Attachment_3_AC_43.13-1B_-_Acceptable_Methods_Techniques _and_Practices_-_Aircraft_Inspection_and_Repai.pdf

ADVISORY

CIRCULAR

AC 43.13-1B

ACCEPTABLE METHODS,

TECHNIQUES, AND

PRACTICES AIRCRAFT

INSPECTION AND REPAIR

September 8, 1998

DEPARTMENT OF TRANSPORTATION

FEDERAL AVIATION ADMINISTRATION

Flight Standard Service

Regulatory Support Division

For sale by the Superintendent of Documents; U.S. Government Printing Office; Washington, DC 20402

Advisory

Circular

TITLE 14 OF THE CODE OF FEDERAL REGULATIONS (14 CFR) GUIDANCE MATERIAL

9/8/98 AC 43.13-1B

Contents Paragraph Page

Subject: ACCEPTABLE METHODS, Date: 9/8/98 AC No: 43.13-1B TECHNIQUES, AND PRACTICESAIRCRAFT Initiated by: AFS-610 Change:

INSPECTION AND REPAIR

1. PURPOSE. This advisory circular (AC) contains methods, techniques, and practices acceptable to the Administrator for the inspection and repair of nonpressurized areas of civil aircraft, only when there are no manufacturer repair or maintenance instructions. This data generally pertains to minor repairs. The repairs identified in this AC may also be used as a basis for FAA approval for major repairs. The repair data may also be used as approved data, and the AC chapter, page, and paragraph listed in block 8 of FAA form 337 when:

a. the user has determined that it is appropriate to the product being repaired;

b. it is directly applicable to the repair being made; and

c. it is not contrary to manufacturer’s data.

2. CANCELLATION. The AC 43.13-1A dated 1988 is canceled.

3. REFERENCE: Title 14 of the Code of Federal Regulations part 43, section 43.13(a) states that each person performing maintenance, alteration, or preventive maintenance on an aircraft, engine, propeller, or appliance shall use the methods, techniques, and practices prescribed in the current manufacturer’s maintenance manual or Instructions for Continued Airworthiness prepared by its manufacturer, or other methods, techniques, or practices acceptable to the Administrator, except as noted in section 43.16. FAA inspectors are prepared to answer questions that may arise in this regard. Persons engaged in the inspection and repair of civil aircraft should be familiar with 14 CFR part 43, Maintenance, Preventive Maintenance, Rebuilding, and Alteration, and part 65, Subparts A, D, and E of Certification:

Airmen Other Than Flight Crewmembers, and the applicable airworthiness requirements under which the aircraft was type certificated.

4. ACKNOWLEDGMENTS. The FAA would like to thank the following persons and organization for their assistance in producing AC 43.13-1B: Richard Finch, Richard Fischer, Michael Grimes, Ray Stits, William A.

Watkins, and the SAE, Aerospace Electronics and Electrical Systems Division. Acknowledgment is also extended to all in the aviation community who commented on the document.

5. COMMENTS INVITED. Comments regarding this AC should be directed to DOT/FAA;

ATTN: Airworthiness Programs Branch, AFS-610; PO Box 25082; Oklahoma City, OK 73125

Acting Deputy Director, Flight Standards Service

Paragraph Page

CHAPTER 1. WOOD STRUCTURE

SECTION 1. MATERIALS AND PRACTICES

1-1.......................................................................................................................... GENERAL 1 1-2. ........................................................................................................................................ WOODS 1

FIGURE 1-1.RELATIVE SHRINKAGE OF WOOD MEMBER DUE TO DRYING 1

TABLE 1-1. ...... SELECTION AND PROPERTIES OF AIRCRAFT WOOD 1

FIGURE 1-2. .................................................TAPERING OF FACEPLATE 1 1-3........................................................................................MODIFIED WOOD PRODUCTS 1 1-4.......................................................................................................................ADHESIVES 1 1-5............................................................................................... BONDING PRECAUTIONS 1 1-6............................................... PREPARATION OF WOOD SURFACES FOR BONDING 1 1-7..............................................................................................APPLYING THE ADHESIVE 1 1-8........................................................................................ASSEMBLY TIME IN BONDING 1 1-9.............................................................................................. BONDING TEMPERATURE 1 1-10..................................................................................................CLAMPING PRESSURE 1 1-11............................................................................METHOD OF APPLYING PRESSURE 1

1-12.1-17. [RESERVED.] ..............................................................................................................................1-8

