U.S . Department of Transportation Federal Aviation Administration Advisory Circular Subject: Aircraft Electrical Wiring Interconnection Systems Training Program Date: 11/20/07 AC No: 120-94 Initiated by: AFS-300/ Change:
ANM-100
1. PURPOSE. This advisory circular (AC) provides guidance for developing an enhanced electrical wiring interconnection systems (EWIS) training program.
2. APPLICABILITY.
a. The guidance provided in this document is directed to air carriers, air operators, and repair stations. It may also be used by type certificate (TC) holders and Supplemental Type Certificate (STC) holders. The recommendations in this AC can be applied to any aircraft training program.
b. This material is neither mandatory nor regulatory in nature and does not constitute a regulation. It describes acceptable means, but not the only means, for demonstrating compliance with the applicable regulations. We will consider other methods of demonstrating compliance that an applicant may elect to present. While these guidelines are not mandatory, they are derived from extensive Federal Aviation Administration (FAA) and industry experience in determining compliance with the relevant regulations. On the other hand, if we become aware of circumstances that convince us that following this AC would not result in compliance with the applicable regulations, we will not be bound by the terms of this AC, and we may require additional substantiation as a basis for finding compliance.
c. This material does not change or create any additional regulatory requirements nor does it authorize changes in or permit deviations from existing regulatory requirements.
d. Terms used in this AC such as “shall” or “must” are used only in the sense of ensuring applicability of this particular method of compliance when the acceptable method of compliance described herein is used.
3. HOW THIS INFORMATION WAS DERIVED.
a. The National Transportation Safety Board (NTSB) recommended that we address all wiring issues identified in the FAA’s Aging Systems Plan, either through rulemaking or through other means. The NTSB specifically cited the need for improved training of personnel to ensure adequate recognition and repair of potentially unsafe wiring conditions.
(Reference NTSB Safety Recommendations A-00-105 through -108, September 19, 2000.)
This AC responds to the NTSB training improvement recommendation.
b. To address the issues identified in our Aging Systems Plan, in 1998 we established the Aging Transport Systems Rulemaking Advisory Committee (ATSRAC). The ATSRAC provides a forum for airlines, manufacturers, and other regulatory authorities to make recommendations to us based on the Aging Systems Plan. These recommendations address EWIS certification issues, development of a standard wiring practices manual, enhanced EWIS maintenance requirements, and EWIS training.
c. The guidance in this AC is based on recommendations submitted to us by ATSRAC. It is derived from the best practices training developed through extensive research by ATSRAC Industry Working Groups 5, 8, and 11. We endorse these best practices. Adoption of the recommendations in this AC will result in a training program that will improve the awareness and skill level of aviation personnel in EWIS production, modification, maintenance, inspection, and repair. This AC promotes a policy of providing wiring training for all personnel who come into contact with aircraft EWIS as part of their job and tailors the training for each workgroup to their particular needs.
d. To fully realize the objectives of this AC, air carriers, air operators, repair stations, TC holders, and STC holders will need to rethink their current approach to maintaining and modifying aircraft wiring and systems. This may require more than simply updating maintenance manuals and work cards and enhancing training. Maintenance personnel need to be aware that aircraft EWIS should be maintained with the same level of attention and intensity as any other system in the aircraft. They also need to recognize that visual inspection of wiring has inherent limitations. Small defects such as breached or cracked insulation, especially in small gage wire, may not always be apparent. Therefore effective wiring maintenance combines visual inspection techniques with improved wiring maintenance practices and training.
4. BACKGROUND.
a. Title 14 of the Code of Federal Regulations (14 CFR) Part 121, § 121.1111 and part 129, § 129.111, both titled “Electrical Wiring Interconnection Systems (EWIS) Maintenance Program,” require operators to include in their maintenance program inspections and procedures for EWIS.
