NAVAIR_01-1A-1 _Ch.3.pdf

15 SEPTEMBER 2010

TO 1-1A-1

NAVAIR 01-1A-1

TECHNICAL MANUAL

ENGINEERING HANDBOOK SERIES FOR AIRCRAFT REPAIR

GENERAL MANUAL FOR

STRUCTURAL REPAIR

(ATOS)

This manual supersedes TO 1-1A-1 and NAVAIR 01-1A-1, dated 15 November 2006.

DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited.

DESTRUCTION NOTICE - For unclassified, limited documents, destroy by any method that will prevent disclosure of contents or reconstruction of the document.

PUBLISHED UNDER AUTHORITY OF THE SECRETARY OF THE AIR FORCE

0801LP1106264

NAVAIR 01-1A-1

A

LIST OF EFFECTIVE PAGES

Dates of issue for original and changed pages are:

Original 0 15 September 2010

Insert latest changed pages; dispose of superseded pages in accordance with applicable regulations.

NOTE: On a changed page, the portion of the text affected by the latest change is indicated by a vertical line or other change symbol in the outer margin of the page. Changes to illustrations are indicated by miniature pointing hands. Changes to wiring diagrams are indicated by shaded areas.

The total number of pages in this manual is 202, consisting of the following:

Page #Change No. No.

Page #Change No. No.

Title 0 A 0 i - v 0 vi Blank 0 vii - xi 0 xii Blank 0 1-1 -1-10 0 2-1 - 2-14 0 3-1 - 3-25 0 3-26 Blank 0 4-1 - 4-19 0 4-20 Blank 0 5-1 - 5-9 0

5-10 Blank 0 6-1 - 6-19 0 6-20 Blank 0 7-1 - 7-11 0 7-12 Blank 0 8-1 - 8-28 0 9-1 - 9-22 0 A-1 - A-7 0 A-8 Blank 0 B-1 - B-2 0 C-1 - C-8 0 Index-1 - Index-8 0

