AC65-15A
• Airframe & Powerplant MECHANICS
AIRFRAME HANDBOOK
HE DE TRANSPOPTN U.S. DEPARTMENT OF TRANSPORTATION
SO PATES OF ANO FEDERAL AVIATION ADMINISTRATION
AIRFRAME AND POWERPLANT
MECHANICS
AIRFRAME HANDBOOK U.S. DEPARTMENT OF TRANSPORTATION
FEDERAL AVIATION ADMINISTRATION
FLIGHT STANDARDS SERVICE First Edition 1972 First Revision 1976 ... .
For sale by the U.S. Government Printing Office Superintendent of Documents, Mail Stop: SSOP, Washington, DC 20402-9328 ISBN 0-16-036209-1
PREFACE 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, furdamentals 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, tabric covering, structural repairs, and aircraft welding. The hand book 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.
Grateful acknowledgement is extended to the manufacturers of engines, propellers, and powerplant accessories for their cooperation in making material available for inclusion in this handbook.
Copyright material is used by special permission of the following organizations and may not be extracted or reproduced without permission of the copyright owner.
Monsanto Chemicals Co. Skydrol ® Fluids Townsend Corporation Cherry Rivets Acres Sleeves J. O. King, Inc. Acres Sleeves Gravines, Inc. Fire Extinguishers Walter Kidde Fire Extinguishers DuPont De Nemours Fire Extinguishants National Fire Protection Association Fire Extinguisher and Extinguishant Specifications National Association of Fire Fire Extinguishers Extinguisher Distributors Flight Safety Foundation Refueling Data American Petroleum Institute Aviation Fuels Exxon Corporation Aviation Fuels Parker Hannifin Aircraft Fittings Goodyear Tire and Rubber Co. Aircraft Tires Aircraft Wheels Aircraft Brakes Firestone Aircraft Tires
Bendix Energy Controls Aircraft Wheels Aircraft Brakes Rohm and Haas Plastics Douglas Aircraft Company Portable Oxygen Generators in the DC-10 Aviation Maintenance Foundation, Inc. Air Conditioning BF Goodrich Aircraft Tires Aircraft Wheels Aircraft Brakes Puritan Equipment, Inc. Portable Oxygen Generators The advancements in aeronautical technology dictate that an instructional handbook must be under continuous review and brought up to date periodically to be Flight Standards requested comments, from the certificated mechanic schools on the three handbooks. As a result, the handbooks have been updated to this extent:
indicated errors have been corrected, new material has been added in the areas which were indicated as being deficient, and some material has becu rearranged to improve the usefulness of the handbooks.
We would appreciate having errors brought to our attention, as well as receiving suggestions for improving the usefulness of the handbooks. Your comments and suggestions will be retained in our files until such time as the next revision will be accomplished.
Address all correspondence relating to these handbooks to:
U.S. Department of Transportation Federal Aviation Administration Flight Standards National Field Ofice P.O. Box 25082 Oklahoma City, Oklahoma 73125 The companion handbooks to AC 65-15A are the Airframe and Powerplant Mechanics General Handbook, AC 65-9A and the Airframe and Powerplant Mechanics Powerplant Handbook, AC 65-12A.
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CONTENTS PREFACE iii
CONTENTS CHAPTER 1. AIRCRAFT STRUCTURES General Major Structural Stresses - Fixed-Wing Aircraft -- Fuselage ------ Wing Structure Nacelles or Pods Empennage - Flight Control Surfaces Landing Gear Skin and Fairing Access and Inspection Doors.
Helicopter Structures CHAPTER 2. ASSEMBLY AND RIGGING General Theory of Flight Aerodynamics The Atmosphere 27 Pressure Density Humidity Bernoulli's Principle and Subsonic Flow Motion Airfoils Center of Gravity Thrust and Drag Axes of an Aircraft Stability and Control Control __- Flight Control Surfaces - Control Around the Longitudinal Axis Control Around the Vertical Axis Control Around the Lateral Axis - Tabs ---- Boundary Layer Control Devices - Forces Acting on a Helicopter -- Helicopter Axes of Flight - High-Speed Aerodynamics Typical Supersonic Flow Patterns Aerodynamic Heating -- Flight Control Systems Hydraulic Operated Control Systems Cable Guides Mechanical Linkage
CHAPTER 2. ASSEMBLY AND RIGGING-(Cont.)
Torque Tubes --------- Stops --- Control Surface Snubbers and Locking Devices Aircraft Rigging ------ Rigging Checks ...
Adjustment of Control Surfaces Helicopter Rigging ---- Principles of Balancing or Re-balancing - Re-balancing Procedures Methods ..
CHAPTER 3. AIRCRAFT FABRIC COVERING Aircraft Fabrics ------.
Miscellaneous Textile Materials Seams --- Applying Covering Covering Wings ..- Covering Fuselages -_- Ventilation, Drain, and Inspection Openings Repair of Fabric Covers - Replacing Panels in Wing Covers Re-covering Aircraft Surface with Glass Cloth Causes of Fabric Deterioration Checking Condition of Doped Fabric Testing Fabric Covering Strength Criteria for Aircraft Fabric Dopes and Doping - 107 Dope Materials -- 108 Aluminum-Pigmented Dopes Temperature and Humidity Effects on Dope Common Troubles in Dope Application Technique of Application Number of Coats Required 111 CHAPTER 4. AIRCRAFT PAINTING AND FINISHING General --.
