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 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-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 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 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

Use of aircraft “shelf wire” and aircraft wire life projection

Management

Suppose that your customer wants to know if the wiring in the cables, harnesses, or devices that your company produced is good. What if they have questions about aircraft wire life projection. Perhaps the cable that you used was a MIL-spec wire, but had been on the shelf or in the manufacturing plant for a number of years. Rewiring all of the devices produced would likely take a great deal of time and labor and push the delivery of your product out many months. So what steps can you take to prove to your customer that the cable is still good?

Step 1. Determine the Extent of the Questionable Wire Usage

If the amount of wire used is rather limited, in some cases it might be cost effective to simply remove the wire. In other cases, additional alternative may need to be considered.

Step 2. Speak with Those Handling the Wires

Those that put the wire into the harnesses or devices are usually the first to know if there were problems. These technicians should be asked questions like:

wire life projection
Using wire that has been sitting on the shelf for 20 years? Check before you use.
  • Were there any problems experienced with this type of wire?
  • Did any lengths of the wire have to be thrown away due to poor quality?

Sometimes this first hand knowledge of handling the wire may be good enough for your customer.

Step 3. Perform a Visual Inspection

Examine the wire for visible defects. Is the insulation flaking off or are there a number of cracks in the topcoat? Is there any discoloration visible?  It is likely if the wire insulation was extremely poor condition that some action would have been taken by the technicians piecing together the product. If the wire is in good condition, consider allowing your customer to personally inspect a wire sample.

If you are interested in wire life projection, you may want to read The “Big 3” aircraft wire system degradation assessment options.

Step 4. Selected Testing

The last step would be to perform a select array of tests on a sample of the wire.  Because performance of all of the tests outlined in a wire specification would cost too much and would be a waste or resources, a select few tests can be performed to test most of the material properties of the insulation and conductor. Additionally, if there is a specific problem, then perhaps a single testing method could be employed. This can be done at a fraction of the cost and provide a significantly faster turnaround time for a result. Lectromec has experience developing such plans that can be done quickly and effectively to meet the needs of your customers.

Lectromec first evaluates the conditions under which wire will be placed, then, with our knowledge of wire insulation failure mechanisms (physical, thermal, and mechanical) for most wire insulations, a reduced test set can be developed and delivered to be reviewed with your customer. Once the testing is agreed upon, Lectromec performs the tests and delivers a report on the condition of your wiring.

Determining the best most effective solution to satisfy your customer’s needs is important. Whether this can be accomplished with a simple report from technicians using the wire or needs a selected number of tests, it is important to ensure that the wiring systems are in peak condition to ensure system reliability. And, if in the end testing is needed, Lectromec will be available to meet your needs.

Lectromec

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.