# Zero in this column indicates an original page.

i

TABLE OF CONTENTS

Chapter Page

LIST OF ILLUSTRATIONS iii

LIST OF TABLES v

INTRODUCTION vii

SAFETY SUMMARY ix

1 A DESCRIPTION OF THE MAIN ELEMENTS

IN AIRCRAFT STRUCTURE 1-1

1.1. Principal Structural Units 1-1

1.1.1. Fuselage 1-1

1.1.2. Engine Mounts 1-1

1.1.3. Nacelle 1-1

1.1.4. Wings 1-1

1.1.5. Stabilizers 1-1

1.1.6 Control Surfaces 1-1

1.1.7. Landing Gear 1-1

1.2. Fuselage 1-1

1.2.1 General 1-1

1.2.2. Structure 1-1

1.3. Engine Mounts 1-3

1.3.1. General 1-3

1.3.2 Structure 1-4

1.4. Nacelles 1-4

1.4.1. General 1-4

1.4.2. Structure 1-4

1.5. Wings 1-4

1.5.1 General 1-4

1.5.2. Structure 1-4

1.5.3. Inspection and Maintenance of the

Wings, Fuselage, and Nacelles 1-5

1.6. Stabilizers 1-6

1.6.1. General 1-6

1.6.2. Structure 1-6

1.7. Control Surfaces 1-6

1.7.1. General 1-6

1.7.2. Structure 1-8

1.8. Landing Gear 1-10

2 DAMAGE ASSESSMENT 2-1

2.1. Causes of Aircraft Damage 2-1

2.2. Damage Classifications 2-2

2.3. Repair Classifications 2-5

2.4. Investigation of Damage 2-6

2.5. Nondestructive Inspection 2-6

Chapter Page

2.5.1. Nondestructive Inspection (NDI) 2-6

2.5.2. Damage Types 2-6

2.6. NDI Techniques 2-7

3 GENERAL WORKING PRACTICE 3-1

3.1. Repair of Aircraft Structures 3-1

3.2. Aluminum-Alloy Stressed Skin

Structure 3-1

3.3. Aluminum-Alloy Sheet

Substitutions 3-1

3.3.1. Explanation of Substitution Table 3-1

3.3.2. Explanation of Rule 1 3-4

3.3.3. Explanation of Rule 2 3-4

3.4. Rivets and Riveting Practice 3-4

3.5. Replacement of Spotwelds and

Worn Lamina 3-5

3.5.1. General 3-5

3.5.2. Removal of Spot Welds 3-5

3.5.3. Spot Weld Failures 3-6

3.6. Fasteners 3-9

3.7. Extracting Broken Screws 3-9

3.8. Advanced Composite Repair 3-9

3.9. Tubing Repair 3-10

3.9.1. General 3-10

3.9.2. Identification of Tubing Systems 3-11

3.9.3. Tubing Damage 3-11

3.9.4. Repairs 3-11

3.10. Repair of Threaded Installations 3-11

3.11. Stop-Drilling Cracks in Sheet Material

(Low- and Medium- Stress Areas) 3-12

3.11.1. Crack Inspection 3-12

3.11.2. Crack Evaluation 3-13

3.11.3. Crack Repair and Treatment 3-13

3.12. Blending Scratches 3-13

3.13. Typical Repair Examples 3-14

4 MATERIALS AND THEIR

IDENTIFICATION 4-1

4.1. Material Specifications 4-1

4.2. Terminology 4-1

4.2.1. Terms for the Study and Use of

Materials 4-1

4.2.2. Steel 4-4

4.2.3. Aluminum 4-8

4.2.4. Titanium 4-11

4.2.5. Magnesium 4-16

4.2.6. Advanced Composites 4-17

4.2.7. Transparent Plastics 4-18

4.2.8. Safety Glass 4-19

ii

TABLE OF CONTENTS—Continued

Chapter Page

5 FASTENERS 5-1

5.1. General 5-1

5.2. Threaded Fasteners 5-1

5.3. Rivets 5-4

6 WELDING 6-1

6.1. Welding 6-1

6.1.1. General Processes 6-1

6.1.2. Definitions 6-1

6.2. Welding Positions 6-2

6.3. Types Of Welds 6-4

6.4. Shielded Metal Arc Welding (SMAW) 6-6

6.4.1. SMAW Process 6-6

6.4.2. Electrical Shock Hazard 6-6

6.4.3. Welding Equipment 6-6

6.4.4. Electrodes 6-7

6.4.5. Electrode Classification and Codin 6-7

6.4.6. Striking an Arc 6-8

6.4.7. Maintaining the Proper Arc Length 6-10

6.4.8. Penetration 6-10

6.4.9. Depositing Weld Metal 6-11

6.4.10. Spatter 6-11

6.4.11. Jigs and Fixtures 6-12

6.4.12. Storage of Electrodes 6-12

6.5. Gas Tungsten Arc Welding (GTAW) 6-12

6.5.1. GTAW Process 6-12

6.5.2. GTAW Welding Process 6-12

6.5.3. Welding Equipment 6-12

6.5.4. Wire Feed Systems 6-13

6.5.5. Electrodes 6-13

6.5.6. Filler Metals 6-14

6.5.7. Power Supplies 6-16

6.5.8. Advantages of GTAW 6-16

6.5.9. Limitations of GTAW 6-16

6.6. GTAW Process Variations 6-17

7 ADHESIVES AND BONDING 7-1

7.1. General 7-1

7.2. Advantages and Disadvantages of

Adhesive Bonding 7-1

7.2.1. Advantages 7-1

7.2.2. Disadvantages 7-1

7.3. Classification of Adhesive Materials 7-2

7.3.1. Functional Classification 7-2

7.3.2. Type Classification 7-2

Chapter Page

7.4. Types of Adhesive Bonded Joints 7-4

7.4.1. Lap Joints 7-4

7.4.2. Joggle Lap Joints 7-4

7.4.3. Beveled Lap Joints 7-4

7.4.4. Butt Joints 7-4

7.4.5. Strap Joints 7-4

7.5. Design Considerations 7-4

7.5.1. Stresses 7-4

7.5.2. Compatibility 7-6

7.5.3. Fabrication 7-6

7.6. Surface Preparation 7-6

7.7. Selection of Adhesive 7-8

7.8. Curing of Adhesive Bonds 7-8

7.9. Adhesive Primer Selection 7-8

7.10. Debonding of Honeycomb

with Dry Ice 7-10

7.10.1. Insulated Enclosure 7-10

7.10.2. Packing 7-10

7.10.3. Removal Procedure 7-10

7.10.4. Dry Ice Substitute 7-10

7.11. Additional Information 7-11

8 METAL WORKING 8-1

8.1. General Shop Practices 8-1

8.2. Sheet Metal Forming 8-1

8.3. Forming Terminology 8-1

8.4. Flat Pattern Development 8-1

8.5. Bend Allowance 8-1

8.6. Setback 8-1

8.7. Minimum Sheet Metal Bend Radii 8-3

8.8. Flat Pattern Layout Procedures 8-3

8.9. Bend Line 8-3

8.10. Forming Operations 8-3

8.11. Box Pan or Cornice Brake

Machine Forming 8-9

8.12. Slip Roll Machine Forming 8-9

8.13. Hand Forming 8-9

8.14. Joggling 8-23

8.15. Working Titanium Alloys 8-26

8.16. Cutting and Grinding Titanium Alloys 8-26

8.17. Drilling and Reaming Titanium Alloys 8-26

8.18. Dies and Joggle Blocks 8-26

8.19. Forming Titanium Alloys 8-26

8.20. Cold-Forming Titanium Alloys 8-27

8.21. Elevated-Temperature-Forming of

Titanium Alloys 8-27

8.22. Titanium Stress-Relieving

and Annealing 8-27

8.23. Locating Blind Holes 8-27

iii

TABLE OF CONTENTS—Continued

Chapter Page

9 CABLE REPAIR 9-1

9.1. General 9-1

9.2. Cable Damage 9-3

9.3. Cable Repair 9-3

9.4. Fabrication of Cable Assemblies 9-5

9.5. Tools 9-9

9.6. Marking of Cable Assemblies 9-9

9.7. Cable Corrosion Serviceability

Standards 9-9

9.8. Testing 9-9

9.8.1 Proof Load 9-9

9.8.2 Full Strength 9-9

9.8.3 Evaluation 9-9

9.9. Repair Specifications and

Part Numbers 9-9

A GRIT PLAST SILANE (GBS)

PROCESS A-1

A.1. Materials A-1 A.2. Equipment A-3 A.3. Process A-3

B PHOSPHORIC ACID NON-TANK

ANODIZE (PANTA) PROCEDURES B-1

B.1. Materials 9-5

C SPECIAL CONSIDERATIONS

REGARDING FASTENER HOLES C-1

C.1. General Process Requirements C-1 C.2. Cutting Fluids (Sources) C-1

Chapter Page

C.3. General Practices to Produce Quality Holes in Metallic Aircraft Structures C-1

C.4. Drill Motors C-2 C.5. Cutting Tools C-2 C.6. Cutting Speeds and Feeds C-2 C.7. Cutting Fluids C-2 C.8. Hole Quality C-3 C.9. Cold Working (CW) Of Fastener

Holes; Split Sleeve Method C-3 C.10. Process Description C-3 C.11. Engineering Background and

Justification C-3 C.12. Mandrels C-4 C.13. Nondestructive Inspection C-4 C.14. Lubricants C-4 C.15. Applied Expansion C-4 C.16. Edge Margin Requirements C-4 C.17. Hole Spacing Requirement C-4 C.18. Cold Worked Hole Diameter C-4 C.19. Post Sizing of Cold Worked

Holes for Fastener Fit C-5 C.20. Oversizing C-5 C.21. Countersinking and Deburring C-5 C.22. Rework of Previously

Countersunk Holes C-5 C.23. Hole Diameter vs Sheet

Thickness Ratio C-5 C.24. Shear Discontinuities C-5 C.25. Surface Upset C-5

INDEX INDEX 1

LIST OF ILLUSTRATIONS

Figure Title Page

1-1. Principle Structural Units 1-2 1-2. Semimonocoque Fuselage Design 1-3 1-3. Aircraft Wing Design 1-5 1-4. Typical Tail Structures 1-7 1-5. Typical Stabilizer Structures 1-7 1-6. Types of Wing Flaps 1-9 1-7. Leading Edge Flaps 1-10

2-1. Negligible Damage 2-3 2-2. Damage Repairable by Patching 2-4 2-3. Damage Repairable by Insertion 2-4 2-4. Damage Requiring Replacement 2-5

Figure Title Page

2-5. Typical Borescope 2-8 2-6. Types of Borescopes 2-8 2-7. Locating Cracks by Radiography 2-10 2-8. Eddy Currents Produced in a

Conductor by a Varying Electromagnetic Field 2-11

2-9. Path of Eddy Currents Around a Crack 2-11. .