SECTION 2. HEALTH AND SAFETY

1-18........................................................................................................................ GENERAL 1 1-19........................... SANDING IN AREAS OF EXISTING BOND JOINTS AND FINISHES 1 1-20.................................................................HANDLING OF ADHESIVES AND FINISHES 1

1-21.1-26. [RESERVED.] ..............................................................................................................................1-9

SECTION 3. INSPECTION

1-27........................................................................................................................ GENERAL 1 1-28............................................................... TYPES OF DETERIORATION AND DAMAGE 1 1-29................................................................................................ INSPECTION METHODS 1

FIGURE 1-3. ........ LIKELY AREAS TO INCUR STRUCTURAL DAMAGE 1

1-30.1-35. [RESERVED.] ............................................................................................................................1-14

SECTION 4. REPAIRS

1-36........................................................................................................................ GENERAL 1 1-37.....................................REPLACEMENT OF DRAIN HOLES AND SKIN STIFFENERS 1

1-38.........................................................CONTROL SURFACE FLUTTER PRECAUTIONS 1 1-39............................................................................................................... SCARF JOINTS 1

FIGURE 1-4.CONSIDERATION OF GRAIN DIRECTION WHEN MAKING SCARF

JOINTS 1-15

1-40..................................................................................................... SPLICING OF SPARS 1

FIGURE 1-5.METHOD OF SPLICING SOLID OR LAMINATED RECTANGULAR

SPARS 1-17

FIGURE 1-6. .......................... METHOD OF SPLICING SOLID “I” SPARS 1

FIGURE 1-7. .........................................REPAIRS TO BUILT-UP “I” SPAR 1

FIGURE 1-8.METHOD OF SPLICING BOX SPAR FLANGES (PLATE METHOD) 1

1-41................................................................................................... SPAR REPLACEMENT 1 1-42................................................................................... SPLICING OF BOX SPAR WEBS 1

FIGURE 1-9. .........................METHOD OF SPLICING BOX SPAR WEBS 1

1-43.........................REPLACING SOLID-TYPE SPARS WITH LAMINATED-TYPE SPARS 1

1-44..............................................SPAR LONGITUDINAL CRACKS AND LOCAL DAMAGE

......................................................................................................................................... 1-16

FIGURE 1-10..METHOD OF REINFORCING A LONGITUDINAL CRACK

AND/OR LOCAL DAMAGE IN A SOLID SPAR. ............................................................. 1-22

1-45.................................................................................... ELONGATED HOLES IN SPARS

......................................................................................................................................... 1-18

1-46...................................................................................................................RIB REPAIRS

......................................................................................................................................... 1-18

FIGURE 1-11..................................................... REPAIR OF WOOD RIBS

1-23

FIGURE 1-12.................TYPICAL WING COMPRESSION RIB REPAIRS

1-24

1-47............................................................................................... PLYWOOD SKIN REPAIR

......................................................................................................................................... 1-20

1-48......................................... DETERMINATION OF SINGLE OR DOUBLE CURVATURE

......................................................................................................................................... 1-20

1-49.................................................REPAIRS TO SINGLE CURVATURE PLYWOOD SKIN

......................................................................................................................................... 1-20

TABLE 1-2.MINIMUM RECOMMENDED BEND RADII FOR AIRCRAFT

PLYWOOD 1-25

1-50............................................... REPAIRS TO DOUBLE CURVATURE PLYWOOD SKIN

......................................................................................................................................... 1-22

1-51......................................................................................................TYPES OF PATCHES

......................................................................................................................................... 1-25

FIGURE 1-13.................................................................SPLAYED PATCH

1-27

FIGURE 1-14........................................................... SURFACE PATCHES

FIGURE 1-15............SCARF PATCHES (BACK OF SKIN ACCESSIBLE)

FIGURE 1-16... SCARF PATCHES (BACK OF SKIN NOT ACCESSIBLE)

FIGURE 1-17........................................ OVAL PLUG PATCH ASSEMBLY

FIGURE 1-18.....................................ROUND PLUG PATCH ASSEMBLY

1-28

1-29

1-30

1-32

1-33

1-52............................................................................................................... FABRIC PATCH

......................................................................................................................................... 1-31

1-53.1-63. [RESERVED.] ........................................................................................................................... 1-33

SECTION 5. FINISHING WOOD STRUCTURES

1-64........................................................................................................................ GENERAL

