Civil Avionics Systems E-Book

Ian Moir

• Herausgeber: John Wiley & Sons
• Kategorie: Fachliteratur
• Serie: Aerospace Series (PEP)
• Sprache: Englisch

Seitenzahl: 786

Veröffentlichungsjahr: 2013

Beschreibung

Civil Avionics Systems, Second Edition, is an updated and in-depth practical guide to integrated avionic systems as applied to civil aircraft and this new edition has been expanded to include the latest developments in modern avionics. It describes avionic systems and potential developments in the field to help educate students and practitioners in the process of designing, building and operating modern aircraft in the contemporary aviation system. Integration is a predominant theme of this book, as aircraft systems are becoming more integrated and complex, but so is the economic, political and technical environment in which they operate. Key features: * Content is based on many years of practical industrial experience by the authors on a range of civil and military projects * Generates an understanding of the integration and interconnectedness of systems in modern complex aircraft * Updated contents in the light of latest applications * Substantial new material has been included in the areas of avionics technology, software and system safety The authors are all recognised experts in the field and between them have over 140 years' experience in the aircraft industry. Their direct and accessible style ensures that Civil Avionics Systems, Second Edition is a must-have guide to integrated avionic systems in modern aircraft for those in the aerospace industry and academia.

Leseprobe

Contents

Cover

Aerospace Series List

Title Page

Copyright

Dedication

About the Authors

Series Preface

Preface to Second Edition

Preface to First Edition

Acknowledgements

List of Abbreviations

Chapter 1: Introduction

1.1 Advances since 2003

1.2 Comparison of Boeing and Airbus Solutions

1.3 Outline of Book Content

1.4 The Appendices

Chapter 2: Avionics Technology

2.1 Introduction

2.2 Avionics Technology Evolution

2.3 Avionics Computing

2.4 Digital Systems Input and Output

2.5 Binary Arithmetic

2.6 The Central Processing Unit (CPU)

2.7 Software

2.8 Microprocessors

2.9 Memory Technologies

2.10 Application-Specific Integrated Circuits (ASICs)

2.11 Integrated Circuits

2.12 Integrated Circuit Packaging

References

Chapter 3: Data Bus Networks

3.1 Introduction

3.2 Digital Data Bus Basics

3.3 Transmission Protocols

3.4 ARINC 429

3.5 MIL-STD-1553B

3.6 ARINC 629

3.7 ARINC 664 Part 7

3.8 CANbus

3.9 Time Triggered Protocol

3.10 Fibre-optic Data Communications

3.11 Data Bus Summary

References

Chapter 4: System Safety

4.1 Introduction

4.2 Flight Safety

4.3 System Safety Assessment

4.4 Reliability

4.5 Availability

4.6 Integrity

4.7 Redundancy

4.8 Analysis Methods

4.9 Other Considerations

References

Chapter 5: Avionics Architectures

5.1 Introduction

5.2 Avionics Architecture Evolution

5.3 Avionic Systems Domains

5.4 Avionics Architecture Examples

5.5 IMA Design Principles

5.6 The Virtual System

5.7 Partitioning

5.8 IMA Fault Tolerance

5.9 Network Definition

5.10 Certification

5.11 IMA Standards

References

Chapter 6: Systems Development

6.1 Introduction

6.2 System Design Guidelines

6.3 Interrelationship of Design Processes

6.4 Requirements Capture and Analysis

6.5 Development Processes

6.6 Development Programme

6.7 Extended Operations Requirements

6.8 ARINC Specifications and Design Rigour

6.9 Interface Control

References

Chapter 7: Electrical Systems

7.1 Electrical Systems Overview

7.2 Electrical Power Generation

7.3 Power Distribution and Protection

7.4 Emergency Power

7.5 Power System Architectures

7.6 Aircraft Wiring

7.7 Electrical Installation

7.8 Bonding and Earthing

7.9 Signal Conditioning

7.10 Central Maintenance Systems

References

Further Reading

Chapter 8: Sensors

8.1 Introduction

8.2 Air Data Sensors

8.3 Magnetic Sensors

8.4 Inertial Sensors

8.5 Combined Air Data and Inertial

8.6 Radar Sensors

References

Chapter 9: Communications and Navigation Aids

9.1 Introduction

9.2 Communications

9.3 Ground-Based Navigation Aids

9.4 Instrument Landing Systems

9.5 Space-Based Navigation Systems

9.6 Communications Control Systems

References

Chapter 10: Flight Control Systems

10.1 Principles of Flight Control

10.2 Flight Control Elements

10.3 Flight Control Actuation

10.4 Principles of Fly-By-Wire

10.5 Boeing 777 Flight Control System

10.6 Airbus Flight Control Systems

10.7 Autopilot Flight Director System

10.8 Flight Data Recorders

References

Chapter 11: Navigation Systems

11.1 Principles of Navigation

11.2 Flight Management System

11.3 Electronic Flight Bag

11.4 Air Traffic Management

11.5 Performance-Based Navigation

11.6 Automatic Dependent Surveillance – Broadcast

11.7 Boeing and Airbus Implementations

11.8 Terrain Avoidance Warning System (TAWS)

References

Historical References (in Chronological Order)

