated 2-way valve. It is the bushing is rotated clockwise to lock the valve in the open position.
closed by spring force.
Ground Connectors
It opens by turning the cap assembly or by connecting the ground depressuriza-
tion coupling. The delivery ground connector (2008 GM) and suction ground connector (2006
GM) are of the self-sealing type.
Figure 14: Hydraulic Service Panel

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RAT Ground Control Panel Figure 15: RAT Control Panel

The RAT ground control panel comprises the controls to stow the RAT. The
GROUND CHECK connector is the connector for the RAT ground test equipment.
The guarded ARM switch supplies electrical power to the STOW/ RESET selector
switch.
Indication lights are checked by using the LAMP test pushbutton. The indication
lights come on during the RAT retraction.
The RAT control panel is protected by means of a cover provided with a window
so that the indication lights can be seen with the cover in the closed position.
The RAT control panels A319/321 to A320 are different. (see 29-22)

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A318/A319/A320/A321 29-12 Blue Hydraulic System

Figure 16: Blue Hydraulic System

RESERVOIR ... GROUND COUPLINGS




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29-13 Yellow Hydraulic System

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A318/A319/A320/A321 29-13 Yellow Hydraulic System

Most of the system components are installed in the yellow hydraulic compartment, Ground Couplings
located in the right hand belly fairing, forward of the main landing gear compart-
On the ground it is possible to pressurize the yellow hydraulic system from a
ment.
ground power unit.
Reservoir
The reservoir is equipped with a direct reading gauge, a quantity indicator and a
low level switch for ECAM indications and warnings.
Normal fill level: 12 l (3.17 US gal).
Maximum gaugeable level: 18 l (4.76 US gal).
Low level warning: 3 ± 0.4 l (0.79 ± 0.1 US gal).

Reservoir Pressurization
The reservoir is normally pressurized with air to prevent cavitation of the pumps.
The reservoir is pressurized to 50 psi (3.43 bar) and is sealed to hold the pressure
when there is no air supply.
The threshold of the air pressure switch is 22 psi (1.52 bar).

Fire Valve
The yellow system fire valve installed in the right hand wing, inboard of the pylon,
is controlled by ENG2 FIRE pushbutton.
When the valve closes it stops the supply of fluid to the Engine Driven Pump.

Engine Driven Pump

The Engine Driven Pump is attached to the accessory gearbox. A solenoid valve
controlled by the ENG 2 PUMP pushbutton selects the pressurized or depressu-
rized mode.
The Engine Driven Pump cooling and lubricating flow passes through a case drain
filter installed in the return line.
Pump outlet pressure is 3000 psi (206 bar) at zero flow.
The Engine Driven Pump includes a blocking valve which isolates the pump from
the hydraulic system when the pump operates in the depressurized mode.
Case drain filter clogging indication: P = 87 ± 8.7 psi (6 ± 0.6 bar).

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Figure 1: Yellow Hydraulic System

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Pressure Switch Electric Pump

A pressure switch monitors the Engine Driven Pump outlet pressure for ECAM in- The yellow electric pump runs if the ELEC PUMP pushbutton is set to ON, or if a
dications. cargo door selector is operated.
The threshold of the pressure switch is 1740 psi (120 bar). The electric pump cooling and lubricating flow passes through the return filter.
A check valve downstream of the pump stops the fluid flow to the pump if the In case of cargo door operation, the PTU is inhibited, the yellow leak measurement
system is pressurized by the Power Transfer Unit (PTU) or by the yellow valve is closed and a signal is sent to SFCC2 to prevent flaps movement.
electric pump. A check valve downstream of the pump stops the fluid flow to the pump if the sys-
tem is pressurized from the Engine Driven Pump or the PTU.
Power Transfer Unit (PTU)
The Power Transfer Unit will run automatically when the differential pressure be- Hand Pump
tween the green and yellow systems is greater than 500 psi (34.5 bar). The hand pump is installed on the ground service panel of the yellow system and
The PTU is inhibited during the first engine start and cargo door operation. is used for manual cargo door operation only. On ground, when no electrical pow-
er is available, the hand pump can be used to open or close the cargo doors.

HAND PUMP & ELECTRIC PUMP

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Figure 2: Yellow Hydraulic System

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High Pressure Manifold HP Filter

The High Pressure filter is equipped with a clogging indicator.
Pressure Switches The clogging indicator operates when the differential pressure is higher than 87 ±
The signals from both pressure switches are sent to the ECAM system, to the 8.7 psi (6 ± 0.6 bar).
Flight Control Computers and to the Flight Augmentation Computer 2.
Accumulator
The threshold of the pressure switches is 1450 psi (99.5 bar).
The accumulator acts as a damper for small changes.
Pressure Transducer It also makes a supply of fluid available in case of any demand.
The pressure transducer provides data for pressure indication on the ECAM and The accumulator is precharged with nitrogen to 1885 psi (130 bar) at 20°C. It holds
sends information to ELAC 1 and 2. 0.18l (0.047 USgal) of useable fluid when it is full.
Leak Measurement Valve Sampling Valve
The leak measurement valve isolates the flight controls when the guarded LEAK A sampling valve is provided on the HP manifold.
MEASUREMENT VALVES pushbutton on the maintenance panel is set to OFF.
The solenoid valve is automatically closed if the yellow electric pump is energized Pressure Relief Valve
by using cargo door selectors. This is to prevent any movement of the flight con- The pressure relief valve connects the high pressure circuit to the return circuit in
trols. case of overpressure.
The relief valve opens at 3436 psi (237 bar) and closes at 3190 psi (220 bar).

HP MANIFOLD & ACCUMULATOR

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Figure 3: Yellow Hydraulic System

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Leak Measurement Manifold

The leak measurement valve block supplies the flight controls of the right hand
wing, left hand wing and tail section via three separate outputs.
Opening a spool valve allows the associated section of the flight controls to be
supplied for leak measurement test.

PTU Manifold
Quick Disconnect
The quick disconnect is used for maintenance operations to prevent Power Trans-
fer Unit operation.

Priority Valve
The priority valve makes sure that all available hydraulic pressure is sent to the
primary flight controls if pressure in the system is reduced.

Solenoid Valve
The solenoid valve, installed in the Power Transfer Unit supply line, stops the
Power Transfer Unit operation.

Return Manifold
The return manifold comprises:
• a return filter equipped with a clogging indicator.
• a temperature switch and two temperature transducers.
The bypass operates when the differential pressure across the filter is more than
29 ± 2.35 psi (2 ± 0.16 bar).
Temperature switch and probes send data to the ECAM for indication and warn-
ings.

Figure 4: Yellow Hydraulic System

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LEAK MEASUREMENT MANIFOLD ... RETURN MANIFOLD

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Yellow Hydraulic System Components

Leakage Measurement Manifold
The ground leakage measurement manifolds of the three hydraulic systems are
identical. The 2- way spool valves are manually opened for ground maintenance
tasks only.

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A318/A319/A320/A321 29 -13 Yellow Hydraulic System

Figure 5: Yellow Leakage Measurement Manifold

A B






 B






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High Pressure Manifold The pressure switch 3151GN sends information to the FWC, the flight control sys-
tem and the auto flight system.
The HP manifold has ports which connect it to the other parts:
• A system pressure inlet from pumps and ground supply. Accumulator
• Two outlets to the Leak Measurement System Manifold. The accumulator is of the cylindrical type with an internal bladder. The metal body
• One outlet and one inlet to the PTU manifold. has an outer layer of kevlar to make it stronger. The accumulator is precharged
• One connection to the accumulator/cargo doors selector valve/brake manifold. with nitrogen to 130bar (1885psi) at 20°C.
It holds 1liter (0,26 US gal) of usable fluid when it is full. The bladder is made of
HP Filter rubber and isolates the nitrogen gas from the hydraulic fluid. A nitrogen charging
The filter element is of the replaceable type. It cannot be cleaned. valve (shrader type) and a direct reading pressure gage are installed on the accu-
The filter also includes a clogging indicator which has to be reset manually after mulator.flight control system only.
replacement of the filter element.
Yellow Hydraulic System Electric Pump
An anti- spill device is also included in the filter in order to prevent any hydraulic
fluid flow when the filter element and the bowl are removed. The electric pump assembly includes an electrical motor (115 VAC - 400 Hz - 3
phases), a pump inlet impeller a piston type hydraulic pump and a blower.
The HP filter has a filtration rating of 15 microns.

Pressure Transducer Yellow Hydraulic System Electric Pump

The pressure transducer measures the system pressure and sends signals to the The electric pump assembly includes an electrical motor (115 VAC - 400 Hz - 3
SDAC for ECAM display and to ELAC 1/ 2 for Flight Control System. phases), a pump inlet impeller a piston type hydraulic pump and a blower.

Fluid Sampling Valve

The sampling valve makes it possible to take samples of fluid for analysis with the
system at full pressure.
The end cap provided with a slot is used as a tool to open the valve.

Pressure Relief Valve

The pressure relief valve protects the system from overpressure. It opens at 237
bar (3436 psi) and closes at 220 bar (3190 psi).

Leakage Solenoid Valve

The leakage solenoid valve controls the fluid flow to the leakage measurement
system manifold. It is normally open. During cargo doors operation the valve is
closed to avoid hydraulic pressure to the flight controls users.

Pressure Switches
The two pressure switches monitor the system pressure, and send a signal at both
low and high pressure.

