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

Getting the Most from Visual Inspections

Maintenance & Sustainment

Good data is anything that can be turned into actionable information; this is a critical element in nearly every project. For those that regularly perform EWIS inspections, unless the data is gathered in such a way to improve the aircraft reliability, address technical errors, and/or be used as part of trend analysis, the effort is wasted.

EWIS inspection is an important part of the EWIS Service Life Assessment Program (SLAP) outlined in MIL-HDBK-525 and MIL-STD-1798. To gain the most value from the EWIS inspection portion, proper preparation is necessary. Here we review what you may be missing in your EWIS inspection effort.

Putting EWIS Inspections into Context

Aircraft EWIS visual inspection is the third task of the military handbook providing guidance on wiring system assessment supporting a life extension effort. This task comes after and is supported by the first two tasks focused on maintenance data analysis and EWIS system safety analysis. The data gathered from the visual inspection task is intended to support the assessment in multiple facets:

  1. Support the data gathered during the EWIS system level assessment (task one) by verifying and/or augmenting the existing system separation data from fuel lines or other wires
  2. Investigate the maintenance action hot spots highlighted from the maintenance data information.
  3. Determine what areas should be sampled from as part of the degradation analysis to be conducted in task four.
EWIS visual inspection
A quick visual inspection of this area could identify three issues. A detailed data-supported inspection can help the long-term reliability of the aircraft.

Getting your Checklist Ready

As with most tasks, the level of preparation determines the performance. While a trained crew will be able to identify many EWIS anomalies, the value of the EWIS inspection goes beyond anomaly detection. The inspection must support the overall SLEP objectives, and should be directed accordingly. The best means of matching the project’s objectives is with a thoroughly developed checklist. The checklists that are included as part of MIL-HDBK-525 provides a good starting point. These checklists provide the fundamentals of the aircraft EWIS inspection, but to get the full value, they must be customized.

Customization

The customization should focus on those areas that have been highlighted in other tasks. Consider the following examples:

  1. During the maintenance data analysis (task #2), the equipment supporting the landing gear is identified as a source of regular maintenance issues. In particular, the two wire harnesses in the wheel well are identified as contributing to a majority of the issues, specifically, the maintenance items indicate data/signal integrity issues. The inspection should include examination of the connectors for proper grounding/shielding, proper connector selection (i.e. ensure they are rated for the environment), and the tightness of the cable/harness bend into the backshell.
  2. During task #1 (EWIS assessment) a pair of wire harnesses, containing redundant systems were collocated in a high maintenance area. The EWIS physical failure analysis found that a minimum of a 2.0” separation distance is necessary to keep the systems isolated. The system design drawing suggest that the systems are separated by 2.5”; the inspection should examine the inter-harness separation distance.

Post Processing

There should be at least two outputs from this task: a report and a re-integration. The first item is a standard inspection report that highlights any findings and items that do not conform to best practices. The findings should include two classifications:

  1. Severity of non-conformity: Typically partitioned by Major and Minor, these identify the criticality and potential impact if not rectified.
  2. In-scope: When an aircraft is built, a set of design principles are placed onto the aircraft. While the inspection should consider modern design requirements and standards (such as AS50881), it should be cognizant of the standards used in the aircraft sustainment.

Second, the results should be re-integrated into the fleet sustainment and not be considered as a standalone item. Hopefully, this will have a positive impact on the EWIS reliability and highlight the areas that can be improved upon.

Conclusion

EWIS sustainment requires the amalgamation of various knowledge and skill sets. Even within the EWIS inspection task, multiple skills must be combined and supported. Knowledgeable application of EWIS risk assessment information, guided by maintenance data analysis, is the best way to get the most value out of the effort. Lectromec has the knowledge and skill sets to get the most value from your EWIS service life extension work. Contact us to find out how we can greatly enhance your service life assessment project’s value.

Michael Traskos

Michael Traskos

President, Lectromec

Michael has been involved in wire degradation and failure assessments for more than a decade. He has worked on dozens of projects assessing the reliability and qualification of EWIS components. Michael is an FAA DER with a delegated authority covering EWIS certification and the chairman of the SAE AE-8A EWIS installation committee.