Aircraft Systems AircraftSystems:Mechanical,electrical,andavionicssubsystemsintegration,Third Edition.IanMoirandAllanSeabridge ©2008JohnWiley&Sons,Ltd. ISBN: 978-0-470-05996-8 Aircraft Systems Mechanical, electrical, and avionics subsystems integration Third Edition Ian Moir Allan Seabridge Copyright © 2008 John Wiley & Sons Ltd, The Atrium, Southern Gate, Chichester, West Sussex PO19 8SQ, England Telephone +44 1243 779777 Email (for orders and customer service enquiries): [email protected] Visit our Home Page on www.wiley.com All Rights Reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, scanning or otherwise, except under the terms of the Copyright, Designs and Patents Act 1988 or under the terms of a licence issued by the Copyright Licensing Agency Ltd, 90 Tottenham Court Road, London W1T 4LP, UK, without the permission in writing of the Publisher. 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Airplanes—Equipment and supplies. I. Seabridge, A. G. (Allan G.) II. Title. TL671.M59 2008 629.135—dc22 2008001330 British Library Cataloguing in Publication Data A catalogue record for this book is available from the British Library ISBN 978-0-470-05996-8 Typeset in 10.5/12.5pt Palatino by Integra Software Services Pvt. Ltd, Pondicherry, India Printed and bound in Great Britain by Antony Rowe Ltd, Chippenham, Wiltshire This book is printed on acid-free paper. To Mike Woodhead 1944 to 2007 Professor of Systems Engineering at Loughborough University An inspiration to all systems engineers and sadly missed Contents Foreword xvii Series Preface xix About the Authors xxi Acknowledgements xxiii List of Abbreviations xxv Introduction xxxv Systems Integration xxxvi Systems Interaction xxxix 1 Flight Control Systems 1 1.1 Introduction 1 1.2 Principles of Flight Control 3 1.3 Flight Control Surfaces 4 1.4 Primary Flight Control 5 1.5 Secondary Flight Control 5 1.6 Commercial Aircraft 7 1.6.1 Primary Flight Control 7 1.6.2 Secondary Flight Control 7 1.7 Flight Control Linkage Systems 9 1.7.1 Push-Pull Control Rod System 10 1.7.2 Cable and Pulley System 11 1.8 High Lift Control Systems 13 1.9 Trim and Feel 15 1.9.1 Trim 15 1.9.2 Feel 17 1.10 Flight Control Actuation 18 1.10.1 Simple Mechanical/Hydraulic Actuation 19 1.10.2 Mechanical Actuation with Electrical Signalling 21 viii Contents 1.10.3 Multiple Redundancy Actuation 22 1.10.4 Mechanical Screwjack Actuator 26 1.10.5 Integrated Actuator Package (IAP) 27 1.10.6 Advanced Actuation Implementations 30 1.11 Civil System Implementations 34 1.11.1 Top-Level Comparison 35 1.11.2 Airbus Implementation 36 1.12 Fly-By-Wire Control Laws 40 1.13 A380 Flight Control Actuation 41 1.14 Boeing 777 Implementation 44 1.15 Interrelationship of Flight Control, Guidance and Flight Management 48 2 Engine Control Systems 51 2.1 Introduction 51 2.1.1 Engine/Airframe Interfaces 52 2.2 Engine Technology and Principles of Operation 53 2.3 The Control Problem 55 2.3.1 Fuel Flow Control 56 2.3.2 Air Flow Control 58 2.3.3 Control Systems 59 2.3.4 Control System Parameters 60 2.3.5 Input Signals 60 2.3.6 Output Signals 62 2.4 Example Systems 62 2.5 Design Criteria 71 2.6 Engine Starting 73 2.6.1 Fuel Control 73 2.6.2 Ignition Control 74 2.6.3 Engine Rotation 75 2.6.4 Throttle Levers 77 2.6.5 Starting Sequence 78 2.7 Engine Indications 78 2.8 Engine Oil Systems 81 2.9 Engine Offtakes 81 2.10 Reverse Thrust 83 2.11 Engine Control on Modern Civil Aircraft 84 3 Fuel Systems 87 3.1 Introduction 87 3.2 Characteristics of Fuel Systems 89 3.3 Description of Fuel System Components 90 3.3.1 Fuel Transfer Pumps 90 3.3.2 Fuel Booster Pumps 91 3.3.3 Fuel Transfer Valves 92 3.3.4 Non-Return Valves (NRVs) 93 Contents ix 3.4 Fuel Quantity Measurement 94 3.4.1 Level Sensors 94 3.4.2 Fuel Gauging Probes 96 3.4.3 Fuel Quantity Measurement Basics 96 