......................................................................................................................................... 1-35

1-65................................................................................................ ACCEPTABLE FINISHES

......................................................................................................................................... 1-35

1-66................................................................................................................PRECAUTIONS

......................................................................................................................................... 1-35

1-67.......................................................................... FINISHING OF INTERIOR SURFACES

......................................................................................................................................... 1-36

1-68.........................................................................FINISHING OF EXTERIOR SURFACES

......................................................................................................................................... 1-36

1-69....................................................................... FINISHING OF END GRAIN SURFACES

......................................................................................................................................... 1-36

Page vi

1-70..............................................................................FINISHING WITH FABRIC OR TAPE

......................................................................................................................................... 1-37

1-71............................................................................................ SEALING OF BOLT HOLES

......................................................................................................................................... 1-37

1-72.1-79. [RESERVED.] ........................................................................................................................... 1-37

CHAPTER 2. FABRIC COVERING

SECTION 1. PRACTICES AND PRECAUTIONS

2-1.......................................................................................................................... GENERAL

........................................................................................................................................... 2-1

2-2.............................................................................................................PROBLEM AREAS

........................................................................................................................................... 2-1

2-3..................................................................................... AIRCRAFT FABRIC-SYNTHETIC

........................................................................................................................................... 2-1

2-4......................................................................................... AIRCRAFT FABRIC-NATURAL

........................................................................................................................................... 2-2

TABLE 2-1. ................................................ COTTON AND LINEN FABRICS

2-3 2-5................................................................................................ RECOVERING AIRCRAFT ........................................................................................................................................... 2-2

TABLE 2-2. ........................ COTTON AND LINEN, TAPES AND THREADS

2-4

2-6...............................................PREPARATION OF THE STRUCTURE FOR COVERING

........................................................................................................................................... 2-2

2-7.................................................................................................................FABRIC SEAMS

........................................................................................................................................... 2-5

FIGURE 2-1. ........................................................................FABRIC SEAMS 2-7

FIGURE 2-2. ...................... TYPICAL METHODS OF ATTACHING FABRIC

2-8 2-8..................................................................................................... COVERING METHODS

........................................................................................................................................... 2-9

Page vii

Contents (continued)

2-9........................................................................................................REINFORCING TAPE

......................................................................................................................................... 2-10

FIGURE 2-3............................................ EXPLODED SIDE VIEW OF RIB

2-10

2-10............................................................................................................................ LACING

......................................................................................................................................... 2-11

FIGURE 2-4.STANDARD EXTERNAL MODIFIED SEINE KNOT USED FOR

SINGLE AND DOUBLE RIB LACING ............................................................................. 2-11

FIGURE 2-5.................................. STARTING STITCH FOR RIB LACING

2-12

FIGURE 2-6.....................................STANDARD SINGLE-LOOP LACING

2-13

FIGURE 2-7............... STANDARD KNOT FOR DOUBLE-LOOP LACING

2-14

FIGURE 2-8............. STANDARD DOUBLE-LOOP LACING (OPTIONAL)

2-15

FIGURE 2-9A.ALTERNATE SEQUENCE TO TIE A MODIFIED SEINE KNOT

FOR RIB LACING............................................................................................................ 2-16

FIGURE 2-9B.ALTERNATE SEQUENCE TO TIE A MODIFIED SEINE KNOT

FOR RIB LACING............................................................................................................ 2-17

FIGURE 2-9C.ALTERNATE SEQUENCE TO TIE A MODIFIED SEINE KNOT

FOR RIB LACING............................................................................................................ 2-18

FIGURE 2-10.......................................................................SPLICE KNOT

2-19

FIGURE 2-11.BLINDSTITCH LACING - SQUARE KNOT SECURED WITH HALF

HITCHES 2-20

2-11........................................................................................................... STITCH SPACING

......................................................................................................................................... 2-19

FIGURE 2-12...................................... FABRIC ATTACHMENT SPACING

2-21

2-12....................................................................................................................FASTENERS

......................................................................................................................................... 2-21

2-13.............................................................................................................FINISHING TAPE

......................................................................................................................................... 2-22

2-14............................................................INSPECTION RINGS AND DRAIN GROMMETS

......................................................................................................................................... 2-22

2-15.2-19. [RESERVED.] ........................................................................................................................... 2-23

SECTION 2. APPLICATION OF DOPE

2-20........................................................................................................................ GENERAL

......................................................................................................................................... 2-25