Chapter 12: Flight Deck Displays

12.1 Introduction

12.2 First Generation Flight Deck: the Electromagnetic Era

12.3 Second Generation Flight Deck: the Electro-Optic Era

12.4 Third Generation: the Next Generation Flight Deck

12.5 Electronic Centralised Aircraft Monitor (ECAM) System

12.6 Standby Instruments

12.7 Head-Up Display Visual Guidance System (HVGS)

12.8 Enhanced and Synthetic Vision Systems

12.9 Display System Architectures

12.10 Display Usability

12.11 Display Technologies

12.12 Flight Control Inceptors

References

Chapter 13: Military Aircraft Adaptations

13.1 Introduction

13.2 Avionic and Mission System Interface

13.3 Applications

Reference

Further Reading

Appendices

Introduction to Appendices

Appendix A: Safety Analysis – Flight Control System

A.1 Flight Control System Architecture

A.2 Dependency Diagram

A.3 Fault Tree Analysis

Appendix B: Safety Analysis – Electronic Flight Instrument System

B.1 Electronic Flight Instrument System Architecture

B.2 Fault Tree Analysis

Appendix C: Safety Analysis – Electrical System

C.1 Electrical System Architecture

C.2 Fault Tree Analysis

Appendix B: Safety Analysis – Engine Control System

D.1 Factors Resulting in an In-Flight Shut Down

D.2 Engine Control System Architecture

D.3 Markov Analysis

Index

Aerospace Series List

Civil Avionics Systems, Second EditionMoir, Seabridge and JukesAugust 2013Modelling and Managing Airport PerformanceZografosJuly 2013Advanced Aircraft Design: Conceptual Design, Analysis and Optimization of Subsonic Civil AirplanesTorenbeekJune 2013Design and Analysis of Composite Structures: With Applications to Aerospace Structures, Second EditionKassapoglouApril 2013Aircraft Systems Integration of Air-Launched WeaponsRigbyApril 2013Design and Development of Aircraft Systems, Second EditionMoir and SeabridgeNovember 2012Understanding Aerodynamics: Arguing from the Real PhysicsMcLeanNovember 2012Aircraft Design: A Systems Engineering ApproachSadraeyOctober 2012Introduction to UAV Systems, Fourth EditionFahlstrom and GleasonAugust 2012Theory of Lift: Introductory Computational Aerodynamics with MATLAB and OctaveMcBainAugust 2012Sense and Avoid in UAS: Research and ApplicationsAngelovApril 2012Morphing Aerospace Vehicles and StructuresValasekApril 2012Gas Turbine Propulsion SystemsMacIsaac and LangtonJuly 2011Basic Helicopter Aerodynamics, Third EditionSeddon and NewmanJuly 2011Advanced Control of Aircraft, Spacecraft and RocketsTewariJuly 2011Cooperative Path Planning of Unmanned Aerial VehiclesTsourdos et al.November 2010Principles of Flight for PilotsSwattonOctober 2010Air Travel and Health: A Systems PerspectiveSeabridge et al.September 2010Unmanned Aircraft Systems: UAVS Design, Development and DeploymentAustinApril 2010Introduction to Antenna Placement and InstallationsMacnamaraApril 2010Principles of Flight SimulationAllertonOctober 2009Aircraft Fuel SystemsLangton et al.May 2009The Global Airline IndustryBelobabaApril 2009Computational Modelling and Simulation of Aircraft and the Environment: Volume 1 – Platform Kinematics and Synthetic EnvironmentDistonApril 2009Handbook of Space TechnologyLey, Wittmann HallmannApril 2009Aircraft Performance Theory and Practice for PilotsSwattonAugust 2008Aircraft Systems, Third EditionMoir and SeabridgeMarch 2008Introduction to Aircraft Aeroelasticity and LoadsWright and CooperDecember 2007Stability and Control of Aircraft SystemsLangtonSeptember 2006Military Avionics SystemsMoir and SeabridgeFebruary 2006Design and Development of Aircraft SystemsMoir and SeabridgeJune 2004Aircraft Loading and Structural LayoutHoweMay 2004Aircraft Display SystemsJukesDecember 2003Civil Avionics SystemsMoir and SeabridgeDecember 2002

This edition was published in 2013 © 2013 John Wiley & Sons, Ltd

First Edition published in 2003 © 2003 John Wiley & Sons, Ltd

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Library of Congress Cataloging-in-Publication Data

Moir, I. (Ian) Civil avionic systems / Ian Moir, Allan Seabridge, Malcolm Jukes. -- 2nd edition. 1 online resource. Some parts of ECIP data have title: Civil avionics systems Includes bibliographical references and index. Description based on print version record and CIP data provided by publisher; resource not viewed. ISBN 978-1-118-53672-8 (ePub) – ISBN 978-1-118-53673-5 (Adobe PDF) – ISBN 978-1-118-53674-2 (MobiPocket) – ISBN 978-1-118-34180-3 (cloth) 1. Avionics. I. Seabridge, A. G. (Allan G.) II. Jukes, Malcolm. III. Title. IV. Title: Civil avionics systems. TL695 629.135–dc23 2013023778

A catalogue record for this book is available from the British Library

ISBN: 978-1-118-34180-3

This book is dedicated to Sheena, Sue and Marianne who once again allowed us to indulge our passion for aircraft engineering.

We also wish to acknowledge the passing of a friend, colleague, fellow author, and Series Editor: a major contributor to the Aerospace Series. A vital member of the global aerospace engineering community who passed away on 22 November 2012.

An aerospace systems engineer ‘par excellence’

Roy Langton, 1939 to 2012

About the Authors

Ian Moir, after 20 years in the Royal Air Force as an engineering officer, went on to Smiths Industries in the UK where he was involved in a number of advanced projects. Since retiring from Smiths (now GE aviation), he is now in demand as a highly respected consultant. Ian has a broad and detailed experience working in aircraft avionics systems in both military and civil aircraft. From the RAF Tornado and Army Apache helicopter to the Boeing 777 electrical load management system (ELMS), Ian's work has kept him at the forefront of new system developments and integrated systems in the areas of more-electric technology and system implementations. With over 50 years of experience, Ian has a special interest in fostering training and education and further professional development in aerospace engineering.

Allan Seabridge was until 2006 the Chief Flight Systems Engineer at BAE Systems at Warton in Lancashire in the UK. In over 45 years in the aerospace industry, his work has included the opportunity to work on a wide range of BAE Systems projects including Canberra, Jaguar, Tornado, EAP, Typhoon, Nimrod, and an opportunity for act as reviewer for Hawk, Typhoon and Joint Strike Fighter, as well being involved in project management, research and development, and business development. In addition, Allan has been involved in the development of a range of flight and avionics systems on a wide range of fast jets, training aircraft, and ground and maritime surveillance projects. From experience in BAE Systems with Systems Engineering education, he is keen to encourage a further understanding of integrated engineering systems. An interest in engineering education continues since retirement with the design and delivery of systems and engineering courses at a number of UK universities at undergraduate and postgraduate level. Allan has been involved at Cranfield University for many years and has recently started a three-year period as External Examiner for the MSc course in Aerospace Vehicle Design.

Malcolm Jukes has over 35 years of experience in the aerospace industry, mostly working for Smiths Aerospace at Cheltenham, UK. Among his many responsibilities as Chief Engineer for Defence Systems Cheltenham, Malcolm managed the design and experimental flight trials of the first UK electronic flight instrument system (EFIS) and the development and application of head-up displays, multifunction head-down displays, and mission computing on the F/A-18, AV8B, Eurofighter Typhoon, Hawk and EH101 aircraft. In this role, and subsequently as Technology Director, he was responsible for product technical strategy and the acquisition of new technology for Smiths UK aerospace products in the areas of displays and controls, electrical power management systems, fuel gauging and management systems, and health and usage monitoring systems. One of his most significant activities was the application of AMLCD technology to civil and military aerospace applications. Malcolm was also a member of the UK Industrial Avionics Working Group (IAWG), and is now an aerospace consultant and university lecturer operating in the areas of displays, display systems, and mission computing.

Between them the authors have been actively involved in undergraduate, postgraduate and supervisory duties in aerospace at the Universities of Bristol, Bath, City, Cranfield, Lancaster, Loughborough, Imperial, Manchester, and the University of the West of England. The authors are course leaders for the postgraduate Avionics Systems and Aircraft Systems modules for the Continuous Professional Development in Aerospace (CPDA) course delivered by a consortium of the Universities of Bristol, Bath and the West of England to UK aerospace companies including BAE Systems, Airbus UK and Augusta Westland.

Series Preface

The field of aerospace is wide ranging and covers a variety of products, disciplines and domains, not merely in engineering but in many related supporting activities. These combine to enable the aerospace industry to produce exciting and technologically challenging products. A wealth of knowledge is retained by practitioners and professionals in the aerospace fields that is of benefit to other practitioners in the industry, and to those entering the industry from University.