b. Section 121.375 requires that each certificate holder or person performing maintenance or preventative maintenance have a training program to ensure that each person (including inspection personnel) who determines the adequacy of work done is fully informed about procedures and techniques and new equipment in use. Although there is not a direct training requirement in § 129.14 requires that each foreign air carrier and each foreign person operating a U.S.-registered aircraft maintain that aircraft in accordance with a program approved by the FAA Administrator. Guidance for this requirement is provided by AC 129-4, Maintenance Programs for U.S.-Registered Aircraft Operated Under 14 CFR Part 129. It is this guidance material and that of 14 CFR part 43 that we have traditionally used to ensure that maintenance performed on aircraft operated under part 129 is accomplished by properly trained personnel.
c. This AC provides guidance for developing an EWIS training program as required by those sections. The training syllabus and curriculum for those personnel, identified in paragraph 6 of this AC as Target Groups 1 and 2, are in Appendix A, Electrical Wiring Interconnection Systems (EWIS) Minimum Initial Training Program Content for Target Groups 1 and 2, to this AC.
d. This AC also provides guidance on the development of EWIS training programs for personnel who are not directly involved in the maintenance and inspection of EWIS.
(1) Although there is not a regulatory requirement for EWIS training for them, operators may choose to provide EWIS training. The training syllabus and curriculum for these personnel, identified in paragraph 6 of this AC as Target Groups 3 through 8, are in Appendix B, Electrical Wiring Interconnection Systems (EWIS) Minimum Initial Training Program Content for Target Groups 3 through 8, to this AC.
(2) We believe that training personnel in these groups would greatly enhance awareness of the importance of EWIS safety in the overall safe operation of aircraft. Although these groups are not directly involved in the maintenance of EWIS, they have the potential to have an adverse impact on EWIS. This can occur through inadvertent contact with EWIS during aircraft cleaning or when individuals perform maintenance unrelated to EWIS that could impact the integrity of EWIS. Mechanics leaving drill shavings on wire bundles is one example of how this could occur. Some people prepare paperwork that guides mechanics, and training this target group in EWIS can ensure proper attention to EWIS issues.
5. DEVELOPING AN EWIS TRAINING PROGRAM.
a. The objective of this EWIS training program is to give operators or maintenance repair organizations a model for developing their own EWIS training program. This training can benefit personnel whether such training is required by regulation or developed and adopted voluntarily by an organization. It will help ensure that proper processes, procedures, methods, techniques, and practices are used when performing maintenance, preventive maintenance, inspection, alteration, repair, and cleaning of EWIS.
b. This program was developed for eight different target groups and may be used for initial and recurrent training. Depending on their duties, some personnel may fall into more than one target group and therefore would need to fulfill all objectives of each of their associated target groups. Paragraph 6 of this AC provides details of each target group.
6. TRAINING TARGET GROUPS.
Target Group 1: Personnel Performing Electrical Wiring Interconnection Systems Maintenance—These personnel work directly at maintaining or modifying EWIS.
Examples:
• FAA – Electricians, avionics/Airframe and Powerplant (A&P) technicians.
• European Union Aviation Safety Agency (EASA) – Part-66 Cat B1 and Cat B2 personnel (licensed technician, avionic) and avionic skilled workers.
4 Target Group 2: Personnel Performing Maintenance Inspections on Electrical Wiring Interconnection Systems—These personnel perform EWIS inspections but do not directly maintain or modify EWIS.
Examples:
• FAA – Inspectors/A&P technicians.
• EASA – Part-66 Cat B1 and Cat B2 licensed personnel.
Target Group 3: Personnel Performing Electrical/Avionic Engineering on In-Service Aircraft—These are personnel authorized to design EWIS installations, modifications, and repairs.
Examples:
• FAA/EASA – Electrical/avionic engineers.
Target Group 4: Personnel Performing General Maintenance/Inspections Not Involving Wire Maintenance—These personnel perform maintenance on aircraft that may require removal/reconnection of electrical connective devices such as removing and replacing line replaceable units.
Examples:
• FAA – A&P technicians.
• EASA – Part-66 Cat A (licensed technician – minor maintenance and simple repair) or B1 (licensed technician – excluded avionics).
Target Group 5: Personnel Performing Other Engineering or Planning Work on In-Service Aircraft—These are personnel authorized to design mechanical/structural systems installations, modifications, and repairs, or personnel authorized to plan maintenance tasks.