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A318/A319/A320/A321 29 -13 Yellow Hydraulic System

Figure 6: Yellow HP Manifold

A
D
C










 
 


C


  


 


 

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A318/A319/A320/A321 29-13 Yellow Hydraulic System

Yellow Hydraulic System Electric Pump Protection detected the Current Transformer sends a signal to the phase unbalance detector
which stops the supply of electrical power to the electric pump. A test pushbutton
A Current Transformer and a Phase Unbalance Detector give protection if there is is provided on the Phase Unbalance Detector to simulate a malfunction. An indi-
a fault in the electric pump motor or in the supply. The Current Transformer com-
cator light comes on to show that both units have operated correctly.
pares the flow of current in each phase of the AC motor supply. If a difference is
Figure 7: Current Transformator-Phase Unbalance Detector

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Yellow Engine Driven Pump 2 Figure 8: Yellow Engine Driven Pump

The Engine Driven Pump (EDP), which is of the variable displacement type, is at-
tached to the accessory gearbox on the bottom of the engine via keyhole slots and
installation bolts. The suction line has a quick disconnect self-sealing coupling to
facilitate pump removal/ installation.

EDP 2 Case Drain Filter

The filter is equipped with a pop- out clogging indicator. It operates when the dif-
ferential pressure across the filter is 87 ± 8.7 psi (6 ± 0.6 bar). There is no bypass
device if the filter element is clogged.
The filtration rating is 15 microns.

EDP 2 Pressure Switch

The switch monitors the output pressure of the engine driven pump. It sends a low
pressure signal at 1740 ± 72.5 psi (120 ± 5 bar pressure decreasing) and stops
the signal before the pressure reaches 2200 psi (152 bar pressure increasing).

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Engine Fire Valve 28 VDC type motor. An indicator, in the valve housing, shows the valve position
(open or shut).
The fire valve, which is of the ball valve type is installed in the RH wing between
the rear spar and the false rear spar inboard of the pylon. The electric motor is a
Figure 9: EDP Fire Shut Off Valve

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Reservoir tem. The reservoir is divided into two parts. The lower part is always full. A transfer
tube enables hydraulic fluid exchange with the upper part which constitutes the flu-
The reservoir is made of two moulded light alloy sections welded together. The top
id reserve.
of the reservoir has a manifold for the components of the air pressurization sys-
Figure 10: Yellow Reservoir

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Drain Valve Figure 11:

A hollow type drain valve is installed at the bottom of the reservoir. The valve is
opened by turning (counter- clockwise) and pushing the bushing/valve pin assem-
bly. Then the bushing is rotated clockwise to lock the valve in the open position.

Low Level Switch

The low level switch is a float operated switch which includes a relay and a magnet
which keeps the contacts open when the float is high. A metal shroud around the
float operates as a damper for small changes in the fluid level.

Air Pressure Gage

The reservoir pressure gage displays the air pressure in a range of 0- 75 psi (0- 5
bar).

Air Pressure Switch

The air pressure switch closes when the pressure decreases to 22 ± 1.5 psi (1.5
± 0.1 bar). The contacts open when the pressure increases to 25 psi (1.7 bar).

Air Relief Valve

The air relief valve relieves pressure to the atmosphere in the event of a system
overpressurization (77 psi/ 5.3 bar).

Level Transmitter
The level transmitter permits:
• Direct reading of the hydraulic fluid level.
• Transmission of the level indication to the cockpit.
It includes an arm fitted with a float which drives a gear train on a magnetic cou-
pling. The synchro transmitter shaft supports a pointer to permit direct reading of
the fluid level.

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Return Manifold Temperature Transmitter

The LP return manifold is the connection point for return lines from different parts The temperature transmitter connected to the SDAC comprises:
of the LP system. • a temperature switch which operates at 95 ± 2.2°C (203 ± 4°F).
The LP filter and a temperature transmitter are directly connected to the manifold. • two temperature transmitters which measure fluid temperature between -55°C
(+ 131°F) and 120°C (248°F).
LP Return Filter
The LP RETURN filter has a filtration rating of 3 microns. The bypass device al-
lows fluid to go from the inlet to the outlet without filtration. ( P > 58 psi)
Figure 12: Return Filter

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Yellow PTU-Manifold
Components at the manifold:
• Priority valve
• Check Valves
• PTU-solenoid valve

PTU-Solenoid Valve
It allows PTU operation in case of a hydraulic pressure malfunction.

Priority Valve
It stops the supply of fluid to non-essential consumers if the system pressure is too
low. (Close at 1885 psi)

Yellow Brake Manifold

The yellow brake manifold supplies the alternate or the parking brake system.
Components at the brake manifold:
• Accumulator pressure transmitter
• Pressure relief valve
• Check valves

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Figure 13: PTU-Manifold

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Yellow Ground Service Panel

Reservoir Depressurization Valve
The reservoir depressurization valve is a manually operated 2- way valve. It is nor-
mally closed by spring force. It opens by turning the cap assembly or by connect-
ing the ground depressurization coupling.

Cargo Door Selector Valve

Ground Connectors
The delivery ground connector (3008GM) and suction ground connector
(3006GM) are of the self- sealing type.

Cargo Door Hand Pump

The hand pump is a two stage type pump and supplies 10 ml per stroke at a high 198CB
pressure or 40 ml per stroke at a low pressure. (P < 290 psi = low pressure mode)
The same hand pump lever (3270GM) is used for yellow and green hand
pump operation.

Figure 14: Yellow Ground Service Panel

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Figure 15: Yellow Hand Pump

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Figure 16: Yellow Hydraulic System

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A318/A319/A320/A321 29 -15 Maintenance Practices

29-15 Maintenance Practices

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A318/A319/A320/A321 29-15 Maintenance Practices

Hydraulic Reservoir Pressurizing System Filter

A filter fitted with a clogging indicator is installed in the reservoir pressurization unit
General to filter the air from the different supply sources.
An air pressure system is provided to pressurize each hydraulic reservoir in order
to ensure adequate fluid supply to the pumps. Water Separator
Each reservoir is pressurized by air at 50 psi (3.5 bar). The system also remains A water separator is installed on the reservoir pressurization unit. It makes sure
airtight in the event of pressurization system failure or after engine shutdown. that the air delivered to the reservoirs is clear of any fluid.
There are two drain valves which prevent freezing of the water in the RPU. One is
Sources an automatic drain valve which is opened after each engine or APU shutdown, the
The pressure sources are engine 1, via a restrictor or both engines and the APU, other one is a manual self- sealing drain valve.
via the pneumatic manifold. The pressure sources are:
• the engine 1 HP compressor (usual operation). Reservoir Check Valves
• the pneumatic system in case of loss of engine1. Downstream of the reservoir pressurization unit, the air supply is divided into three
• the ground supply. flows to supply the reservoirs through their related check valve. The green and yel-
low check valves are installed between the floor beams above the hydraulic bay
Restrictor and the blue one is installed in the Aft cargo compartment.

A restrictor limits the airflow and reduces the temperature of the high pressure air Pressure Gage
to a satisfactory level.
An air pressure gage is installed on each hydraulic reservoir to indicate the actual
The restrictor also prevents too much bleed air leakage in case of a leak down- pressure. LOW AIR PRESS warning is generated by the pressure switch if the
stream of the restrictor. pressure is less than 22 psi / (37 psia / 1.52 bar).
Reservoir Pressurization Unit Pressure Relief Valve
The reservoir pressurization unit (RPU) controls the pressure of the air supplied to
A pressure relief valve, installed on each reservoir, relieves pressure to the atmos-
the reservoirs.
phere in the event of a system overpressure.
Pressure Reducing Valve The threshold of the pressure relief valve is 77 psi (5.3 bar).
A pressure reducing valve is fitted to the reservoir pressurization unit.
Manual Depressurization Valve
In normal operation, the delivery pressure of engine 1 has priority over the pres-
A manual depressurization valve is fitted on each ground service panel to depres-
sure supply from the pneumatic manifold.
surize each reservoir.
Pressure reducing valve outlet pressure: 50 psi (3.5 bar).
WARNING: When using the manual depressurization valve put on eye protection
Two check valves prevent any reverse flow. and keep away from the outlet of the valve.
The air can be hot and contain particles of dust and/ or hydraulic fluid.
Ground Connector
Pressurized air from a ground supply cart goes directly to the reservoir pressuri-
zation unit through a ground connector.

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Figure 1: Reservoir Pressurizing System

GENERAL ... MANUAL DEPRESSURIZATION VALVE

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Figure 2: Hydraulic Reservoir Pressurizing System

FILTER WITH
CLOGGING
INDICATOR
COUPLING SOCKET ... CHECK VALVE

MANUAL
VALV
DRAIN
AUTOMATIC E
DRAIN VALVE

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A318/A319/A320/A321 29 -15 Maintenance Practices

Figure 3: Hydraulic Reservoir Filling

Z151

CLOGGING INDICATOR

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A318/A319/A320/A321 29-15 Maintenance Practices

Hydraulic Reservoir Filling Figure 4: Reservoir Filling Filter

Coupling Socket
The coupling socket is used to fill the reservoir from a pressurized ground hydrau-
lic supply.
The coupling socket includes a check valve.

Restrictor
A restrictor located between the coupling socket and the reservoir filling selector
valve protects the system against over pressure.

Hand Pump
The hand pump is used to refill the reservoirs if no ground cart is available.
The hand pump lever is on the yellow ground service panel. A specific filling valve
including a filter and a check valve is installed on the hand pump.
The function of the handpump is equal to handpump in the yellow hydraulic sys-
tem.
Reservoir Filling Selector Valve
Filling Filter The reservoir filling selector valve directs the hydraulic fluid from the supply source
The filter of the reservoir filling system is equipped with a clogging indicator. to the reservoir of the selected system. Do not depressurize the hydraulic reservoir
to refill it.
No bypass possibility on this filter.
In the NEUTRAL position, an internal thermal relief valve protects the selector
valve from thermal expansion of the fluid.

Reservoir Quantity Indicator

A reservoir quantity indicator allows refilling monitoring. It shows the contents of
the selected hydraulic reservoir which is indicated by one of the three colored
lights.
The direct reading gauges are used if no electrical power supply is available.