The Aerospace Series aims to be a practical and topical series of books aimed at engineering professionals, operators, users and allied professions such as commercial and legal executives in the aerospace industry. The range of topics is intended to be wide ranging, covering design and development, manufacture, operation and support of aircraft as well as topics such as infrastructure operations, and developments in research and technology. The intention is to provide a source of relevant information that will be of interest and benefit to all those people working in aerospace.

Avionic systems are an essential and key component of modern aircraft that control all vital functions, including navigation, traffic collision avoidance, flight control, data display and communications. It would not be possible to fly today's advanced aircraft designs without such sophisticated systems.

This 2nd edition of Civil Avionics Systems provides many additions to the original edition, taking into account many of the innovations that have appeared over the past decade in this rapidly advancing field. The book follows the same successful format of the first edition, and is recommended for those wishing to obtain either a top-level overview of avionic systems or a more in-depth description of the wide range of systems used in today's aircraft.

Peter Belobaba, Jonathan Cooper and Allan Seabridge

Preface to Second Edition

It has been over ten years since the first edition of Civil Avionics Systems was published. The book has been in print since that time and it is used as a course text book for a number of university undergraduate and postgraduate courses. It continues to be popular with students and practitioners, if the sales are anything to go by, and the authors continue to use it as the basis of lectures whilst continuously updating and improving the content.

However, much has happened in the world of commercial aviation and in the technological world of avionics since the first publication, prompting a serious update to the book. Despite worldwide economic recession, people still feel a need to fly for business and leisure purposes. Airlines have introduced new and larger aircraft and also introduced more classes to improve on the basic economy class, with more people choosing premium economy and even business class for their holiday flights. This has seen the introduction of the world's largest airliner, the Airbus A380, and an airliner seriously tackling some of the environmental issues in the form of the Boeing B787.

In the field of avionics there have been many advances in the application of commercial data bus networks and modular avionic systems to reduce the risk of obsolescence. Global navigation systems including interoperability of European, US, Russian and Chinese systems and associated standards will seek to improve the ability of aircraft to navigate throughout the world, maybe leading to more ‘relaxed’ rules on navigation and landing approaches. The crew have been served well with ergonomically improved flight decks providing improved situational awareness through larger, clearer, head-down displays and the addition of head-up displays, with enhanced flight vision and synthetic vision systems.

Propulsion systems have improved in the provision of thrust, reduced noise, improved availability and economic operation. Modern airliners are beginning to move towards more-electric operation.

All these topics and more are covered in this new edition, at considerable effort to keep the book to a reasonable number of pages.

Preface to First Edition

This book on ‘Civil Avionic Systems’ is a companion to our book on ‘Aircraft Systems’. Together the books describe the complete set of systems that form an essential part of the modern military and commercial aircraft. There is much read across – many basic aircraft systems such as fuel, air, flight control and hydraulics are common to both types, and modern military aircraft are incorporating commercially available avionic systems such as liquid crystal cockpit displays and flight management systems.

Avionics is an acronym which broadly applies to AVIation (and space) electrONICS. Civil avionic systems are a key component of the modern airliner and business jet. They provide the essential aspects of navigation, human machine interface and external communications for operation in the busy commercial airways. The civil avionic industry, like the commercial aircraft industry it serves, is driven by regulatory, business, commercial and technology pressures and it is a dynamic environment in which risk must be carefully managed and balanced against performance improvement. The result of many years of improvement by systems engineers is better performance, improved safety and improved passenger facilities.

‘Civil Avionic Systems’ provides an explanation of avionic systems used in modern aircraft, together with an understanding of the technology and the design process involved. The explanation is aimed at workers in the aerospace environment – researchers, engineers, designers, maintainers and operators. It is, however, aimed at a wider audience than the engineering population, it will be of interest to people working in marketing, procurement, manufacturing, commercial, financial and legal departments. Furthermore it is intended to complement undergraduate and post graduate courses in aerospace systems to provide a path to an exciting career in aerospace engineering. Throughout the book ‘industry standard’ units have been used, there is therefore a mix of metric and Imperial units which reflects normal parlance in the industry

The book is intended to operate at a number of levels:

Providing a top level overview of avionic systems with some historical background.Providing a more in-depth description of individual systems and integrated systems for practitioners.Providing references and suggestions for further reading for those who wish to develop their knowledge further.

We have tried to deal with a complex subject in a straightforward descriptive manner. We have included aspects of technology and development to put the systems into a rapidly changing context. To fully understand the individual systems and integrated architectures of systems to meet specific customer requirements is a long and complicated business. We hope that this book makes a contribution to that understanding.

Ian Moir and Allan Seabridge 2002

Acknowledgements

Many people have helped us with this book, albeit unknowingly in a lot of cases. Some of the material has come from our lecturing to classes of short-course delegates and continuing professional development students. The resulting questions and discussions inevitably help to develop and improve the material. Thanks are due to all those people who patiently listened to us and stayed awake.

Colleagues in industry have also helped us in the preparation. Mike Hirst critiqued a number of chapters, and Brian Rawnsley of GE Aviation reviewed and advised upon the latest regulatory issues. Our Airbus UK course mentors Barry Camwell, Martin Rowlands and Martin Lee provided invaluable advice and really gave a stimulus to generating a lot of new material. We have also been helped by Leon Skorczewski and Dave Holding who have joined in the avionics courses by providing material and lectures.

BAE Systems, Cranfield University and the University of the West of England have invited us to lecture on their continuing professional development courses, which opens the door to discussions with many mature students. We wish to thank the organisers of the courses and also the students.

We have been guided throughout the preparation of the manuscript by Anne Hunt, Tom Carter and Eric Willner at John Wiley's at Chichester, and also to Samantha Jones, Shikha Jain from Aptara Delhi and Wahidah Abdul Wahid from Wiley Singapore for the proof-reading, copy-editing and publishing stages of production. Their guidance and patience is, as always, gratefully received.