TABLE 2-3. ...........................................SAFETY TIPS FOR DOPE/PAINT

2-26

TABLE 2-4. ..................................................................TIPS FOR DOPING

2-26

2-21......................................... DOPE APPLICATION PROCEDURE (NATURAL FABRICS)

......................................................................................................................................... 2-26

2-22........................................................................................COVERING OVER PLYWOOD

......................................................................................................................................... 2-28

2-23.............................................................................. COATING APPLICATION DEFECTS

......................................................................................................................................... 2-29

2-24.2-29. [RESERVED.] ........................................................................................................................... 2-31

SECTION 3. INSPECTION AND TESTING

Page viii

Paragraph Page

2-30........................................................................................................................ GENERAL

......................................................................................................................................... 2-33

2-31...............................................................................................FABRIC IDENTIFICATION

......................................................................................................................................... 2-34

2-32........................................................................................... COATING IDENTIFICATION

......................................................................................................................................... 2-34

2-33..........................................................STRENGTH CRITERIA FOR AIRCRAFT FABRIC

......................................................................................................................................... 2-35

2-34............................................................................................................FABRIC TESTING

......................................................................................................................................... 2-35

2-35................................................................................... REJUVENATION OF DOPE FILM

......................................................................................................................................... 2-36

2-36.2-41. [RESERVED.] ........................................................................................................................... 2-36

SECTION 4. REPAIRS TO FABRIC COVERING

2-42........................................................................................................................ GENERAL

......................................................................................................................................... 2-37

2-43............................................................ REPAIR OF TEARS AND ACCESS OPENINGS

......................................................................................................................................... 2-37

FIGURE 2-13........................................... REPAIR OF TEARS IN FABRIC

2-38 2-44...................................................................................................SEWN-PATCH REPAIR ......................................................................................................................................... 2-38 FIGURE 2-14........................................................ HAND-STITCH DETAIL

2-39 2-45.......................................................................................... DOPED-ON PATCH REPAIR ......................................................................................................................................... 2-39

2-46.2-51. [RESERVED.] ........................................................................................................................... 2-40

Page ix

9/8/98 AC 43.13-1B

Paragraph Page

Chapter 3. Fiberglass And Plastics

SECTION 1. REPAIR OF LIGHT LOAD LAMINATE STRUCTURES

3-1.......................................................................................................................... GENERAL

........................................................................................................................................... 3-1

3-2.................................................................................FIBERGLASS LAMINATE REPAIRS

........................................................................................................................................... 3-1

FIGURE 3-1...............................TYPICAL LAMINATE (FACING) REPAIR

3-2

FIGURE 3-2................................ TYPICAL CORE AND FACING REPAIR

3-2

FIGURE 3-3......................................TYPICAL STEPPED JOINT REPAIR

3-3 3-3.......................................................................................................... REPAIRING HOLES

........................................................................................................................................... 3-3

FIGURE 3-4.......................PREPARING THE FIBERGLASS SANDWICH

3-3

FIGURE 3-5.SCARFED REPAIR TO A NONSTRUCTURAL LAMINATED

FIBERGLASS COMPONENT ........................................................................................... 3-4

FIGURE 3-6.BALANCED LAYUP SAME AS ORIGINAL NUMBER OF PLIES,

PLUS ONE EXTRA PLY.................................................................................................... 3-4

FIGURE 3-7.......................................... TYPICAL SCARF JOINT REPAIR

3-5

FIGURE 3-8.CAREFULLY CUT THROUGH EACH LAYER OF FIBERGLASS

CLOTH AND

...............................................REMOVE IT FROM THE DAMAGED AREA

3-5 3-4................................................................ SAMPLE BAGGING AND CURING PROCESS

........................................................................................................................................... 3-5

FIGURE 3-9.................... SAMPLE BAGGING LAYUP CROSS SECTION

3-6

3-5.3-9. [RESERVED.] ................................................................................................................................. 3-8

SECTION 2. METALLIC SANDWICH SECONDARY STRUCTURE REPAIRS

3-10.............................REPAIRS TO METALLIC SANDWICH SECONDARY STRUCTURE

........................................................................................................................................... 3-9

