Advisory Circular SECTION 2, CHAPTER 3, PARA 23a CALLS

Advisory CircularAC 21-99(0)NOVEMBER 2005AIRCRAFT WIRING AND BONDINGSECTION 2, CHAPTER 3, PARA 23a CALLS OUT NEED TO FOLD BACK SHIELD BRAIDS BEFORE USING SOLDER SPLICESCONTENTS1. References2. Purpose3. Status of this ACSection 11. IntroductionSection 21. Wire and Cable2. Identifying Wire and Cable3. Preparing Wire and Cable4Electrical Wire Installation5. Repairing Wire and Cable6. Solderless Terminations and Splices7. Soldering8. Lacing and Tying9. Wiring: Lock, Shear and Seal10. General Purpose Connectors11. Electric Connector Sealing Compound12. RF Connectors and Cabling13. Bonding and Grounding14. Earthing and Bonding of Aircraft and GroundSupport Equipment15. Installation of Busbars, Junction Boxes,Protective Devices and Terminal Boards16. ThermocoupleWireSolderingandInstallation17. Aged Aircraft Wiring18. Aircraft Electrical System – Inspection19. Fibre Optics1.2.REFERENCESCivil Aviation Safety Regulations(CASR) Part 21.RTCA DO-160D:EnvironmentalConditions and Test Procedures for AirborneEquipment Section 16 (Power Input).SAE Aerospace AS50881 WiringAerospace Vehicles.Federal Aviation Administration (FAA)Advisory Circular 43.13-1B:AcceptableMethods, Techniques and Practices – AircraftInspection and Repair.PURPOSEThe purpose of this Advisory Circular is to provideguidance material for maintenance of aircraftelectrical systems and bonding of aircraft.3.STATUS OF THIS ACThis is the first issue of this Advisory Circular to bewritten on aircraft wiring and bonding procedures.ApprovedNeville ProbertGeneral ManagerManufacturing, Certification and New Technologies OfficeAdvisory Circulars are intended to provide advice and guidance to illustrate a means, but not necessarily the onlymeans, of complying with the Regulations, or to explain certain regulatory requirements by providing informative,interpretative and explanatory material.Where an AC is referred to in a ‘Note’ below the regulation, the AC remains as guidance material.ACs should always be read in conjunction with the referenced regulations24 November 2005

AC 21-99 Aircraft Wiring and BondingTable of ContentsTABLE OF CONTENTSPage NoPara No1111111 to 34567 to 101111131A-11B-11C-11D-11E-11F-11G-11H-11 to 234 to 67 to 16SECTION 1CHAPTER 1INTRODUCTIONGeneralPurpose of ManualScopeIntended UseArrangement of MaterialRevisionsSECTION 2CHAPTER 1WIRE AND CABLEIntroductionReference SpecificationsDefinitionsSelection of Aircraft Electrical Wire and 5038MIL-W-7072NEMA WC 27500MIL-DTL-81381MIL-C-85485Current Ratings of Wire and MaximumAllowable Nicked or Broken StrandsWire Gauge ComparisonCHAPTER 21I-11J-1IDENTIFYING WIRE AND CABLEIntroductionWire Identification Code (Basic)Wire and Component Identification Codes forModificationIdentification MethodsMarking ObjectivesSpacing of Wire IdentificationLocation of Sleeve MarkingMulti-conductor Cable IdentificationCoaxial Cable IdentificationThermocouple Cable IdentificationWire Identification at Terminal Boards andEnclosuresSelection of Identification SleevingWire MarkingSet-up of Marking Machine for Wire StampingSet-up of Marking Machine for Sleeve StampingInstalling Identification Sleeves on WiringIdentification of Wire Bundles and Harnesses111 to 23 to 263666666727 to 282930313233 to 3435367777888373839 to 4041424344i

