Development of standard wiring practices documentation

11/14/07 AC 25-26 (8) Inspection Methods.

(a) Specify a general visual inspection (GVI) or a detailed inspection (DET), as determined by an enhanced zonal analysis procedure. Typical damage to inspect for includes heat damage, chafing, cracked insulation, arcing, delaminated insulation, corrosion, broken wire or terminals, incorrect bend radii, contamination, loose terminals, and deteriorated repairs.

(b) Identify, where applicable, established and emerging new technologies for non-destructive test methods to complement the visual inspection process.

Whenever possible, ensure that inspection methods can detect wiring problems without compromising the integrity of the installation.

(9) Customized Data. Provide a location and procedure to allow users to include customized or unique data such as that for supplemental type certificates, operator-unique maintenance procedures, etc.

8. ALTERNATE PROCEDURE FOR LEGACY DOCUMENTS.

a. The adoption of a new layout and chapter organization may require each organization with an existing SWPM to reorganize and republish that document using the new standardized format. Whether the organization produces a stand-alone manual or provides the SWPM as chapter 20 of a wiring diagram manual, this reorganization would result in a significant economic impact on both the authoring organization and end-users.

b. To address this concern, a conversion tool, identified in paragraph e. below, was devised which takes the following variables into account: • Effects on manufacturers’ current technical document editorial policy as it exists in current legacy documents.

• Costs resulting from an immediate major manual overhaul.

• Inconvenience to end-users who are accustomed to the format they are currently using.

c. When using a traditional paper format SWPM, the most efficient method of retrieving standard procedures and maintenance information has traditionally been to search by using − • the table of contents (TOC) and/or • the indexes (alpha-numerical index and/or numerical index as available).

The ease and speed with which information may be found with these methods relies heavily on the quality of the TOC and/or the indexes. For aircraft maintenance technicians needing 11/14/07 AC 25-26 to locate and extract the pertinent and applicable data necessary to perform a satisfactory design modification or maintenance action, finding relevant data may be time consuming.

d. When using an electronic format, a search engine can often be used. This allows the user to bypass the TOC or indexes in finding the needed procedure or data. By searching with such alternative methods, a user can find information without needing to know the rules, such as ATA references, governing assignment of the subject matter to its place in the TOC.

e. Use of a conversion tool, identified as a master breakdown index (MBI) is one way of presenting a standard means for finding SWPM information until existing paper legacy documents can be physically altered or digitized to an electronic format. The intent of the MBI is to supplement the TOC and existing indexes. It gives users a way to search existing documents using topical information rather than part number, alphabetic subject, or chapter- section-subject reference. The arrangement of the MBI duplicates the standardized format described in Appendix A of this AC, but does not require complete rearrangement of legacy documents to achieve a common way of finding information. The MBI acts as a conversion key to effectively convert an existing document arrangement into the standardized arrangement. In essence the MBI duplicates in paper form for legacy documents the electronic search engine used in HTML-based documents.

11/14/07 AC 25-26 This is an example of an MBI that could be used to mitigate the need for reformatting legacy documents to achieve the standardized format discussed in this AC.

MASTER BREAKDOWN INDEX GROUP MAJOR TOPIC APPEARS IN THIS DOCUMENT AS SUBJECT SAFETY PRACTICES 20-10-10 AIRPLANE ENVIRONMENTAL AREAS 20-20-12 GENERAL DATA CONSUMABLE MATERIALS 20-00-11 WIRING MATERIALS 20-10-13 COMMON TOOLS 20-00-13 EWIS PROTECTION DURING MAINTENANCE 20-10-20 EWIS CLEANING 20-10-20 ELECTRICAL WIRING INTERCONNECTION EWIS INSPECTION 20-10-20 SYSTEM (EWIS) MAINTENANCE EWIS TESTING 20-10-13 EWIS DISASSEMBLY 20-10-19 EWIS REPAIR AND REPLACEMENT 20-20-00 20-10-11 WIRE SEPARATION / SEGREGATION WIRING 20-10-12 INSTALLATION ELECTRICAL BONDS AND GROUNDS 20-30-60 20-10-17 WIRE HARNESS INSTALLATION 20-10-18 Installation of Sleeves on Wiring WIRE AND CABLE TYPES 20-00-15 WIRING ASSEMBLY WIRE MARKING 20-60-01 11/14/07 AC 25-26 MASTER BREAKDOWN INDEX GROUP MAJOR TOPIC APPEARS IN THIS DOCUMENT AS SUBJECT WIRE HARNESS ASSEMBLY 20-50-01 WIRE INSULATION AND CABLE JACKET 20-90-12 REMOVAL TERMINATION TYPE (SPECIFICS OF 20-61-44 TERMINATIONS) DEVICE TYPE (SPECIFICS OF ELECTRICAL 20-80-09 Assembly of Leach ELECTRICAL DEVICES DEVICE) Relay Sockets 20-73-00 Fuel Quantity UNIQUE WIRING ASSEMBLIES/INSTALLATIONS SPECIFIC SYSTEM WIRING Indicating System AIRLINE CUSTOMIZED AIRLINE SPECIFIED 20-91-00 DATA /s/Ali Bahrami Ali Bahrami Manager, Transport Airplane Directorate Aircraft Certification Service

11/14/07 AC 25-26 Appendix A

APPENDIX A

STANDARDIZED ORGANIZATION FOR STANDARD WIRING PRACTICES MANUALS (SWPM) (Groups, Major Topics, Sequence, and Description of Minimum Content) GROUP MAJOR TOPIC DESCRIPTION Safety regulations and general safety precautions to prevent injury to personnel SAFETY PRACTICES and damage to the airplane.