FIGURE 3-10.....................TYPICAL TYPES OF CORE REPLACEMENT

3-10

FIGURE 3-11............. TYPICAL UNDERCUT CORE MATERIAL CAVITY

3-10

FIGURE 3-12.CROSS SECTION OF BONDED AND BOLTED OVERLAP

REPAIRS 3-11

FIGURE 3-13.........................................HONEYCOMB CORE REMOVAL

3-11

FIGURE 3-14..... REMOVING HONEYCOMB CORE FROM A TAPERED

CONTROL SURFACE..................................................................................................... 3-11

FIGURE 3-15..........................REMOVAL OF CORE WITH CORE KNIFE

3-11 FIGURE 3-16................................................DETAILS OF CORE REPAIR 3-12 3-11....................................................................................................................... FINISHING

......................................................................................................................................... 3-12

3-12.3-17. [RESERVED.] ........................................................................................................................... 3-13

SECTION 3. TRANSPARENT PLASTICS

Page x

Paragraph Page

3-18........................................................................................................................ GENERAL

......................................................................................................................................... 3-15

3-19............................................................................................STORAGE AND HANDLING

......................................................................................................................................... 3-15

3-20............................................................ FORMING PROCEDURES AND TECHNIQUES

......................................................................................................................................... 3-15

3-21.........................................................................................................................HEATING.

......................................................................................................................................... 3-16

FIGURE 3-17....................................... HANGING OF ACRYLIC SHEETS

3-16

3-22.............................................................................................................................FORMS

......................................................................................................................................... 3-16

3-23..................................................................................................... FORMING METHODS

......................................................................................................................................... 3-17

TABLE 3-1.TYPICAL TEMPERATURES FOR FORMING ACRYLIC SHEETS

3-17

FIGURE 3-18.DRILL HAVING AN INCLUDED ANGLE OF APPROXIMATELY

150°, ...................................................... USED TO DRILL ACRYLIC PLASTICS 3-18

FIGURE 3-19..........UNIBIT DRILL FOR DRILLING ACRYLIC PLASTICS

3-18

FIGURE 3-20.............. APPLYING PRESSURE TO ACRYLIC PLASTICS

3-19

Page xi

Paragraph Page

3-24....................................................................................................REPAIR OF PLASTICS

......................................................................................................................................... 3-19 FIGURE 3-21...................................................STOP-DRILLING CRACKS 3-20 FIGURE 3-22........................................................... SURFACE PATCHES 3-20 FIGURE 3-23......................................................... PLUG PATCH REPAIR 3-21 3-25..............................................CLEANING AND POLISHING TRANSPARENT PLASTIC

......................................................................................................................................... 3-21

3-26............................................................................................... REPLACEMENT PANELS

......................................................................................................................................... 3-21

3-27..................................................................................... INSTALLATION PROCEDURES

......................................................................................................................................... 3-22

3-28.3-39. [RESERVED.] ........................................................................................................................... 3-22

SECTION 4. WINDSHIELDS, ENCLOSURES, AND WINDOWS

3-40........................................................................................................................ GENERAL

......................................................................................................................................... 3-23

FIGURE 3-24.TEMPORARY REPAIRS TO CRACKED WINDSHIELDS OR

WINDOWS 3-24

3-41..................................................................................................................PROTECTION ......................................................................................................................................... 3-24 3-42........................................................................................ WINDSHIELD INSTALLATION ......................................................................................................................................... 3-24

3-43.3-47. [RESERVED.] ........................................................................................................................... 3-25

Chapter 4. Metal Structure, Welding, And Brazing

SECTION 1. IDENTIFICATION OF METALS

4-1.......................................................................................................................... GENERAL ........................................................................................................................................... 4-1

TABLE 4-1. ................................. FERROUS (IRON) ALLOY MATERIALS

4-1 4-2............................................................................... IDENTIFICATION OF STEEL STOCK ........................................................................................................................................... 4-1

TABLE 4-2. ......... NUMERICAL SYSTEM FOR STEEL IDENTIFICATION

4-2

TABLE 4-3.EXAMPLES OF STAINLESS AND HEAT-RESISTANT STEELS

NOMINAL COMPOSITION (PERCENT)........................................................................... 4-2

4-3...................................................................INTERCHANGEABILITY OF STEEL TUBING

........................................................................................................................................... 4-2

4-4.................................................................................... IDENTIFICATION OF ALUMINUM

........................................................................................................................................... 4-2

TABLE 4-4.BASIC TEMPER DESIGNATIONS AND SUBDIVISIONS FROM

ALUMINUM ALLOYS ........................................................................................................ 4-3

4-5.4-15. [RESERVED.] ............................................................................................................................... 4-3

