View Latest Blog Entries
Close
Categories
Testing & Assessment Certification Aging Wires & Systems Standard & Regulation Management Maintenance & Sustainment Conference & Report Research Protection & Prevention Arcing Miscellaneous
Popular Tags
Visual Inspection AS50881 MIL-HDBK MIL-HDBK-525 High Voltage FAR Electromagnetic Interference (EMI) FAR 25.1707 AS4373 Maintenance Wire System Arcing Damage
All Tags in Alphabetical Order
2021 25.1701 25.1703 abrasion AC 33.4-3 Accelerated Aging ADMT Aging Systems AIR6808 AIR7502 Aircraft Power System aircraft safety Aircraft Service Life Extension Program (SLEP) altitude arc damage Arc Damage Modeling Tool Arc Fault (AF) Arc Fault Circuit Breaker (AFCB) Arc Track Resistance Arcing Arcing Damage AS22759 AS22759/87 AS23053 AS4373 AS4373 Method 704 AS50881 AS5692 AS6019 AS83519 AS85049 AS85485 AS85485 Wire Standard ASTM D150 ASTM D2671 ASTM D8355 ASTM F2696 ASTM F2799 ASTM F3230 ASTM F3309 ATSRAC Attenuation Automated Wire Testing System (AWTS) Automotive backshell batteries Bent Pin Analysis Best of Lectromec Best Practice bonding Cable Cable Bend cable testing Carbon Nanotube (CNT) Certification Chafing Chemical Testing Circuit Breaker circuit design Circuit Protection Coaxial cable cold bend collision comparative analysis Compliance Component Selection Condition Based Maintenance Conductor conductors conduit Connector connector selection connectors contacts Corona Corrosion Corrosion Preventing Compound (CPC) Cracking D-sub data analysis data cables degradat Degradation Delamination Derating design safety development diagnostic Dielectric breakdown dielectric constant Dimensional Life disinfectant Distributed Power System DO-160 dry arc dynamic cut through E-CFR Electrical Aircraft Electrical Component Electrical Power Electrical Testing Electromagnetic Interference (EMI) Electromagnetic Vulnerability (EMV) EMC EMF EN2235 EN3197 EN3475 EN6059 End of Service Life End of Year Energy Storage engines Environmental Environmental Cycling environmental stress ethernet eVTOL EWIS certification EWIS Component EWIS Design EWIS Failure EWIS sustainment EWIS Thermal Management EZAP FAA FAA AC 25.27 FAA AC 25.981-1C FAA Meeting failure conditions Failure Database Failure Modes and Effects Analysis (FMEA) FAQs FAR FAR 25.1703 FAR 25.1707 FAR 25.1709 fault tree Fixturing Flammability fleet reliability Flex Testing fluid exposure Forced Hydrolysis fuel system fuel tank ignition Functional Hazard Assessment functional testing Fundamental Articles Future Tech galvanic corrosion Glycol Gold Gold plating Green Taxiing Grounding hand sanitizer handbook Harness Design Hazard Analysis health monitoring heat shrink heat shrink tubing high current high Frequency high speed data cable High Voltage HIRF History Hot Stamping Humidity Variation HV system ICAs IEC60172 IEEE Inspection installation installation safety Instructions for Continued Airworthiness insulating material insulating tape Insulation insulation breakdown insulation resistance insulation testing interchangeability IPC-D-620 ISO 17025 Certified Lab ISO 9000 J1673 Kapton Laser Marking life limit life limited parts Life prediction life projection Lightning liquid nitrogen lunar maintainability Maintenance Maintenance costs Mandrel mean free path measurement mechanical stress Mechanical Testing MECSIP MIL-C-38999 MIL-C-85485 MIL-DTL-17 MIL-DTL-23053E MIL-DTL-3885G MIL-DTL-38999 MIL-E-25499 MIL-HDBK MIL-HDBK-1646 MIL-HDBK-217 MIL-HDBK-454 MIL-HDBK-516 MIL-HDBK-522 MIL-HDBK-525 MIL-HDBK-683 MIL-STD-1353 MIL-STD-1560 MIL-STD-1798 MIL-STD-464 MIL-T-7928 MIL-T-81490 MIL-W-22759/87 MIL-W-5088 MIL–STD–5088 Military 5088 modeling moon MS3320 NASA NEMA27500 Nickel nickel plating No Fault Found OEM off gassing Outgassing Over current Overheating of Wire Harness Parallel Arcing part selection Partial Discharge partial discharge at altitude Performance physical hazard assessment Physical Testing polyimdie Polyimide-PTFE Power over Ethernet power system Power systems predictive maintenance Presentation Probability of Failure Product Quality PTFE pull through Radiation Red Plague Corrosion Reduction of Hazardous Substances (RoHS) regulations relays Reliability Research Resistance Revision C Rewiring Project Risk Assessment S&T Meeting SAE SAE Committee Sanitizing Fluids Secondary Harness Protection Separation Requirements Series Arcing Service Life Extension Severe Wind and Moisture-Prone (SWAMP) Severity of Failure shelf life Shield Shielding Shrinkage signal cable Silver silver plated wire silver-plating skin depth skin effect Small aircraft smoke Solid State Circuit Breaker Space Certified Wires Splice standards Storage stored energy supportability Sustainment System Voltage Temperature Rating Temperature Variation Test methods Test Pricing Testing testing standard Thermal Circuit Breaker Thermal Endurance Thermal Index Thermal Runaway Thermal Shock Thermal Testing tin Tin plated conductors tin plating tin solder tin whiskering tin whiskers top 5 Transient Troubleshooting TWA800 UAVs UL94 USAF validation verification video Visual Inspection voltage voltage differential Voltage Tolerance vw-1 wet arc white paper whitelisting Wire Ampacity Wire Bend Wire Certification Wire Comparison wire damage wire failure wire performance wire properties Wire System wire testing Wire Verification wiring components work unit code