Target Group 6: Other Service Staff with Duties in Proximity to Electrical Wiring Interconnection Systems—These are personnel whose duties would bring them into contact/view of aircraft EWIS. This group would include, but not be limited to, aircraft cleaners, cargo loaders, fuelers, lavatory servicing personnel, deicing personnel, and push-back personnel.
Target Group 7: Flight Deck Crew.
Target Group 8: Cabin Crew.
7. ESSENTIAL ELEMENTS FOR A TRAINING PROGRAM.
a. Initial Training—Initial training should be conducted for each designated work group.
The initial training program content for Target Groups 1 and 2 is outlined in Appendix A.
Initial training program content for Target Groups 3 through 8 is outlined in Appendix B.
Curriculum and lesson plans for each dedicated module identified in Appendices A and B are given in Appendix C, Electrical Wiring Interconnection Systems (EWIS) Curriculum and
5 Lesson Plans. A list of definitions for terms used in the curriculum and lesson plans is included in Appendix D, Definitions.
(1) The most important criterion is to meet the objectives of the lesson plans (Appendix C), using classroom discussion, computer-based instruction, or hands-on practical training.
(2) Assessment means or criteria for achieving objectives should be at the discretion of the training organization. Examples of assessment means or achievement criteria are written tests, oral tests, or demonstration of skills.
(3) Supporting documentation such as advisory circulars is an integral part of training and should be used to support development of the curriculum and lesson plans.
b. Refresher Training—Refresher training should be conducted at least every 2 years. It could consist of a review of previously covered material plus any new material or revisions to publications. Refresher training would follow the Electrical Wiring Interconnection System (EWIS) Minimum Initial Training Program (Appendix A or B) for that particular target group.
8. AC FEEDBACK FORM. For your convenience, the AC Feedback Form is the last page of this AC. Note any deficiencies found, clarifications needed, or suggested improvements regarding the contents of this AC on the Feedback Form.
/s/ James J. Ballough James J. Ballough Director, Flight Standards Service, Aviation Safety /s/ John J. Hickey John J. Hickey Director, Aircraft Certification Service, Aviation Safety
Appendix A A-1
APPENDIX A
ELECTRICAL WIRING INTERCONNECTION SYSTEMS (EWIS) MINIMUM INITIAL TRAINING PROGRAM CONTENT FOR TARGET GROUPS 1 AND 2 Target Group 1: Personnel Performing Electrical Wiring Interconnection Systems Maintenance Target Group 2: Personnel Performing Maintenance Inspections on Electrical Wiring Interconnection Systems TARGET GROUP 1 2
A - GENERAL ELECTRICAL WIRING INTERCONNECTION SYSTEM PRACTICES Know or demonstrate safe handling of airplane electrical systems, line replaceable units (LRU) and tooling, troubleshooting procedures, and electrical measurement.
1. Safety practices X X
2. Electrostatic discharge sensitive (ESDS) device handling and protection X X
3. Tools, special tools, and equipment X
4. Verifying calibration/certification of instruments, tools, and equipment X
5. Required wiring checks using troubleshooting procedures and charts X
6. Measurement and troubleshooting using meters X
7. LRU replacement general practices X X B – WIRING PRACTICES DOCUMENTATION Understand how the applicable airplane wiring system overhaul or wiring practices manual is organized or constructed and demonstrate navigation through the documents to find information.
1 2
8. Standard wiring practices manual structure/overview X X
9. Chapter cross-reference index X X
10. Important data and tables X X
11. Wiring diagram manuals X X
12. Other documentation as applicable X X C – INSPECTION Know the different types of inspections, zonal areas and typical damage, and how human factors affect inspections.
1 2
13. General Visual Inspection (GVI), Detailed Inspection (DET), Special Detailed Inspection (SDI), and zonal inspection, and their criteria and standards X X
14. Human factors in inspection X X
15. Zonal areas of inspection X X
16. Wiring system damage X X D – HOUSEKEEPING Know the contamination sources, materials, and cleaning and protection procedures.
1 2
17. Airplane external contamination sources X X
18. Airplane internal contamination sources X X
Appendix A A-2 TARGET GROUP 1 2
19. Other contamination sources X X
20. Contamination protection planning X
21. Protection during airplane maintenance and repair X
22. Cleaning processes X E – WIRE Know or demonstrate correct identification of different wire types, their inspection criteria and damage tolerance, and repair and preventative maintenance procedures.