Check Valve
The hydraulic fluid is sent to the reservoirs via a check valve and the filter of the
low- pressure return circuit.
The check valves isolate the main hydraulic systems from the reservoir filling sys-
tem when it is not in use.

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Hand Pump
Description
The hand pump is installed on the ground service panel of the green hydraulic sys-
tem. It provides the flow of fluid to fill the reservoirs if a ground supply is not avail-
able. The hand pump is the same as the hand pump installed on the ground
service panel of the Yellow system. The hand pump has two suction connections.
One is for use when the pump is installed in the Green system, the other for instal-
lation in the Yellow system.
The hand pump is a two-stage type. It can supply 40 ml per stroke at low pressure
(LP) or 10 ml per stroke at high pressure (HP). The hand pump operates in the LP
mode up to 20 +5 -5 bar (290 +72 -72 psi). At that pressure, a pressure-operated
valve opens and connects the two large chambers. Thus the supply comes only
from the two small chambers. In the HP mode, the hand pump can supply fluid at
206 bar (3000 psi) nominal pressure.
The pump has a HP pressure relief valve which opens at between 234 and 237.5
bar (3400 and 3445 psi) . Also in the pump are eight check valves which control
the flow of fluid between the chambers of the pump.
The hand pump handle is the same one as is used for the Yellow system pump. It
is kept in the ground service panel of the Yellow hydraulic system.

Figure 5: Green Filling Hand Pump

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GENERAL & FWD SYSTEM

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Seal Drain System Presentation

General
The seal drain system collects hydraulic fluid from the seal drains of some hydrau-
lic components.
The hydraulic fluid which may escape from some hydraulic components (leak or
abnormal condition such as hydraulic reservoir overfilling or internal overpressure)
is drained into collector tanks.

Forward System
The forward system consists of flexible hoses and rigid pipes connected to a col-
lector tank.
The forward collector tank is attached between the frames 40 and 41 in the yellow
hydraulic compartment.
The components which are drained into the forward collector tank located in the
yellow hydraulic compartment are:
• Blue electric pump
• Yellow electric pump
• Slats Power Control Unit (PCU)
• Green hydraulic reservoir
• Yellow hydraulic reservoir

AFT System
The aft system consists of flexible hoses and rigid pipes connected to a collector
tank.
The aft collector tank is attached to the right side of the keel beam in the main hy-
draulic compartment.
The components which are drained into the aft collector located in the main land-
ing gear compartment are:
• Flaps Power Control Unit (PCU)
• Power Transfer Unit (PTU)
• Constant Speed Motor/Generator (CSM/G) AFT SYSTEM
• Blue hydraulic reservoir

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A318/A319/A320/A321 29-15 Maintenance Practices

Figure 6: Forwards Seal Drain System

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A318/A319/A320/A321 29 -15 Maintenance Practices

Leakage Measurement System Presentation

The yellow system has been chosen as an example.

General
The return flow of a hydraulic system is equal to the user’s demand flow plus the
permanent internal leakage.
Even with users at neutral, there is a permanent flow. If the permanent flow
is too high the corresponding system operation will be affected.
The flight controls users are permanently supplied through Leak Measurement
Valves. These valves have to be closed during leak hydraulic system test.
Internal leakage (full system check) is measured for each group of users through
manually operated shut- off valves.

Hydraulic System Test

To test a complete hydraulic system, a hydraulic ground cart equipped with a flow
meter has to be used to pressurize the circuit.

Precautions
Before starting the test make sure that all servocontrols are in their neutral position
and that the spoilers are retracted. Do not forget to disconnect the isolation cou-
pling of the PTU to prevent inadvertent pressurization of the green system by the
PTU.
The internal leakage flow rate is indicated by the flow meter.
If the flow rate is too high, a full system check has to be carried out to find out the
faulty group of hydraulic users (RH wing, LH wing, Tail section, Central section).

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Figure 7: Leakage Measurement System

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Full System Check

Once the hydraulic system is pressurized from the ground cart, make sure that the
ELAC’s, SEC’s and FAC2 are set to ON to supply the hydraulic users.
The Flight Controls surfaces must be kept in the neutral position.
The internal leakage check has to be done with the hydraulic fluid at its nor-
mal working temperature.
The full system check is carried out by checking successively the four sections of
the hydraulic system with the corresponding Leakage Measurement Valve in the
closed position.
The indicated flow must be compared to the theoretical one and if the flow is over
the limit the failed component belongs to this group of users.

Component Check
Each type of hydraulic component has a maximum permitted internal leakage lim-
it.
The total leakage of the components within a section must be less than the
permitted maximum for that section. All together, the total leakages of the
sections must not be more than the leakage permitted for the complete sys-
tem.
If the internal leakage is too high, the faulty component must be identified and re-
placed.
High leakage rate causes an increase of component temperature.
If a servocontrol is considered to be faulty, it must be disconnected and the corre-
sponding hydraulic section rechecked.
If the internal leakage rate is now within the limits, the servocontrol is confirmed
as defective.

TANK DRAINAGE

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Figure 8: Leakage Measurement System

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Figure 9: Leak Measurement Manifolds and Solenoid Valves

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Figure 10: Leak Measurement Valves Electrical Control

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 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -20 Auxiliary Hydraulic Power

29-20 Auxiliary Hydraulic Power electric pump supplies the Yellow main hydraulic system and, through the PTU,
also supplies the Green main hydraulic system.
On the ground, the electric pump starts automatically (when the aircraft has AC
General power) if the cargo compartment doors are set to open or close. At the same time,
the PTU and the flight control circuits of the Yellow hydraulic system are isolated.
The auxiliary hydraulic power systems are those which supply the aircraft when Thus, there is no danger of movement of the flight controls when the hydraulic sys-
the supply from the main pumps is not available. The auxiliary systems and their tem is pressurized.
related main systems are:
• the Blue auxiliary system (Ram Air Turbine (RAT) (Ref. 29-22-00), which sup-
plies the Blue hydraulic system,
• the power transfer (Ref. 29-23-00), between the Green and the Yellow hydrau-
lic systems,
• the electric pump (Ref. 29-24-00), which supplies the Yellow hydraulic system.
There is also a hand pump (Ref. 52-36-00) which supplies the hydraulic power of
the cargo compartment doors only.
The power transfer system has a Power Transfer Unit (PTU) which transfers hy-
draulic power (in either direction) between the Green and Yellow hydraulic sys-
tems. The connection between the Green and Yellow sides of the PTU is
mechanical. Thus no hydraulic fluid can get from one system into the other. Oper-
ation of the power transfer system is automatic, with the PTU armed all of the time.
The PTU starts to operate when one of the two hydraulic systems has a pressure
approximately 500 psi (34.47 bar) less than the other system.
Operation of the PTU can be stopped (or the PTU can be disarmed) from the flight
compartment if required. The PTU can also be isolated hydraulically for mainte-
nance to make it possible to pressurize only the Green or the Yellow hydraulic sys-
tem.
The RAT supplies the Blue main hydraulic system with hydraulic power. Deploy-
ment of the RAT into the airflow is automatic when there is a total loss of AC power
(when the aircraft speed is greater than 100 kts). The flight or the maintenance
crew can deploy the RAT from the flight compartment. When the RAT deploys au-
tomatically (or by use of the ELEC OVRD switch), the constant speed motor/gen-
erator (CSM/G) also automatically operates. Thus, the aircraft is supplied with
electrical power and the Blue main system is pressurized. Once deployed, hydrau-
lic power is necessary to retract the RAT. It is only possible to retract the RAT
when the aircraft is on the ground.
The electric pump of the Yellow auxiliary hydraulic system can also supply the Yel-
low main hydraulic system with hydraulic power. Operation of the pump is not au-
tomatic, the pump is switched on from the flight compartment. On the ground, the

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 Training Manual Hydraulic Power
A318/A319/A320/A321 29-20 Auxiliary Hydraulic Power

RESERVOIR DEPRESSURIZATION/PRESSURISATION (2)

WARNING

WARNING: PAY ATTENTION TO PROTECT YOUR HANDS AND

YOUR FACE FROM THE AIR WHICH COMES OUT
WHEN YOU OPEN RESERVOIR MANUAL
DEPRESSURIZATION VALVES. THE AIR MAY BE
HOT AND CONTAIN HYDRAULIC FLUID. USE
APPROPRIATE SAFETY WEAR.

WARNING

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A318/A319/A320/A321 29 -22 Ram Air Turbine (RAT)

29-22 Ram Air Turbine (RAT)

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A318/A319/A320/A321 29-22 Ram Air Turbine (RAT)

General
The blue auxiliary hydraulic power system supplies hydraulic power from the ram
air turbine (RAT) to the blue main hydraulic power system.
The RAT is installed in the belly fairing on the left side. When necessary, an actu-
ator extends the RAT into the airflow. The actuator extends the RAT into the air-
flow automatically when there is a total AC failure. (AC bus 1 and AC bus 2
deenergized) and aircraft in flight (>100kts)
It is possible to extend the RAT into the airflow at any point in the flight envelope
of the aircraft.
The maintenance crews can also extend the RAT manually from the flight com-
partment.
It is only possible to retract the RAT when the aircraft is on the ground.

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A318/A319/A320/A321 29 -22 Ram Air Turbine (RAT)

Figure 1: RAM Air Turbine

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A318/A319/A320/A321 29-22 Ram Air Turbine (RAT)

RAM Air Turbine A319/A321

In an emergency, the blue auxiliary system supplies hydraulic power to the air-
craft. Electrical power can also be supplied through the blue auxiliary System by
the constant speed motor generator (CSMG). The system supplies hydraulic pow-
er in less than 4.5 seconds from the time it gets the electrical command to extend
the RAT. The hydraulic power available from the RAT is sufficient to supply the
flight controls and the CSMG (for electrical power). The RAT is available and will
operate through the entire flight envelope. The RAT has a stall protection device
which prevents a RAT stall below the governed speed range. The stall protection
device limits the maximum power the pump can take from the turbine. When the
stall protection device is in operation, the pump displacement is adjusted to get a
constant RAT speed not related to the aircraft Speed.