2-10. Detecting Flaw with Ultrasonic

Inspection Method 2-11 2-11. Fluorescent Penetrant Action 2-12 2-12. Crack in Bar Magnet Attracting

Magnetic Particles 2-13 iv

LIST OF ILLUSTRATIONS—Continued

Figure Title Page

2-13. Electric Current Creating a Circular Magnetic Field in a Part 2-13

3-1. Aluminum Alloy Sheet Substitution and Conversion Table for Commercial Temper Designations 3-2

3-2. Drill Sizes for Removal of Spot Weld 3-5 3-3. Method of Shearing Spot Welds for Riveting 3-6 3-4. Locating and Transcribing Tool 3-6 3-5. Spot Weld Shearing Chisel 3-7 3-6. Piloting Drill 3-7 3-7. Drilling Holes 3-7 3-8. Removing Spot Welded Skin from Structure 3-7 3-9. Repair for Sheared Spot Welds 3-8 3-10. Drilling a Hole in a Broken Screw 3-9 3-11. Removing a Broken Screw 3-10 3-12. Stress Concentration and Blending 3-14 3-13. Typical Splice Repair 3-15 3-14. Typical Splice Tee Repair 3-16 3-15. Typical Angle Repair 3-17 3-16. Typical Channel Repairs 3-18 3-17. Typical Zee Repair 3-21 3-18. Typical Rib Repair 3-23 3-19. Typical Aluminum Honeycomb Repair 3-24. . .

4-1. Tension Load Example 4-1 4-2. Compression Load Example 4-2 4-3. Shear Load Example 4-2 4-4. Bending Load Example 4-3 4-5. Torsion Load Example 4-4

5-1. Parts of a Screw 5-2

6-1. Positions of Welding for Groove Welds 6-3

6-2. Positions of Welding for Fillet Welds 6-3 6-3. Types of Joints 6-5 6-4. SMAW Process 6-6 6-5. Typical SMAW Circuit 6-7 6-6. Scratch Method of Starting the Arc 6-10 6-7. Touch Method of Starting the Arc 6-10 6-8. Arc Distance and Angle of Electrode 6-11 6-9. Typical GTAW Welding Equipment 6-13 6-10. Standard Welding Symbols 6-18

7-1. Types of Adhesive-Bonded Joints 7-5

8-1. Technical Forming Terms 8-2 8-2. Bend Allowance 8-3

Figure Title Page

8-3. Setback Dimensions (Bend Tangent Adjustment) 8-4

8-4. Minimum Bend Radii 8-6 8-5. Layout Development 8-8 8-6. Use of Bend Lines on Cornice Brake 8-9 8-7. Cornice Brake Operation 8-11 8-8. Form Block and Cornice Brake

Correction Allowance 8-13 8-9. Forming Parts 8-14 8-10. Hand-Forming Concave Surfaces 8-15 8-11. Hand-Forming Convex Surfaces 8-16 8-12. Hand-Forming Extruded Shapes 8-17 8-13. Joggle Dimension Chart -

Flat Sheet, Joggle Cold 8-19 8-14. Joggle Dimension Chart - Flanged

Sheet, Rubber Formed and Joggle Cold 8-21

8-15. Joggle Dimension Chart - Extruded or Bent Sheet Sections, Die Joggle 8-23

8-16. Forming Joggle Using Cornice Brake 8-24

8-17. Forming Joggle Using Joggle Blocks 8-25

8-18. Forming Joggle Using Joggle Clip 8-26

8-19. Drills for Titanium 8-28 8-20. Locating and Transcribing Tool 8-28

9-1. Flexible Cable Cross-Section 9-1 9-2. Cable Fittings 9-2 9-3. Negligible Damage to 7 x 19

Control Cables 9-3 9-4. Lockclad Cable - Minor Deviations 9-4 9-5. Lockclad Cable - Repair 9-4 9-6. Types of Cable Terminals 9-5 9-7. Preparation of a Woven Cable Splice 9-6 9-8. Cable Clamp for Woven Splice 9-7 9-9. Wrapped Soldered Splice 9-8 9-10. Roebling Roll Splice 9-8 9-11. Strands Labeled for Learning

Roebling Roll Splice 9-8 9-12. Beginning the Splice Using a Marlin

Spike 9-8 9-13. Continuing the Splice 9-8 9-14. Further Progress in Splicing 9-9

A-1. Grit Containment Box Example A-4

C-1. Split Sleeve Cold Working of Fastener Holes C-7

C-2. Steps of the Cold Working Process C-8 v/(vi Blank)

LIST OF TABLES

Number Title Page

1 Related Air Force (TO) and NAVAIR (TM) Publications viii

2-1 Types of Damage 2-2 2-2 Advantages and Disadvantages of

Common Aircraft NDI Techniques 2-14

3-1 Drill and Extractor Sizes 3-10

4-1 Cross-Reference of Steel Specifications 4-6

4-2 Basic Temper Designations and Subdivisions for Aluminum Alloys 4-10

4-3 Cross-Reference for Common Aluminum Alloys 4-12

4-4 Typical Mechanical Properties of Common Aluminum Alloys 4-13

4-5 Mechanical Properties of Titanium 4-15 4-6 Density of Structural Metals 4-16 4-7 Fiber Reinforcement 4-18 4-8 Resins 4-18 4-9 Prepregs and Laminates 4-19

5-1 Hole Size Fits 5-3 5-2 Rivet Identification and Characteristics 5-7. . .

5-3 Shear Strength of Aluminum Alloy

Rivets (Pounds Per Rivet) 5-9

6-1 Most Common Welding Processes 6-1 6-2 Size and Capacity of

Electrode Holders 6-8 6-3 Recommended Filter Lens Shade

Used in SMAW 6-8 6-4 Carbon and Low-Alloy, Steel-Covered Electrode Identification System 6-9

6-5 Typical Amperage Ranges for Selected SMAW Electrodes 6-11

6-6 Selection of GTAW Electrodes 6-15 6-7 Recommended Current Ranges for Welding with Thoriated GTAW Electrodes 6-15

6-8 Recommended Current Ranges for Welding with EWP and EWZr GTAW Electrodes 6-15

Number Title Page

6-9 Recommended Electrode Sizes and Current Ranges for GTAW Welding of Carbon, Low-Alloy, and Stainless Steels 6-15

6-10 Recommended Electrode Sizes and Current Ranges for GTAW Welding of Aluminum with EWP Electrodes Using AC and High-Frequency Current 6-16

7-1 Types of Adhesives 7-3 7-2 Adhesives Classified by Form 7-4 7-3 Surface Preparation Treatments for Adhesive Bonding (Tank Immersion) 7-7

7-4 Non-Tank Surface Preparation Treatments for Adhesive Bonding on Aluminum, Titanium, Steel, and Fiberglass 7-9

7-5 Federal and Military Adhesive Specifications 7-10

7-6 Thermosetting Adhesives Classified by Activation and Cure Requirements 7-11. . .