3.4.4 Tank Shapes 97 3.4.5 Fuel Properties 98 3.4.6 Fuel Quantity Measurement Systems 101 3.4.7 Fokker F50/F100 System 101 3.4.8 Airbus A320 System 103 3.4.9 ‘Smart' Probes 104 3.4.10 Ultrasonic Probes 105 3.5 Fuel System Operating Modes 105 3.5.1 Pressurisation 106 3.5.2 Engine Feed 106 3.5.3 Fuel Transfer 108 3.5.4 Refuel/Defuel 109 3.5.5 Vent Systems 111 3.5.6 Use of Fuel as a Heat Sink 112 3.5.7 External Fuel Tanks 112 3.5.8 Fuel Jettison 113 3.5.9 In-Flight Refuelling 114 3.6 Integrated Civil Aircraft Systems 116 3.6.1 Bombardier Global Express 117 3.6.2 Boeing 777 119 3.6.3 A340-500/600 Fuel System 120 3.7 Fuel Tank Safety 128 3.7.1 Principles of Fuel Inerting 129 3.7.2 Air Separation Technology 130 3.7.3 Typical Fuel Inerting System 131 3.8 Polar Operations – Cold Fuel Management 133 3.8.1 Minimum Equipment List (MEL) 133 3.8.2 Cold Fuel Characteristics 134 3.8.3 Fuel Temperature Indication 135 4 Hydraulic Systems 137 4.1 Introduction 137 4.2 Hydraulic Circuit Design 138 4.3 Hydraulic Actuation 142 4.4 Hydraulic Fluid 144 4.5 Fluid Pressure 145 4.6 Fluid Temperature 145 4.7 Fluid Flow Rate 146 4.8 Hydraulic Piping 146 4.9 Hydraulic Pumps 147 4.10 Fluid Conditioning 151 x Contents 4.11 Hydraulic Reservoir 152 4.12 Warnings and Status 152 4.13 Emergency Power Sources 153 4.14 Proof of Design 154 4.15 Aircraft System Applications 155 4.15.1 The Avro RJ Hydraulic System 156 4.15.2 The BAE SYSTEMS Hawk 200 Hydraulic System 161 4.15.3 Tornado Hydraulic System 161 4.16 Civil Transport Comparison 163 4.16.1 Airbus A320 164 4.16.2 Boeing 767 165 4.17 Landing Gear Systems 167 4.17.1 Nose Gear 167 4.17.2 Main Gear 168 4.17.3 Braking Anti-Skid and Steering 169 4.17.4 Electronic Control 172 4.17.5 Automatic Braking 173 4.17.6 Multi-Wheel Systems 175 4.17.7 Brake Parachute 178 5 Electrical Systems 181 5.1 Introduction 181 5.1.1 Electrical Power Evolution 181 5.2 Aircraft Electrical System 184 5.3 Power Generation 185 5.3.1 DC Power Generation 185 5.3.2 AC Power Generation 186 5.3.3 Power Generation Control 188 5.4 Primary Power Distribution 199 5.5 Power Conversion and Energy Storage 201 5.5.1 Inverters 201 5.5.2 Transformer Rectifier Units (TRUs) 201 5.5.3 Auto-Transformers 202 5.5.4 Battery Chargers 202 5.5.5 Batteries 203 5.6 Secondary Power Distribution 203 5.6.1 Power Switching 203 5.6.2 Load Protection 204 5.7 Typical Aircraft DC System 207 5.8 Typical Civil Transport Electrical System 208 5.9 Electrical Loads 210 5.9.1 Motors and Actuation 210 5.9.2 DC Motors 211 5.9.3 AC Motors 212 5.9.4 Lighting 212 Contents xi 5.9.5 Heating 213 5.9.6 Subsystem Controllers and Avionics Systems 213 5.9.7 Ground Power 214 5.10 Emergency Power Generation 214 5.10.1 Ram Air Turbine 215 5.10.2 Backup Power Converters 215 5.10.3 Permanent Magnet Generators (PMGs) 216 5.11 Recent Systems Developments 218 5.11.1 Electrical Load Management System (ELMS) 218 5.11.2 Variable Speed Constant Frequency (VSCF) 220 5.11.3 270 VDC Systems 227 5.11.4 More-Electric Aircraft (MEA) 227 5.12 Recent Electrical System Developments 228 5.12.1 Airbus A380 Electrical System Overview 229 5.12.2 A400M 234 5.12.3 B787 Electrical Overview 234 5.13 Electrical Systems Displays 237 6 Pneumatic Systems 239 6.1 Introduction 239 6.2 Use of Bleed Air 240 6.3 Engine Bleed Air Control 244 6.4 Bleed Air System Indications 247 6.5 Bleed Air System Users 247 6.5.1 Wing and Engine Anti-Ice 248 6.5.2 Engine Start 250 6.5.3 Thrust Reversers 251 6.5.4 Hydraulic Systems 251 6.6 Pitot Static Systems 252 6.6.1 Innovative Methods of Pitot-Static Measurement 256 7 Environmental Control Systems 259 7.1 Introduction 259 7.2 The Need for a Controlled Environment 260 7.2.1 Kinetic Heating 260 7.2.2 Solar Heating 261 7.2.3 Avionics Heat Loads 262 7.2.4 Airframe System Heat Loads 262 7.2.5 The Need for Cabin Conditioning 262