1 2
23. Wire identification, type and construction X X
24. Insulation qualities and damage limits X X
25. Inspection criteria and standards for wire and wire bundles X
26. Wire bundle installation practices X X
27. Typical damage and areas found (airplane specific) X X
28. Maintenance and repair procedures X X
29. Sleeving X X
30. Unused wires-termination and storage X X
31. Electrical bonding and grounds X X F – CONNECTIVE DEVICES Know or demonstrate the procedures to identify, inspect, and find the correct repair for typical types of connectors found on the applicable airplane.
1 2
32. General connector types and identification X X
33. Cautions and protections X X
34. Visual inspection procedures X X
35. Typical damage found X X
36. Repair procedures X X G – CONNECTIVE DEVICE REPAIR Demonstrate replacement procedures for all parts of typical types of connectors found on the applicable airplane.
1 2
37. Circular connectors X
38. Rectangular connectors X
39. Terminal blocks-modular X
40. Terminal blocks- non-modular X
41. Grounding modules X
42. Pressure seals X NOTE: For Target Group 2, items A3, A4, A6 may not be required, but as new inspection tooling becomes available it may be appropriate to require tooling training. In addition, these items would be valuable for voluntary training for inspector awareness.
Appendix B B-1
APPENDIX B
ELECTRICAL WIRING INTERCONNECTION SYSTEMS (EWIS) MINIMUM INITIAL TRAINING PROGRAM CONTENT FOR TARGET GROUPS 3 THROUGH 8 Target Group 3: Personnel Performing Electrical/Avionic Engineering on In-Service Aircraft Target Group 4: Personnel Performing General Maintenance/Inspections Not Involving Wire Maintenance Target Group 5: Personnel Performing Other Engineering or Planning Work on In-Service Aircraft Target Group 6: Other Service Staff with Duties in Proximity to Electrical Wiring Interconnection Systems Target Group 7: Flight Deck Crew Target Group 8: Cabin Crew Target Groups 3 4 5 6 7 8
A - GENERAL ELECTRICAL WIRING INTERCONNECTION SYSTEM
PRACTICES Know or demonstrate safe handling of airplane electrical systems, line replaceable units (LRU), and tooling, troubleshooting procedures, and electrical measurement.
1. Safety practices X X X X
2. Electrostatic discharge sensitive (ESDS) device handling and protection X
7. LRU replacement general practices X
B – WIRING PRACTICES DOCUMENTATION Target Groups 3 4 5 6 7 8 Understand how the applicable airplane wiring system overhaul or wiring practices manual is organized or constructed and demonstrate navigation through the documents to find information.
8. Standard wiring practices manual structure/overview X
9. Chapter cross-reference index X
10. Important data and tables X
11. Wiring diagram manuals X
12. Other documentation as applicable X
C – INSPECTION Target Groups 3 4 5 6 7 8 Know the different types of inspections, zonal areas and typical damages, and how human factors affect inspections.
13. General Visual Inspection (GVI), Detailed Inspection (DET), Special Detailed Inspection (SDI), and zonal inspection and their criteria and standards X X X
14. Human factors in inspection X X
15. Zonal areas of inspection X X
16. Wiring system damage X X X Low level Low level Low level
Appendix B B-2
D – HOUSEKEEPING Target Groups 3 4 5 6 7 8 Know the contamination sources, materials, and cleaning and protection procedures.
17. Airplane external contamination sources X X X X X
18. Airplane internal contamination sources X X X X X
19. Other contamination sources X X X X X
20. Contamination protection planning X X X
21. Protection during airplane maintenance and repair X X X
22. Cleaning processes X X X X
E – WIRE Target Groups 3 4 5 6 7 8 Know or demonstrate correct identification of different wire types, their inspection criteria and damage tolerance, and repair and preventative maintenance procedures.