9-1. Cure Time 9-4 9-2. Test Loads for Cable Terminal Splices 9-10 9-3. Cable Repair Specifications 9-10 9-4. Turnbuckle Assembly 9-11 9-5. MS20658 Fork End Cable Terminal 9-17. . .

9-6. MS21259 Threaded Cable Terminal 9-18 9-7. MS20667 Fork End Cable Terminal 9-19. . .

9-8. MS20668 Eye End Cable Terminal 9-20 9-9. MS20663 Double Shank Ball

End Cable Terminal 9-21 9-10. MS20664 Single Shank Ball

End Cable Terminal 9-22

C-1 Maximum Recommended Drill Speeds for Holes up to 0360 Inch Diameter C-5

C-2 Maximum Recommended Reaming Speeds for Holes up to 0360 Inch Diameter C-6

C-3 Recommended Flex Honing Parameters C-6

C-4 Recommended Speeds for Countersinking and Counterboring C-6

C-5 Recommended Cutting Fluids C-6

THIS PAGE LEFT INTENTIONALLY BLANK

INTRODUCTION

1. GENERAL. with the weapon system-specific repair manuals. If a con-flict occurs, the weapon system-specific repair manuals

Technical Order (TO) 1-1A-1 is one of a series of manuals shall take precedence.

prepared to assist personnel engaged in the general mainte-

The procedures described in this manual are compatiblenance and repair of military aircraft. This manual covers with those currently used by airframe manufacturers.general aircraft structural repair.

Repair and maintenance performed according to this man-

This is a Joint-Service manual and some information may ual should result in quality equivalent to that in the original be directed at one branch of the service and not the other. installation.

Wherever the text of the manual refers to Air Force

Repairs are made under varying conditions. All materials,technical orders for supportive information, refer to the tools, and machinery needed to make repairs may becomparable Navy documents (see Table 1).

available, together with sufficient time and freedom from

The satisfactory performance of aircraft requires continu- interruption, to ensure striving for perfection. At times, ous attention to maintenance and repair to maintain aircraft machinery, materials, and tools may not be available or structural integrity. Improper maintenance and repair tech- adequate. Time may be a pressing factor. Combat condi-niques can pose an immediate and potential danger. The tions may also be a factor. Wherever possible, repairs reliability of aircraft depends on the quality of the design, covered in this manual keep two principal types of user in as well as the workmanship used in making the repairs. mind:

It is important that maintenance and repair operations be • Repair personnel operating under base repair condi-made according to the best available techniques to elimi- tions nate, or at least minimize, possible failures. • Repair personnel making repairs in combat areas

Navy and Marine Corps personnel SHALL submit Under base repair conditions, the weapon system-specific changes/corrections at www.natec.navy.mil, the Technical repair manuals take precedence over any guidance Publication Discrepancy Reporting (TPDR) process on- presented in TO 1-1A-1.

line. Instructions for submission of TPDRs are in COM-

Under combat conditions, the weapon system-specific bat-NAVAIRFORINST 4790.2 (NAMP), Volume V, Chapter tle damage repair TO takes precedence over any guidance10.

presented in TO 1-1A-1.

2. SOURCES OF INFORMATION.

For other repair instances, certain procedures must be used in all cases because special tools and machinery areThis manual contains up-to-date information and practices required.for aircraft structural repair. It has been compiled from information contained in AC-43.13-2A (Acceptable Meth-

4. ARRANGEMENT OF MATERIAL.ods, Techniques, and Practices: Aircraft Inspection and

Repair), weapon system-specific structural repair manuals, This manual is divided into eight chapters. Each chapterand applicable military and commercial specifications. In describes and illustrates the recommended procedure for aaddition, guidance published by the American Society for single subject or a related series of operations.Metals (ASM), the American Society for Testing and

Materials (ASTM), and the American Welding Society The manuals listed in Table 1 supplement and form a part (AWS) has been included where appropriate. of TO 1-1A-1. These supplemental manuals contain general information for their respective application of topic and3. INTENDED USE.

should be consulted first. For Navy, refer to the applicable aircraft specific or system specific technical manuals andThis manual is intended primarily for personnel who main- Maintenance Requirements Cards (MRCs).tain and repair military aircraft under government contract or at military bases. Its use is mandatory for such person-nel, except where any procedure contained in it conflicts vii

Table 1. Related Air Force (TO) and NAVAIR (TM) Publications

Agency Number Title Air Force TO 1-1-3 Preparation, Inspection, and Repair of Aircraft Fuel, Oil, and Water-

Alcohol Cells and Integral Tanks

Navy TM 01-1A-35 Maintenance Instructions Organizational, Intermediate, and Depot for Aircraft Fuel Cells and Tanks

Air Force TO 1-1-4 Exterior Finishes, Insignia, and Markings Applicable to Aircraft and Missiles

Navy ----- No single general series publication is available

Air Force TO 1-1-8 Application of Organic Coatings (Paint and Allied Materials)

Navy 15-01-500 Organizational, Intermediate, and Depot Maintenance Preservation of Na-val Aircraft

Air Force TO 1-1-17 Storage of Aircraft and Missile Systems

Navy ----- No single general series publication is available

Air Force TO 1-1-24 Maintenance Repair and Electrical Requirements for Fiberglass Airborne Radomes

Navy TM 01-1A-22 Maintenance Instructions Organizational, Intermediate, and Depot -Air-craft Radomes and Antenna Covers

Air Force TO 1-1-689.3 Cleaning and Corrosion Prevention Control, Volume III, Avionics and Electronics

Navy TM 01-1A-509-3 Cleaning and Corrosion Control, Volume III, Avionics and Electronics

Air Force TO 1-1-690 General Advanced Composite Repair Process

Navy TM 01-1A-21 Organizational and Intermediate Maintenance, General Composite Repair

Air Force TO 1-1-698.2 Cleaning and Corrosion Control, Volume II, Aircraft

Navy TM 01-1A-509-2 Cleaning and Corrosion Control, Volume II, Aircraft

Air Force TO 1-1A-8 Engineering Manual Series for Aircraft and Missile Repair Structural Hardware

