Appendix C C-4
MODULE A
GENERAL ELECTRICAL WIRING INTERCONNECTION SYSTEMS (EWIS)
PRACTICES
1. Safety practices
a. Current is lethal – first aid
b. Applying power to the airplane
c. Isolating the circuit
d. Airplane warnings
e. Human factors
2. Electrostatic discharge sensitive (ESDS) device handling and protection
a. ESDS devices
b. Sources of electrostatic discharge
c. Soft and hard failures
d. ESDS safety procedures
e. ESDS handling/packing procedures
3. Tools, special tools, and equipment
a. General hand tools
b. Specialized tools
c. Automated tools and equipment
4. Verifying calibration/certification of instruments, tools, and equipment
a. Tools requiring calibration/certification
b. Determining calibration/certification requirements
c. Typical problems
5. Required wiring checks using troubleshooting procedures and charts
a. Troubleshooting procedures manuals, including fault isolation manual (all chapters)
b. Aircraft maintenance manual/illustrated parts catalog
c. Wiring schematics/troubleshooting graphics
d. Wiring diagrams
e. The troubleshooting process
f. Testing of line replaceable unit (LRU) connectors
g. Troubleshooting exercises
h. Company “no fault found” policy and data
6. Measurement and troubleshooting using meters
a. Voltage, current, and resistance
b. Continuity
c. Insulation
d. Short to ground
e. Loop impedance
Appendix C C-5
7. LRU replacement general practices
a. Different retention devices
b. Certification considerations (e.g., Category (CAT) 2/CAT 3 landing)
c. LRU re-racking procedures
d. “No fault found” data (airplane specific)
e. Built-in test equipment (BITE)
Appendix C C-6
ELECTRICAL WIRING INTERCONNECTION SYSTEMS (EWIS) LESSON PLAN MODULE B: WIRING PRACTICES DOCUMENTATION Overview With Module B, the instructor lays the groundwork for safe, effective maintenance and repair of airplane EWIS. The intent of this module is to teach how to locate desired information in the standard wiring practices manual (SWPM), wiring diagram manuals, and other applicable documentation. The instructor may vary the depth and scope of the topics to be covered depending on the type of airplane to be maintained and the skills of the students.
Objectives After completion of this module, the student is able to demonstrate the following:
1. Knowledge of applicable subchapters and sections to follow during normal and non-normal electrical maintenance procedures.
2. How to use cross-reference indexes, chapter tables of contents, and subject tables of contents to find specific material within each subchapter and section.
3. How to use the associated tables for replacement of wire, connective devices and contacts, and associated components, including approved replacements.
4. How to use wiring diagram manuals.
5. How to use other documentation (as applicable).
Hands-On Equipment and Teaching Aids Normal classroom lecture can be used for the majority of the training. The SWPM, wiring diagram manuals, and other applicable documentation should be made available to the class for hands-on exploration of the material.
Appendix C C-7
MODULE B
WIRING PRACTICES DOCUMENTATION
1. Standard wiring practices manual (SWPM) structure/overview
a. Table of contents
b. Subchapter titles
c. Section structure
d. General procedures
2. SWPM cross-reference index
a. Cross-reference index – alphanumeric
b. Cross-reference index – standard part number
c. Cross-reference index – suppliers
d. Equivalence tables – standard part numbers
3. SWPM important data and tables
a. Contact crimp tools, insertion/extraction tools
b. Wire insulation removal tools
c. Electrical cable binding
d. Wire type codes and part numbers identification
e. Connective devices types and contacts
f. Terminal blocks and terminations
g. Terminal blocks modules, grounding modules, and contacts
h. Cleaning procedures
i. Repair procedures
4. Wiring Diagram Manuals (WDM)
a. Front matter
b. Diagrams
c. Charts
d. Lists
5. Other documentation (as applicable)
Appendix C C-8
ELECTRICAL WIRING INTERCONNECTION SYSTEMS (EWIS) LESSON PLAN MODULE C: INSPECTION Overview With Module C, the instructor lays the groundwork for safe, effective maintenance and repair of airplane wiring systems by teaching the inspection skills for identifying wiring system damage.
The instructor may vary the depth and scope of the topics to be covered depending on the type of airplane to be maintained and the skills of the students.
Objectives After completion of this module the student is able to demonstrate the following:
1. Knowledge of the different types of inspections.
• General Visual Inspection (GVI).
• Detailed Inspection (DET).
• Special Detailed Inspection (SDI).