SECTION 2. TESTING OF METALS

4-16.....................................................................................................HARDNESS TESTING

........................................................................................................................................... 4-5

4-17......................................................................................ROCKWELL HARDNESS TEST

........................................................................................................................................... 4-5

4-18........................................................................................... BRINELL HARDNESS TEST

........................................................................................................................................... 4-5

Page xii

Paragraph Page

4-19.......................................................................................... VICKERS HARDNESS TEST

........................................................................................................................................... 4-6

4-20.........................................................................................MICROHARDNESS TESTING

........................................................................................................................................... 4-6

4-21................................................................................................................... INDENTIONS

........................................................................................................................................... 4-7

FIGURE 4-1.COMPARISON OF INDENTATION MADE BY KNOOP AND

VICKERS INDENTERS

..................... IN THE SAME WORK METAL AND AT THE SAME LOADS

4-7 4-22......................................................................................................MAGNETIC TESTING

........................................................................................................................................... 4-8

4-23......................................................................................................ALUMINUM TESTING

........................................................................................................................................... 4-8

TABLE 4-5.HARDNESS VALUES FOR ALUMINUM ALLOYS. (REFERENCE

MIL-H-6088G.) 4-8

4-24.4-35. [RESERVED.] ............................................................................................................................. 4-8

Page xiii

SECTION 3. PRECAUTIONARY MEASURES

4-36.................................................................FLUTTER AND VIBRATION PRECAUTIONS

........................................................................................................................................... 4-9

4-37....................................................................................LOAD FACTORS FOR REPAIRS

......................................................................................................................................... 4-10

4-38................................................... TRANSFER OF STRESSES WITHIN A STRUCTURE

......................................................................................................................................... 4-10

4-39.4-49. [RESERVED.] ........................................................................................................................... 4-10

SECTION 4. METAL REPAIR PROCEDURES

4-50........................................................................................................................ GENERAL

......................................................................................................................................... 4-11

4-51................................... RIVETED (OR BOLTED) STEEL TRUSS-TYPE STRUCTURES

......................................................................................................................................... 4-11

4-52................................................................................ALUMINUM ALLOY STRUCTURES

......................................................................................................................................... 4-11

4-53.........................................SELECTION OF ALUMINUM FOR REPLACEMENT PARTS

......................................................................................................................................... 4-12

4-54.....................................................HEAT TREATMENT OF ALUMINUM ALLOY PARTS

......................................................................................................................................... 4-12

4-55............................................................................................................ BENDING METAL

......................................................................................................................................... 4-13

TABLE 4-6.RECOMMENDED RADII FOR 90-DEGREE BENDS IN ALUMINUM

ALLOYS 4-14

4-56.........................................................................................................................SETBACK ......................................................................................................................................... 4-13

FIGURE 4-2................................... SETBACK FOR A 90-DEGREE BEND

4-13

TABLE 4-7.K-CHART FOR DETERMINING SETBACK FOR BENDS OTHER

THAN 90 DEGREES ....................................................................................................... 4-15

FIGURE 4-3.METHODS OF DETERMINING SETBACKS FOR BENDS OTHER

THAN 90 DEGREES ....................................................................................................... 4-16 4-57.........................................................................................................................RIVETING ......................................................................................................................................... 4-14

FIGURE 4-4.RIVET IDENTIFICATION AND PART NUMBER BREAKDOWN

4-16

TABLE 4-8. ...................................... AIRCRAFT RIVET IDENTIFICATION

4-17

FIGURE 4-5.RIVET HOLE SPACING AND EDGE DISTANCE FOR SINGLE-LAP

SHEET SPLICES ............................................................................................................ 4-20

FIGURE 4-6......... RIVETING PRACTICE AND RIVET IMPERFECTIONS

4-21

FIGURE 4-7........SELF PLUGGING FRICTION-LOCK CHERRY RIVETS

4-22

FIGURE 4-8.MECHANICAL-LOCK (BULBED CHERRY) CHERRY RIVET

4-23

FIGURE 4-9.............................................................CHERRY MAX RIVET

4-24

FIGURE 4-10.............................................................OLYMIC-LOK RIVET

4-25

FIGURE 4-11.........................................................................HUCK RIVET

4-26

Page xiv

9/8/98 AC 43.13-1B

Paragraph Page

4-58.................REPAIR METHODS AND PRECAUTIONS FOR ALUMINUM STRUCTURE

......................................................................................................................................... 4-25