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A318/A319/A320/A321 29 -22 Ram Air Turbine (RAT)

Figure 2: RAM Air Turbine Extended

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A318/A319/A320/A321 29-22 Ram Air Turbine (RAT)

Figure 3: Installation of the RAT Safety Device

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A318/A319/A320/A321 29 -22 Ram Air Turbine (RAT)

RAT De-Icing Device

The RAT has a de-icing device which is installed in the nose of the turbine hub.
The de-icing device produces heat which keeps the nose temperature to 3 deg.C
(37.40 deg.F) minimum. This temperature prevents icing conditions at the turbine
hub when the RAT is in operation.
The de-icing device does not use external power sources. The heat is produced
by the eddy current heating device. The heating device has two basic compo-
nents, an electrically conductive aluminium plate and an even number of samar-
ium cobalt magnets. The magnets are cicumferrentially mounted on a stationary
magnetic plate. When relative rotation take place, the flux field, when it passes
through the aluminium plate, produces a current. As aluminium has an electrical
resistance, power is generated which is than dissipated in the form of heat.
A special inspection tool can be used to check the proper position of the magnets.

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A318/A319/A320/A321 29-22 Ram Air Turbine (RAT)

Figure 4: RAT-De-Icing Device

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 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -22 Ram Air Turbine (RAT)

Figure 5: RAT Extension Logicl

703PP
AC BUS 1
28VDC
HOT BUS AC BUS 2
Automatic
Aircraft Speed Deployment
> 100 Kts

CSM/G
AUTO

701PP
28VDC
HOT BUS

Deploy Signal to
Hydr. Override Solenoids
EXTN
SOL 1

28VDC
BAT 2

Elec. Override
CSM/G
MAN

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A318/A319/A320/A321 29-22 Ram Air Turbine (RAT)

RAT Description
The main components of the blue auxiliary systems are:
• the RAT,
• the leg assembly with its pivot,
• the hydraulic pump,
• the ejection jack,
• the RAT control panel and
• selector switches to extend the RAT from the flight compartment.
All the components are in the left belly fairing.
The RAT control panel (3GE) is part of the blue ground-service panel in the left
rear belly fairing. The control panel (3GE) has the controls witch operate the RAT
retraction.
A pushbutton switch is installed on the hydraulic control Panel 40VU in the Cock-
pit. This switch permits the pilot to manually select the deployment of the RAT.
When it is on stand-by, the RAT stays retracted in its stow compartment. In an
emergency, the RAT is deployed (automatically or manually) to supply hydraulic
power to the blue main hydraulic system.
The turbine is a constant-speed variable-pitch unit with two blades. The mechan-
ical governor and the pitch-change mechanism are installed in the hub. The tur-
bine is attached to the lower end of the leg assembly and operates the gearbox
which drives the hydraulic pump. The hydraulic pump has a stall protection which
makes sure that the power demand from the pump does not exceed the power
available from the turbine.
An index mechanism installed on the front of the leg assembly locks the turbine
hub assembly in the correct position. The turbine hub has markings which allows
easy alignment between the turbine hub and the index mechanism. This then per-
mits the RAT to be stowed.

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A318/A319/A320/A321 29 -22 Ram Air Turbine (RAT)

Figure 6: RAM Air Turbine

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A318/A319/A320/A321 29-22 Ram Air Turbine (RAT)

During the deployment of the RAT, the index mechanism disengages from the tur-
bine hub when the leg is not more than 10 deg. before full extension. The RAT re-
tracts hydraulically with the hydraulic supply from the blue electric pump or from a
ground supply. The retraction of the RAT is operated by the RAT control panel
(3GE). The RAT can retract only if the turbine is in the correct position and the in-
dex mechanism is engaged. If the index mechanism is not engaged, it is neces-
sary to turn the turbine manually until the index mechanism engages. The RAT will
also not retract if the ground test tool is still attached.
The ejection jack is attached to the top end of the leg assembly and the RAT
mounting frame. The ejection jack extends the RAT into the airflow with the forte
of a spring. Therefore no hydraulic power is necessary to extend the RAT. Hydrau-
lic power is required to retract the RAT. You can retract the RAT only when the
aircraft is on the ground.
Two solenoids and one proximity switch are installed on the top of the ejection
jack. The two solenoids release a lock and the RAT extends. The RAT extends
when at least one solenoid is energized. An extend leck keeps the RAT in the ex-
tended position.
A stow proximity switch gives a signal to the ECAM system if the RAT actuator is
extended. Two links attach the RAT compartment doors to the leg assembly and
open the doors when the RAT extends. The two links also keep the RAT doors
closed when the RAT is in its normal stow position. The stowed proximity sensor
sends a signal to the RAT control panel and the indicator light RAT STOWED
comes on when the RAT is locked in its retracted position.

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Figure 7: Rat Stowage and Servicing-Retraction Procedure

GEAR BOX
COVER PLATE

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A318/A319/A320/A321 29-22 Ram Air Turbine (RAT)

Operation Figure 8: RAT Stowage

Retraction Position
In the retracted position, the RAT is kept in the RAT stow compartment with the
doors closed. The leg assembly has two links which are attached to the stow com-
partment doors and keep them closed. The internal lock in the ejection jack locks
the RAT in the retracted position. The index mechanism on the leg assembly locks
the turbine blades so that they can not turn. The turbine blades are at the fine
pitch.

Extension
The extension of the RAT is controlled by the:
• manual Operation of the pushbutton switch OVRD HYD 2805GE on the HYD
section of the overhead Panel 40VU, or
• manual Operation of the pushbutton switch OVRD ELEC 24XE on the over-
head panel 21VU, or
• automatic control in the event of a total failure of the AC busses 1 and 2.
When the RAT receives an automatic or manual command to extend, one of the
two deploy solenoids operates and releases the internal jack. Spring pressure
causes the ejection jack to extend, which extends the RAT into the airflow. The
RAT compartment doors open with the extension of the RAT. When the RAT ex-
tends, the stowed proximity switch operates and sends a Signal to the ECAM Sys-
tem where the legend RAT OUT appears.
The index mechanism disengages automatically when the RAT is 8 degrees from
its fully extended position. As the RAT is caught by the airstream, the actuator op-
erates as a shock absorber which prevents high-shock loads on the RAT and air-
craft structure. When the rod of the actuator is at its maximum extension,
movement of the turbine assembly stops.

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Figure 9: RAT Control

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A318/A319/A320/A321 29-22 Ram Air Turbine (RAT)

RAM Air Turbine A320 To make sure that sufficient inlet pressure for the RAT is available, the air pres-
sure in the blue system reservoir is monitored. A pressure transmitter is installed
In an emergency, the blue auxiliary system supplies hydraulic power to the air- on the air manifold of the reservoir. The pressure transmitter sends information to
craft. The blue auxiliary system can also supply the aircraft with electrical power the SDAC/FWC. If the air pressure during flight decreases to less than 3.1 bar ab-
through the constant speed motor/generator (CSM/G). The System supplies hy- solute (45 psi) a class 2 warning is given when the aircraft lands.
draulic power in less than 5s from the time it gets the electrical command to extend
the RAT. The hydraulic power available from the RAT (with the landing gear re-
tracted) is sufficient to supply the flight controls and the CSM/G (for electrical pow-
er). When the landing gear is extended, the effect of the nosegear on the airflow
reduces the performance of the RAT. Because of that the CSM/G is automatically
switched off when the landing gear is extended. The aircraft gets its supply of elec-
trical power from the batteries. Thus, the RAT has only to supply hydraulic power
for the flight controls. The RAT is available and will operate through all of the flight
envelope, but it will stall if the airspeed is less than 130 knots.

RAT Description
The main components of the blue auxiliary system are:
• the RAT,
• the leg assembly with its pivot,
• the hydraulic pump,
• the RAT actuator,
• the RAT ground retraction module,
• the RAT ground check module (GCM)
• the RAT control Panel,
• selector switches to extend the RAT from the flight compartment.
The RAT control panel and the selector switches are in the left belly fairing. The
RAT control panel is part of the blue ground-service panel.
When the RAT is in its stowed position, the system is monitored for faults. If a fault
is found, the lower display unit (DU) of the ECAM shows the RAT fault warning.
These faults will cause a RAT fault warning:
• the RAT is not in its stowed position (and no manual or automatic selection has
been made to extend it),
• the change-over valve in the ground check module is in the “ground check” po-
sition (there is an unwanted electrical supply to the change-over valve),
• there is hydraulic pressure in the "retract" side of the RAT jack (the jack control
module is in the wrong configuration).

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Figure 10: RAM Air Turbine-RAT Extended

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A318/A319/A320/A321 29-22 Ram Air Turbine (RAT)

Figure 11: Installation of the RAT Safety Device

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A318/A319/A320/A321 29 -22 Ram Air Turbine (RAT)

Figure 12: RAT Deploy (Extended ) Logig

703PP
AC BUS 1
28VDC
HOT BUS AC BUS 2
Automatic
Aircraft Speed Deployment
> 100 Kts
CSM/G
AUTO

701PP
28VDC
HOT BUS

Deploy Signal to
Hydr. Override Solenoids
EXTN
SOL 1

28VDC
BAT 2

Elec. Override
CSM/G
MAN

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A318/A319/A320/A321 29-22 Ram Air Turbine (RAT)

Operation
Retracted Position
In the retracted position, the RAT is in the RAT compartment with the doors
closed. The leg assembly is connected to the doors and keeps them closed. The
internal lock in the RAT actuator locks the RAT in the retracted position. The index
lock mechanism on the leg locks the turbine blades so that they can not turn. The
turbine blades are at maximum coarse pitch. A calibrated flow of warm oil from the
high-pressure bleed in the GCM is supplied to the leg assembly and the pump.