• Zonal inspection.
• Enhanced zonal analysis procedure (EZAP).
2. Knowledge of criteria and standards of inspection and the correct tools to use to ensure inspection procedures and standards are achieved so that all defects will be found.
3. Knowledge of how human factors (for example fatigue and complacency on the part of the inspector) can affect inspection and how to combat their effects.
4. Knowledge of specific zonal inspection requirements related to system affiliation and environmental conditions.
5. How to recognize typical electrical wiring interconnection system (EWIS) damage such as hot gas damage, external mechanically-induced damage, fluid contamination, chafing, corrosion, and signs of overheating of wire, wire bundles, and connective and control device assemblies.
Hands-On Equipment and Teaching Aids Normal classroom lecture can be used for the majority of this training. The Airlines for America (A4A) Specification 117 video on wire maintenance and color photos of actual wiring system damage could be used to show typical problems found on the airplane. Examples of discrepancies should be made available to the students. AC 25-27, Development of Transport Category Airplane Electrical Wiring Interconnection Systems Instructions for Continued Airworthiness Using and Enhanced Zonal Analysis Procedure, is recommended as a source for typical aircraft wiring installations and areas of concern.
Appendix C C-9
MODULE C
INSPECTION
1. Types of inspections
a. General Visual Inspection (GVI)
b. Detailed Inspection (DET)
c. Special Detailed Inspection (SDI)
d. Zonal inspection
e. Enhanced zonal analysis procedure (EZAP)
2. Criteria and standards
a. Tools
b. Criteria/standards
c. Inspection procedures
3. Human factors in inspection Examples:
a. Fatigue
b. Complacency
4. Zonal areas of inspection
a. Zonal areas of inspection
b. Zonal inspection procedures and standards
5. Electrical wiring interconnection systems (EWIS) damage
a. Damage from swarf1/metal shavings and other foreign objects
b. External mechanically-induced damage
c. Hot-gas-induced damage
d. Fluid contamination
e. Vibration/chafing
f. Corrosion
g. Signs of overheating
1 See Appendix D for definition.
Appendix C C-10
ELECTRICAL WIRING INTERCONNECTION SYSTEMS (EWIS) LESSON PLAN MODULE D: HOUSEKEEPING Overview With Module D, the instructor lays the groundwork for safe, effective maintenance and repair of airplane electrical wiring interconnection systems (EWIS) by teaching housekeeping strategies to keep the EWIS free of contamination. The instructor may vary the depth and scope of the topics to be covered depending on the type of airplane to be maintained and the skills of the students.
Objectives At the completion of this module the student is able to demonstrate the following:
1. How to recognize external contamination and other damage due to external environmental conditions.
2. Knowledge of airplane internal contamination sources, so that inspection processes can be effectively carried out and contamination damage easily recognized.
3. How to recognize other possible contamination sources.
4. Knowledge of planning procedures to be followed on EWIS areas in different parts of the airplane.
5. Knowledge of procedures and processes to protect the EWIS during maintenance and repair.
6. Knowledge of the process of cleaning EWIS during maintenance and repair.
Hands-On Equipment and Teaching Aids Normal classroom lecture can be used for the majority of the training. The Airlines for America (A4A) Specification 117 wire maintenance video and color photos of actual EWIS contamination could be used to show typical problems found on the airplane. Relevant Aircraft Maintenance Manual (AMM) and/or standard wiring practices manual (SWPM) procedures should be used.
The Aging Transport Systems Rulemaking Advisory Committee (ATSRAC) Working Group 1 Non-Intrusive Inspection Final Report could be used to identify typical housekeeping issues. AC 25-27, Development of Transport Category Airplane Electrical Wiring Interconnection Systems Instructions for Continued Airworthiness Using and Enhanced Zone Analysis Procedure, is recommended as a source for typical aircraft wiring installations and areas of concern.