Ian Moir, Allan Seabridge and Malcolm Jukes January 2013

List of Abbreviations

3-Dthree-dimensional4-Dfour-dimensionalABSautomatic braking systemACalternating currentACAdvisory CircularACARSARINC Communications and Reporting SystemACEactuator control electronicsACKreceiver acknowledgeACFDAdvanced Civil Flight DeckACPaudio control panelADCair data computerADCanalogue to digital conversion/converterADDairstream direction detectorADFautomatic direction findingADIattitude director indicatorADIaircraft direction indicatorADIRSAir Data & Inertial Reference SystemADIRUAir Data and Inertial Reference Unit (B777)ADMair data moduleADPair-driven pumpADS-Aautomatic dependent surveillance – addressADS-Bautomatic dependent surveillance – broadcastAEWairborne early warningAEW&CAirborne Early Warning and ControlAFDCautopilot flight director computerAFDSautopilot flight director systemAFDXAviation Full DuplexAHartificial horizonAHRSattitude and heading reference systemAIMApple–IBM–Motorola allianceAIMSAircraft Information Management System (B777)AlaluminiumALARPAs Low as Reasonably PracticalALTbarometric altitudeALUarithmetic logic unitAMamplitude modulationAMCCApplied Micro Circuits CorporationAMLCDactive matrix liquid crystal displayANOAir Navigation OrderANPactual navigation performanceAoAangle of attackAOCairline operation communicationAOR-EAzores Oceanic Region – EastAOR-WAzores Oceanic Region – WestAPEXApplication ExecutiveAPIApplication Programming InterfaceAPUauxiliary power unitARAuthorisation RequiredARINCAir Radio Inc.ARMAdvanced RISC machineASCBAvionics Standard Communications Bus (Honeywell)ASCIIAmerican Standard Code for Information InterchangeASIairspeed indicatorASICapplication-specific integrated circuitASPCUair supply and pressure control unitASTORAirborne Stand-off RadarATAAir Transport AssociationATCair traffic controlATIair transport indicatorA to Danalogue to digitalATMair traffic managementATNaeronautical telecommunications networkATRAir Transport RadioATSair traffic servicesATSUAir Traffic Service Unit – Airbus unit to support FANSAWACSAirborne Warning and Control SystemAWGAmerican Wire GaugeBBlue Channel (hydraulics) AirbusBAGbandwidth allocation gapBATbatteryBCbus controllerBCDbinary coded decimalBGAball grid arrayBGANBroadcast Global Area NetworkBITbuilt-in-testBLCbattery line contactorsBPCUbus power control unitBPCUbrake power control unitbpsbits per secondBRNAVbasic area navigationBSCUbrake system control unitBTBbus tie breakerBTCbus tie contactorBTMUbrake temperature monitoring unitCCentreCCentre Channel (hydraulic) AirbusCC Band (3.90 to 6.20 GHz)C1Centre 1 (Boeing 777)C2Centre 2 (Boeing 777)CACourse/Acquisition – GPS Operational ModeCAACivil Airworthiness AuthorityCANbusa widely used industrial data bus developed by BoschCAScalibrated air speedCASTCertification Authorities Software TeamCat IAutomatic Approach Category ICat IIAutomatic Approach Category IICat IIIAutomatic Approach Category IIICat ICategory I AutolandCat IICategory II AutolandCat IIIACategory IIIA AutolandCat IIIBCategory IIIB AutolandCCAcommon cause analysisCCRcommon computing resourceCCScommunications control systemCDcollision detectionCd/m2candela per square metreCDUcontrol and display unitCDRcritical design reviewCFconstant frequencyCFcourse to a fixCFITcontrolled flight into terrainCFRCode of Federal RegulationsCLBconfigurable logic blockCMAcommon mode analysisCMCSCentral Maintenance Computing System (Boeing)C-MOScomplementary metal-oxide semiconductorCMSCentral Maintenance System (Airbus)CNSCommunications, Navigation, SurveillanceCO2carbon dioxideC of Gcentre of gravityCOMcommandCOMMScommunications modeCOMPASSChinese equivalent of GPS (Bei Dou)COTScommercial off-the-shelf systemsCPIOMcentral processor input/output moduleCPUcentral processing unitCRIconfiguration reference itemCRCcyclic redundancy checkCRDCcommon remote data concentrator (A350)CRTcathode ray tubeCScertification specificationCSDconstant speed driveCSDBCommercial Standard Data BusCSMAcarrier sense multiple accessCSMA/CDcarrier sense multiple access/collision detectionCTCcabin temperature controllerCucopperCVRcockpit voice recorderCVScombined vision systemCWcontinuous waveCW/FMcontinuous wave/frequency modulatedDAdecision altitudeDACdigital to analogue conversion/converterDALdesign assurance leveldBdecibelDCdirect currentDCDUData-Link Control & Display Unit (Airbus)DC TIE CONTDC tie contactorDef StanDefence StandardDFdirect to a fixDFDAUdigital flight data acquisition unitDFDRdigital flight data recorderDFDRSdigital flight data recording systemDGdirectional gyroDGPSDifferential GPSDHdecision heightDIPdual in-line packageDLPdigital light projectorDMDdigital micro-mirrorDMEdistance measuring equipmentDoDDepartment of Defense (US)D-RAMdynamic random access memoryDTEDDigital Terrain Elevation DataDTIDepartment of Trade and IndustryD to Adigital to analogueDTSAdynamic time-slot allocationDUdisplay unitDVORDoppler VOREeastEADIelectronic ADIEASequivalent airspeedEASAEuropean Aviation Safety AuthorityEBHAelectrical backup hydraulic actuatorECEuropean CommunityECAMElectronic Centralised Aircraft Monitor (Airbus)ECBexternal power contactorECCerror correcting codeECCMelectronic counter-counter measuresECMelectronic counter measuresECSenvironmental control systemEDPengine-driven pumpEEelectrical equipmentEEPROMelectrically erasable programmable read only memoryEFBelectronic flight bagEFISelectronic flight instrument systemEFVSenhanced flight vision systemEGPWSenhanced ground proximity warning systemEHAelectro-hydrostatic actuatorEHFextremely high frequencyEHSIelectronic HSIEICASEngine Indicating & Crew Alerting System (Boeing)EISelectronic instrument systemELACelevator/aileron computer (A320)ELCUelectrical load control unitELINTelectronic intelligenceELMSElectrical Load Management SystemEMelectromagneticEMAelectromechanical actuatorEMIelectromagnetic interferenceEMPelectrical motor pumpEMRelectromagnetic radiationEOFend of frameEPCelectrical power contactorEPLDelectrically programmable logic deviceEPROMelectrically programmable read only memoryESAEuropean Space AgencyESMelectronic support measuresESS, EssessentialESSenvironmental stress screeningETAestimated time of arrivalETOPSextended twin operationsETOXerase-through-oxideEUelectronic unitEUEuropean UnionEUROCAEEuropean Organisation for Civil Aviation EquipmentEVSenhanced vision system (EASA nomenclature)EWelectronic warfareFAfix to an altitudeFAAFederal Aviation AuthorityFACFlight Augmentation Computer (Airbus)FADECfull authority digital engine controlFAFfinal approach fixFANSfuture air navigation systemFANS1Future Air Navigation System implemented by BoeingFANSAFuture Air Navigation System implemented by AirbusFARFederal Airworthiness RequirementsFBWfly-by-wireFCDCflight control data concentratorFCPflight control panelFCPCflight control primary computer (A330/340)FCSCflight control secondary computer (A330/340)FCUflight control unitFDAUflight data acquisition unitFDDIfibre-distributed data interfaceFDRflight data recorderFETfield effect transistorFFTfast Fourier transformFGMCFlight Management & Guidance Computer – Airbus terminology for FMSFHAfunctional hazard assessmentFIFOfirst-in, first-outFLflight levelfLfoot-LambertFLIRforward-looking infra-redFLOTOXfloating gate tunnel oxideFMEAfailure modes and effects analysisFMECAfailure mode effects and criticality analysisFMESfailure modes and effects SummaryFMGCflight management guidance computerFMGECFlight Management Guidance & Envelope Computer (A330/340)FMGUFlight Management Guidance UnitFMSflight management systemFMSPflight mode selector panelFOGfibre-optic gyroscopeFoRfield of regardFPGAfield programmable gate arrayFQMSfuel quantity management systemFRACASfailure reporting and corrective action systemfssampling frequencyFSCCflap/slat control computerFSEUflap/slat electronic unitFSFFlight Safety FoundationFSKfrequency shift keyFTAfault tree analysisFTEflight technical errorFTPfoil twisted pairFWCflight warning computerGGreen Channel (hydraulics) AirbusG44th generationGAgeneral aviationGalileoEuropean equivalent of GPSGAMAGeneral Aviation Manufacturer's AssociationGBASground-based augmentation systemGCBgenerator control breakerGCUgenerator control unitGEOSgeostationary satelliteGHzgigaHertzGLCgenerator line contactorGLONASSRussian equivalent of GPS (GLObal'naya NAvigatsionnaya Sputnikovaya Sistema)GNSSglobal navigation satellite systemGPMgeneral processing moduleGPSGlobal Positioning SystemGPWSground proximity warning systemHEarth's magnetic fieldH2OwaterHaheight of aircraftHASHardware Accomplishment SummaryHDDhead-down displayHDMIhigh-definition multimedia interfaceHFhigh frequencyHFDLhigh-frequency data linkHFDSHead-up Flight Display System (Thales)HgmercuryHGSHead-up Guidance System (Rockwell Collins)HIRFhigh-intensity radio fieldHMIhuman–machine interfaceHOODhierarchical object-oriented designHSIhorizontal situation indicatorHtheightHUDhead-up displayHVGShead-up display visual guidance systemHVPHardware Verification PlanH/WhardwareHXholding to a fixHXX component of HHYY component of HHzHertzHZZ component of HI3, I4INMARSAT satellitesIAPintegrated actuator packageIASindicated airspeedIAWGIndustrial Avionics Working GroupICintegrated circuitICAOInternational Civil Aviation OrganisationICDinterface control documentICOinstinctive cut-outIDidentifierIDGintegrated drive generatorIEEEInstitution of Electrical and Electronics EngineersIFinitial fixIFALPAInternational Federation of Air Line Pilots' AssociationsIFEin-flight entertainmentIFFidentification friend or foeIFF/SSRidentification friend or foe/secondary surveillance radarIFRinternational flight rulesIFSDin-flight shut