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

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

Smoke Resistance

The smoke resistance test places a high current through the wire/cable to determines if the insulation/jacket will produce smoke. The current is increase on the specimen until the conductor temperature reaches the rated insulation temperature. This test can be adjusted to examine the impact of wires/cables or secondary protection in the same harness. This of […] 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

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

Age Degradation

Some wire insulation types have well-defined accelerated aging processes, whereas others are rather non-active in terms of standard aging (heat, strain, and humidity). This procedure provides a vetted process for assessing the age degradation process for polyalkene wire. For non-polyalkene insulated wire/cable types, see Thermal Index. Life cycling of polyalkene wire is a three-step process […] Read more

Humidity – Connectors

Exposure to humidity is among the most common means of electrical equipment degradation. The humidity testing offers a means of assessing the potential for a in-service connector and/or crimped contact degradation due to heat and humidity. The problems are most pronounced on components with significant imperfections in the component plating. This test seeks to assess […] Read more

Thermal Shock

Temperature cycling can cause rapid degradation of wire/cable insulation integrity. This can manifest and insulation splits, cracks, and/or delamination. Often an overlooked test method for assessment, the thermal shock test proves and excellent means of assessing the construction quality of a wire or cable. The test focuses on a single high-temperature to low-temperature exposure and […] Read more

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