AIRPLANE Definition of types of areas within which wiring configuration and wiring ENVIRONMENTAL AREAS component selection is constrained.

GENERAL Wiring maintenance processing materials (solvents, aqueous cleaners, CONSUMABLE MATERIALS DATA lubricants, etc.).

Materials that become an integral part of the wiring configuration excluding WIRING MATERIALS wire and cable; e.g., sleeves, shield material, tie material, sealants, etc.

COMMON TOOLS Description and operation of common tools.

EWIS PROTECTION DURING Procedures to protect EWIS during airplane maintenance and modification.

MAINTENANCE To support inspection as well as prevention of degradation and preparation for EWIS CLEANING repair, recommended cleaning materials and procedures based on type of contamination.

Criteria for correct installation, correct wiring assembly configuration; damage conditions and limits for wiring components (wire and cable, termination types, EWIS INSPECTION electrical devices); factors that warrant disassembly for inspection; EWIS determination of cause of damage. MAINTENANCE EWIS TESTING Wiring integrity testing.

Data and procedures for inspection, cleaning when applicable. Also supports EWIS DISASSEMBLY new wiring installation.

Repair of wiring installation, wiring assembly configuration, wiring components EWIS REPAIR AND (wire and cable, wiring terminations, electrical devices); wire and cable REPLACEMENT replacement; wiring functional identification.

WIRING WIRE Explanation of separation/segregation categories, separation/segregation INSTALLATION SEPARATION/SEGREGATION identification, and necessary conditions for maintaining separation/segregation.

A-1 11/14/07 AC 25-26 Appendix A STANDARDIZED ORGANIZATION FOR STANDARD WIRING PRACTICES MANUALS (SWPM) (Groups, Major Topics, Sequence, and Description of Minimum Content) GROUP MAJOR TOPIC DESCRIPTION ELECTRICAL BONDS AND Bond surface preparation, ground hardware configurations, bond integrity GROUNDS testing.

WIRE HARNESS Routing, supports; wiring protection, factors affecting wiring assembly INSTALLATION configuration; connection to equipment, new wiring, removal from service.

Principal material components of airplane wiring, including type identification, WIRE AND CABLE TYPES basic description, and alternative wire types (replacements, substitutions).

WIRE MARKING Marking, applicable conditions.

Wiring assembly configuration: assembly materials, layout, overall protection, WIRE HARNESS ASSEMBLY factors affecting wiring installation.

WIRE INSULATION AND Wire and cable: insulation removal, jacket removal; associated damage limits, WIRING CABLE JACKET REMOVAL tool description and operation.

ASSEMBLY Wiring terminations and accessories (connectors, terminal lugs, splices, backshells, etc.) grouped by termination type from simple to complex: a. Common data or procedures by group (if any), e.g., tool description and TERMINATION TYPE operation, definition of internal damage and limits, internal cleaning, ( e.g., SOURIAU 8950 SERIES accessories.

CONNECTORS) b. By individual type - part numbers and description, definition of internal damage and limits (if not specified by common data), disassembly, assembly, installation.

Electrical devices (circuit breakers, relays, switches, filters, lamps, etc.) grouped by device type: a. Common data or procedures by group (if any), e.g., tool description and DEVICE TYPE ELECTRICAL operation, definition of internal damage and limits, internal cleaning, ( e.g., KLIXON 7274 SERIES DEVICES accessories.

CIRCUIT BREAKER) b. Devices by individual type - part numbers and description, definition of internal damage and limits (if not specified by common data), disassembly, assembly, installation.

A-2 11/14/07 AC 25-26 Appendix A STANDARDIZED ORGANIZATION FOR STANDARD WIRING PRACTICES MANUALS (SWPM) (Groups, Major Topics, Sequence, and Description of Minimum Content) GROUP MAJOR TOPIC DESCRIPTION For wiring that has a necessarily specific configuration (e.g., primary flight control, fuel quantity indicator system, etc.): SPECIFIC SPECIFIC WIRING SYSTEM ASSEMBLY a. Applicable conditions for repair and replacement.

WIRING b. Disassembly, assembly, installation, assembly integrity testing.

AIRLINE CUSTOMIZED AIRLINE SPECIFIED Reserved for airline use.

DATA A-3

11/14/07 AC 25-26 Appendix B APPENDIX B RELATED REGULATIONS AND DOCUMENTS a. Regulations. You can download an electronic copy of 14 CFR from the Internet at http://www.gpoaccess.gov/cfr/. A paper copy can be ordered by sending a request to the U.S. Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402-0001, or by calling telephone number (202) 512-1800; or by sending a request by facsimile to (202) 512-2250.

