Aircraft Systems

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

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

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

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 A 320 164

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

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

7.2.6 The Need for Avionics Conditioning 263

7.3 The International Standard Atmosphere (ISA) 263

7.4 Environmental Control System Design 266

7.4.1 Ram Air Cooling 266

7.4.2 Fuel Cooling 267

7.4.3 Engine Bleed 267

7.4.4 Bleed Flow and Temperature Control 269

7.5 Cooling Systems 271

7.5.1 Air Cycle Refrigeration Systems 271

7.5.2 Turbofan System 272

7.5.3 Bootstrap System 272

7.5.4 Reversed Bootstrap 274

7.5.5 Ram Powered Reverse Bootstrap 274

7.5.6 Vapour Cycle Systems 275

7.5.7 Liquid Cooled Systems 276

7.5.8 Expendable Heat Sinks 277

7.6 Humidity Control 278

7.7 The Inefficiency of Present Systems 279

7.8 Air Distribution Systems 279

7.8.1 Avionics Cooling 279

7.8.2 Unconditioned Bays 280

7.8.3 Conditioned Bays 280

7.8.4 Conditioned Bay Equipment Racking 281

7.8.5 Ground Cooling 282

7.8.6 Cabin Distribution Systems 283

7.9 Cabin Noise 284

7.10 Cabin Pressurisation 284

7.11 Hypoxia 287

7.12 Molecular Sieve Oxygen Concentrators 288

7.13 g Tolerance 291

7.14 Rain Dispersal 292

7.15 Anti-Misting and De-Misting 293

7.16 Aircraft Icing 293

8 Emergency Systems 297

8.1 Introduction 297

8.2 Warning Systems 298

8.3 Fire Detection and Suppression 301

8.4 Emergency Power Sources 305

8.5 Explosion Suppression 307

8.6 Emergency Oxygen 308

8.7 Passenger Evacuation 308

8.8 Crew Escape 310

8.9 Computer-Controlled Seats 312

8.10 Ejection System Timing 313

8.11 High Speed Escape 314

8.12 Crash Recorder 314

8.13 Crash Switch 315

8.14 Emergency Landing 315

8.15 Emergency System Testing 317

9 Rotary Wing Systems 319

9.1 Introduction 319

9.2 Special Requirements of Helicopters 320

9.3 Principles of Helicopter Flight 321

9.4 Helicopter Flight Control 324

9.5 Primary Flight Control Actuation 325

9.5.1 Manual Control 326

9.5.2 Auto-Stabilisation 328

9.5.3 Autopilot Modes 330

9.6 Key Helicopter Systems 333

9.6.1 Engine and Transmission System 335

9.6.2 Hydraulic Systems 338

9.6.3 Electrical System 340

9.6.4 Health Monitoring System 341

9.6.5 Specialised Helicopter Systems 342

9.7 Helicopter Auto-Flight Control 343

9.7.1 EH 101 Flight Control System 343

9.7.2 NOTAR Method of Yaw Control 346

9.8 Active Control Technology 349

9.9 Advanced Battlefield Helicopter 350

9.9.1 Target Acquisition and Designator System (TADS)/Pilots Night Vision System (PNVS) 350

9.9.2 AH-64 C/D Longbow Apache 353

9.10 Tilt Rotor Systems 357

9.10.1 Tilt Rotor Concept and Development 357

9.10.2 V-22 Osprey 358

9.10.3 Civil Tilt Rotor 366

10 Advanced Systems 371

10.1 Introduction 371

10.1.1 STOL Manoeuvre Technology Demonstrator (SMTD) 371

10.1.2 Vehicle Management Systems (VMS) 372

10.1.3 More-Electric Aircraft 372

10.1.4 More-Electric Engine 373

10.2 Stealth 374

10.2.1 Joint Strike Fighter (JSF) 374

10.3 Integrated Flight and Propulsion Control (IFPC) 375

10.4 Vehicle Management System 377

10.5 More-Electric Aircraft 381

10.5.1 Engine Power Offtakes 381

10.5.2 Boeing 787 (More-Electric) Electrical System 382

10.5.3 More-Electric Hydraulic System 384

10.5.4 More-Electric Environmental Control System 386

10.6 More-Electric Actuation 388

10.6.1 Electro-Hydrostatic Actuators (EHA) 388