downIFUinterface unitIFZindependent fault zoneIGSOinclined geostationary orbitIITimage intensifierILSinstrument landing systemIMAintegrated modular avionicsINinertial navigationIn Hginches of mercuryINMARSATInternational Maritime Satellite organisationINSinertial navigation systemINVinverterI/Oinput/outputIOCinitial operational capabilityIOMinput/output moduleIORIndian Ocean RegionIPInternet protocolIPFDIntegrated Primary Flight Display (Honeywell SVS)IPTintegrated product teamIRinfra-redIRSinertial reference systemISISintegrated standby instrument systemISOInternational Organization for StandardizationITCZInter-Tropical Convergence ZoneJAAJoint Airworthiness AuthorityJARJoint Airworthiness RequirementJSFJoint Strike FighterJTIDSJoint Information Tactical Information Distribution SystemK1K1 band (10.90 to 17.25 GHz)KaKa band (36.00 to 46.00 GHz)kbpskilobits per secondkmkilometresKuKu band (33.00 to 36.00 GHz)kVAkilovolt-ampskWkilowattLLeft Channel (hydraulics) BoeingLLeftLL Band (0.39 to 1.55 GHz)LAASLocal Area Augmentation SystemLANlocal area networkLBASlocally based augmentation systemLCCleadless chip carrierLCDliquid crystal displayLCoSliquid crystal on siliconLEDlight emitting diodeLFlow frequencyLNAVlateral navigationLPVlocaliser performance with vertical guidanceL/R DVTlinear/rotary differential variable transformerLRGlaser ring gyroLRMline-replaceable moduleLROPSlong-range operationsLRUline-replaceable unitLsLs band (0.90 to 0.95 GHz)LSBleast significant bitLSBlower side-bandLSIlarge-scale integrationLVDTlinear variable differential transformerLWIRlong wave infra-redMMachMmomaximum operating Mach numberMAMarkov analysisMACmedia access controlMADmagnetic anomaly detectorMASPSMinimum Aviation System Performance StandardMATmaintenance access terminalMAUmodular avionics unitMbpsmegabits per secondMCDUmulti-function control and display unitMCUmodular concept unitMDAminimum descent altitudeMDHminimum descent heightMEAmore-electric aircraftMELminimum equipment listMEOSmedium Earth orbit satelliteMFmedium frequencyMFDmultifunction displayMHRSmagnetic heading and reference systemMHzmegaHertzMIL-STDmilitary standardMIPSmillion instructions per secondMISRAMotor Industry Software Reliability AssociationmKmilliKelvinMLSmicrowave landing systemMMRmulti-mode receiverMode AATC Mode signifying aircraft call signMode CATC Mode signifying aircraft call sign and altitudeMode SATC Mode signifying additional aircraft dataMOPSminimum operational performance standardsMON/MonmonitorMOSmetal oxide semiconductorMOSFETmetal oxide semiconductor field effect transistorMPAmaritime patrol aircraftMPCDmultipurpose control and displaymrmilli-radianMRTTmulti-role tanker transportMSImedium-scale integrationMSLmean sea-levelMTBFmean time between failuresMTBRmean time between removalsMTImoving target indicatorMTOWmaximum take-off weightMVAmega-volt ampsMWIRmedium wave infra-redNnorthNAnumerical apertureNASANational Aeronautics and Space AdministrationNATSNational Air Transport SystemNAVnavigation modeNBPno-break powerNDnavigation displayNDBnon-directional beaconNETDnoise-equivalent temperature differenceNextGenNext Generation Air Transport System (USA)NICnetwork interface controllerNiCdnickel cadmium (battery)nmnautical mile – a unit of distance used within the maritime and aeronautical community (1 nm is equivalent to 6070 feet)nmnanometers – electromagnetic radiation characteristic associated with electro-optic wavelengths. (0.1 nm is equivalent to 1 angstrom unit ). Visible light is in the region of 4000 to 7000  NOTAMNotice to AirmenNRZnon-return-to-zeroNVRAMnon-volatile random access memoryO3ozoneOAToutside air temperatureOBOGSon-board oxygen generation systemODICISOne Display for a Cockpit Interactive SolutionO-LEDorganic light emitting diodeOMGObject Management GroupOMTobject modelling techniqueOOAobject-oriented analysisOODobject-oriented designOOOIOUT-OFF-ON-IN: the original simple ACARS message formatOOPobject-oriented programmingOp Ampoperational amplifierPBNperformance based navigationPCpersonal computerPCIperipheral component interconnectPCUpower control unitPDRpreliminary design reviewPEDpersonal electronic devicePFCprimary flight control computerPFDprimary flight displayPGApin grid arrayPHACPlan for Hardware Aspects of CertificationPIOpilot induced oscillationPLDprogrammable logic devicePMApermanent magnet alternatorPMATportable maintenance access terminalPMCPCI Mezzanine CardPMGpermanent magnet generatorPoRpoint of regulationPORPacific Ocean RegionPowerPCPower Optimization With Enhanced RISC – Performance ComputingPPSPrecise Positioning Service (GPS)PRAparticular risks analysisPRNAVPrecision Area NavigationPROMprogrammable read only memoryPsstatic pressurePSEUproximity switch electronic unitPSRprimary surveillance radarPSSApreliminary system safety assessmentPSUpower supply unitPttotal pressureqdynamic pressureQFEelevationQNHbarometric altitudeQuadraxdata bus wiring technique favoured by Airbusρair density (rho)RrangeRRight Channel (hydraulics) BoeingRrightRAResolution AdvisoryR&Dresearch and developmentRad Altradar altimeterRAERoyal Aircraft EstablishmentRAIMreceiver autonomous integrity monitoringRAMrandom access memoryRATram air turbineRDCremote data concentratorRFconstant radius to a fixRFradio frequencyRFIRequest for InformationRFPRequest for ProposalRFUradio frequency unitRISCreduced instruction set computer/computingRIUremote interface unitRLGring laser gyroRMIradio-magnetic indicatorRMPradio management panelRNAVarea navigationRNAV (GNSS)see RNP APCHRNAV (GPS)see RNP APCHRNPrequired navigation performanceRNP APCHRNP ApproachRNP AR APCHRNP with Authorisation Required ApproachROMread only memoryRPCremote power controllerRPDUremote power distribution unitRSSroot sum squaresRTremote terminalRTCARadio Technical Committee AssociationRTLregister transfer levelRTOSreal time operating systemRTRremote transmission requestRTZreturn-to-zeroRVDTrotary variable differential transformerRVRrunway visual rangeRVSMreduced vertical separation minimumRxReceiver, receiveSsouthSS band (1.55 to 5.20 GHz)SAselective availabilitySAAspecial activity airspaceSAAARSpecial Aircraft & Aircrew Authorisation Required (US equivalent of RNP APCH)SAARUSecondary Attitude & Air Data Reference Unit (B777)SAESociety of Automotive EngineersSAHRUsecondary attitude and heading referenceSARsynthetic aperture radarSASstandard altimeter settingSATstatic air temperatureSATCOMsatellite communicationsSATNAVsatellite navigationSBsidebandSBASspace-based augmentation systemSCSpecial Committee 213 (RTCA/MASPS)SDRsystem design reviewSDUsatellite data unitSECsecondary elevator computerSELCALselective callingSESARSingle European Sky ATM ResearchSESAR JUSESAR Joint UnderstandingSFCCslat/flap control computer (A330/340)SGsymbol generatorSGsynchronisation gapSHsample and holdSHFsuper high frequencySiO2silicon dioxideSIDstandard instrument departureSIGINTsignals intelligenceSIMserial interface moduleSLRsideways-looking radarSMDsurface-mount deviceSMTsurface-mount technologySpstatic pressureSPSStandard Positioning Service (GPS)SOFstart of frameSOICsmall outline integrated circuitSNMPsimple network management protocolSPCstatistical process controlS-RAMstatic random access memorySRRsystem requirements reviewSSAsystem safety assessmentSSBsingle sidebandSSDsolid state deviceSSIsmall-scale integrationSSPCsolid state power controllerSSRsecondary surveillance radarSSRsoftware specification reviewSSTSupersonic TransportSSTPshielded screen twisted pairSTARstandard terminal arrival requirementsSTCSupplementary Type CertificateSTPscreened twisted pairS/UTPshielded unscreened twisted pairSVservo-valveSVSsynthetic vision systemS/WsoftwareSWIRshort wave infra-redSysMLSystems Modelling LanguageTATraffic AdvisoryTACANtactical air navigationTACCOtactical commanderTAStrue airspeedTATtotal air temperatureTAWSTerrain Avoidance Warning SystemTCASTraffic Collision Avoidance SystemTCVTerminal Configured VehicleTDMAtime division multiplex allocationTDZtouchdown zoneTerpromterrain profile mappingTFtrack to a fixTFTPtrivial file transfer protocolTGterminal gapTHStailplane horizontal stabiliserTIterminal intervalTIRtotal internal reflectionTLBtranslation look-aside bufferTptotal pressureTPMUtyre pressure monitoring unitTRtransmitter/receiverTRUtransformer rectifier unitTSOTechnical Standards OrderTTLtransistor-transistor logicTTPtime triggered protocolTwinaxdata bus technique favoured by BoeingTxTransmit, transmitterUARTuniversal asynchronous receiver transmitterUAVunmanned air vehicleUDPuser datagram protocolUHFultra high frequencyUKUnited KingdomULAuncommitted logic arrayULDunderwater locating deviceUMLUnified Modelling LanguageUPSUnited Parcel ServicesUS, USAUnited States of AmericaUSNOUnited States Naval ObservatoryUSBupper sidebandUSMSutility systems management systemUTPunshielded twisted pairUVultra violetVvelocityVmomaximum operating speedVACvolts ACVDCvolts DCVDRVHF digital radioVFvariable frequencyVGAvideo graphics adapterVGSVisual Guidance System (Honeywell/BAE Systems)VHDLvery high speed integrated hardware description languageVHFvery high frequencyVHFDLvery high frequency data linkVLvirtual linkVLFvery low frequencyVLSIvery large scale integrationVMCvisual meteorological conditionsVMSvehicle management systemVNAVvertical navigationVORVHF omni-rangingVORTACVOR TACANVSvertical speedVSCFvariable speed/constant frequencyVSIvertical speed indicatorVSDvertical situation displayV/UHFvery/ultra high frequencyWwattWAASWide Area Augmentation SystemWWIIWorld War IIXX axisXX band (5.20 to 10.90 GHz)XbXb band (6.25 to 6.90 GHz)YY axisYYellow Channel (hydraulics) AirbusZZ axisZOHzeroth order holdZSAzonal safety analysis

