Design and Development of Aircraft Systems

Provides a significant update to the definitive book on aircraft system design

This book is written for anyone who wants to understand how industry develops the customer requirement for aircraft into a fully integrated, tested, and qualified product that is safe to fly and fit for purpose. The new edition of Design and Development of Aircraft Systems fully expands its already comprehensive coverage to include both conventional and unmanned systems. It also updates all chapters to bring them in line with current design practice and technologies taught in courses at Cranfield, Bristol, and Loughborough universities in the UK.

Design and Development of Aircraft Systems, 3^rd Edition begins with an introduction to the subject. It then introduces readers to the aircraft systems (airframe, vehicle, avionic, mission, and ground systems). Following that comes a chapter on the design and development process. Other chapters look at design drivers, systems architectures, systems integration, verification of system requirements, practical considerations, and configuration control. The book finishes with sections that discuss the potential impact of complexity on flight safety, key characteristics of aircraft systems, and more.

• Provides a holistic view of aircraft system design, describing the interactions among subsystems such as fuel, navigation, flight control, and more
• Substantially updated coverage of systems engineering, design drivers, systems architectures, systems integration, modelling of systems, practical considerations, and systems examples
• Incorporates essential new material on the regulatory environment for both manned and unmanned systems
• Discussion of trends towards complex systems, automation, integration and the potential for an impact on flight safety 

Design and Development of Aircraft Systems, 3^rd Edition is an excellent book for aerospace engineers, researchers, and graduate students involved in the field.

Allan Seabridge has over 50 years of experience in aerospace systems engineering, business development, and research & development, and has developed systems and engineering courses at UK universities. He has retired from full time engineering and enjoys spending time at an aircraft company heritage group.

Ian Moir spent 20 years as an Engineering Officer in the Royal Air Force and has broad and detailed experience working in aircraft avionics systems at a major UK avionics company. Ian has now retired from aerospace activities and is enjoying a life of leisure in the Cotswolds, whilst retaining an interest in aerospace.

