Impact of Wires Used as Ladders

May 22, 2019 Devon Gonteski

Ideally, an aircraft’s EWIS aging is considered and monitored over time, but something as simple as gripping and pulling a wire or cable can change its electrical performance, specifically conductivity and resistance. Read more

How Much Does the Aircraft Environment Impact Wire Life?

March 1, 2019 Michael Traskos

When looking to select any aircraft component, typically the first means of down selecting from the wide variety of components that exists is based on the component’s performance characteristics i.e. can it perform the function to support the system. Next, the question then evolves to selecting those components that are best suited for the environmental conditions. This last part is more than just selecting the parts that are rated for the environmental conditions but also those that will have a long service life in those conditions. Ideally, the part will be reliable the entire service life of the aircraft and not require any replacement or additional maintenance; however, that usually is not the case (see Lectromec’s article on the immortal wire/cable). Read more

Use of MIL-T-81490 cable in place of a MIL-DTL-17 cable

December 20, 2018 Michael Traskos

A common ‘go-to’ cable for RF applications is the MIL-DTL-17 cable. Many of the MIL-DTL-17 cables are rated to 1 GHz, some to 12.4 GHz (like M17/128), and only a couple at 20GHz (e.g. M17/130 and M17/133 – a word of caution with the /130 and /133 constructions: these are unjacketed cables with an exposed external conductor/shield). There is the M17/205 construction that is spec’d for up to 50GHz, but that comes with a caveat: attenuation. The accompanying figure shows the attenuation per 100ft of M17/205 cable; while the attenuation does rise quickly with higher frequencies, the specification does not provide any attenuation limits beyond 10 GHz. 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

25.981 is Not a Barrier – Part 2

September 18, 2018 Michael Traskos

FAA regulation 25.981 covers the requirements of fuel tank ignition prevention. While there are numerous elements that must be considered as part of the 25.981 regulation, this is a Lectromec series of articles, and here we focus on the electrical hazards that must be identified and mitigated as part of certification. Read more

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

Galvanic Corrosion and Red Plague

July 7, 2018 Devon Gonteski

Some have brushed the issue aside saying that they have never seen it, thus it is not a problem. To put the issue of red plague into perspective, a worst-case estimate suggests as much as 3% of braided silver-plated copper shields have some degree of red plague. Across the aerospace industry, this equates to millions of dollars each year in scraped products, rewiring, and maintenance actions. Read more

Unwanted Energy Storage in Cables – Dielectric Constant

June 22, 2018 Tristan Epp Schmidt

A good wire insulation is more than just preventing electrical energy from leaving the conductor; there are dozens of properties that are important to its performance and usability. One of these that is easy to overlook is the wire’s dielectric constant. Read more

Getting the Right Data

May 2, 2018 Michael Traskos

How important is it to have the right data on your wire and cable products? For those seeking qualification to a product standard, having test data that matches the requirements is important. Without this data, qualification cannot happen. But what about the products that fall outside of industry standards? How many tests are necessary to […] Read more

Shield Grounding and EMI Protection – Part 2

March 20, 2018 Michael Traskos

EMI, the concept of electromagnetic interference, is a relatively simple one to convey: radiated energy from other sources induces a voltage in another circuit. But like many things, the simplicity of its description belies the true complexity of mitigating it. Shielding of signal wires, wire harness shielding, shielding of power wires, induced noise studies are […] Read more

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