23. Wire identification, type and construction X
24. Insulation qualities and damage limits X
25. Inspection criteria and standards of wire and wire bundles X
26. Wire bundle installation practices X
27. Typical damage and areas found (airplane specific) X X X Low level Low level Low level
28. Maintenance and repair procedures X
29. Sleeving X
30. Unused wires-termination and storage X
31. Electrical bonding and grounds X X Bond X
F – CONNECTIVE DEVICES Target Groups 3 4 5 6 7 8 Know or demonstrate the procedures to identify, inspect, and find the correct repair for typical types of connectors found on the applicable airplane.
32. General connector types and identification X
33. Cautions and protections X
34. Visual inspection procedures X
35. Typical damage found X
36. Repair procedures X
Appendix C C-1
APPENDIX C
ELECTRICAL WIRING INTERCONNECTION SYSTEMS (EWIS) CURRICULUM
AND LESSON PLANS Overview This training is targeted at each person who performs airplane maintenance, inspections, alterations, or repairs on electrical wiring interconnection systems (EWIS) and/or structure. This course can be used by training providers for all maintenance persons at any stage in their careers.
A person can be trained to the appropriate level using the applicable modules depending on that person’s experience, work assignment, and operator’s policy.
This curriculum is divided into the following training modules.
MODULE A: General Electrical Wiring Interconnection Systems (EWIS) Practices This module lays the groundwork for safe, effective maintenance and repair of airplane EWIS and removal and replacement of line replaceable units (LRU), including built-in test equipment (BITE) testing, without damage to the airplane or injury to the student.
MODULE B: Wiring Practices Documentation The intent of this module is to teach the student how to locate desired information in the standard wiring practices manual (SWPM), wiring diagram manuals, and other applicable documentation.
MODULE C: Inspection This module teaches students the skills of inspection to identify wiring system damage.
MODULE D: Housekeeping This module teaches the student housekeeping strategies to keep the EWIS free of contamination.
MODULE E: Wire This module teaches the student about wire selection and inspection strategies.
MODULE F: Connective Devices This module teaches the student about identification, inspection, and repair of connective devices found on the airplane.
MODULE G: Connective Devices Repair This module is primarily a hands-on class, emphasizing the repair and replacement of connective devices found on the airplane. The list of types of connective devices in this module, and the training for them, can be used to cover typical connectors for airplanes and can be adjusted to suit training requirements.
Appendix C C-2
ELECTRICAL WIRING INTERCONNECTION SYSTEMS (EWIS) LESSON PLAN MODULE A: GENERAL ELECTRICAL WIRING INTERCONNECTION SYSTEMS (EWIS) PRACTICES Overview With Module A, the instructor lays the groundwork for safe, effective maintenance and repair of airplane EWIS and removal and replacement of line replaceable units (LRU), including built-in test equipment (BITE) testing, without damage to the airplane or injury to the student.
The instructor may vary the depth and scope of the topics to be covered, depending on the type of airplane to be maintained and skills of the students.
Objectives After completion of this module the student is able to demonstrate the following:
1. Knowledge of safety procedures for normal and non-normal maintenance procedures so the student can protect him/herself and the airplane.
2. Recognizing electrostatic discharge sensitive (ESDS) equipment and demonstrating standard anti-static procedures so that no damage occurs to that equipment.
3. Correct use of hand tools, including specialized and automated tools and equipment.
4. Verification of calibration of electrical measuring instruments, tools, and equipment so that correct maintenance procedures may be carried out.
5. The process and procedures for successfully using troubleshooting procedures and charts of current airplane faults and knowledge of re-occurring problems causing “no fault found” on removed LRUs.
6. Correct use of electrical meters for measuring voltage, current, resistance, continuity, insulation, and short to ground.
7. Knowledge of removal and replacement techniques for LRUs, so that no damage will occur to the LRU or airplane connector.
Hands-On Equipment and Teaching Aids Normal classroom lecture can be used for the majority of this training. The following hands-on equipment, teaching aids, and training exercises are recommended to expedite learning.
Equipment
• Airplane manuals
• Meters and circuits
• Company policy
Appendix C C-3 Teaching Aids
• Multimedia/training aids Training Exercises
• LRU removal and replacement
• ESDS device handling and protection
• Calibration/certification of instruments, tools, and equipment
• Wiring checks using troubleshooting procedures and charts
• Measurement and troubleshooting using meters