Getting the Right Bonds

November 22, 2019 Michael Traskos

Things were so much easier with aluminum aircraft structures. The structure acted as an EMI shield, electrical grounding could be done right to the structure without additional effort, and the electrical mating of the structure was straight forward. Now, with composite structures, aircraft design concepts such as electrical bonding, particularly in the case of handling lightning strikes, becomes more important.

When done right, the impact of a lightning strike should have a limited impact.

In this article, we review the concepts around primary aircraft bonding, its requirements, and the implementation as they relate to lightning strike.

DO-160, EWIS, and EMI

August 6, 2018 Michael Traskos

Designing a circuit diagram for a system comprised of Line Replaceable Units (LRUs) is usually a straightforward process: identify the inputs and outputs of the system and connect them with wires and cables. Taking that simple high-level circuit diagram and implementing the physical design into an application can be quite difficult. This requires the proper connectors, optimized the physical routing, and ensuring negligible impact from electromagnetic interference (EMI). From an implementation perspective, it cannot be understated how much EMI can impact system performance ranging from degraded performance to make a system completely inoperable. Thankfully, there are test methods to evaluate the susceptibility of electromagnetic interference of a wire harness design. 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.