Navy TM 01-1A-8 Engineering Manual Series for Aircraft and Missile Repair Structural Hardware

Air Force TO 1-1A-9 Engineering Series for Aircraft Repair - Aerospace Metal General Data and Usage Factors

Navy TM-01-1A-9 Engineering Series for Aircraft Repair - Aerospace Metal General Data and Usage Factors

Air Force TO 1-1A-12 Fabrication, Maintenance, and Repair of Transparent Plastics

Navy TM 01-1A-12 Fabrication, Maintenance and Repair of Transparent Plastics

Air Force TO 1-1A-14 Installation and Repair Practices, Aircraft Electric and Electronic Wiring

Navy TM 01-1A-505-1 Installation and Repair Practices, Aircraft Electric and Electronic Wiring

Air Force TO 1-1A-15 General Maintenance Instructions for Support Equipment

Navy ----- No single general series publication is available

Air Force TO 33B-1-1 Nondestructive Inspection Methods

Navy TM 01-1A-16 Nondestructive Inspection Methods

Air Force TO 42A3-1-2 General Uses of Cements, Sealants, and Coatings

Navy TM 01-1A-507 General Use of Cements, Sealants, and Coatings viii

SAFETY SUMMARY

1. GENERAL SAFETY INSTRUCTIONS. 3. FLIGHT LINE SAFETY PRECAUTIONS.

Many of the repair practices described in this manual Personnel working in or around aircraft on the flight line require technicians to use chemicals or perform physical shall observe flight line safety precautions and regulations actions that may cause injury or death, or damage to at all times.

equipment when procedures are not followed properly. This

4. CHEMICAL SAFETY.safety summary includes general safety precautions and instructions. These precautions and instructions must be

Aircraft maintenance chemicals (e.g., abrasives, cleaners,understood and applied during operation and maintenance corrosion preventatives, paint strippers, surface treatments,to ensure personnel safety and to protect equipment. Before sealants, paints, and solvents) may be hazardous. Properperforming any task, all WARNINGS, CAUTIONS, and use of personal protective equipment is essential to preventNOTES included in that task shall be reviewed and skin, eyes, and respiratory and digestive tracts from beingunderstood.

exposed to these chemicals. Use the following safety

2. WARNINGS, CAUTIONS, AND NOTES. precautions:

• Learn the warnings and cautions for using specificWARNINGs and CAUTIONs are used in this manual to maintenance chemicals and procedures. Observe manu-highlight operating or maintenance procedures, practices, facturer’s warning labels and the warnings and cautionsconditions, or statements that are considered essential to the in this manual and other applicable maintenanceprotection of personnel (WARNING) or equipment (CAU-instructions manuals.TION). WARNINGs and CAUTIONs immediately precede

• Use personal protective equipment (e.g., goggles, respi-the step or procedure to which they apply. NOTEs are used rators, gloves, boots, and aprons) as recommended byin this manual to highlight operating or maintenance proce-the local safety office, industrial hygienist, bio-environ-dures, practices, conditions, or statements that are not mental engineer, material safety data sheet (MSDS),essential to the protection of personnel or equipment.

DOD 6050-LR, or this manual.NOTEs may precede or follow the step or procedure,

• Make sure that sufficient ventilation exists. Cartridgedepending on the information to be highlighted. The head-respirators only filter out the airborne contaminationings used and their definitions are as follows.

for which they were designed. A respiratory hazard exists if oxygen is depleted or displaced.

WARNING • When flammable materials are used, make sure that all ignition sources have been removed from the area.

Ensure that only explosion-proof or pneumatically

Highlights an essential operating or mainte- powered equipment is used. Ensure that firelighting nance procedure, practice, condition, or state- equipment is readily available and in working order.

ment that, if not strictly observed, could result • Do not mix maintenance chemicals unless written in injury to or death of personnel, or long-term instructions specifically direct a mixing procedure.

health hazards. Many combinations of chemicals are incompatible and may produce toxic fumes and violent reactions. Liquid oxygen is not compatible with most organic materials.CAUTION Explosions have occurred when liquid oxygen comes into contact with greases or oils.

• Use only the materials recommended by this manualHighlights an essential operating or mainte-and other applicable maintenance instruction manuals.nance procedure, practice, condition, or state- Use only those chemicals and procedures recom-ment that, if not strictly observed, could result mended for specific aircraft components. Some chemi-in damage to or destruction of equipment, or cals are incompatible with certain aircraft materials.loss of mission effectiveness.

For example, acidic surface treatments can cause high-strength steel to become brittle, and chemical paintNOTE removers will dissolve canopy materials.

Highlights an essential operating or mainte-

5. MECHANICAL SAFETY.nance procedure, condition, or statement.

Without the proper safety devices and tools, aircraft main-tenance procedures may present severe mechanical hazards ix

(e.g., loss of control of tools, falling, cuts from sharp usually the best source of information concerning environ-surfaces, impact of flying debris from high-speed tools). mental restrictions.

The following safety precautions should always be

7. MATERIAL SAFETY DATA SHEETS.followed:

• Learn the warnings and cautions required for specific The following MSDS data provide the necessary informa-maintenance procedures. Observe manufacturer’s tion for the safe handling of hazardous substances when warning labels and the warnings and cautions in this used:

manual and other applicable maintenance instruction

• The MSDS of a substance describes its identity, rele-manuals.

vant health hazard information, telephone numbers,• Use personal protective equipment (e.g., goggles, respi-precautions for use, personnel protective equipment,rators, gloves, boots, and aprons) as recommended by and safe handling information.the local safety office, industrial hygienist, bio-environ-

• The Occupational Safety and Health Administrationmental engineer, MSDS, DOD 6050-LR, or this man- (OSHA) Hazard Communications Standard requiresual.

that manufacturers and distributors provide MSDS to• Use the necessary safety devices (e.g., safety harnesses, users of chemicals. For each chemical used in thesafety lines) and tools fitted with safety devices (e.g., workplace, a corresponding MSDSs must exist. Indi-chip guards, belt guards).

viduals must have access to the MSDS for each of the• Use only those procedures recommended by this man-chemicals used in their work areas.ual and other applicable maintenance instruction manu-

• An MSDS is a primary source of information whenals. Unauthorized procedures can result in personal determining the risks associated with any substanceinjury, damage to equipment or property, or loss of used in the workplace. An MSDS includes usefulaircraft flight-worthiness.

information on toxicity, reactivity, and physical proper-• Unless specifically allowed by shop safety procedures, ties of a substance. The Department of Environmentalremove rings, watches, and other metallic objects that Health and Safety will supply MSDSs to all depart-may be caught in moving parts.

ments, supervisors, or users upon request.• Use compressed air carefully. Objects propelled by

• Although no standard format exists for MSDSs, thecompressed air can cause severe personal injury.