About the Authors xiii

Series Preface xv

Acknowledgements xvii

Glossary of Terms xix

1 Introduction 1

1.1 General 1

1.2 Systems Development 3

1.3 Skills 8

1.4 Human Aspects 9

1.4.1 Introduction 9

1.4.2 Design Considerations 10

1.4.3 Legislation 12

1.4.4 Summary of Legal Threats 12

1.4.5 Conclusions 13

1.5 Overview 14

Exercises 17

References 17

Further Reading 17

2 The Aircraft Systems 19

2.1 Introduction 19

2.2 Definitions 19

2.3 Everyday Examples of Systems 21

2.4 Aircraft Systems of Interest 24

2.4.1 Airframe Systems 28

2.4.2 Vehicle Systems 28

2.4.3 Interface Characteristics of Vehicle Systems 30

2.4.4 Avionics Systems 31

2.4.5 Interface Characteristics of Vehicle and Avionics Systems 31

2.4.5.1 Vehicle Systems 32

2.4.5.2 Avionics Systems 32

2.4.6 Mission Systems 32

2.4.7 Interface Characteristics of Mission Systems 33

2.5 Ground Systems 33

2.6 Generic System Definition 34

Exercises 37

References 37

Further Reading 37

3 The Design and Development Process 39

3.1 Introduction 39

3.2 Definitions 39

3.3 The Product Lifecycle 41

3.4 Concept Phase 46

3.4.1 Engineering Process 48

3.4.2 Engineering Skills 48

3.5 Definition Phase 50

3.5.1 Engineering Process 52

3.5.2 Engineering Skills 53

3.6 Design Phase 56

3.6.1 Engineering Process 56

3.6.2 Engineering Skills 57

3.7 Build Phase 58

3.7.1 Engineering Process 59

3.7.2 Engineering Skills 59

3.8 Test Phase 60

3.8.1 Engineering Process 60

3.8.2 Engineering Skills 60

3.9 Operate Phase 61

3.9.1 Engineering Process 62

3.9.2 Engineering Skills 63

3.10 Disposal or Retirement Phase 63

3.10.1 Engineering Process 65

3.10.2 Engineering Skills 65

3.11 Refurbishment Phase 65

3.11.1 Engineering Process 66

3.11.2 Engineering Skills 66

3.12 Whole Lifecycle Tasks 66

3.13 Summary 67

Exercises 69

References 70

Further Reading 70

4 Design Drivers 73

4.1 Introduction 73

4.2 Design Drivers in the Business Environment 75

4.2.1 Customer 76

4.2.2 Market and Competition 76

4.2.3 Capacity 77

4.2.4 Financial Issues 77

4.2.5 Defence Policy 78

4.2.6 Leisure and Business Interests 78

4.2.7 Politics 79

4.2.8 Technology 79

4.2.9 Global Economy 80

4.3 Design Drivers in the Project Environment 80

4.3.1 Standards and Regulations 80

4.3.2 Availability 81

4.3.3 Cost 81

4.3.4 Programme 82

4.3.5 Performance 82

4.3.6 Skills and Resources 82

4.3.7 Health, Safety, and Environmental Issues 83

4.3.8 Risk 84

4.4 Design Drivers in the Product Environment 84

4.4.1 Functional Performance 84

4.4.2 Human–Machine Interface 85

4.4.3 Crew and Passengers 86

4.4.4 Stores and Cargo 86

4.4.5 Structure 87

4.4.6 Safety 87

4.4.7 Quality 87

4.4.8 Environmental Conditions 87

4.5 Design Drivers in the Product Operating Environment 88

4.5.1 Heat 88

4.5.2 Noise 89

4.5.3 RF Radiation 89

4.5.4 Solar Energy 90

4.5.5 Altitude 91

4.5.6 Temperature 91

4.5.7 Contaminants, and Destructive and Hazardous Substances 92

4.5.8 Lightning 92

4.5.9 Nuclear, Biological, and Chemical Contamination 92

4.5.10 Vibration 93

4.5.11 Shock 93

4.6 Interfaces with the Sub-system Environment 93

4.6.1 Physical Interfaces 94

4.6.2 Power Interfaces 94

4.6.3 Data Communication Interfaces 95

4.6.4 Input/Output Interfaces 95

4.6.5 Status/Discrete Data 95

4.7 Obsolescence 96

4.7.1 Introduction 96

4.7.2 The Threat of Obsolescence in the Product Lifecycle 97

4.7.2.1 Requirements Specification 98

4.7.2.2 People 99

4.7.2.3 Regulations 101

4.7.2.4 Design, Development, and Manufacture 101

4.7.2.5 The Supply Chain 103

4.7.3 Managing Obsolescence 103

4.8 Ageing Aircraft 106

4.8.1 Introduction 106

4.8.2 Some Examples 107

4.8.3 Systems Issues 108

4.8.4 Certification Issues 109

Exercises 109

References 110

Further Reading 110

5 System Architectures 113

5.1 Introduction 113

5.2 Definitions 114

5.3 System Architectures 115

5.3.1 Vehicle Systems 117

5.3.2 Avionic Systems 118

5.3.3 Mission Systems 118

5.3.4 Cabin Systems 119

5.3.5 Data Bus 119

5.4 Architecture Modelling and Trade-off 120

5.5 Example of a Developing Architecture 123

5.6 Evolution of Avionics Architectures 126

5.6.1 Distributed Analogue Architecture 127

5.6.2 Distributed Digital Architecture 128

5.6.3 Federated Digital Architecture 130

5.6.4 Integrated Modular Architecture 132

5.7 Example Architectures 135

5.7.1 Example 1: System Architecture 135

5.7.2 Example 2: Flight Control System 136

5.7.3 Example 3: Radar System 138

5.7.4 Example 4: Vehicle Systems Management 139

Exercises 149

References 149

Further Reading 149

6 System Integration 151

6.1 Introduction 151

6.2 Definitions 153

6.3 Examples of System Integration 153

6.3.1 Integration at the Component Level 153

6.3.2 Integration at the System Level 154

6.3.3 Integration at the Process Level 160

6.3.4 Integration at the Functional Level 163

6.3.5 Integration at the Information Level 166

6.3.6 Integration at the Prime Contractor Level 166

6.3.7 Integration Arising from Emergent Properties 167

6.3.8 Further Examples of Integrated Systems 169

6.3.8.1 The Airframe 169

6.3.8.2 Propulsion 171

6.3.8.3 Air Systems 171

6.4 System Integration Skills 172

6.5 Management of System Integration 175

6.5.1 Major Activities 175