Extension
When the RAT gets a command to extend (from automtic or manual selection),
one of the two solenoids operates and releases the retract lock. Spring pressure
extends the actuator witch extends the RAT into the airflow. The contacts of the
stow limit switch close and send a signal to the ECAM system. The compartment
doors open automtically as the RAT extends. The index lock mechanism disen-
gages automatically when the RAT is 5 degrees from its fully extended position.
The turbine can then start to turn.
The turbine blades are in coarse pitch immediately after the RAT is extended. As
the turbine starts, fluid flows from the outlet of the high-pressure pump through the
flow-sensitive valve of the GCM to the low-pressure system. Thus the turbine can
get to its operating speed before the full load of the hydraulic pump is applied. The
gerotor purnp supplies servo pressure as the turbine speed increases and the
blade pitch angle decreases. The flow from the RAT pump increases and closes
the flow-sensitive by-pass valve. At the same time a flow-sensitive valve in the leg
assembly operates and stops the warm oil bleed.
The turbine speed increases to its controlled value (5400 rpm) and the RAT pump
supplies the blue main system of the aircraft.

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A318/A319/A320/A321 29 -22 Ram Air Turbine (RAT)

Figure 13: RAT Extended and Operational

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A318/A319/A320/A321 29-22 Ram Air Turbine (RAT)

Figure 14: RAT IN Operation Retraction

It is possible to retract the RAT only when the aircraft is on the ground. Retraction
is controlled from the RAT control panel in the blue system ground service panel.
The system must be in this condition before retraction of the RAT is started:
• blue main system pressurized,
• 28 V DC supply to the RAT control panel,
• the turbine in its index position.
The turbine is turned manually to the index position, which is indicated by the
alignment marks on the turbine and leg.
When the ARM switch is set to its ‘ON’ position, electrical power is supplied to the
STOW selector switch. When the switch is set to the STOW position, electrical
power is supplied to the solenoid in the ground retraction module.

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A318/A319/A320/A321 29 -22 Ram Air Turbine (RAT)

Figure 15: RAT Control Panel

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A318/A319/A320/A321 29-22 Ram Air Turbine (RAT)

The solenoid operates the pilot valve and connects the high-pressure supply of the Figure 16: Stow (Retract) Logic
aircraft to the retract side of the RAT actuator. The high-pressure fluid operates
the pressure switch of the ground retraction module and the warning light on the
RAT control panel comes on. Thus there is an indication that the RAT retraction
module is not in its flight position.
The high-pressure supply releases the actuator extend lock and retracts the actu-
ator and RAT assembly into the RAT compartment. Return fluid from the actuator
goes directly into the aircraft low-pressure system. When the RAT gets to its fully
retracted position. The actuator retract lock engages and holds the RAT in place.
At the same time the stow limit switch on the actuator operates and stops the sup-
ply to the solenoid of the RAT ground retraction module. The RAT ground retrac-
tion module goes back to its flight position and stops the high-pressure supply to
the jack. The warning light on the RAT control panel goes off.
If the STOW switch is released during retraction, the supply of electrical power to
the solenoid of the RAT ground retraction module stops. The RAT retraction mod-
ule goes to its flight position and the RAT extends because of actuator spring pres-
sure. The RAT will also go back to its extended position if the retract lock does not
engage.
If the turbine is not correctly lined up, and a STOW selection is made, the RAT will
start to retract. When the leg gets to 8.5 degrees from full extension, the turbine
index switch operates. The supply to the solenoid of the RAT ground retraction
module stops and the module goes to its flight position. The RAT then returns to
its extended position.

for training purposes only

29-22-24
 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -22 Ram Air Turbine (RAT)

Figure 17: RAT Control

for training purposes only

29-22-25
 Training Manual Hydraulic Power
A318/A319/A320/A321 29-22 Ram Air Turbine (RAT)

RAT STOWAGE AND SERVICING - RETRACTION PROCEDURE

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 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -23 Power Transfer System (PTU)

RAT STOWAGE AND SERVICING (2) JOB SET-UP

EXTENSION PROCEDURE Put the warning notices in the position to tell persons not to stand
directly behind or in the extension area of the RAT.
Put the safety barriers in position.
WARNING: PUT THE SAFETY DEVICES AND THE WARNING
Energize the A/C electrical circuit.
NOTICES IN POSITION BEFORE YOU START A TASK
Make sure that these C/Bs are closed: 106VU.
ON OR NEAR:
- THE FLIGHT CONTROLS,
- THE FLIGHT CONTROL SURFACES,
- THE L/G AND THE RELATED DOORS,
- COMPONENTS THAT MOVE.
MAKE SURE THAT THE TRAVEL RANGES OF THE
FLIGHT CONTROL SURFACES ARE CLEAR BEFORE
YOU PRESSURIZE/DEPRESSURIZE A HYDRAULIC
SYSTEM.
MAKE SURE THAT THE RAM AIR TURBINE (RAT)
TRAVEL RANGE IS CLEAR BEFORE YOU EXTEND
THE RAT.
PLACE SAFETY BARRIERS IN POSITION AND FIT
THE RAT PROTECTIVE EQUIPMENT AS PER AMM
PROCEDURE.
DO NOT STAND IN FRONT OF OR BESIDE THE RAT
PROPELLER ASSEMBLY DURING THE FUNCTIONAL
TEST.

NOTE: Note: do not operate the RAT deployment solenoids for more
than 60 sec. You can operate them more than once, but you
must then let them cool down for 30 min.

EXTENSION PROCEDURE - JOB SET-UP

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29-22-27
 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -23 Power Transfer System (PTU)

RAT STOWAGE AND SERVICING (2)

EXTENSION PROCEDURE (continued)
PROCEDURE
On the hydraulic panel, open the protective cover and push the
MANual ON/AUTO switch in the EMERgency ELECtrical PoWeR
panel.
Make sure that the RAT extend.
Install the protective covers on the turbine blades.

NOTE: Note: make sure that a second person is on the ground near
the RAT to observe the extension of the RAT.
Note: do not operate the RAT deployment solenoids for
more than 60 seconds. You can operate them more than
once. When the operation time (solenoids energized) is max.
60 seconds, you must let solenoids cool for 30 minutes.

EXTENSION PROCEDURE - PROCEDURE

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29-22-28
 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -23 Power Transfer System (PTU)

RAT STOWAGE AND SERVICING (2)

RETRACTION PROCEDURE

WARNING: PUT THE SAFETY DEVICES AND THE WARNING

NOTICES IN POSITION BEFORE YOU START A TASK
ON OR NEAR:
- THE FLIGHT CONTROLS,
- THE FLIGHT CONTROL SURFACES,
- THE L/G AND THE RELATED DOORS,
- COMPONENTS THAT MOVE.
MAKE SURE THAT THE TRAVEL RANGES OF THE
FLIGHT CONTROL SURFACES ARE CLEAR BEFORE
YOU PRESSURIZE/DEPRESSURIZE A HYDRAULIC
SYSTEM.
MAKE SURE THAT THE GROUND SAFETY-LOCKS
ARE IN POSITION ON THE L/G.

CAUTION: make sure that the RAT is retracted completely before you
release the "RAT stow" switch. If the retraction sequence
stops just before the rat enters the bay in the fairing this will
cause damage to RAT actuator.
JOB SET-UP
Make sure that the warning notices are in position.
Make sure that the safety barriers are in position.
Energized the A/C electrical circuits.
Pressurize the blue hydraulic system.
Make sure that this C/B is closed: 49VU.

RETRACTION PROCEDURE - JOB SET-UP

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29-22-29
 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -23 Power Transfer System (PTU)

RAT STOWAGE AND SERVICING (2)

RETRACTION PROCEDURE (continued)
PROCEDURE
Open the door of the RAT ground control panel.
Remove the protective cover from the turbine blades.
Turn the turbine blades with your hands until the arrows on the turbine
hub and the gearbox align.
On the RAT ground control panel set the ARM switch to the on
position.
Move the STOW/RESET switch to the STOW position and hold it
there until:
- the RAT STOWED indicator light comes on,
- the ACTUATOR PRESSURE light comes on.
Make sure that the RAT retracts.
Release the STOW/RESET switch: the ACTUATOR PRESSURE
light goes off.
Set the switch 28V DC to the OFF position: the RAT STOWED light
goes off.

RETRACTION PROCEDURE - PROCEDURE

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 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -23 Power Transfer System (PTU)

RAT STOWAGE AND SERVICING (2) Put the A/C back to the serviceable condition:
- depressurize the blue hydraulic system,
RETRACTION PROCEDURE (continued) - de-energized the A/C electrical circuits,
- if you have completed all work in the deploy area to the RAT, remove
CLOSE-UP
the SAFETY DEVICE-RAT.
Close access:
- close the door of the RAT ground control panel,
- close the access doors,
- remove the warning notices,
- remove the safety barriers.

RETRACTION PROCEDURE - CLOSE-UP

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29-22-31
 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -23 Power Transfer System (PTU)

RAT TEST (3) GROUND CHECKOUT UNIT PRESENTATION

A cable provides electrical connection between the RAT control panel
PRECAUTIONS and the connector on the ground checkout unit.

