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Aging aircraft wiring is a problem affecting the entire aviation industry. Lectromec’s evaluation of the 2016 service difficulty reports found that aircraft over 25 years old are more than two times likely to suffer problems with their wiring system.

Key Takeaways
  • Bulk maintenance data analysis of EWIS failures is possible with advanced tools
  • Predictive analysis of EWIS failures can help to organizations preemptively address EWIS issues
  • Knowing your fleet’s EWIS health opens new options for maintenance

In response to this information, some have said that aging aircraft wiring is inevitable, and nothing can be done short of full wire system replacement. The same people feel as though the EWIS inspections of aging aircraft wire systems have limited effectiveness and are equivalent to trying to hold back the ocean tide with a sheet of plywood.

This leads to the question, are we doomed to suffer from aging aircraft wire? In Lectromec’s opinion, the answer is no.

While this may have been the case 20 years ago, the industry has come a long way. There are methods, procedures, and assessments to get a handle on aging wire. These tools and techniques have evolved significantly to the point that it is now possible to provide predictive, not reactive, assessments on aircraft wiring. These predictive analysis techniques make it possible for maintainers to better plan for the future of their aircraft.

This article covers how this can be done. We go through the methods and analyses that make it possible to ensure the longevity of your aging aircraft wire.

Data Analysis

Across all segments of the aerospace industry, there is one constant; the true impact of degraded wire system is under-represented. This is more fully described in other articles Lectromec has published, but it can be summed up by three letters: NFF.

Insulation Resistance Test Animation
Break the cycle of NFF. Learn how much EWIS contributes to your maintenance problems.

Frequently when a problem is finally solved by addressing the root cause, that is eventually added to the maintenance entry for the system and not specifically attributed to wiring. This makes it difficult to do bulk queries and data analysis on the maintenance data.

However, by using advanced data analysis techniques, such as those developed by Lectromec, it is possible to not only pull out those maintenance records with a high likelihood of being attributed to wire system issues but also identified the chain of events eventually solved by addressing the root cause, the aging wire system.

The root of these data analysis techniques is the work Lectromec has put into the review of thousands of maintenance records. This made it possible to identify the common keywords/phrases and understand the methods by which wire failures are described. This work has culminated in the development of advanced data analysis tools for EWIS failure identification.

While these tools do not provide the necessary information for predictive maintenance, it does provide a good basis to understand the scope of the problem.

Aging Aircraft Wire
If you knew that your wiring system would be more than twice as likely to fail in 10 years, and that you could do something today to reduce the failure rate, would you? Contact Lectromec to find out how.

For example: If the maintenance data analysis shows an average of 30 wire issues per aircraft per year, this sets the baseline for assessment. But what if this data can be supported by an aging analysis showing an increased failure rate over the next five years? Would that make the information more useful?

Preventative maintenance

An old banana is easy to identify; the brown age spots, texture change, and overall firmness are different from one that is new and fresh. Unfortunately, the same cannot be said for all aircraft wiring type. Modern wire insulations are complex polymers that have multiple modes of degradation.

Some wire types are more prone to radio cracks in the insulation, where others are more likely to suffer from hardened insulation. Depending upon the environmental factors, some wire insulations will split along the length of the wire.

To make it possible to predict the future performance, and potential degradation of EWIS components, 30 years of research and analysis have been performed by Lectromec. This research has provided the foundation and framework to make predictive maintenance of wiring systems possible. And with each area of the aircraft having different environmental factors, maintenance, and operational considerations, the degradation is nonuniform but can be assessed and future performance can be predicted.

After the data

Without the EWIS health information and without knowing how the wire system will degrade over the coming decade, the options are limited. Those looking to maintain an aging aircraft wiring system without health information are limited to:

  • Reactive wire system maintenance
  • Unnecessary full wire harness replacement
  • Broad unfocused wire system inspections

Maintainers willing to be more proactive in their EWIS maintenance can move forward with a larger set of options:

  • Identify the high-risk areas to enhance maintenance
  • Data to support focused preventive maintenance actions
  • Identify the limited areas in need of replacement
  • Support decisions on obsolescence planning
  • Clarify life extension needs.

Making a Difference for Your Fleet

Aircraft wires age, but that does not mean that they are unusable. With proper analysis identification of the aging, it is possible to predict the remaining service life, and what is necessary to maintain aircraft airworthiness. For a long time, the problem has been a lack of techniques and reliable methods to protect their performance. As a member of the industry for the last 34 years, Lectromec has helped multiple fleets move from being reactive to be proactive about their wiring system.

The start with a preliminary assessment of the fleets that you maintain, contact Lectromec. As specialists in the certification of aircraft wire system to wire system components, we can help you get from where you are to where you want to be. Contact us today to setup an appointment.

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.