6.5.2 Major Milestones 175

6.5.3 Decomposition and Definition Process 178

6.5.4 Integration and Verification Process 178

6.5.5 Component Engineering 178

6.6 Highly Integrated Systems 178

6.6.1 Integration of Primary Flight Control Systems 179

6.7 Discussion 182

Exercises 184

References 186

Further Reading 186

7 Verification of System Requirements 187

7.1 Introduction 187

7.2 Gathering Qualification Evidence in the Lifecycle 189

7.3 Test Methods 191

7.3.1 Inspection of Design 192

7.3.2 Calculation 192

7.3.3 Analogy 193

7.3.4 Modelling and Simulation 193

7.3.4.1 Modelling Techniques 197

7.3.5 Test Rigs 206

7.3.6 Environmental Testing 207

7.3.7 Integration Test Rigs 207

7.3.8 Aircraft Ground Testing 209

7.3.9 Flight Test 210

7.3.10 Trials 211

7.3.11 Operational Test 212

7.3.12 Demonstrations 212

7.4 An Example Using a Radar System 212

7.5 Summary 214

Exercises 215

References 215

Further Reading 216

8 Practical Considerations 217

8.1 Introduction 217

8.2 Stakeholders 218

8.2.1 Identification of Stakeholders 218

8.2.2 Classification of Stakeholders 219

8.3 Communications 220

8.3.1 The Nature of Communication 222

8.3.2 Examples of Organisation Communication Media 223

8.3.2.1 Mechanisms for Generating Information 225

8.3.2.2 Unauthorised Access 225

8.3.2.3 Data Storage and Access 226

8.3.2.4 Data Discipline 227

8.3.3 The Cost of Poor Communication 227

8.3.4 A Lesson Learned 228

8.4 Giving and Receiving Criticism 230

8.4.1 The Need for Criticism in the Design Process 230

8.4.2 The Nature of Criticism 230

8.4.3 Behaviours Associated with Criticism 231

8.4.4 Conclusions 232

8.5 Supplier Relationships 232

8.6 Engineering Judgement 234

8.7 Complexity 234

8.8 Emergent Properties 235

8.9 Aircraft Wiring and Connectors 236

8.9.1 Aircraft Wiring 236

8.9.2 Aircraft Breaks 237

8.9.3 Wiring Bundle Definition 238

8.9.4 Wiring Routing 239

8.9.5 Wiring Sizing 239

8.9.6 Aircraft Electrical Signal Types 241

8.9.7 Electrical Segregation 242

8.9.8 The Nature of Aircraft Wiring and Connectors 242

8.9.9 Use of Twisted Pairs and Quads 244

8.10 Bonding and Grounding 246

Exercise 248

References 248

Further Reading 248

9 Configuration Control 249

9.1 Introduction 249

9.2 Configuration Control Process 249

9.3 A Simple Portrayal of a System 250

9.4 Varying System Configurations 252

9.4.1 System Configuration A 252

9.4.2 System Configuration B 253

9.4.3 System Configuration C 254

9.5 Forwards and Backwards Compatibility 255

9.5.1 Forwards Compatibility 255

9.5.2 Backwards Compatibility 256

9.6 Factors Affecting Compatibility 256

9.6.1 Hardware 257

9.6.2 Software 257

9.6.3 Wiring 258

9.7 System Evolution 258

9.8 Configuration Control 259

9.8.1 Airbus A380 Example 261

9.9 Interface Control 264

9.9.1 Interface Control Document 264

9.9.2 Aircraft-level Data Bus Data 266

9.9.3 System Internal Data Bus Data 266

9.9.4 Internal System Input/Output Data 267

9.9.5 Fuel Component Interfaces 267

9.10 Control of Day-to-Day Documents 267

Exercise 268

10 Aircraft System Examples 269

10.1 Introduction 269

10.2 Design Considerations 269

10.3 Safety and Economic Considerations 271

10.4 Failure Severity Categorisation 272

10.5 Design Assurance Levels 272

10.6 Redundancy 273

10.6.1 Architecture Options 274

10.6.1.1 Simplex Architecture 274

10.6.1.2 Duplex Architecture 276

10.6.1.3 Dual/Dual Architecture 276

10.6.1.4 Triplex Architecture 276

10.6.1.5 Quadruplex Architecture 276

10.6.2 System Examples 277

10.6.2.1 Major Systems Event 277

10.6.2.2 Flight Critical Event 278

10.7 Integration of Aircraft Systems 280

10.7.1 Engine Control System 282

10.7.2 Flight Control System 283

10.7.3 Attitude Measurement System 284

10.7.4 Air Data System 284

10.7.5 Electrical Power System 285

10.7.6 Hydraulic Power System 286

10.8 Integration of Avionics Systems 287

References 290

11 Integration and Complexity: The Potential Impact on Flight Safety 291

11.1 Introduction 291

11.2 Integration 291

11.3 Complexity 294

11.4 Automation 298

11.5 Impact on Flight Safety Discussion 299

11.6 Single-pilot Operations 302

11.7 Postscript: Chaos Discussion 303

Exercises 307

References 307

Further Reading 308

12 Key Characteristics of Aircraft Systems 309

12.1 Introduction 309

12.2 Aircraft Systems 311

12.3 Avionics Systems 326

12.4 Mission Systems 336

12.5 Sizing and Scoping Systems 343

12.6 Analysis of the Fuel Penalties of Aircraft Systems 345

12.6.1 Introduction 345

12.6.2 Basic Formulation of Fuel Weight Penalties of Systems 346

12.6.3 Application of Fuel Weight Penalties Formulation for Multi-phase Flight 349

12.6.4 Analysis of Fuel Weight Penalties Formulation for Multi-phase Flight 350

12.6.5 Use of Fuel Weight Penalties to Compare Systems 350

12.6.6 Determining Input Data for Systems Weight Penalties Analysis 351

12.6.6.1 Lift/Drag Ratio 351

12.6.6.2 Specific Fuel Consumption 352

12.6.6.3 System Mass 352

12.6.6.4 System Drag Increase 352

12.6.6.5 Increase in sfc Due to Systems Power Off-takes 352

Nomenclature 354

References 354

13 Conclusions 357

13.1 What’s Next? 359

13.2 A Historical Footnote 361

References 362

Index 363

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