AC 21-99 Aircraft Wiring and BondingCHAPTER 3PREPARING WIRE AND CABLEIntroductionCutting Wire and CableStripping Wire and CableTinning Wire and CableTerminating Shielded CableCHAPTER 412 to 67 to 1314 to 2021 to 24112225889913182526282812345 to 1415 to 3233 to 3435 to 394041 to 4647 to 5960 to 7677 to 7980 to 8586 to 8889 to 102113812 to 34 to 67 to 21REPAIRING WIRE AND CABLEIntroductionSingle Wire RepairMulti-conductor RepairMIL-STD-1553 Data Bus Cable RepairCHAPTER 611256ELECTRICAL WIRING INSTALLATIONIntroductionReference SpecificationsDefinitionsWire TypesWire Groups and BundlesRouting and InstallationConduitMetallic ConduitNon-metallic ConduitHeat-shrinkable TubingCable ClampsConnections to Terminal Boards and BusbarsInstallation of Wires in ConduitInstallation of ConnectorsInstallation of Wire in Junction BoxesTerminal Junction SystemCHAPTER 5Table of ContentsSOLDERLESS TERMINATIONS ANDSPLICESIntroduction1Reference Specifications1Description1Terminating Small Copper Wires withPre-insulated Terminal Lugs2Terminating Large Copper Wires7Crimping Procedure for MS25441 Tools9Terminating Aluminium Wire9Splicing Small Copper Wires11Splicing Procedure for M81824 EnvironmentalSplices12Splicing High Temperature Wires12Splicing Aluminium Wires13Multi-splicing13Environment Resistant Wire Disconnect Splices 13Splicing to Reduce Wire Size13Inspection of Crimped Connections14Terminal Junction Systems14Terminations and Tooling6A-1Stud Size and Corresponding Terminal LugDimension Reference Chart6B-1Disconnect Splices and Tooling6C-1Crimp Tool Testing6D-1CHAPTER 7iiSOLDERING1 to 234 to 78 to 1415 to 192021 to 2526 to 293031323334353637

AC 21-99 Aircraft Wiring and BondingIntroductionReference Specifications and StandardsDefinitions and DescriptionsHeat Application MethodsPreparation and Maintenance of the SolderingIronSoldering OperationInspecting a Finished Solder JointCHAPTER 81 to 345 to 1112 to 1534616 to 2021 to 3738 to 401112234571 to 234 to 78 to 101112 to 1516 to 2021 to 30311111 to 234 to 728 to 13314 to 211124510101122222525333536363840464848521 to 345 to 1112 to 1415 to 2627 to 2829 to 3334 to 3536 to 3940 to 424344 to 4950 to 5556 to 575859 to 616263 to 7273 to 7778 to 7980 to 8485 to 8657586570738787 to 8889 to 9495 to 979899 to 108109 to 111WIRING: LOCK, SHEAR AND SEALIntroductionReference SpecificationsDefinitionsGeneral Procedures for Lock, Shear and SealWiringSpecific Procedures for Lock, Shear and SealWiringCHAPTER 101113LACING AND TYINGIntroductionReference SpecificationsDefinitionsMaterialsGeneral PrecautionsLacingTyingSelf-clinching Cable Straps and Spiral WrapLacing and Tying in High Temperature AreasCHAPTER 9Table of ContentsGENERAL PURPOSE CONNECTORSIntroductionReference SpecificationsDescriptionInsulating Sleeves and Heat-shrinkable TubingSoldering ProcedureCrimp ContactsHand Crimping Tools for Connector ContactsTool Inspection GaugingTypes of Contact Positioning DevicesCrimping ProceduresCrimping Tool KitsInstalling and Removing Crimp Type ContactsShield ConnectionsContinuity TestTest LeadsProtection of Electrical ConnectorsPotting ConnectorsConnector AccessoriesBoot Repair ProceduresRectangular ConnectorsMIL-DTL-83723 Circular ConnectorsMIL-DTL-5015 ConnectorsMIL-C-26482, MIL-C-26500 and MIL-C-81703ConnectorsMIL-C-81511 ConnectorsMIL-DTL-38999 ConnectorsM and MS Connector Cable ClampsMIL-C-81659 ConnectorsMultiple Termination Connectorsiii