Part 21 Certification Procedures for Products and Parts.

Part 25 Airworthiness Standards: Transport Category Airplanes.

Part 43 Maintenance, Preventive Maintenance, Rebuilding, and Alteration.

Part 91 General Operating and Flight Rules.

Part 121 Operating Requirements: Domestic, Flag, and Supplemental Operations.

Part 125 Certification and Operations: Airplanes Having a Seating Capacity of 20 or More Passengers or a Maximum Payload Capacity of 6,000 Pounds or More; and Rules Governing Persons on Board Such Aircraft.

Part 129 Operations: Foreign Air Carriers and Foreign Operators of U.S.- Registered Aircraft Engaged in Common Carriage.

Part 145 Repair Stations.

b. Advisory Circulars (AC). You can download an electronic copy of the latest version of the following ACs from the FAA Internet at http://rgl.faa.gov.

• 25-16 Electrical Fault and Fire Protection and Prevention • 25.981-1 Fuel Tank Ignition Source Prevention Guidelines • 25.1701-1 Certification of Electrical Wiring Interconnection Systems on Transport Category Airplanes • 43-12 Preventive Maintenance B-1 11/14/07 AC 25-26 Appendix B • 43.13-1 Acceptable Methods, Techniques and Practices—Aircraft Inspection and Repair • 43-204 Visual Inspection For Aircraft • 43-206 Inspection, Prevention, Control, and Repair of Corrosion on Avionics Equipment • 65-15 Airframe & Powerplant Mechanics Airframe Handbook [Chapter 11, Aircraft Electrical Systems] c. Reports. You can download an electronic copy of the following reports from the “Final Reports” section of the Aging Transport Systems Rulemaking Advisory Committee (ATSRAC) website: www.mitrecaasd.org/atsrac .

• “Aging Systems Task Force, Aging Transport Systems, Task 1 and Task 2 Final Report,” dated August 1, 2000.

• “Aging Transport Systems Rulemaking Advisory Committee, Task 3 Final Report,” dated March 26, 2001.

• “Final Report ATSRAC Task Group 4,” dated September 28, 2000.

• “Final Report, ATSRAC HWG Task 7, Electrical Standard Wire Practices Manual (ESWPM),” dated October 31, 2002.

• “Transport Aircraft Intrusive Inspection Project (An Analysis Of The Wire Installations Of Six Decommissioned Aircraft), Final Report,” The Intrusive Inspection Working Group, dated December 29, 2000.

d. Other Documents.

• Air Transport Association (ATA) Specification 117 (Wiring Maintenance/Practices/Guidelines). You can download an electronic copy of this ATA document from http://www.airlines.org/ .

• FAA Policy Statement No. PS-ANM100-2000-00105 (also numbered ANM- 01-04). System Wiring Policy for Certification of Part 25 Airplanes, issued June 25, 2001. You can download an electronic copy of this policy memorandum from the FAA Internet at http://rgl.faa.gov.

B-2

11/14/07 AC 25-26 Appendix C APPENDIX C Following are the discussions of Appendix H 25.5 published in the Federal Register on October 6, 2005 (70 FR 58508), in Notice of Proposed Rulemaking No 05-08, Enhanced Airworthiness Program for Airplane Systems/Fuel Tank Safety (EAPAS/FTS), at the time this rule was proposed .

pg. 58532-34 Appendix H to Part 25 – Instructions for Continued Airworthiness The proposed Appendix H 25.5 would also require that the following information be included in ICA applicable to EWIS: • Standard wiring practices data.

• Wire separation design guidelines.

• Information to explain the airplane’s EWIS identification method required by the proposed § 25.1711.

• Electrical load data and instructions for updating that data. Such information will help ensure that those modifying, repairing, or installing new EWIS will not perform any action that will adversely affect previously certified systems and unintentionally introduce potential hazards.

Standard wiring practices are defined as standards developed by the specific airplane manufacturer or industry-wide standards for the repair and maintenance of EWIS. They include procedures and practices for the installation, repair, and removal of EWIS components, including information about wire splices, methods of bundle attachment, connectors and electrical terminal connections, bonding, and grounding. Although a standard wiring practices manual is not a design manual, and those designing a new EWIS modification for a specific model airplane should not use it as such, it does provide the designer with insight into the types of EWIS components used by the TC holder and the procedures recommended by the manufacturer for maintenance or repair that supports continued airworthiness of the components.

pg. 58540 Paperwork Reduction Act Required information, use, and respondents (6) The proposed revision to part 25 Appendix H would require that future manufacturers include acceptable EWIS practices in their ICA, presented in C-1 11/14/07 AC 25-26 Appendix C a standard format. This information would be used by maintenance personnel for wiring maintenance and repairs. The requirement is necessary because information about cautionary tasks during maintenance that can prevent situations that could compromise safety need to be available to maintenance personnel.

Standard wiring practices manuals, in which this information is presented, often differ from manufacturer to manufacturer and so are difficult for maintenance personnel to find specific information in. The requirement for a standard format is meant to correct this. Because of this proposal, manufacturers would change their Standard Wiring Practices Manuals (SWPM).

C-2