1

Introduction

1.1 Advances since 2003

The principles of avionics systems are unchanged but new innovations have been introduced since the first edition of Civil Avionics Systems was published in 2003. Many of these advances have been incorporated into modern aircraft, and research continues to improve the aircraft and the air transportation system. Notable advances include:

The A380 and B787 aircraft have been introduced into service.The use of commercial off-the-shelf (COTS)-based data bus networks have significantly increased: in particular, ARINC 664 at the aircraft level, and CANbus at the intra-system level have been widely adopted.The introduction of advanced (3rd generation) IMA implementations on A380, B787 and emergent on A350.More-electric aircraft (MEA) implementations; in part on A380 and more extensively on B787.The rapid growth of global navigation satellite systems (GNSSs) in addition to GPS. The Russian GLONASS has been reconstituted in recent years, and COMPASS (China) and Galileo (European Union) systems are being established.The introduction of the electronic flight bag (EFB), most recently with iPad implementations by some organisations.The introduction of improved ground-based augmentation systems (GBAS)-based approaches.Significant improvements in flight deck displays using COTS glass in rectangular format. The trend towards larger display surfaces has continued, indeed escalated.Wider adoption of head-up displays and the use of enhanced vision systems (EVS) to help mitigate reduced visibility as a limiting factor in flight operations.The development of synthetic vision systems (SVSs) to provide an aid for location of runways and other objects.

