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Aircraft Airframe Handbook, Airframe and Power Plant Mechanics
612 pages
U.S. Department of Transportation

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Open: Aircraft Powerplant Handbook, Airframe and Power Plant Series

This handbook was developed and first printed in 1972 as one of a series of three handbooks for persons preparing for certification as an airframe or powerplant mechanic. It is intended that this handbook will provide basic information on principles, fundamentals and technical procedures in the subject matter areas relating to the airframe rating. It is designed to aid students enrolled in a formal course of instruction as well as the individual who is studying on his own. Since the knowledge requirements for the airframe and powerplant ratings closely parallel each other in some subject areas, the chapters which discuss fire protection systems and electrical systems contain some material which is also duplicated in the Airframe and Powerplant Mechanics Powerplant Handbook, AC 65-12A.

This volume contains information on airframe construction features, assembly and rigging, fabric covering, structural repairs, and aircraft welding. The handbook also contains an explanation of the units which make up the various airframe systems.

Because there are so many different types of aircraft in use today, it is reasonable to expect that differences exist in airframe components and systems. To avoid undue repetition, the practice of using representative systems and units is carried out throughout the handbook. Subject matter treatment is from a generalized point of view, and should be supplemented by reference to manufacturers' manuals or other textbooks if more detail is desired. This handbook is not intended to replace, substitute for, or supersede official regulations or the manufacturers' instructions.

TOC

PREFACE - iii
CONTENTS v
CHAPTER 1. AIRCRAFT STRUCTURES
General 1
Major Structural Stresses 1
Fixed-Wing Aircraft ---- 2
Fuselage ---- 2
Wing Structure --- 6
Nacelles or Pods -- 13
ED1pennage -- 16
Flight Control Surfaces -- 18
Landing Gear 23
Skin and Fairing -- 24
Access and Inspection Doors --~ 24
Helicopter Structures ---- 24

CHAPTER 2. ASSEMBLY AND RIGGING
General 27
Theory of Flight -- 27
Aerodynamic 27
The Atmosphere --- 27
Pressure ---- 27
Density 28
Humidity --- 28
Bernoulli's Principle and Subsonic Flow --- 29
Motion 29
Airfoils 30
Center of Gravity -- 33
Thrust and Drag -- 33
Axes of an Aircraft 35
Stability and Control ---- 35
Control 39
Flight Control Surfaces -- 40
Control Around the Longitudinal Axis ---- 41
Control Around the Vertical Axis --- 44
Control Around the Lateral Axis ---- 44
Tabs -- 45
Boundary Layer Control Devices ---- 48
Forces Acting on a Helicopter - 49
Helicopter Axes of Flight 55
High-Speed Aerodynamics ---- 56
Typical Supersonic. Flow Patterns --- 59
Aerodynamic Heating --- 64
Flight Control Systems -- 64
Hydraulic Operated Control System 65
Cable Guides 66
Mechanical Linkage ---- 68
Torque Tubes 68
Stops -- 68
Control Surface Snubbers and Locking Devices -- 69
Aircraft Rigging -- 70
Rigging Checks --- 72
Adjustment of Control Surfaces 75
Helicopter Rigging 77
Principles of Balancing or Re-balancing --- 80
Re-balancing Procedures 83
Methods 83

CHAPTER 3. AIRCRAFT FABRIC COVERING
Aircraft Fabrics --- 85
Miscellaneous Textile Materials 88
Seams - 89
Applying Covering 91
Covering 1Vings --- 93
Covering Fuselages 95
Ventilation, Drain, and Inspection Openings ---- 95
Repair of Fabric Covers - 99
Replacing Panels in Wing Covers ---~---- 103
Re-covering Aircraft Surface with Glass Cloth --- 104
Causes of Fabric Deterioration 104
Checking Condition of Doped Fabric 106
Testing Fabric Covering - 106
Strength Criteria for Aircraft Fabric 107
Dopes and Doping- 107
Dope Materials ---- 108
Aluminum-Pigmented Dopes -- 109
Temperature and Humidity Effects on Dope ---- 109
Common Troubles in Dope Application ---- 109
Technique of Application 110
Number of Coats Required ---- 111

CHAPTER 4. AIRCRAFT PAINTING AND FINISHING
General 113
Finishing Materials 113
Paint Touch up ---- 117
Identification of Paint Finishes 117
Paint Removal ----~----~---- 117
Restoration of Paint Finishes -- 118
Nitrocellulose Lacquer Finishes 118
Acrylic Nitrocellulose Lacquer Finish 119
Epoxy Finishes --- 120
Fluorescent Finishes ---- 121
Enamel Finishes --- 121
Paint System Compatibility --- 122
Methods of Applying Finishes - 122
Preparation of Paint ---- 123
Common Paint Troubles - 124
Painting Trim and Identification Numbers 125
Decalcomanias (Decals) - 125

