Life-Limiting High Voltage Parts

March 15, 2022 Michael Traskos

Life-Limited EWIS parts can be useful where high voltage conditions make component degradation rates uncertain. Though accelerated aging can offer insight to the component’s condition, further observations of high-voltage systems will be needed for accurate degradation predictions. Read more

ICA Guidance for HIRF and Lightning Protection

February 21, 2022 Laura Wishart

The advisory circular 33.4-3, issued by the FAA offers guidance for developing adequate ICA for an aircraft’s HIRF and lighting protection functions. Read more

Relative Thermal End Point Time and Temperature Index

The chemical composition of a wire’s insulation degrades at elevated temperature; this test provides data to establish curves describing the rate of degradation with respect to the exposure temperature. Samples are divided into four groups; each group is exposed to a selected temperature for defined time intervals. The time intervals are determined by an estimate […] Read more

Review of EWIS for Sustainment

January 30, 2020 Michael Traskos

We measure everything that matters. In the last decade, the efforts of organizations to measure EWIS has been progressively increasing. Perhaps this is because wiring is now considered a system, or because regulations and requirements have emerged, or it may be due to a better understanding of the EWIS maintenance costs. Whatever the reason for better EWIS maintenance issue quantification, it has been a positive because there is data available to substantiate aircraft maintenance actions. The old saying is, “You can’t beat something with nothing”, and for too many years, EWIS maintainers were trying to take on EWIS maintenance without supporting data. Read more

Principles of EWIS System Safety (25.1709)

June 4, 2019 Michael Traskos

Of the regulations encapsulating the 25.17XX EWIS group, none is more complicated than 25.1709. This regulation, consisting of only 31 words, can be the result of thousands of hours of labor, hundreds of pages of documentation, and requiring inputs from just about every system group working on the vehicle. If you step back from the regulation and ask, “What is necessary to show compliance?” it comes down to several factors. Here, we review some of the basic principles of 25.1709, where it impacts and interacts with other systems in the vehicle. Read more

Have we Reached the End of Aging Aircraft Wiring Systems?

October 17, 2018 Michael Traskos

The way some in the aerospace industry maintain their aircraft wiring system can only lead an external observer to reason that aircraft wiring is impervious to damage with a life-span greater than the sun. When considering this thought, the question arose, “It is possible that aircraft wiring reached a point where aging/degradation is a thing of the past?” Read more

Should Polyimide Insulated Wire be Trusted?

September 25, 2018 Michael Traskos

The history of polyimide insulated wire is one that has numerous opinions and a lot of misconceptions. After several incidents involving polyimide wire on aircraft in both military and commercial, many within the aerospace industry refused to put any polyimide insulated wire/cable onto the aircraft they design/maintain. As is often the case with components involved in incidents, a lot of facts and myths get jumbled together. Read more

Condition Based Maintenance and Risk Quantification

June 29, 2018 Michael Traskos

Aircraft maintenance is usually broken down one of two ways: by physical zones or by systems. The mechanical equipment and subsystems integrity program, also known as MECSIP, is the US Air Force’s approach to addressing aircraft sustainment and maintenance through focused system evaluation. Last week, MECSIP managers from many of the Air Force fleets gathered in Dayton, Ohio to discuss the latest developments, procedures, and technologies for addressing the MECSIP needs of their fleets. Read more

Aging Aircraft Wire

May 22, 2018 Michael Traskos

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 were more than two times likely to suffer problems with their wiring system. There are tools and analyses to get ahead of these issues. Read more

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