National Commission’s National Code of Practice for

6. HAZARDOUS MATERIALS. the Preparation of Material Safety Data Sheets [NOHSC:2011(1994)] 3 requires that each MSDS sec-

Repair and maintenance activities must comply with local, tion contain certain information (see table 1, Material state, and federal laws restricting the use and disposal of Safety Data Sheet Section Requirements).

hundreds of chemical ingredients and thousands of chemi-cal products. Base safety and environmental personnel are x

Section Section Requirement 1 Chemical Product and Company Identification. This section includes the address, telephone number of the manufacturer, names of different grades of the material and any applicable generic names, and emergency phone numbers to use in the event of an accident or accidental release of this material.

2 Composition and Information on Ingredients. This section lists all ingredients that are hazard-ous, individually or in combination with other ingredients. Some MSDSs list only the hazardous ingredients. Some list hazardous ingredients plus other significant ingredients. Other MSDSs list haz-ardous ingredients present as 1 percent or more of the total formula (0.1 percent if they are carcinogen-ic). And others simply list all the ingredients.

3 Hazards Identification. This section describes the color, shape, odor, and vapors of the material. It also describes potential health risks to the eyes or skin, as well as the effects of inhalation or ingestion.

This section also lists information about flammability, combustibility, and explosiveness.

4 First-Aid Measures. This section describes how to treat overexposure to a chemical, along with antidotes that can be administered to a victim. This section may also include information for physicians about clinical testing and treatment.

5 Fire and Explosion Hazards. This section covers fire-fighting measures, the use of appropriate fire extinguishers, and basic fire-fighting requirements. It also includes information about the flammable properties of the chemical, including the flash point, the upper and lower flammable limits, the flammability classification, the autoignition temperature, and the release of flammable vapors.

6 Accidental Release Measures. This section includes information about containment techniques, cleanup procedures, and emergency equipment required for spills and other releases of the chemical.

The information in this section primarily benefits emergency response personnel.

7 Handling and Storage. This section emphasizes proper precautions for the unique properties of the material. This section lists practices that minimize contact between the worker and the material, as well as the risk of fire, explosion, or spills.

8 Exposure Controls and Personal Protection. This section may include information about prac-tices or useful equipment for minimizing worker exposure, as well as guidance on personal protective equipment and exposure.

9 Physical and Chemical Properties. The following characteristics of the hazardous material are listed in this section: odor, physical state, pH level, vapor pressure, vapor density, boiling point, freezing or melting point, water solubility, and specific gravity or density. Some of the following information about a chemical may also be included (when appropriate): heat value, particle size, volatile organic compounds content, softening point, evaporation rate, viscosity, bulk density, molecular weight, and molecular formula.

10 Stability and Reactivity. This section describes conditions that could result in a hazardous chemical reaction. Also included here is information about chemical stability, incompatibility with other chemi-cals, hazardous polymerization, and hazardous materials created as the material decomposes.

11 Toxicological Information. This section includes background data (including the results of tests and studies involving the chemical) used to determine the hazards presented by this chemical.

12 Ecological Information. The information included in this section is intended to help environmental professionals determine the impact of the chemical on the environment in the event of a release.

13 Disposal Considerations. This section provides information about chemical classification under the waste disposal laws, chemical and physical properties of the material, and special disposal instructions.

14 Transport Information. This section contains basic shipping classification information.

15 Regulatory Information. This section contains information about the regulatory status of the materi-als, including its components and regulated uses. In addition to OSHA regulations, this section may discuss the regulations of other federal agencies or those regulations of other nations.

16 Other Useful Information. This section contains any additional information the manufacturer thinks might be useful to the user.

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CHAPTER 1

A DESCRIPTION OF THE MAIN ELEMENTS IN AIRCRAFT STRUCTURE

1.1 PRINCIPAL STRUCTURAL UNITS. 1.1.7 Landing Gear. The structures that support the aircraft while on the ground or water are the landing gear.

The principal structural units of an aircraft consist of the Landing gear may incorporate shock-absorbing struts, usu-fuselage, engine mount, nacelle, wings, stabilizers, control ally hydraulic.

surfaces, and landing gear (see Figure 1-1).

1.2 FUSELAGE.

1.1.1 Fuselage. The fuselage is the main structure (or

body) of the aircraft. The wings and tail units are attached 1.2.1 General. Fuselages for various types of aircraft to the fuselage. On single-engine aircraft, the fuselage have much in common from the viewpoint of outline and houses the crew, passengers, cargo, and power plant. On general design. They vary principally in size and in the multi-engine aircraft, however, the power plants are nor- arrangement of the compartments. Detail design varies with mally mounted on nacelles. Nacelles are separate units that the manufacturer and mission requirements of the aircraft.

are similar in design and construction to the fuselage.

1.2.2 Structure.Nacelles are attached to the wing structure or fuselage.

1.1.2 Engine Mounts. Engine mounts are used to attach 1.2.2.1 Fuselage Designs. The fuselage is the main struc-ture or body of an aircraft. It provides space for cargo,the power plant to the aircraft. On most single-engine controls, accessories, passengers, and other equipment. Inaircraft, they are mounted on the front end or nose of the single- or multi-engine aircraft, its design may be such thatfuselage. On most multi-engine aircraft they are attached to it houses the power plant. Power plants may also beor incorporated into the nacelle structure. On jet-engine attached to the fuselage or suspended from the wingaircraft, engine mounts are incorporated into the fuselage, structure. The fuselages of modern military aircraft typi-on the sides of the fuselage, or at the back of the aircraft.

cally rely on some form of stiffened shell design. This

1.1.3 Nacelle. The nacelle is a faired structure attached design may be divided into two classes: monocoque and semimonocoque. Different portions of the same fuselageto the wing or fuselage. It supports the engine, engine may belong to either class, however, semimonocoquemount, and its accessories, and may or may not incorporate design is most common (see Figure 1-2).provisions for retractable landing gear or provide space for additional useful load.