CHAPTER 5. AIRCRAFT STRUCTURAL REPAIRS
Basic Principles of Sheet Metal Repair --·:.: 127
General Structural Repair ---- 129
Inspection of Damage --- 130
Classification of Damage 131
Stresses in Structural Members 131
Special Tools and Devices for Sheet Metal - 133
Metalworking Machines - 136
Forming Machines - 141
Forming Operations and Terms 145
Making Straight Line Bends -- 146
Setback 148
Making Layouts ---··---- 151
Hand Forming ---- 155
Rivet Layout 164
Rivet Installation -- 166
Preparation of Rivet Holes ---- 168
Driving Rive~ ---- 173
Rivet Failures ---- 175
Removing Rive~ -- 177
Special Rive~ 177
Self-Plugging (Friction Lock) Rivets 178
Self-Plugging (Mechanical Lock) Rivets -- 181
Pull-Thru Rivets -- 184
Rivets 184
Dill Lok-Skrus and Lok-Rivets - 186
Deutsche Rivets ---- 187
Hi-Shear Rivets --- 187
Specific Repair Types --- 189
Structural Sealing - 198
Metal Bonded Honeycomb ---- 200
Construction Features --- 201
Damage 201
Repairs 202
Repair Materials -- 205
Potted Compound Repair 206
Glass Fabric Cloth Overlay Repairs - 208
One Skin .and Core Repair Procedures ---- 209
Plastics 213
Transparent Plastics ---- 213
Storage and Protection -- 214
Forming Plastics -- 215
Installation Procedures -- 220
Laminated Plastics - 221
Fiber Glass Component - 221
Radomes ---- 223
Wooden Aircraft Structures --- 224
Inspection of Wooden Structures ---- 224
Service and Repair of Wooden Structures - 228
Glues -- 230
Gluing - 232
Spliced Joints 234
Plywood Skin Repairs --- ·---- 235
Spar and Rib Repair --- 242
Bolt and Bushing Holes - 244
Rib Repairs - 245

CHAPTER 6. AIRCRAFT WELDING
General 247
Oxyacetylene Welding Equipment --- 248
Welding Positions - 255
Welded Joints 255
Expansion and Contraction of Metals 257
Correct Forming of a Weld --- 258
Oxyacetylene Welding of Ferrous Metals -- 258
Welding Nonferrous Metals Using Oxyacetylene - 260
Titanium ---- 262
Cutting Metal Using Oxyacetylene -- 263
Brazing Methods -- 264
Soft Soldering ---- 265
Electric Arc Welding --- 266
Welding Procedures and Techniques - 269
Welding of Aircraft Steel Structures 276

CHAPTER 7. ICE AND RAIN PROTECTION
General 285
Pneumatic Deicing Systems --- 286
Deicer Boot Construction 287
Deicing System Components --- 288
Pneumatic Deicing System Maintenance -- 291
Thermal Anti-Icing Systems --- 293
Pneumatic System Ducting --- 296
Ground Deicing of Aircraft --- 299
Windshield Icing Control Systems --- 300
Water and Toilet Drain Heaters ---- 303
Rain Eliminating Systems ---- 303
Maintenance of Rain Eliminating Systems - 308

CHAPTER 8. HYDRAULIC AND PNEUMATIC POWER SYSTEMS
Aircraft Hydraulic Systems --- 309
Hydraulic Fluid --- 309
Types of Hydraulic Fluids ---- 310
Phosphate Ester Base F1uids -- 311
Filters - 313
Basic Hydraulic System - 315
Reservoirs --- .316
Pressure Regulation ---- 323
Actuating Cylinders ---- 328
Selector Valves --- 329
Aircraft Pneumatic Systems --- 331
Pneumatic System Components 334
Typical Pneumatic Power System --- 338

CHAPTER 9. LANDING GEAR SYSTEMS
General 341
Main Landing Gear Alignment, Support, Retraction --- 348
Emergency Extension Systems - 351
Landing Gear Safety Devices -- 351
Nose wheel Steering System --- 354
Shimmy Dampers - 356
Brake Systems ---- 360
Brake Assemblies -~ 366
Inspection and Maintenance of Brake Systems -- 372
Aircraft Landing Wheels 373
Aircraft Tires 377
Aircraft Tire Maintenance ---- 379
Tire Inspection-Mounted On Wheel 381
Tire Inspection-Tire De mounted --- 382
Tube Inspection --- 384
Mounting and De mounting --- 385
Causes of Air Pressure Loss in Tubeless Aircraft Tires - 389
The Wheel -- 390
Good Pressure Gage Practice -- 391
Repairing --- 392
Operating and Handling Tips - 394
Tube Repair - 396
Sidewall Inflated Aircraft Tires 396
Tire Inspection Summary 397
Antiskid System --- 399
Landing Gear System Maintenance -- 400