1.2 Comparison of Boeing and Airbus Solutions

While the avionics technologies are applied in general to provide solutions to the same problem statement, there are a range of alternative philosophies and architectures that will provide safe and certifiable solutions for an aircraft. Boeing and Airbus adopt different approaches for a number of different system implementations; that is not to say that one solution is any better than another. The different approaches merely reflect the design cultures that exist within the respective manufacturers.

Table 1.1 lists a number of areas where the Boeing and Airbus approaches differ and which are described more fully in the body of the text.

Table 1.1 Comparison of Boeing and Airbus solutions

ImplementationBoeing approachAirbus approachIMA implementation (Chapter 6)B777: First generation – AIMS/ELMS B787: Third generation using cabinets and supplier-furnished RIUs A380: CPIOMs and subsystem supplier-furnished RDCs A350: CPIOMs and generic cRDCsOnboard maintenance (Chapter 7)Embedded maintenance display and PMAT optionsDedicated hardware in CMCMore-electric technology (Chapter 7)B787: 500 kVA/channel at 230 VAC No bleed air off-take from engine. Electric ECS, engine starting and anti-icingA380: 150 kVA/channel at 115 VAC 2 ‘H’ + 2 ‘E’ architecture – blue hydraulics channel subsumed into electrical implementation Use of EBHAsData bus wiring (Chapter 7)Twinax wiringQuadrax wiringAircraft wiring (Chapter 7)Not < 22 AWGNot < 24 AWGFly-by-wire (Chapter 10)Conventional control yoke for pitch and roll inputs Trio-triplex computing using dissimilar hardware Similar softwareSidestick controller for pitch and roll inputs Multiple dual COM/MON computing Dissimilar hardware and softwareElectronic flight bag (Chapter 11)Class I/Class II Fixed or dockedClass III Laptop/iPad/TabletFANS embodiment (Chapter 11)[B737;B747;B757;B767;B777] Fixed hardware with software upgrades/incrementsAdditional hardware: ATSU/DCDU

1.3 Outline of Book Content

The contents of this book are aimed mainly at commercial transport aircraft, but the principles described are also applicable to military types. This particularly applies to large military aircraft that are conversions of commercial aircraft in which the platform avionics will generally remain, with mechanisms for connecting it to military system additions. The description of avionics systems may be subdivided into three areas which together provide the total aircraft function (see Figure 1.1). The chapters that describe these functional areas are listed below under the headings:

Enabling technologies and techniques (1.3.1).Functional avionics systems (1.3.2).The flight deck (1.3.3).

FIGURE 1.1 Interrelationship of enabling technologies and aircraft system

1.3.1 Enabling Technologies and Techniques

The enabling technologies described have a history that is interesting because it shows a comparison of modern implementations with their improvements in performance, mass, availability and safety. It is interesting also because it demonstrates how technology in the consumer market is being applied successfully into what was once thought to be a very specific and ‘high end’ market of aerospace. What is clear today is that many ‘off the shelf’ products can be used to advantage. Technology is still advancing and the following chapters try to point to the direction in which is it going:

Chapter 2 – Avionics TechnologyChapter 3 – Data Bus NetworksChapter 4 – System SafetyChapter 5 – Avionics ArchitecturesChapter 6 – Development Processes.

1.3.2 Functional Avionics Systems

The chapters in this section provide description of the functional systems of the aircraft and should be used in conjunction with companion books in the Wiley Aerospace Series to gain a complete picture of the modern aircraft and the aerospace environment. As far as possible, given the constraints of security and commercial sensitivities, there are descriptions of the latest aircraft to enter service, sufficient at least to gain an appreciation of avionic systems.

Chapter 7 – Electrical Systems and InstallationChapter 8 – SensorsChapter 9 – Communications and Navigation AidsChapter 10 – Flight Control SystemsChapter 11 – Navigation Systems and PBNChapter 13 – Military Aircraft Adaptations.

1.3.3 The Flight Deck

The flight deck is an amalgam of avionics technology and human–machine interface in a secure and comfortable environment to allow the flight crew to operate effectively during short haul and very long haul flights. This is an area that has seen great advances in the ability to provide information about the progress of the flight and the status of the aircraft and its systems. Advances are still being made which predict radical changes in the future, which is why this subject enjoys its own chapter.

Chapter 12 – Flight Deck Displays.

Each of the chapters listed above contain both introductory and detailed descriptions of the respective subject matter. Given the integrated and interrelated nature of avionics technology and functions, cross-references have been made where appropriate in the main body of the text to help the reader to make the necessary links.

1.4 The Appendices

To assist the reader in understanding how some of the analytical tools such as dependency diagrams, fault tree analysis (FTA) and Markov analysis may be applied to typical systems, four appendices have included. These appendices address the following systems:

Appendix A: Safety Analysis – Flight Control SystemAppendix B: Safety Analysis – Electronic Flight Instrument SystemAppendix C: Safety Analysis – Electrical SystemAppendix D: Safety Analysis – Engine Control System

The analyses in the Appendices are presented in a simple mathematical fashion to provide the reader with purely advisory and illustrative material: they should not be considered as definitive analyses of the standard that would be demanded during formal aircraft system design. Nevertheless, it is hoped that they will aid the reader in appreciating some of the design issues that need to be considered early on in the design process. (During formal design, engineers utilise dedicated design tools that undertake the appropriate analysis in a rigorous fashion. At the same time, these tools provide the required documentation to the standard necessary to convince the certification authorities that the design is safe.)

2

Avionics Technology

2.1 Introduction

The purpose of this chapter is to introduce the reader to the general principles and technologies employed in avionics computing. It is not intended to be a detailed and complete dissertation on the theory of computer science; the reader is directed to the references and other materials on that subject. Rather, the objective is to provide the reader with an awareness of computer science, the terminology, the principles involved and how these have been applied to avionics systems computing.

Firstly this chapter discusses the evolution of avionics systems from their inception as hardwired electromechanical (relay) logic, through analogue electronics into task-oriented digital computing with embedded application software in today's integrated modular avionics architectures.

This chapter will introduce the reader to the basic principles of digital computing and the major components used, for example, microprocessors and data storage devices such as read/write and read-only memories. It will outline the process fabrication and packaging of large-scale integrated circuits (ICs) in transistor–transistor logic (TTL) and complementary metal-oxide semiconductor (C-MOS) technologies. It will discuss the design of custom devices such as application-specific integrated circuits (ASICs) and field programmable gate arrays (FPGAs), and the special considerations required for the certification of complex hardware (RTCA-DO-254). It will discuss the interfacing of real-world analogue signals using operational amplifiers to filter, scale and condition signals prior to their transference into the digital domain by analogue-to-digital and digital-to-analogue conversion processes.

Whilst much of the technologies and components used in avionics computers are similar to those used in desktop/office computing, this chapter will highlight the different requirements and hence different implementations for real-time embedded avionics systems in terms of throughput, latency, accuracy, precision and resolution.

2.2 Avionics Technology Evolution

2.2.1 Introduction

The first major impetus for use of electronics in aviation occurred during World War II. Communications were maturing and the development of airborne radar using the magnetron, thermionic valve and associated technologies occurred at a furious pace throughout the conflict. Transistors followed in the late 1950s and 1960s and supplanted thermionic valves for many applications. The improved cost-effectiveness of transistors led to the development of early avionics systems throughout the 1960s and 1970s.