Understanding aircraft wire differentiation to improve EWIS

Management

The amount of aircraft wire on a civil aircraft has increased in recent decades such that today’s typical aircraft has hundreds of miles of wire connecting all of its subsystems. The increase in the amount of wire on an aircraft, coupled with weight concerns, has lead to progressively thinner and lighter insulation materials. Wires used on today’s aircraft are 70% lighter and occupy 20% of the space of their 1950’s counterparts. When considering that the insulation on today’s wires can be as thin as three human hairs, we should realize that modern aircraft wiring is a fragile, yet critical component of the overall aircraft electrical interconnect system. Each insulation material has advantages and disadvantages that make it perform well under some circumstances and unacceptably in others. Some wires are especially resistant to fire, others are resistant to chafing. Before selecting a type of wire to install on an aircraft, one should understand the properties of the insulating material and the environmental conditions to which the wire is exposed (Lectromec’s testing services) can provide the data you need to select the right wire for your application).

Additionally, identifying types of wire can be extraordinarily difficult because wires come in a variety of colors and may not have any identifying markings. It is also difficult to identify wire based on the type of aircraft in which it is found and even experts on the subject are often unable to identify wire types with only a visual inspection. We have presented two types of wire and summarized their properties to illustrate the wide range of advantages and disadvantages to different types of insulation.

wire differentiation

Aromatic Polyimide (Cross Section Photo of M81381-11)

  1. Trade names: Kapton™, Apical™
  2. Identification codes: BMS 13-51, MIL-W-81381/7 through /14 and /17 through /21, DMS 7007, and others
  3. Aircraft used in:
    • Space Shuttle
    • Airbus
    • B727
    • B737
    • DC-10
    • F-14
    • F-16
    • P-3 (Not all-inclusive)
  4. Advantages:
    • Lightweight, typically 4.6lbs./1,000 ft. (6.8 kg/km)(20 AWG)
    • Good abrasion and cut-through resistance
    • Passes standard low temperature chemical flame tests
    • Excellent thermal and electrical properties
  5. Disadvantages:
    • Will crack or delaminate when it ages
    • Prone to wet and dry arc tracking
    • Will deteriorate when exposed to heat or stress
    • The only insulation type mentioned by the Federal Aviation Administration (FAA) as not to be mixed with other insulation types because of its propensity to cut through softer insulations
  6. Overall: Widely used in commercial, aerospace and military vehicles because of its light-weight and resistance to abrasion. Not found on new aircraft as much because of its propensity to sustain high temperature electrical arcs. Note: the preceding information applies only to the H-film build seen in the left column photo. The DuPont OasisTM insulation will be addressed in a future Lectrogram.

Polyvinyl Chloride (Constructed with Nylon topcoat)

wire differentiation
  1. Trade name: Quad 4™ (Cross Section Photo of Quad 4&trade)
  2. Identification codes: BMS 13-13, MIL-W-5086/1 and /2
  3. Aircraft used in:
    • B707
    • B727
    • B737
    • DC-8
    • DC-9
    • KC-135
    • A-10
    • C-130 (Not all-inclusive)
  4. Advantages:
    • Good resistance to chafing (thicker insulation)
  5. Disadvantages:
    • Loss of dimension and weight over time
    • Discolors with moderate heating
    • Produces harmful gasses and smoke when it burns
    • Comparatively low temperature rating measured against aromatic polyimide
    • Heavy, about 6.8 pounds/1,000 ft (10 kg/km) (20 AWG)
  6. Overall: Will not pass the FAA’s 60º flame test. Gasses from burning are extremely harmful if inhaled. Although this wire does not meet current standards, it is still found on some older aircraft.

It is not just insulation that protects wires, but also a trained maintenance staff. When maintaining or replacing wires, it is vitally important to understand their properties. The wrong wire placed in the wrong environment can significantly impact aircraft airworthiness. Proper electrical systems maintenance and care can both improve aircraft readiness and help retain the resale value of your aircraft.

Michael Traskos

This article was written by the Lectromec technical team. Aircraft wiring is our passion and we strive to make a contribution to the field by sharing our expertise through blogs, podcasts, and videos. We hope you find this information helpful. We also encourage you to submit comments and spur discussions.