WARNING: PUT THE SAFETY DEVICES AND THE WARNING The ground checkout unit provides a visual indication of the RAT rpm
NOTICES IN POSITION BEFORE YOU START A TASK and the blue system pressure delivered by the RAT during a ground check.
ON OR NEAR:
- THE FLIGHT CONTROLS, RAT GROUND TEST MOTOR PRESENTATION
- THE FLIGHT CONTROL SURFACES,
To test the RAT performance on ground, a ground test motor must be
- THE L/G AND THE RELATED DOORS,
connected to the RAT gearbox. The RAT ground test motor is driven by
- COMPONENTS THAT MOVE.
a hydraulic ground cart.
MAKE SURE THAT THE TRAVEL RANGES OF THE
FLIGHT CONTROL SURFACES ARE CLEAR BEFORE
YOU PRESSURIZE/DEPRESSURIZE A HYDRAULIC
SYSTEM.
MAKE SURE THAT THE SAFETY LOCKS ARE IN
POSITION ON THE L/G.
MAKE SURE THAT THE RAM AIR TURBINE (RAT)
TRAVEL RANGE IS CLEAR BEFORE YOU EXTEND
THE RAT.
PLACE SAFETY BARRIERS IN POSITION AND FIT
THE RAT PROTECTIVE EQUIPMENT AS PER AMM
PROCEDURE.
DO NOT STAND IN FRONT OF OR BESIDE THE RAT
PROPELLER ASSEMBLY DURING THE FUNCTIONAL
TEST.

NOTE: Note: do not operate the RAT deployment solenoids for more RAT GROUND TEST MOTOR PRESENTATION
than 60 sec. You can operate them more than once, but you
must then let them cool down for 30 min.

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 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -23 Power Transfer System (PTU)

RAT TEST (3)

MAIN STEPS OF THE TEST OPERATION To functionally check the RAT on ground it is necessary to:
- manually deploy the RAT from the cockpit,
PREPARATION OF RAT TEST - connect the ground test motor to the RAT gearbox,
- connect the ground checkout unit to the RAT control panel,
- connect the RAT flow control test kit to the blue ground service
panel.

MAIN STEPS OF THE TEST OPERATION - PREPARATION OF RAT TEST

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 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -23 Power Transfer System (PTU)

RAT TEST (3)

MAIN STEPS OF THE TEST OPERATION (continued)
RAT EXTENTION
When the RAT is extended on the ejection spring jack, the RAT leg
drops, opening mechanically the doors.

MAIN STEPS OF THE TEST OPERATION - RAT EXTENTION

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 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -23 Power Transfer System (PTU)

RAT TEST (3)

MAIN STEPS OF THE TEST OPERATION (continued)
RAT TEST
Shown is the ground control unit box, which contains the control unit
and the electrical cable. The identification label is located outside the
box on the top cover. When the box is opened, in the top cover is still
electrical cable, which must be connected to the control unit and to
the RAT control panel test plug. On the ground control unit is fitted
two digital indicators. The left inside indicator is to monitor the speed
of the RAT. The RH side is to monitor the pressure delivered by RAT
pump. On the RH side lower part is located the power switch with its
red indicator light and on the LH side the electrical fuse. Here is the
hydraulic motor, which has to be installed on the gearbox after removal
of the back cover plate. The motor is fitted with the three screws. The
supplant shaft drives the hydraulic pump shaft through the turbine
pump shaft. Its hydraulic supply is a hydraulic ground cart via two
self-sealing couplings. This unit is used to create a flow in blue
hydraulic circuit, to check the flow and pressure regulation of the
RAT pump. Here is the valve to control the bypass flow.
On the opposite side is located the monitoring indicators:
- a digital flow meter indicator, a pressure indicator, a temperature
indicator and on/off switch.
- this tool is connected to the blue servicing panel self sealing MAIN STEPS OF THE TEST OPERATION - RAT TEST
couplings.

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 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -23 Power Transfer System (PTU)

29-23 Power Transfer System (PTU)

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29-23-1
 Training Manual Hydraulic Power
A318/A319/A320/A321 29-23 Power Transfer System (PTU)

PTU General
The aircraft has a power transfer system to transfer hydraulic power between the
green and yellow systems. This is necessary if one of the engine pumps fails. It
also makes it possible to pressurize the green system from the yellow system for
maintenance (with the yellow system electric pump).
The power transfer system is always armed when the hydraulic systems are pres-
surized. However, the crew can switch it off if necessary.
The connection between the two systems is mechanical. It is impossible for fluid
to get from one system to the other.
When the isolation coupling is disconnected (during ground maintenance opera-
tions only), there is no transfer of power.

PTU Description
When the pressure differential between the green and yellow systems is greater
than or equal to 500 psi (34.5 bar) , the system with the greater pressure transfers
power to the other system. The power is transferred through the Power Transfer
Unit (PTU). The PTU of the green and yellow systems is connected to the green
and yellow system solenoid valves respectively.
When the yellow electric pump starts because of operation of the cargo doors,
movement of the flight controls is prevented. Electrical power is supplied to the two
solenoid valves 1012GL and 3012GL and the solenoid valve of the yellow leakage
measurement system 3150GP. Thus no hydraulic power is supplied to the green
or yellow systems.
Two solenoid valves (one in each system) keep the PTU either armed or off. The
solenoid valve 1012GL of the green system is connected to the green PTU mani-
fold. The solenoid valve 3012GL of the yellow system is connected to the yellow
PTU manifold. The two solenoid valves operate at the same time. The PTU switch
on the overhead panel 40VU controls the solenoid valves.

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29-23-2
 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -23 Power Transfer System (PTU)

Figure 1: Power Transfer - Schematic

 
 

   

 
   
   

 
  









   

  


 
 
 
 
  

 
 






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29-23-3
 Training Manual Hydraulic Power
A318/A319/A320/A321 29-23 Power Transfer System (PTU)

Figure 2: Power Transfer Unit

 
















 




 
 

 
  
  
 






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29-23-4
 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -23 Power Transfer System (PTU)

Figure 3: Hydraulic System Green/Yellow

NW Steering Flaps
Yaw Damper 1 Landing Gear
Rudder Slats & Flaps
Flaps & WTB Yaw Damper 2
Slats L & R WTB Priority Rudder Priority
P P
Valve Valve
Stabilizer Flaps L WTB
L Elevator Stabilizer
L & R Spoiler 1 R Elevator
L & R Aileron L & R Spoiler 2
L & R Spoiler 5 L & R Spoiler 4

Leak Measurement Leak Measurement

Valve Valve

Normal Brake Alternate Brake

Reverser Eng. 1 Reverser Eng. 2

S S
System System
Accu Accu
MP MP Cargo Doors

Power
Eng. 2
Transfer Elec
Pump
Eng. 1 Unit Pump
M
Pump

Eng. 2
Eng. 1 M Fire M
Fire Valve Valve Hand
Pump

Green Reservoir Yellow Reservoir

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29-23-5
 Training Manual Hydraulic Power
A318/A319/A320/A321 29-23 Power Transfer System (PTU)

Figure 4: Power Transfer Unit/Green and Yellow PTU Manifolds

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29-23-6
 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -23 Power Transfer System (PTU)

Power Transfer Unit Components It is used to isolate the secondary flight controls from pressure supply in case of
low hydraulic pressure.
Power Transfer Unit (PTU)
Green PTU Manifold
There are three hydraulic connections on both sides of the PTU:
The green high pressure manifold is connected to the PTU through the green PTU
• High Pressure
manifold.
• Low Pressure
• Case drain Solenoid Valve
The high pressure and case drain connections on the PTU are of the standard It is installed in the PTU supply line.
type union. Only the low pressure connections are self-sealing quick release cou- When the solenoid is energized the valve closes.
plings.
When the solenoid valve is de-energized, the spool moves to open the valve.
Table 1: PTU Performance
Priority Valve
Flow Motor Inlet Pump Outlet Pump The green priority valve is installed on the PTU manifold.
Direction Flow Flow Pressure It is used to isolate the secondary flight controls from pressure supply in case of
low hydraulic pressure.
Yellow to 119 l/min (31.44 95 l/min (25.10 206 bar (2987 psi)
Green USgal/min) Usgal/min) between 20 and 80 l/min Brake Selector Valve
(max.) (max.) (5.28 and 21.13 USgal/min) It allows the normal braking system to be pressurized.
It is fitted to the green PTU manifold.
Green to 76 l/min (20.08 55 l/min (14.53 206 bar (2987 psi)
Yellow USgal/min) USgal/min) between 13 and 55 l/min
Isolation Coupling
(max.) (max.)
An isolation coupling is installed in the PTU manifold of the yellow hydraulic sys-
tem.
Yellow PTU Manifold
It is the only way to isolate the PTU for maintenance operations. There is no trans-
The yellow high pressure manifold is connected to the PTU through the yellow fer of power between the two systems (green and yellow) when the isolation cou-
PTU manifold. The yellow PTU manifold also has a connection to the flap system. pling is disconnected.
Solenoid Valve It is a quick-release coupling which seals automatically when it is disconnected. It
also has a ratchet lock to keep it connected.
It is installed in the PTU supply line, this solenoid valve operates at the same time
with the other solenoid valve (1012GL) installed on the green PTU manifold.
When the solenoid is energized the valve closes.
When the solenoid valve is de-energized, the spool moves to open the valve.

Priority Valve
The yellow priority valve is installed on the PTU manifold.

for training purposes only

29-23-7
 Training Manual Hydraulic Power
A318/A319/A320/A321 29-23 Power Transfer System (PTU)

Figure 5: Power Transfer Unit Electrical Control

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 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -99 CFDS

29-99 CFDS

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29-99-1
 Training Manual Hydraulic Power
A318/A319/A320/A321 29-99 CFDS

General
The CFDS SYSTEM REPORT/ TEST menu does not include the hydraulic menu
page.
The purpose of this module is to present the access to the LAST LEG REPORT
of the Auto Flight, Flight Controls, Instrument and Landing Gear systems, in case
of failure of certain hydraulic components.
The hydraulic system components monitored by the AFS, the F/CTL, the INST
and the L/G systems are:
• the pressure switches
• the pressure transmitters
• the temperature transmitters
• the quantity indicators.