10.6.2 Electro-Mechanical Actuators (EMA) 388

10.6.3 Electric Braking 388

10.7 More-Electric Engine 389

10.7.1 Conventional Engine Characteristics 390

10.7.2 More-Electric Engine Characteristics 390

10.8 Impact of Stealth Design 393

10.8.1 Lockheed F-117A Nighthawk 394

10.8.2 Northrop B-2 Spirit 396

10.8.3 Joint Strike Fighter - F-35 Lightning II 401

10.9 Technology Developments/Demonstrators 402

10.9.1 Fault Tolerant 270VDC Electrical Power Generation System 402

10.9.2 Thermal and Energy Management Module 402

10.9.3 AFTI F-16 Flight Demonstration 403

11 System Design and Development 407

11.1 Introduction 407

11.1.1 Systems Design 408

11.1.2 Development Processes 408

11.2 System Design 408

11.2.1 Key Agencies and Documentation 408

11.2.2 Design Guidelines and Certification Techniques 409

11.2.3 Key Elements of the Development Process 410

11.3 Major Safety Processes 411

11.3.1 Functional Hazard Analysis (FHA) 412

11.3.2 Preliminary System Safety Analysis (PSSA) 413

11.3.3 System Safety Analysis (SSA) 414

11.3.4 Common Cause Analysis (CCA) 414

11.4 Requirements Capture 415

11.4.1 Top-Down Approach 415

11.4.2 Bottom-Up Approach 416

11.4.3 Requirements Capture Example 416

11.5 Fault Tree Analysis (FTA) 418

11.6 Dependency Diagram 420

11.7 Failure Modes and Effects Analysis (FMEA) 422

11.8 Component Reliability 423

11.8.1 Analytical Methods 423

11.8.2 In-Service Data 424

11.9 Dispatch Reliability 424

11.10 Markov Analysis 425

11.11 Development Processes 427

11.11.1 The Product Life Cycle 427

11.11.2 Concept Phase 428

11.11.3 Definition Phase 430

11.11.4 Design Phase 431

11.11.5 Build Phase 432

11.11.6 Test Phase (Qualification Phase) 433

11.11.7 Operate Phase 433

11.11.8 Disposal or Refurbish 434

11.11.9 Development Programme 435

11.11.10 'V' Diagram 437

11.12 Extended Operations (ETOPS) 438

12 Avionics Technology 441

12.1 Introduction 441

12.2 The Nature of Microelectronic Devices 443

12.2.1 Processors 446

12.2.2 Memory Devices 446

12.2.3 Digital Data Buses 447

12.2.4 A 429 Data Bus 449

12.2.5 MIL-STD-1553b 451

12.2.6 ARINC 629 Data Bus 453

12.2.7 COTS Data Buses 456

12.3 Data Bus Integration of Aircraft Systems 460

12.3.1 Experimental Aircraft Programme (EAP) 460

12.3.2 Airbus A330/340 461

12.3.3 Boeing 777 462

12.3.4 Regional Aircraft/Business Jets 463

12.3.5 A380 Avionics Architecture 464

12.3.6 Boeing 787 Avionics Architecture 467

12.3.7 COTS Data Buses - IEEE 1394 468

12.4 Fibre Optic Buses 469

12.5 Avionics Packaging Standards 470

12.5.1 Air Transport Radio (ATR) 470

12.5.2 Modular Concept Unit (MCU) 470

12.6 Typical LRU Architecture 471

12.7 Integrated Modular Avionics 473

13 Environmental Conditions 477

13.1 Introduction 477

13.2 Environmental Factors 479

13.2.1 Altitude 479

13.2.2 Temperature 480

13.2.3 Contamination by Fluids 482

13.2.4 Solar Radiation 483

13.2.5 Rain, Humidity, Moisture 484

13.2.6 Fungus 485

13.2.7 Salt Fog/Salt Mist 485

13.2.8 Sand and Dust 486

13.2.9 Explosive Atmosphere 486

13.2.10 Acceleration 487

13.2.11 Immersion 487

13.2.12 Vibration 488

13.2.13 Acoustic Noise 488

13.2.14 Shock 489

13.2.15 Pyroshock 490

13.2.16 Acidic Atmosphere 490

13.2.17 Temperature, Humidity, Vibration, Altitude 490

13.2.18 Icing/Freezing Rain 491

13.2.19 Vibro-Acoustic, Temperature 491

13.2.20 RF Radiation 491

13.2.21 Lightning 492

13.2.22 Nuclear, Biological and Chemical 493

13.3 Testing and Validation Process 493

Index 499