Finishing Materials - Paint Touchup -- Identification of Paint Finishes Paint Removal --- Restoration of Paint Finishes Nitrocellulose Lacquer Finishes Acrylic Nitrocellulose Lacquer Finish Epoxy Finishes Fluorescent Finishes Enamel Finishes --- Paint System Compatibility Methods of Applying Finishes Preparation of Paint ---.
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CHAPTER 4. AIRCRAFT PAINTING AND FINISHING-(Cont.)
Common Paint Troubles Painting Trim and Identification Numbers Decalcomanias (Decals) CHAPTER 5. AIRCRAFT STRUCTURAL REPAIRS Basic Principles of Sheet Metal Repair General Structural Repair Inspection of Damage Classification of Damage Stresses in Structural Members 131 Special Tools and Devices for Sheet Metal Metalworking Machines Forming Machines Forming Operations and Terms Making Straight Line Bends Setback Making Layouts Hand Forming Rivet Layout Rivet Installation Preparation of Rivet Holes Driving Rivets ..
Rivet Failures Removing Rivets Special Rivets - Self-Plugging (Friction Lock) Rivets Self-Plugging (Mechanical Lock) Rivets Pull-Thru Rivets Rivnuts Dill Lok-Skrus and Lok-Rivets Deutsch Rivets Hi-Shear Rivets Specific Repair Types Structural Sealing Metal Bonded Honeycomb Construction Features Damage - Repairs Repair Materials Potted Compound Repair Glass Fabric Cloth Overlay Repairs One Skin and Core Repair Procedures Plastics - Transparent Plastics - Storage and Protection Forming Plastics ---- Installation Procedures Laminated Plastics - Fiber Glass Components Radomes Wooden Aircraft Structures _- Inspection of Wooden Structures - Service and Repair of Wooden Structures Glues Gluing vii
CHAPTER 5. AIRCRAFT STRUCTURAL REPAIRS-(Cont.)
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 Welding of Aircraft Steel Structures 276 CHAPTER 7. ICE AND RAIN PROTECTION General Pneumatic Deicing Systems Deicer Boot Construction Deicing System Components Pneumatic Deicing System Maintenance 291 Thermal Anti-Icing Systems 293 Pneumatic System Ducting 296 Ground Deicing of Aircraft Windshield Icing Control Systems 300 Water and Toilet Drain Heaters Rain Eliminating Systems Maintenance of Rain Eliminating Systems CHAPTER 8. HYDRAULIC AND PNEUMATIC POWER SYSTEMS Aircraft Hydraulic Systems Hydraulic Fluid ----. 309 Types of Hydraulic Fluids 310 Phosphate Ester Base Fluids 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 vili
CHAPTER 9. LANDING GEAR SYSTEMS-(Cont.)
Emergency Extension Systems -- Landing Gear Safety Devices Nosewheel Steering System .
Shimmy Dampers Brake Systems Brake Assemblies Inspection and Maintenance of Brake Systems Aircraft Landing Wheels -- Aircraft Tires - 377 Aircraft Tire Maintenance 379 Tire Inspection-Mounted On Wheel 381 Tire Inspection-Tire Demounted 382 Tube Inspection Mounting and Demounting Causes of Air Pressure Loss in Tubeless Aircraft Tires The Wheel Good Pressure Gage Practice - Repairing Operating and Handling Tips.
Tube Repair 396 Sidewall-Inflated Aircraft Tires 396 Tire Inspection Summary Antiskid System Landing Gear System Maintenance 400 CHAPTER 10. FIRE PROTECTION SYSTEMS General Fire Detection Systems Types of Fires - Fire Zone Classification 412 Extinguishing Agent Characteristics Fire Extinguishing Systems 417 Reciprocating Engine Conventional CO2 System 417 Turbojet Fire Protection System - 419 Turbine Engine Fire Extinguishing System 420 Turbine Engine Ground Fire Protection Fire Detection System Maintenance Practices Fire Detection System Troubleshooting Fire Extinguisher System Maintenance Practices Fire Prevention and Protection -.
Cockpit and Cabin Interiors -.
Smoke Detection Systems - CHAPTER 11. AIRCRAFT ELECTRICAL SYSTEMS General -.
Lacing and Tying Wire Bundles - Cutting Wire and Cable Emergency Splicing Repairs Connecting Terminal Lugs to Terminal Blocks Bonding and Grounding Connectors Conduit -- Electrical Equipment Installation Aircraft Lighting Systems ------ Maintenance and Inspection of Lighting Systems ix
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 Quanity System 485 Angle-of-Attack Indicator 487 Tachometers -- 488 Synchroscope 491 Temperature Indicators 491 Ratiometer Electrical 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 Installatoin of Aircraft Antenna Systems 537 CHAPTER 14. CABIN ATMOSPHERE CONTROL SYSTEM Need for Oxygen 539 Compusition of the Atmosphere 539 Pressurization 541 Air Conditioning and Pressurization Systems 543
CHAPTER 14. CABIN ATMOSPHERE CONTROL SYSTEM—(Cont.)
Basic Requirements Sources of Cabin Pressure Supercharger Instruments Pressurization Valves Cabin Pressure Control System - 551 Air Distribution 556 Air Conditioning System Heating Systems Combustion Heaters Maintenance of Combustion Heater Systems 564 Cooling Systems -- Air Cycle Cooling System Air Cycle System Component Operation 568 Electronic Cabin Temperature Control System 574 Electronic Temperature Control Regulator 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 Oygen Masks --- 597 Servicing Gaseous Oxygen Systems 598 Prevention of Oxygen Fires or Explosions 600