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29-99-2
 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -99 CFDS

Auto Flight System (AFS)

The green pressure switch 1151GN sends a signal to the Flight Augmentation
Computer 1 (FAC1) and the yellow pressure switch 3151GN sends a signal to
FAC2.
Figure 1: CFDS: Auto Flight System

ELAC 1,2
SEC 1
BSCU
SDAC 1, 2

ELAC 1,2
SEC 2,3
SDAC 1,2

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 Training Manual Hydraulic Power
A318/A319/A320/A321 29-99 CFDS

Flight Controls (F/CTL)

The blue, yellow and green HP manifold pressure switches (2151GN- 3151GN-
1151GN) send a signal to the Elevator Aileron Computers (ELACs) and to the
Spoiler Elevator Computers (SECs).
The pressure switches (10CE2- 10CE3- 10CE1) belonging to the Flight Control
System send a signal to ELACs and SECs.
The blue, yellow and green HP manifold pressure transmitters (2065GN-
3065GN- 1065GN) send a signal to the ELACs.

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29-99-4
 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -99 CFDS

Figure 2: CFDS: Flight Controls

SDAC 1,2

SDAC 1,2

NEXT
PAGE

SDAC 1,2

FAC 2
SDAC 1,2
NEXT
PAGE

SDAC 1,2

BSCU
FAC 1
SDAC 1,2

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29-99-5
 Training Manual Hydraulic Power
A318/A319/A320/A321 29-99 CFDS

Instruments
The blue, yellow and green HP manifold pressure transmitters (2065GN-3065GN
1065GN) send a signal to the System Data Acquisition Concentrator (SDACs) for
ECAM display.
The blue, yellow and green temperature transmitters (2381GR-3381GR-1381GR)
send a signal to the SDACs for ECAM display.
The blue, yellow and green hydraulic quantity indicators (2000GQ-3000QR-
1000GQ) send a signal to the SDACs for ECAM display.
The blue air pressure switch (2387GH) sends a signal to the SDACs for
A320 ECAM display (class 2 failure), if the airpressure in the blue reservoir
decreases to less than 45 PSIA.
The pressure switch gives a signal in flight (flight phases 5, 6, 7) which
is then memorized only and displayed after landing.
(flight phases 8, 9, 10).

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 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -99 CFDS

Figure 3: CFDS: Instruments

NEXT
PAGE

NEXT
PAGE

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29-99-7
 Training Manual Hydraulic Power
A318/A319/A320/A321 29-99 CFDS

Landing Gear (L/G)

The green HP manifold pressure switch 1151GN sends a signal to the Braking and
Steering Control Units (BSCU A and BSCU B).
Figure 4: CFDS: Landing Gear

ELAC 1,2 ELAC 1,2

SDAC 1,2 SEC 2,3

ELAC 1,2
SEC 1
FAC 1
SDAC 1,2

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29-99-8
 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -23 Power Transfer System (PTU)

HYDRAULIC POWER LEVEL 2 (2)

SERVICING
RESERVOIR AIR PRESSURIZATION
All three reservoirs are pressurized to 50 psi to prevent pump
cavitations.
The non-return valves in each reservoir supply manifold, make sure
that the pressure will be maintained for up to 12 hours after engine
shutdown on ground, and for up to 3 hours following a failure of the
air supply in flight.
Each reservoir has a depressurization valve on its associated service
panel. For long time depressurization, a depressurization tool may be
installed on the depressurization valve.
A 77 psi pressure relief valve is installed onto the supply manifold at
each reservoir.
All tree reservoirs are pressurized from Engine 1 for normal supply
and the bleed air system for alternate supply at 43 psi.
The air pressurization manifold has a ground supply connection.
It is put into the blue hydraulic bay and regulates normal or ground
supply to 50 psi.
Cleanable filters have clogging indicators.
There are two water drains, one is automatic after engines and APU
shut down, and the other is manually operated.
After maintenance on the hydraulic system, the reservoir pressurization
can be done via a pneumatic ground cart connected to the reservoir
pressure unit, the APU, or the pneumatic system ground connection.

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29-100-1
 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -23 Power Transfer System (PTU)

SERVICING - RESERVOIR AIR PRESSURIZATION

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 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -23 Power Transfer System (PTU)

HYDRAULIC POWER LEVEL 2 (2)

SERVICING (continued)
FLUID LEVEL CHECK
The following Aircraft Configuration is needed for a correct fluid
level check and servicing:
- the speed brakes and spoilers must be retracted,
- the thrust reversers stowed,
- the cargo doors closed,
- all system accumulators empty of fluid and pressurized with nitrogen
to the correct pressure,
- the accumulators pre-charge pressure must be checked,
- the reservoirs pressurized with air,
- the landing gear must be in down position with the landing gear
doors closed (one door may be open),
- and the brake accumulator may be pressurized with fluid.

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 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -23 Power Transfer System (PTU)

SERVICING - FLUID LEVEL CHECK

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 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -23 Power Transfer System (PTU)

HYDRAULIC POWER LEVEL 2 (2)

SERVICING (continued)
RESERVOIR FILLING
Switch on the yellow electric pump to make sure that the brake
accumulator is pressurized, then switch the pump off.
Connect the selected servicing source to the green servicing panel.
When the panel hand pump is used, connect the hose to the hand pump
and insert it into the fluid container, and then install the pump handle.
The handle is stowed at the yellow servicing panel.
When the external pump is used, connect the lower filling port and
set the minimum flow, do not exceed 435 psi.
Then select the reservoir to be filled, confirming associated light is
ON, and fill with fluid to the upper end of the scale.

NOTE: Over filling the reservoir will result in an inadequate

pressurization.
The reservoir level is also affected by large changes in ambient
temperature. For every 10 °C change, the green volume changes by
0.85 Lt, the blue volume changes by 0.51 Lt, and the yellow volume
changes by 0.64 Lt.

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 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -23 Power Transfer System (PTU)

SERVICING - RESERVOIR FILLING

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 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -23 Power Transfer System (PTU)

HYDRAULIC POWER LEVEL 2 (2)

SERVICING (continued)
BLEEDING
If you have filled the reservoir after:
- maintenance,
- or removal/installation of large hydraulic components,
- or hydraulic fluid low level (loss of the hydraulic system),
- or high loss of hydraulic fluid,
Do the related bleeding procedure to make sure that the quantity of
hydraulic fluid in the system is correct.
After maintenance of the hydraulic system upstream of the EDP,
loosen the nut of the case drain hose so that the air (or hydraulic fluid
mixed with air bubbles) comes out of the connection. Check:
- make sure that the air pressure in the reservoir of the associated
hydraulic system is not less than 50 psi (if necessary, pressurize the
reservoir),
- read the gauge of the associated reservoir and make a note of the
fluid level,
- depressurize the reservoir of the associated hydraulic system,
- after 5 minutes, read the gauge again and make a note of the level,
- compare both levels,
- if the difference between both levels is more than 2 liters, do the
bleeding procedures again until the result is satisfactory.

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29-100-7
 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -23 Power Transfer System (PTU)

SERVICING - BLEEDING

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 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -23 Power Transfer System (PTU)

HYDRAULIC POWER LEVEL 2 (2)

SERVICING (continued)
HIGH PRESSURE (HP), CASE DRAIN, AND LOW
PRESSURE (LP) FILTERS
The three Hydraulic Systems have:
- a HP filter in the pressure line, in the reservoir filling system, and
the normal braking system,
- an LP filter in the return line,
- a case drain filter in the case drain line of the EDP's.
The HP and the case drain filters have a red clogging indicator, which
pops out when the filter is clogged (dirty).
The LP filters have a replaceable filter elements and a by-pass system.

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29-100-9
 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -23 Power Transfer System (PTU)

SERVICING - HIGH PRESSURE (HP), CASE DRAIN, AND LOW PRESSURE (LP) FILTERS

for training purposes only

29-100-10
 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -23 Power Transfer System (PTU)

SERVICING - HIGH PRESSURE (HP), CASE DRAIN, AND LOW PRESSURE (LP) FILTERS

for training purposes only

29-100-11
 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -23 Power Transfer System (PTU)

HYDRAULIC POWER LEVEL 2 (2)

SERVICING (continued)
ACCUMULATORS
Each system has an accumulator, located in their associated hydraulic
bays.
The yellow brake system has an accumulator for emergency braking
and parking brake.
The nitrogen pre-charge is adjusted at the accumulator in accordance
to the ambient temperature.
On system pressurization the accumulators will each take
approximately 1 Lt. of fluid.
Each accumulator has a nitrogen pressure indicator.

SERVICING - ACCUMULATORS

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29-100-12
 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -23 Power Transfer System (PTU)

HYDRAULIC POWER LEVEL 2 (2)

SERVICING (continued)
EXTERNAL LEAK TEST OF COMPONENTS
A leak is the quantity of fluid that comes out of a component and that
is sufficient to become a drop or drops, or will possibly become a
drop of approximately 20 drops =1 cc, and 75600 drops =1 gallon.
A leakage is a quantity of fluid on the surface of a component that is
not sufficient to become a drop.
A stain is an area on the surface of a component that has a different
color. It is usually caused when fluid leakage becomes dry on the
component surface after a high temperature operation.
For a correct analysis of component leak rates, you must obey the
subsequent steps:
- the seal obtained at hydraulic tube connections is obtained on
metal-to-metal surfaces. If a leak cannot be stopped by tightening the
nut to the specified torque, the joint is probably defective and should
be repaired.
- when possible, activate components for some cycles before carrying
out the external leakage check.
- dynamic seals are easy to examine for leakage while in the static
condition because pistons, slide valves and swivel joints move only
during a short time interval. Many components cannot be obviously SERVICING - EXTERNAL LEAK TEST OF COMPONENTS
monitored during operation.
- by following the AMM procedure operate the related component,
- after operation, inspect the component. If there is a sign of any
external leakage, compare the quantity of leakage with the values
given in the AMM table for specified limits.