Appendix C C-11
MODULE D
HOUSEKEEPING
1. Airplane external contamination sources
a. Deicing fluids
b. Water and rain
c. Snow and ice
d. Miscellaneous contamination (e.g., cargo/beverage spillage)
e. Air erosion
2. Airplane internal contamination sources
a. Hydraulic oils
b. Engine and auxiliary power unit (APU) oils
c. Fuel
d. Greases
e. Contaminants from galleys and toilets
f. Lint/dust
g. Bleed air and hot areas
h. Hazardous materials
3. Other contamination sources
a. Paint
b. Corrosion inhibitor
c. Metal shavings/swarf
d. Foreign objects (screws, washers, rivets, tools, etc.)
e. Animal waste
4. Contamination protection planning
a. Have a plan – types of plans/area mapping
b. Protection and caution recommendations
c. Procedures
d. Keep cleaning
5. Protection during airplane maintenance and repair
a. Recommended general maintenance protection procedures
b. Recommended airframe repair protection procedures
c. Recommended powerplant repair protection procedures
6. Cleaning processes
a. Fluid contamination
(1) Snow and ice
(2) Deicing fluid
(3) Cargo spillage
Appendix C C-12
(4) Water and rain
(5) Galley contaminants
(6) Toilet water waste
(7) Oils and greases
(8) Pressure wash
b. Solid contamination
(1) Metal shavings/swarf
(2) Foreign objects (screws, washers, rivets, tools, etc.)
c. Environmental contamination
(1) Lint and dust
(2) Paint
(3) Corrosion inhibitor
(4) Animal waste
Appendix C C-13
ELECTRICAL WIRING INTERCONNECTION SYSTEMS (EWIS) LESSON PLAN MODULE E: WIRE Overview With Module E, the instructor lays the groundwork for safe, effective maintenance, alteration, and repair of airplane electrical wiring interconnection systems (EWIS) by teaching wire selection and inspection strategies. The instructor may vary the depth and scope of the topics to be covered depending on the type of airplane to be maintained and the skills of the students.
Objectives At the completion of this module the student is able to demonstrate the following:
1. The procedure for identifying specific wire types using airplane manuals.
2. Knowledge (from approved data) of different insulation types and their relative qualities.
3. Knowledge of inspection criteria for wire and wire bundles.
4. Knowledge of standard installation practices for wire and wire bundles (airplane specific).
5. Knowledge of typical damage that can be found (airplane specific).
6. Repair procedures for typical damage found on the student’s type of airplane.
7. Procedures for fitting different types of sleeving (airplane specific).
8. Knowledge of procedures for termination and storage of unused wires.
9. Knowledge of correct installation practices for electrical bonds and grounds (airplane specific).
Hands-On Equipment and Teaching Aids Normal classroom lecture can be used for the majority of this training, with hands-on practice for the repair procedures in section 6. Standard wiring practices manuals (SWPM) and Wiring Diagram Manuals (WDM) should be made available to the class for hands-on use so that wire identification, inspection, installation, and repair procedures can be fully explored. Examples of wire discrepancies should also be made available to the student. The Aging Transport Systems Rulemaking Advisory Committee (ATSRAC) Working Group 1 Intrusive Inspection Final Report could be used to identify typical wire issues. AC 25-27, Development of Transport Category Airplane Electrical Wiring Interconnection Systems Instructions for Continued Airworthiness Using and Enhanced Zonal Analysis Procedure, is recommended as a source of information on typical aircraft wiring installations and areas of concern.
Appendix C C-14
MODULE E WIRE
1. Identification, type, and construction
a. Wire type codes – alphanumeric
b. Wire type codes – specification and standard part number
c. Wire type codes – specified wire and alternate
d. Manufacturer identification
2. Insulation qualities
a. Types of insulation
b. Typical insulation damage and limitations
c. Carbon arcing
3. Inspection criteria and standards for wire and wire bundles
a. Inspection of individual wiring
b. Inspection of wire bundles
4. Wire bundle installation practices
a. Routing
b. Segregation rules
c. Clearance
d. Clamp inspection
e. Clamp removal and fitting
f. Conduit types and fitting
g. Raceways
h. Heat shields and drip shields
5. Typical damage from different causes and areas found (airplane specific)
a. Vibration
b. Heat
c. Corrosion
d. Contamination
e. Personnel traffic passage
6. Maintenance and repair procedures
a. Wire damage assessment and classification
b. Approved repairs/improper repairs
c. Shielded wire repair
d. Repair techniques
e. Terminals and splices
f. Preventative maintenance procedures
Appendix C C-15
7. Sleeving
a. Identification sleeves
b. Shrink sleeves
c. Screen braid grounding crimp sleeves
d. Screen braid grounding solder sleeves
8. Unused wires – termination and storage
a. Termination – end caps
b. Storage and attachment
9. Electrical bonding and grounds
a. Inspection standards
b. Primary bonding (High Intensity Radiated Field (HIRF) protection)
c. Secondary bonding (system grounding)
d. Lightning strikes