1.2.2.1.1 Monocoque Design. Monocoque design relies

on the strength of the skin (also known as the shell or1.1.4 Wings. The wings constitute the main lifting sur-covering) to carry the various loads. True monocoqueface of the aircraft while in flight and are designated as construction does not use formers, frame assemblies, orright and left. The right and left sides of an aircraft are bulkheads to give shape to the fuselage. Instead, the skinrelative to the right- and left-hand sides, respectively, of the carries all fuselage stresses. Since no bracing members arepilot seated in the cockpit.

present, the skin must be strong enough to keep the fuselage rigid. Thus, the biggest challenge in monocoque1.1.5 Stabilizers. Stabilizers (or tail surfaces) are design is maintaining enough strength while keeping theairfoils whose primary purpose is to increase aircraft stabil-weight within allowable limits. The advantage of a mono-ity. They are mounted at the rear end of the fuselage and coque design is that it is relatively easy to manufacture.consist of the fin or fins and the horizontal stabilizer.

Despite this advantage, the weight penalty makes it imprac-tical and inefficient to use monocoque construction except1.1.6 Control Surfaces. Control surfaces are movable in relatively small areas of the fuselage that carry onlysurfaces used to control aircraft in flight. They consist of limited loads. To overcome the strength-to-weight problemailerons, elevators, and rudders. Auxiliary surfaces such as of monocoque design, a modification calledtabs, flaps, slats, and spoilers are also considered control semimonocoque design was developed.surfaces.

1-1

T O

1-1A -1

N A

V A

IR

01-1A

-1

F igure 1-1.

P rinciple Structural U nits

1-2

Figure 1-2. Semimonocoque Fuselage Design

1.2.2.1.2 Semimonocoque Design. Semimonocoque commonly known by the trade name Alclad. The pure design may use any combination of longerons, stringers, aluminum cladding on both sides serves as a protective bulkheads, and frames to reinforce the skin and maintain coating to the base metal. Extrusions are generally of 2024;

the cross-sectional shape of the fuselage. The skin, which is however, 2014 is being used for extrusions with web fastened to all of these members, helps resist shear load thickness greater than 1/8 inch. In addition to aluminum, and, together with the longitudinal members, the tension stainless steel, titanium, and various composite materials and bending loads. Longerons resist the majority of fuse- are also used in fuselage structure.

lage bending loads. Stringers help resist fuselage bending

1.3 ENGINE MOUNTS.and stabilize the skin in compression. Bulkheads are used where concentrated loads are introduced into the fuselage,

1.3.1 General. Engine mounts are designed to meet thesuch as those at wing, landing gear, and tail surface attach points. Frames are used primarily to maintain the shape of specific conditions of a particular installation, such as the fuselage and improve the stability of the stringers in location on aircraft, method of attachment, and size and compression. type of the engine they were intended to support. Although they may vary widely in their appearance, the basic features

1.2.2.2 Fuselage construction. Today’s modern military of engine mount construction and structural intent are aircraft are constructed from various materials. The most similar. Engine mounts are usually constructed as a single common material being used for fuselage construction is unit that may be detached quickly and easily from the aluminum alloy. Common fuselage materials, such as 7075 supporting structure. In many cases, they are removed from and 2024 aluminum, are about three times lighter than the aircraft and replaced with the engine and its accessories steel. Following heat treatment, these alloys are approxi- as a complete assembly or power unit.

mately equal in strength to mild steel. For some uses (e.g.,

1.3.2 Structure.surface covering), the alloy is made in sheets with a thin covering of pure aluminum on both sides. In this form, it is

1-3

1.3.2.1 Engine Mount Design. A primary consideration in cases, nacelles are designed to transmit engine loads to the the design of engine mounts and support fittings is to wing.

render the engine and its equipment accessible for mainte-

1.4.2 Structure. The structure and materials used innance and inspection. These mounts and support fittings are typically made of some type of corrosion-resistant steel nacelle construction are similar to those used for the with an ultimate strength of 180,000 to 200,000 psi. fuselage. The nacelle consists of skin, cowling, structural members, a firewall, and engine mounts. Skin and cowling

1.3.2.2 The exact location of the engine mounts and their cover the outside of the nacelle. Both are usually made of attachments are specific to the aircraft they have been sheet aluminum alloy, stainless steel, magnesium, or tita-designed for, but the conditions to which they are subjected nium. Regardless of the material used, the skin is usually are similar: attached to the framework by rivets. The structural mem-bers include lengthwise members, such as longerons and

• Engine mounts and support fittings operate in a high- stringers, and widthwise or vertical members, such as temperature environment. bulkheads, rings, and formers. The firewall, which sepa-

• Engine mounts and support fittings are susceptible to rates the engine compartment from the rest of the aircraft, fatigue failure caused by high-vibration inertial loads. is usually made of stainless steel sheet metal. In some

• Engine mounts and support fittings are also susceptible aircraft, the firewall is made of titanium.

to stress corrosion attack due to the harsh environment and the quality of the materials used. Therefore, the 1.5 WINGS.

material properties and surface finish of engine mounts and support fittings must be of the highest quality to 1.5.1 General. The wings of an aircraft are designed to help prevent stress corrosion failures. In addition, pro- provide lifting forces when moved rapidly through the air.

tective coatings are used to shield the engine mounts The particular design for any given aircraft depends on a from the environment. number of factors (e.g., size, weight, and mission of the aircraft; desired landing speed; and desired rate of climb).1.3.2.3 For corrosion removal limits and procedures, con- Some wings are designed to pivot or swing forward forsult the applicable -3 (structural repair instructions) or -23 low-speed maneuverability and swing rearward for high-(aircraft-specific corrosion prevention and control hand-speed capability. Frequently the larger compartments of thebook) TOs.

wings contain, or are themselves used as, fuel tanks (see Figure 1-3).1.3.2.4 Inspection intervals for mount fittings can be obtained from the applicable -6 TO, Aircraft Scheduled 1.5.2 Structure.

Inspection and Maintenance Requirements Manual.

1.5.2.1 Wing Design. Variations in design and construc-1.3.2.5 Engine mount installation and removal procedures tion depend upon the manufacturer and mission perform-can be found in the applicable -2 TO series manuals ance requirements. Wing structure is based on one of three(organizational maintenance instructions).

fundamental designs: monospar, multispar, or box beam.