FIGURE 4-12.TYPICAL REPAIR METHOD FOR TUBULAR MEMBERS OF

ALUMINUM ALLOY......................................................................................................... 4-28

FIGURE 4-13.TYPICAL REPAIR FOR BUCKLED OR CRACKED METAL WING

RIB CAPSTRIPS 4-29

FIGURE 4-14.TYPICAL METAL RIB REPAIRS (USUALLY FOUND ON SMALL

AND MEDIUM-SIZE AIRCRAFT).................................................................................... 4-30

FIGURE 4-15......................... TYPICAL REPAIRS OF TRAILING EDGES

4-31

FIGURE 4-16.TYPICAL REPAIRS OF STRESSED SHEET METAL

COVERINGS 4-32

FIGURE 4-17................... TYPICAL STRINGER AND FLANGE SPLICES

4-33

FIGURE 4-18.EXAMPLE OF STRINGER SPLICE (MATERIAL-2017 ALLOY)

4-34

FIGURE 4-19........ APPLICATION OF TYPICAL FLANGE SPLICES AND

REINFORCEMENT ......................................................................................................... 4-35

TABLE 4-9.NUMBER OF RIVETS REQUIRED FOR SPLICES (SINGLE-LAP

JOINT)

IN BARE 2014-T6, 2024-T3, 2024-T3, AND 7075-T6 SHEET, CLAD 2014-T6,

2024-T3, 2024-T36, AND 7075-T6 SHEET, 2024-T4, AND 7075-T6 PLATE,

............. BAR, ROD, TUBE, AND EXTRUSIONS, 2014-T6 EXTRUSIONS

4-37

TABLE 4-10.NUMBER OF RIVETS REQUIRED FOR SPLICES (SINGLE-LAP

JOINT)

. IN 2017, 1017 ALCLAD, 2024-T3 ALCLAD SHEET, PLATE, BAR, ROD,

.........................................................................TUBE, AND EXTRUSIONS 4-38

TABLE 4-11.NUMBER OF RIVETS REQUIRED FOR SPLICES (SINGLE-LAP

JOINT)

....................................................... IN 5032 (ALL HARDNESSES) SHEET 4-39

Page xv

4-59................................................................................REPAIRING CRACKED MEMBERS ......................................................................................................................................... 4-40

FIGURE 4-20.EXAMPLE OF INTERMEDIATE FRAME STRINGER SPLICE

(MATERIAL 2017-T3 AL ALLOY).................................................................................... 4-41

FIGURE 4-21.TYPICAL METHODS OF REPAIRING CRACKED LEADING AND

TRAILING EDGES

AND RIB INTERSECTIONS................................................................ 4-42

FIGURE 4-22.TYPICAL METHODS OF REPLACING CRACKED MEMBER AT

FITTINGS 4-43

FIGURE 4-23.TYPICAL METHODS OF REPAIRING CRACKED FRAME AND

STIFFENER COMBINATION .......................................................................................... 4-44

FIGURE 4-24.TYPICAL REPAIRS TO RUDDER AND TO FUSELAGE AT TAIL

POST 4-45

4-60................................................................................STEEL AND ALUMINUM FITTINGS ......................................................................................................................................... 4-40

FIGURE 4-25.TYPICAL METHODS OF REPAIRING ELONGATED OR WORN

BOLT HOLES 4-46

4-61....................................................................................................................... CASTINGS ......................................................................................................................................... 4-40 4-62.................................................. SELECTIVE PLATING IN AIRCRAFT MAINTENANCE ......................................................................................................................................... 4-40

4-63.4-73. [RESERVED.] ........................................................................................................................... 4-51

SECTION 5. WELDING AND BRAZING

4-74........................................................................................................................ GENERAL

......................................................................................................................................... 4-53

TABLE 4-12.CURRENT AND POLARITY SELECTION FOR INERT GAS

WELDING 4-54

FIGURE 4-26.COMMON DEFECTS TO AVOID WHEN FITTING AND WELDING

AIRCRAFT CERTIFICATION CLUSTER........................................................................ 4-55

TABLE 4-13. .................................................................TORCH TIP SIZES

4-55

FIGURE 4-27................. BUTT-WELDING STRENGTH CALCULATIONS

4-56

4-75......................................................................................................TYPES OF WELDING

......................................................................................................................................... 4-56

FIGURE 4-28.BASIC GAS-WELDING FLAMES: EACH HAS DISTINCTIVE

SHAPE, COLOR AND SOUND.

