EWIS Design Changes – How to Achieve a Safe Separation Distance

November 6, 2016 Michael Traskos

Those familiar with aircraft wire system design know the limited available space in which wiring is usually routed. Often in tight quarters with other wire harnesses, redundant systems, and hydraulic lines, it can be very difficult and intimidating to identify safe separation distances in design and for retrofits. Adding to the complexity, a wire harness […] Read more

Ampacity Improvements

October 24, 2016 Michael Traskos

When electrical current flows down a conductor, it gets warm due to resistive heating. The more current that flows, the warmer the conductor gets. Depending on the wire gauge, conductor conductivity, and ambient temperature of the wire location, the conductor temperature reaches the maximum certified temperature. This maximum electrical current is where the outward heat […] Read more

Meeting Requirements for EWIS Certification

October 14, 2016 Michael Traskos

There are more than 17 parts to the FAA’s Electrical Wiring Interconnection System (EWIS) regulations enumerated in the 25.1700 series. To show compliance with each of these regulations require a thorough subject area understanding. More so, as the EWIS evolves in design, it becomes clear that achieving EWIS certification requires a lot of data. If […] Read more

Understanding Coaxial Cables

October 4, 2016 Michael Traskos

The development and use of coaxial cables have come a long way since its invention in 1880. Improvements in design and reliability have made it a frequent feature for aircraft data transmission applications. In the realm of aerospace, a common coaxial specification is the MIL-DTL-17 coaxial cable standard. There are several parts to the MIL-DTL-17 […] Read more

Testing for AS50881

September 23, 2016 Michael Traskos

For several decades now, the AS50881 has been a fundamental knowledge base used for the installation of aircraft wiring systems. The requirements laid out in this standard cover the electrical wiring interconnection system (EWIS) design and recommendations on the selection of qualified parts. Additionally, the design must be verified to show compliance. For commercial aircraft, this may be done as part of the overall certification package. For the military, this may be part of design acceptance. This article covers some of the testing necessary for showing compliance with AS50881.

What are the Potential Issues with Tin Plated Conductors?

September 11, 2016 Tristan Epp Schmidt

Tin plated copper is a common choice for wire conductor within the aerospace industry. The advantages of using tin as the plating for copper conductors is the low cost, increases to solderability, and corrosion resistance. However, tin-plated conductor does have drawbacks. Here we review some on the key differences between common platings for aerospace wires. Read more

Standard Practice for Maintenance of Aircraft Electrical Wiring Systems

September 2, 2016 Michael Traskos

An industry as broad as the aerospace industry will have a variety of standards and recommended practices. The hope is that each standard brings something new through either a higher level of requirements or by providing better guidance to achieve a reliable aircraft. The ASTM Standard F2799 was written with the intention of being, “used […] Read more

EWIS SLEP Reassessment

August 9, 2016 Michael Traskos

In past articles, we have talked about a comprehensive assessment of Electrical Wire Interconnected System (EWIS) Service Life Extension Program (SLEP) that is possible with following the guidance laid out in MIL-HDBK-525. One of the areas that Lectromec did not cover thoroughly in these articles is what to do five or ten years after the […] Read more

Use of Cables on Aircraft – Part 3 – Testing

August 3, 2016 Michael Traskos

To continue the series of articles on NEMA27500 cables discussing their use on aircraft (part 1 and 2), this article focuses on the several tests that are necessary for cable verification and certification. There is some level of performance verification for each part of an aircraft cable. Most cable assessment tests focus on the performance […] Read more

Use of Cables on Aircraft – Part 2

July 14, 2016 Michael Traskos

In this article, we will continue the discussion by exploring the NEMA27500 cable. Four sections were covered in the Part 1 (Specification, identification and shield coverage, conductor size, and wire specification). The remaining three parts covered here are the basic component wires, shielding materials, and the jacket materials. Read more

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