Wing structures of most modern military aircraft are of1.3.2.6 For an illustrated parts breakdown of the engine cantilever design and constructed of metal or advancedmount and support structure, see the applicable -4 TO composite. With few exceptions, the skin is a part of theseries (illustrated parts breakdown).

basic load-bearing wing structure and carries part of the

1.3.2.7 In conjunction with flight load, improper torquing stresses.

of engine mount fasteners can cause fastener failure. This is

1.5.2.2 Wing Construction. Generally, wing structuresa safety-of-flight matter.

have two or more spars running the length of the wing and

1.3.2.8 Whenever damage or other discrepancies in the often through the fuselage. Ribs and bulkheads are placed engine mount structure exceed the tolerance limits of the chordwise, at frequent intervals between the spars, to weapon system-specific repair manuals, contact the weapon maintain spar spacing and wing contour. Sheet aluminum system engineering organization for repair instructions. or advanced composite skin covers the ribs and provides the airfoil surface. During flight, applied air loads are

1.4 NACELLES. imposed directly on the wing skin. These loads are trans-mitted from the skin to the ribs and from the ribs to the

1.4.1 General. The nacelles of most military aircraft are spars. The spars support all distributed loads as well as of similar shape and general design. On multi-engine concentrated weights from the fuselage and power plants.

aircraft, nacelles are streamlined enclosures designed to

1.5.2.3 Similar to fuselages, the metal generally used forhouse and protect the engines. On single-engine aircraft, wing structures is heat-treated aluminum alloy. The sparsthe nacelle becomes a streamlined extension of the fuse-and ribs are generally 2000 or 7000 series extrusions orlage. These structures vary principally with the size of the forgings. The smooth outer covering is usually Alcladaircraft and the size and number of engines. In certain

1-4 aluminum alloy and is attached with rivets or other fasten- 1.5.3.2 Walkways. Walkways are clearly marked on sur-ers. Improvements in the processing of fiber-reinforced and faces, such as the wing or horizontal stabilizer, where honeycomb composites have made it possible to combine a personnel are required to step or walk to perform repair and wide variety of materials for specific applications. These maintenance. The aircraft structure below walkways is improvements have greatly increased the use of advanced stiffened or reinforced to resist loads imposed by foot composites in wing structures. traffic. Areas intended as walkways are usually covered with a nonskid surface coating.

1.5.3 Inspection and Maintenance of the Wings, Fuselage, and Nacelles. 1.5.3.3 Impact damage. Impact damage to a metal wing skin is usually plainly evident and readily identified by the

1.5.3.1 Inspection Openings and Access Doors. The pri- presence of a dent, scratch, gouge, or puncture. An object mary purpose of inspection openings and access doors is to impacting an advanced composite skin often causes delami-provide accessibility to critical, high-stress, and corrosion- nation, disbonding, or other subsurface damage that is not prone areas that require frequent inspection or maintenance. visible on the surface. In either case, an impact that results These inspection openings and access doors can be found in the distortion or failure of the substructure may not be just about anywhere on an aircraft but are generally located apparent until some evidence develops on the surface (e.g., on the lower surface of the wings, fuselage, and nacelles. canted, buckled, or wrinkled skin, and loose rivets). When During inspection, evidence of corrosion may not appear external indications of internal damage are found, perform on the outside but may be present on the inside. This is a thorough investigation of the substructure in this vicinity most likely to occur in areas where moisture and salt spray and repair the damage immediately.

may accumulate. Drain holes are placed in these areas to prevent moisture accumulation and should be kept clean and free of debris at all times.

Figure 1-3. Aircraft Wing Design

1-5

1.5.3.4 Unusually violent maneuvers, extremely turbulent 1.7 CONTROL SURFACES.

air, or hard landings may cause cracks or buckled skin on the upper or lower surface of metal wing structures. While 1.7.1 General.

no individual part may actually rupture, many parts may be distorted or weakened. In the case of advanced composites, damage such as delamination, disbonding, broken fibers, WARNING and core crushing may result. Similar failures may also occur in fuselages.

Exercise care when repairing ailerons, rudders,

1.5.3.4.1 Small cracks may be caused by fatigue or over- and elevators to avoid disturbing static balance.

stressing. These small cracks are frequently found leading away from rivets. Flight control surfaces are hinged or movable airfoils designed to change or maintain the attitude of the aircraft

1.5.3.4.2 Aluminum alloy surfaces with chipped protec- during flight. They are usually divided into two major tive coatings, scratches, or worn spots that expose metal groups: primary and secondary control surfaces.

surfaces should be recoated at once, or corrosion may rapidly develop. The same guidance applies to Alclad 1.7.1.1 The primary or main group of flight control sur-surfaces. Scratches that penetrate the pure aluminum sur- faces consist of ailerons, elevons, elevators, and rudders by face layer will permit corrosion to take place in the alloy which the aircraft is moved about its various axes.

beneath. For more information about acceptable recoating

1.7.1.2 Secondary or auxiliary groups include trailingpractices, refer to TO 1-1-691.

edge flaps, leading edge flaps, speed brakes, spoilers, and

1.6 STABILIZERS. leading edge slats. These devices are used to reduce the force required to operate main control surfaces or to trim

1.6.1 General. Stabilizers (or tail surfaces) of conven- and balance the aircraft in flight.

tional aircraft consist of vertical and horizontal airfoils

1.7.1.3 Wing flaps are generally used to increase lift atlocated at the rear portion of the fuselage. These airfoils are slow speeds. The use of flaps reduces the length of thegenerally referred to as the tail section or empennage. They takeoff run and the landing speed of fast aircraft. Flapsconsist of the horizontal stabilizer or stabilator, elevators, facilitate landing in small or obstructed areas by permittingvertical fins, and rudders (see Figure 1-4 and Figure 1-5).

the gliding angle to be increased without increasing landing

1.6.2 Structure. speed. Speed brakes, slats, and spoilers are used to change the speed of the aircraft in flight.

1.6.2.1 Construction features of tail surfaces are in many

1.7.1.4 Rudders and elevators are members of the empen-ways identical to those of wings. Tail surfaces are usually nage, and ailerons are hinged sections of the main wings.made of metal or advanced composite. The tail surface has The rudder or rudders control the aircraft directionallya cantilever design, with the skin attached to a spar or spars about its vertical axis. The elevators control the aircraftand ribs.

longitudinally about its lateral axis. The ailerons control the

1.6.2.2 The fin maintains directional stability of the air- aircraft laterally about its longitudinal axis. To reduce the craft in flight (i.e., about its turning or vertical axis). The effort required by the pilot to operate the controls, these fin also serves as the base or anchor point to which the primary control surfaces may be aerodynamically balanced.

rudder is attached.