AC 21-99 Aircraft Wiring and BondingCHAPTER 11ELECTRIC CONNECTOR SEALING COMPOUNDIntroductionReference SpecificationsDescriptionGeneral PrecautionsPreparation of Sealing CompoundStorage of Sealing CompoundPreparation of Fluorocarbon Insulated Wirefor PottingMIL-M-24041 Moulding and Potting CompoundCHAPTER 123513 to 1819 to 241114671823263136381 to 234 to 67 to 89 to 1112 to 1415 to 1617 to 1920 to 2223 to 2526 to 2829 to 314132 to 374438 to 40475541 to 5152 to 53111126689101 to 234 to 678 to 1314 to 1718 to 2324 to 2627 to 2829111 to 45 to 213722 to 4344 to 52101111121853 to 6263 to 6667 to 7778 to 8687 to 91EARTHING AND BONDING OF AIRCRAFTAND GROUND SUPPORT EQUIPMENTIntroductionElectrical Grounding for Aircraft SafetyElectrical Earthing and Bonding Proceduresfor Aircraft and GSETesting Interconnection LeadsAircraft Earthing Receptacle InspectionProcedureTesting GSE Connection PointsGround Earthing PointsTesting Ground Earthing PointsMains Operated GSEiv1 to 2345 to 67 to 910 to 12BONDING AND GROUNDINGIntroductionReference SpecificationsDefinitionsGeneral Precautions and ProceduresSelection of HardwarePreparation of Bonding or Grounding SurfacesMethods of Bonding or GroundingBonding and Grounding JumpersTesting Bonds and GroundsRefinishingCHAPTER 14111123RF CONNECTORS AND CABLINGIntroductionReference SpecificationsDescriptionGeneral Precautions and ProceduresSoldering Coaxial Cable to RF ConnectorsBNC and TNC Series ConnectorsC and SC Series ConnectorsHN Series ConnectorsN Series ConnectorsPulse Series ConnectorsMiniature RF ConnectorsSub-miniature RF ConnectorsRF Connectors Used in Fuel Quantity IndicatingSystemsAssembly Procedure for Sub-miniatureConnector ONO89558Assembly Procedure for SMA Termination ofSemi-rigid Cable Using Tool M22520/36Triaxial ConnectorsCHAPTER 13Table of Contents

AC 21-99 Aircraft Wiring and BondingCHAPTER 15INSTALLATION OF BUSBARS, JUNCTIONBOXES, PROTECTIVE DEVICES, ANDTERMINAL BOARDSIntroductionReference SpecificationsPreparation and Installation of BusbarsInstallation of Junction BoxesInstallation of Protective DevicesInstallation of Terminal BoardsCHAPTER 1611133591115151 to 345 to 8910 to 1213 to 2122 to 2728 to 383940 to 42111212 to 131415 to 18AIRCRAFT ELECTRICAL SYSTEM – INSPECTIONIntroductionInspectionCHAPTER 191 to 234 to 1213 to 2122 to 4243 to 50AGED AIRCRAFT WIRINGIntroductionDefinitionsGeneralHandling Aged WiringCHAPTER 18111247THERMOCOUPLE WIRE SOLDERINGAND INSTALLATIONIntroductionReference SpecificationsDescriptionDefinitionsThermocouple Wire PreparationHard Soldering Thermocouple WireSoft Soldering Thermocouple WireThermocouple Wire SplicingMounting AN5537 Connector AssemblyRouting Thermocouple WiringCHAPTER 17Table of Contents1112 to 141112 to 13FIBRE OPTICSIntroductionInformationv

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AC 21-99 Aircraft Wiring and BondingList of TablesLIST OF TABLESTable NoTitlePage NoSECTION 2CHAPTER me Wire Used In Aircraft Electrical InstallationsCommon Aircraft Wire InsulationsSpecification SheetsPart Number CodingConductor SizeConductor StrandingColour CodeSpecification SheetsPart Number CodingColour CodeSpecification SheetsPart Number CodingColour CodeSpecification SheetsPart Number CodingColour CodeSpecification SheetsPart Number CodingWire SizeClassificationCable Part Number BreakdownBasic Wire SpecificationShield IdentificationJacket IdentificationPreferred Cable Identification MethodOptional Cable Identification MethodSpecification SheetsPart Number CodingColour CodeEquivalent Non-kapton Insulated WiresSpecification SheetsComponent WireFinished CableShielded, Jacketed Cable ConstructionUnshielded, Unjacketed Cable ConstructionCable Colour DesignationCurrent Rating of Wires (SAE AS50881)Maximum Allowable Nicked or Broken Strands (SAE AS50881)Wire Gauge –21H–21H–21I–11I–21J–1CHAPTER 22–12–22–3Function and Designation LettersMarking Foil IdentificationRecommended Sizes of Marking Type4883–13–23–3Allowable Nicked or Broken StrandsIdentification of Precision Stripper and BladesApproximate Soldering Iron Sizes for Tinning2463–4Heat Shrink Solder Sleeves For Tin and Silver Plated ConductorsCHAPTER 3i