CHAPTER 10. FIRE PROTECTION SYSTEMS
General 407
Fire Detection Systems -- 408
Types of Fires ---- 411
Fire Zone Classification - 412
Extinguishing Agent Characteristics - 412
Fire Extinguishing Systems --- 417
Reciprocating Engine Conventional C02 System - 417
Turbojet Fire Protection System ---- 419
Turbine Engine Fire Extinguishing System 420
Turbine Engine Ground Fire Protection --- 422
Fire Detection System Maintenance Practices --- 423
Fire Detection System Troubleshooting --- 425
Fire Extinguisher System Maintenance Practices 425
Fire Prevention and Protection 429
Cockpit and Cabin Interiors --- 429
Smoke Detection Systems 430

CHAPTER 11. AIRCRAFT ELECTRICAL SYSTEMS
General 433
Lacing and Tying Wire Bundles ---- 444
Cutting Wire and Cable 446
Emergency Splicing Repairs -- 450
Connecting Terminal Lugs to Terminal Blocks --- 451
Bonding and Grounding 452
Connectors -- 452
Conduit 457
Electrical Equipment Installation --- 457
Aircraft Lighting Systems ---- 459
Maintenance and Inspection of Lighting Systems 464

CHAPTER 12. AIRCRAFT INSTRUMENT SYSTEMS
General -~--- 469
INstrument Cases- 469
Dials -- 469
Range Markings -- 470
Instrument Panels - 470
Repair of Aircraft INstruments 471
Aircraft Pressure Gages ---- _ 471
Pitot-Static System 474
Maintenance of Pitot-Static Systems - 481
Turn-and-Bank indicator 482
Synchro-Type Remote Indicating Instruments --- 483
Remote-Indicating Fuel and Oil Pressure Gages - 485
Capacitor-Type Fuel Quality System 485
Angle-of-Attack Indicator 487
Tachometers - 488
Synchroscope 491
Temperature Indicators - 491
Ratiometer Electric& Resistance Thermometer -- 497
Fuel Flowmeter Systems - 497
Gyroscopic Instruments - 499
Sources of Power for Gyro Operation 501
Vacuum-Driven Attitude Gyros 504
Pressure-Operated Gyros 506
Vacuum System Maintenance Practices --- 506
Electric Attitude Indicator ---- 507
Autopilot System -- 511
Basic Autopilot Components --- 513
Flight Director Systems - 518
Autopilot System Maintenance - 516

CHAPTER 13. COMMUNICATIONS AND NAVIGATION SYSTEMS
General 519
Basic Radio Principles -- 519
Basic Equipment Components - 520
Power Supply ---- 522
Communication Systems - 522
Airborne Navigation Equipment ---- 524
VHF Omnirange System 524
Instrument Landing System --- 525
Distance-Measuring Equipment 528
Automatic Direction Finders -- 529
Radar Beacon Transponder --- 530
Doppler Navigation Systems -- 530
Inertial Navigation System --- 531
Airborne Weather Radar System --- 532
Radio Altimeter --- 533
Emergency Locator Transmitter (ELT) --- 533
Installation of Communication and Navigation Equipment --- 534
Reducing Radio Interference - 536
installation of Aircraft Antenna Systems -- 537

CHAPTER 14. CABIN ATMOSPHERE CONTROL SYSTEM
Need for Oxygen - 539
Composition of the Atmosphere ---- 539
Pressurization 541
Air Conditioning and Pressurization Systems --- 543
Basic Requirements ---- 545
Sources of Cabin Pressure ---- 545
Supercharger Instruments ---- 549
Pressurization Valves --- 550
Cabin Pressure Control System ----, . .,. 551
Air Distribution -- 556
Air Conditioning System 558
Heating Systems -- 559
Combustion Heaters ---- 561
Maintenance of Combustion Heater Systems ---- 564
Cooling Systems --- 565
Air Cycle Cooling System ---- 565
Air Cycle System Component Operation -- 568
Electronic Cabin Temperature Control System -- 574
Electronic Temperature Control Regulator 575
Vapor Cycle System (Freon) - 576
Freon System Components ---- 577
Description of a Typical System --- 580
Air Conditioning and Pressurization System Maintenance --- 583
Cabin Pressurization Operational Checks -- 585
Cabin Pressurization Troubleshooting ---- 586
Oxygen Systems General - 587
Portable Oxygen Equipment -- 587
Smoke Protection Equipment -- 588
Oxygen Cylinders - 588
Solid State Oxygen Systems -- 589
Oxygen Plumbing - 591
Oxygen Valves --- 592
Regulators --- 594
Oxygen System Flow Indicators 597
Pressure Gages --- 597
Oxygen Masks 597
Servicing Gaseous Oxygen Systems - 598
Prevention of Oxygen Fires or Explosions 600