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29-100-13
 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -23 Power Transfer System (PTU)

HYDRAULIC POWER LEVEL 2 (2) HYDRAULIC POWER LEVEL 2 (2)

DAILY CHECKS MAINTENANCE TIPS
During the daily check the reservoirs quantity indication on the ECAM PTU
display unit have to be checked.
In case of incorrect findings during this check, the related AMM tasks PTU inhibition is achieved by closing the solenoid valves (they are
have to be done to restore the system to normal status or to readjust fail safe open) at the PTU manifolds, and for maintenance actions by
quantities and pressures to nominal values. also disconnecting the coupling on the yellow (right) side of the unit.
In case of hydraulic fluid level find below normal, the system needs to The PTU operation is inhibited at first engine start and during cargo
be refilled using the Hand Pump or a Hydraulic Service Cart. door operation.
In case of hydraulic fluid level find above normal, the system needs to
NOTE: At the second engine start, the inhibition is removed when
be drained.
the second engine master switch is set to ON then the PTU
will operate momentarily for self test purpose.
HYDRAULIC POWER LEVEL 2 (2) RAT
The RAT can be tested on ground by using the Ground Check Module.
MEL/DEACTIVATION A RAT retraction module controls the RAT stowage procedure, it is
The fluid quantity have to be checked on the reservoir direct reading gage located on the blue servicing panel.
prior to each flight.
NOTE: To avoid any extension during maintenance work a RAT
The LO LVL Warning has to be checked operative before the first flight.
safety tool must be installed.
The air pressure have to be checked on the reservoir direct reading gage
prior to each flight. SAFETY PRECAUTIONS
To prevent an unwanted operation of the PTU, the isolation coupling
must be disconnected.
Keep the RAT extension area clear of ground equipment and
personnel. Install the RAT safety device before to work in the RAT
area.

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 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -23 Power Transfer System (PTU)

DAILY CHECKS

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 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -23 Power Transfer System (PTU)

MEL/DEACTIVATION

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29-100-16
 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -23 Power Transfer System (PTU)

MAINTENANCE TIPS - PTU ... SAFETY PRECAUTIONS

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 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -23 Power Transfer System (PTU)

HYDRAULIC POWER LEVEL 2 (2)

MAINTENANCE TIPS (continued)
TIGHTENING TORQUES
Before you torque a component or
connection, obey the precautions and
procedures given in the tightening
practices for hydraulic connection
procedure in the AMM Chapter 20.
The tightening torques are given in the
AMM tables chapter 20. When you use an
adapter, the values shown on the dial of
the torque wrench is not the applied
value .To get the correct value, the formula
given on the next picture must be applied.
The drawing shows as an example the
tightening torque for HARRISSON and
PERMASWAGE sleeve nuts and in-line-
check valves and how to use a torque
wrench and adapter.

$1&( 7,36 7,*+7(1,1* 7254 8(6

MAINTENANCE TIPS - TIGHTENING TORQUES

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 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -23 Power Transfer System (PTU)

HYDRAULIC POWER LEVEL 2 (2)

'A' CHECK ITEMS
During the 'A' check:
- the fluid level on the main hydraulic reservoir
indicators have to be checked,
- the air pressure of main hydraulic power
reservoir have to be checked using the reading
gage,
- the clogging indicators on Engine Driven Pump
(EDP) case drain filter (pop out not protruding)
have to be checked,
- the nitrogen charge pressure on hydraulic
power Accumulators have to be checked using
the direct reading gage.
In case or incorrect findings during these checks,
the related AMM tasks have to be done to
restore the system to normal status or to readjust
quantities and pressures to nominal values.

'A' CHECK ITEMS

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 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -23 Power Transfer System (PTU)

HYDRAULIC POWER LEVEL 2 (2)

ENVIRONMENTAL PRECAUTIONS
Do not discharge products such as oil, fuel, solvent, lubricant
either in trash bins, soil or into the water network (drains,
gutters, rain water, waste water, etc...).
Sort waste fluids and use specific waste disposal containers.
Each product must be stored in an appropriate and specific
cabinet or room such as a fire-resistant and sealed cupboard.

ENVIRONMENTAL PRECAUTIONS

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29-100-20
 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -23 Power Transfer System (PTU)

CIRCUIT IDENTIFICATION AND ROUTING (2)

PIPE ROUTING
The A/C has three hydraulically independent systems: blue, green, yellow.
There are no hydraulic pipes in the passenger cabin or flight compartment.

PIPE ROUTING

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 Training Manual Hydraulic Power
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CIRCUIT IDENTIFICATION AND ROUTING (2)

PIPE IDENTIFICATION
Each pipe is identified by a self-adhesive label, which indicates:
- the part number of the pipe,
- the identification of the pipe as a hydraulic pipe, its function with black
dots and the direction of the fluid flow with yellow and blue fields,
- an identification of the system comprising a color code and a number
1, 2 or 3 respectively indicating the Green, Blue, or Yellow system.

PIPE IDENTIFICATION

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 Training Manual Hydraulic Power
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CIRCUIT IDENTIFICATION AND ROUTING (2)

COMPONENT IDENTIFICATION
Each hydraulic component is identified by a placard affixed on the
structure near to it, which gives its Functional Item Number (FIN) and
its designation.

COMPONENT IDENTIFICATION

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29-100-23
 Training Manual Hydraulic Power
A318/A319/A320/A321 29 -23 Power Transfer System (PTU)

CIRCUIT IDENTIFICATION AND ROUTING (2)

CONNECTIONS
The most common connections in the
hydraulic system are shown below. There
are two types of connections:
- permanent connections or permaswage,
- removable connections or standard
straight or special fittings.
The manifolds have bobbin type
connections for some components. The
bobbins are equipped with a square seal
on the component side and an O-ring on
the manifold side.

CONNECTIONS

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29-100-24
 Training Manual Study Questions
A318/A319/A320/A321 Equipment - Furnishing

29-
29-00 Hydraulic Power General 5. In which systems are handpumps installed?

1. How are the hydraulic systems named / numbered? Answer:

Answer:

6. In which system is the RAT installed?

2. Which systems are equipped with an EDP? Answer:
Answer:

7. Where is the system pressure indicated?

3. Which systems are equipped with electrically driven pumps?
Answer:
Answer:

4. Between which systems can the PTU transfer power? 8. Name all pneumatic sources which can pressurize the hydraulic tanks?

Answer: Answer:

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29-1
 Training Manual Study Questions
A318/A319/A320/A321 Equipment - Furnishing

9. Where is the air pressure manifold installed? 29-10 Main Hydraulic System
Answer: 14.Name the differences between the hydraulic systems of A320 / 321?
Answer:

10.Where are the hydraulic tank pressure relief valves installed?

Answer:

29-11 Green Hydraulic System

15.Which engine is driving the green EDP?
11.If the pressure relief valves open, where is the hydr. fluid drained?
Answer:
Answer:

16.Which components are installed at the HP manifold?

12.Where can hydraulic oil be replenished?
Answer:
Answer:

13.Where are the hydraulic tank levels indicated? 17.For what are the sampling valves used?

Answer: Answer:

For training purposes only

29-2
 Training Manual Study Questions
A318/A319/A320/A321 Equipment - Furnishing

18.How can the fire shutoff valve be closed? 22.Where is the oil temperature monitored and indicated?

Answer: Answer:

23.How is the electrical motor of the blue pump cooled?

19.On which manifold is the normal brake selector valve installed?
Answer:
Answer:

29-13 Yellow Hydraulic System

29-12 Blue Hydraulic System 24.How can the yellow electrical pump be switched on?

20.How is the blue hydraulic system pressurized? Answer:

Answer:

25.For what is the electrical pump used? Which users can be pressurized?
Answer:
21.When is the RAT unlocked and extended?

Answer:

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29-3
 Training Manual Study Questions
A318/A319/A320/A321 Equipment - Furnishing

26.For what is the handpump used? Which users can be pressurized? 30.What is the normal position of the manually actuated leak measurement
valves?
Answer:
Answer:

27.For what is the PTU quick disconnect used?

Answer:
29-22 Ram Air Turbine
31.Name the safety instructions regarding the RAT.
Answer:

28.How can the PTU be switched on? When is it switched on automatically?

Answer:

32.Under which conditions is the RAT automatically extended in flight?

Answer:
29.For what is the leak measurement manifold used?
Answer:

33.How can the RAT be extended manually in flight?

Answer:

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29-4
 Training Manual Study Questions
A318/A319/A320/A321 Equipment - Furnishing

34.How can the RAT be stowed? 38.How is the hydraulic tank level indicated on the ECAM?
Answer: Answer:

39.Are the fire shutoff valves monitored?

29-23 Power Transfer Unit Answer:
35.Which hydraulic systems can be pressurized by the PTU?
Answer:

40.How is a system low pressure warning displayed on the ECAM? Indicate color
and pressure limit.
Answer:
36.When is the PTU automatically switched on on ground.
Answer:

41.Are all warnings in all flight phases indicated?

Answer:

29-30 Indicating
37.How are the hydraulic pumps (EDP and ELEC pumps) monitored?
Answer:

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29-5
 Training Manual Study Questions
A318/A319/A320/A321 Equipment - Furnishing

29-99 CFDS
42.Where can you find hydraulic malfunctions in the CFDS?
Answer:

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29-6