For many years avionics were implemented in analogue devices and systems, with signal levels generally being related in some linear or predictive way to an analogue property, such as voltage, current, frequency, pulse-width or phase-shift. This type of analogue system is generally prone to variability due to modelling inaccuracies, intrinsic component and manufacturing tolerances, component temperature, age, drift and other non-linearities.

The principles of digital computing had been understood for a number of years before the technology was applied to aircraft. Digital computing overcomes the variability of analogue computing, providing accurate repeatable results with high precision without being subject to variation due to manufacturing tolerances and thermal effects. However, early digital computers were huge and were confined to mainframe office applications; they were quite impracticable for use in any airborne application until the integrated circuit device implementing whole logic functions on a single device became available.

The first aircraft to be developed in the US using digital techniques was the North American A-5 Vigilante, a US Navy carrier-borne bomber which became operational in the 1960s. The first aircraft to be developed in the UK intended to use digital techniques on any meaningful scale was the ill-fated TSR2 which was cancelled by the UK Government in 1965. The technology employed by the TSR2 was largely based upon transistors, then in comparative infancy. In the UK, it was not until the development of the Anglo-French Jaguar and the Hawker Siddeley Nimrod maritime patrol aircraft in the 1960s that weapon systems seriously began to embody digital computing.

Since the late 1970s and early 1980s digital technology has become increasingly used in the control of aircraft systems, as well as for mission-related systems. The availability of very powerful and low-cost microprocessors and more advanced software development tools has led to the widespread application of digital technology throughout the aircraft. No aircraft system – even the toilet system – has been left untouched

2.2.2 Technology Evolution

The evolution and increasing use of avionics technology for civil applications of engine controls and flight controls since the 1950s is shown in Figure 2.1.

FIGURE 2.1  Evolution of electronics in flight and engine control

Engine analogue controls were introduced by Ultra in the 1950s and comprised electrical throttle signalling used on aircraft such as the Bristol Britannia. Full authority digital engine control (FADEC) became commonly used in the 1980s.

Digital primary flight control with a mechanical backup has been used on the Airbus A320 family, A330 and A340 using side-stick controllers and on the Boeing B777 using a conventional control yoke. Aircraft such as the A380 and the B787 have adopting flight control without any mechanical backup but with electrically signalled backup. Research in the military field is looking at integration of propulsion and flight control to achieve more effective ways of demanding changes of attitude and speed which may lead to more fuel-efficient operations

Avionics systems architecture evolution is summarised in Figure 2.2.

FIGURE 2.2 Avionics architecture evolution – summary

Early avionics systems can be characterised as distributed analogue computing architectures. In this era, each avionics systems function was a ‘point-solution’ implemented using specific hardwired analogue electronics and relays. Changes to functionality required changes to circuitry and interconnectivity.

In the mid-1970s, the first digital systems replaced analogue computers with digital computers. Each computer performed a specific ‘point-solution’ task, hence its name – a task-oriented computer (also known as an embedded computer system). Functionality is determined by the application software running on the target computer hardware, and changes to functionality can be effected by changing the software within the constraints of the signals available and the computer processing power.

High-speed digital data buses such as ARINC 429, MIL-STD-1553B and ARINC 629 facilitated more structured avionics architecture design in the mid-1980s, and brought with it the concept of grouping related functions into an avionics domain, with computers within the domain interconnected by a data bus. Today we call this a federated architecture. It is characterised by a number of functionally interconnected but discrete computers. Each computer has logical functional boundaries associated with the task it performs on the aircraft. Its functionality is determined by the application software running on it. Generally the computer and its embedded application software is a proprietary design of the avionics system company who supplies it. Each computer is a line-replaceable unit (LRU). Form factors are standardised to facilitate accommodation in standardised racking systems. The most universally adopted standards are the Air Transport Radio (ATR) racking system which has now largely been superseded by the modular concept unit (MCU) in civil transport aircraft. The standard fixes the LRU height, depth, connector arrangement and provisions for cooling air; the width may be varied in incremental values commensurate with the complexity of the equipment.

Integrated modular avionics (IMA) is an emerging avionics architecture and packaging technique which is being applied to current generation aircraft such as the Airbus A380, A350 and the Boeing 787. Partial implementations existed on earlier aircraft.

IMA principles introduce a common, open-architecture approach to computing hardware to provide a computationally rich resource platform on which avionics systems application software is executed. A real-time operating system manages the computational resource allocation and ensures system partitioning and segregation. Provision and certification of the hardware and software are independent. A high bandwidth communications network transports information between the computational and input/output (I/O) resources, the latter being implemented in remote data concentrators (RDCs) local to aircraft sensors and effectors. The advantages to be realised by this level of integration are:

volume, weight and maintenance savings;sharing of resources, such as power supplies, across a number of functional modules;standard module designs yielding a more unified approach to equipment design;incremental certification of hardware and application software;management of obsolescence.

Chapter 5 provides a full discussion on avionics systems architectures.

2.3 Avionics Computing

2.3.1 The Nature of an Avionics Computer

An avionics computer is a task-oriented computer or an embedded system. It performs specific avionics functions in real time in accordance with application software stored within it and pre-loaded into its application memory on the ground.

An avionics computer may take a variety of forms. Some main processing computers such as flight management computers, flight control computers and display management computers may resemble what we expect a traditional computer to look like, a box in an avionics rack not that dissimilar to a personal computer under a desk, except that its dimensions are different. Other avionics equipment may not look like computers but in fact have similar computing hardware within them to perform the computational element of the item, such as multifunction displays, control panels, remote data concentrators, inertial reference units, and so on.

A typical avionics computer has the architecture shown in Figure 2.3 and comprises:

A power supply: this converts the 115 VAC 400 Hz aircraft power to conditioned and stabilised power for the internal electronics (typically +5 V for semiconductor devices).Central processing units (CPUs) plus application and data memory: this executes the application software to perform the desired avionics function.I/O interfacing: this interfaces real-world sensors and effectors to the digital world of the CPU.Data bus communications interface: to connect the avionics computer to the avionics data bus network.

FIGURE 2.3 Typical computer architectures

As will be seen later in Chapter 5, an integrated modular avionics architecture has the same elements but distributed differently. The Airbus A380 implements avionics computing in central processor input/output modules (CPIOMs) with standardised, common processors and a range of standardised I/O interfaces. The Boeing 787 implements I/O interfacing in separate remote data concentrators (RDCs) which communicate via the aircraft data network to centralised processors in a common computing resource (CCR) rack.

Whether a federated architecture or an integrated modular avionics architecture, the computational core has a similar architecture, although the implementation has evolved as computer architecture technology has evolved. The computational core comprises a central processing unit which executes application software held in its memory. As discussed in later paragraphs in this chapter, the central processor comprises an arithmetic logic unit which performs mathematical and logical operations in binary arithmetic; the memory comprises two elements, a read-only area of memory which contains the application software, and a read/write area of memory for computational variables.

As indicated in Figure 2.3