................................................... NEUTRAL FLAME IS THE MOST USED 4-57

FIGURE 4-29.SET TIG WELDER TO DC CURRENT, STRAIGHT POLARITY

FOR WELDING MILD STEEL,

..........................................................STAINLESS STEEL AND TITANIUM 4-57

FIGURE 4-30.SET TIG TO AC CURRENT FOR WELDING ALUMINUM AND

MAGNESIUM 4-58

4-76............................................................................. ELECTRIC-RESISTANCE WELDING

......................................................................................................................................... 4-58

FIGURE 4-31.IN SPOT WELDING, HEAT IS PRODUCED BY ELECTRICAL

RESISTANCE BETWEEN

COPPER ELECTRODES. PRESSURE IS SIMULTANEOUSLY APPLIED TO

ELECTRODE TIPS

TO FORCE METAL TOGETHER TO COMPLETE FUSING PROCESS. SPOT

WELD-NUGGET SIZE

Page xvi

Paragraph Page

....................................................... IS DIRECTLY RELATED TO TIP SIZE 4-58 4-77..........................................................................................................................BRAZING ......................................................................................................................................... 4-58

TABLE 4-14.CALCULATED ALLOWABLE STRENGTH OF BASE METAL

4-59 FIGURE 4-32...................................................SILVER BRAZING JOINTS 4-60

FIGURE 4-33............................................ ELECTRIC SOLDERING IRON

4-61 4-78..................................................................... AIRCRAFT PARTS NOT TO BE WELDED ......................................................................................................................................... 4-61 4-79.......................................................................................... WELDING ROD SELECTION ......................................................................................................................................... 4-62

TABLE 4-15. ...CHART SHOWING WELDING FILLER ROD SELECTION

4-62 4-80.................................................................................REPAIR OF TUBULAR MEMBERS ......................................................................................................................................... 4-62

FIGURE 4-34.FINGER PATCH REPAIRS FOR MEMBERS DENTED AT A

CLUSTER 4-63

4-81.......................................................................................REPAIR BY WELDED SLEEVE ......................................................................................................................................... 4-64

FIGURE 4-35.MEMBERS DENTED IN A BAY (REPAIRS BY WELDED SLEEVE)

4-65 4-82........................................................................................REPAIR BY BOLTED SLEEVE ......................................................................................................................................... 4-64 4-83.............................................................................................. WELDED-PATCH REPAIR ......................................................................................................................................... 4-64 FIGURE 4-36. ................................................. WELDED PATCH REPAIR 4-66 4-84........................................................SPLICING TUBING BY INNER-SLEEVE METHOD ......................................................................................................................................... 4-64

FIGURE 4-37............................SPLICING BY INNER-SLEEVE METHOD

4-67 4-85...................................................... SPLICING TUBING BY OUTER-SLEEVE METHOD ......................................................................................................................................... 4-66

FIGURE 4-38.SPLICING BY OUTER-SLEEVE METHOD (REPLACEMENT BY

WELDED OUTSIDE SLEEVE)........................................................................................ 4-68

FIGURE 4-39.TUBE REPLACEMENT AT A STATION BY WELDED OUTER

SLEEVES 4-69

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4-86............................... SPLICING USING LARGER DIAMETER REPLACEMENT TUBES

......................................................................................................................................... 4-67

FIGURE 4-40.SPLICING USING LARGER DIAMETER REPLACEMENT TUBE

4-69 4-87.............................................................. REPAIRS AT BUILT-IN FUSELAGE FITTINGS

......................................................................................................................................... 4-70

FIGURE 4-41................... REPAIRS AT BUILT-IN FUSELAGE FITTINGS

4-71 4-88............................................................................................ ENGINE-MOUNT REPAIRS

......................................................................................................................................... 4-70

4-89................................................................BUILT-UP TUBULAR WING OR TAIL-SPARS

......................................................................................................................................... 4-72

FIGURE 4-42......... STREAMLINE TUBE SPLICE USING ROUND TUBE

(APPLICABLE TO LANDING GEAR).............................................................................. 4-73

4-90....................................................WING-BRACE STRUTS AND TAIL-BRACE STRUTS

......................................................................................................................................... 4-72

FIGURE 4-43........ STREAMLINE TUBE SPLICE USING SPLIT SLEEVE

(APPLICABLE TO WING AND TAIL SURFACE…