Latest Posts

Aircraft wiring schematics require clear standardized diagrams for design, fabrication, installation, maintenance, and safety assessments. This article explores the scope of MIL-HDBK-863, details it prescribes for wiring schematics, discusses some gaps, and other relevant wiring diagram standards.

Impedance matching is crucial to minimize reflection and signal loss in many high frequency EWIS applications. In this article, we discuss the factors impacting cable impedance, its impact on attenuation, and useful factors for selecting the right EWIS components for the application.

The SAE J1127 and J1128 standards define two classes of automotive vehicle wiring. SAE J1127 covers heavy gauge *battery cables* (e.g. starter and chassis ground leads) and SAE J1128 covers lighter *primary wires* used in general purpose wiring harnesses. In this article, we review the J1127 and J1128 wire standards, the extent of testing performed on these wires, how they stack up against aerospace wires, and if there are parts of these standards that could benefit their aerospace counterparts.

In the case of high reliability, high-bandwidth data transmission, quadrax cables may emerge as a viable option for some designs. A typical quadrax cable has two layers of shielding each with at least 85% optical coverage for maximum EMI protection. This article discusses the potential applications, performance capabilities, comparisons to similar cable types, and installation/maintenance challenges of quadrax cables.

The aerospace industry should consider automotive standards like the ISO 6722 as a basis for high-voltage wire qualification. Automotive and aerospace standards development around electrical wiring components will have common characteristics though some might argue that aerospace requires greater reliability. This article reviews the ISO 6722 standard and the performance characteristics that are expected of single core road vehicle wire with voltages between 60 and 600 volts.

The decision of whether to fully complete cable harness assembly before or during installation on aircraft is non-trivial and requires multiple engineering perspectives. The decision may depend on factors such as maturity of the design, available working space on the aircraft, or simply the maneuverability of a completed harness. In this article we discuss many of the considerations that go into this decision and show that there is no one-size-fits-all “correct” approach that applies to all installations.

Partial discharge testing serves as a valuable tool for assessing the health and reliability of wire and cable systems. Understanding the implications of PD test results, including PDIV, PDEV, and factors influencing their values, is essential for ensuring the safety and longevity of critical EWIS components. In this article, we discuss what PD test results mean at the component and system levels.

Understanding the differences in fire and flammability tests for aircraft components is critical to ensuring safety and compliance with FAA regulations. In this article, we discuss the varying fire performance levels —flame resistant, fire resistant, and fireproof— which are tailored to meet the unique challenges posed by different aircraft zones. These distinctions emphasize the importance of precise material design and testing to meet rigorous standards, as outlined in AC 20-135 and AS50881.

EWIS maintenance sometimes includes the demating and remating of electrical connectors for testing, cleaning, removal to access other equipment, etc. The repeated action of mating/demating can cause mechanical stress on the connector and contribute to component degradation. In this article we discuss the MIL-DTL-38999 Durability test method in which connectors are mated/demated for hundreds of cycles to assess the degradation effects that may arise in the life cycle of the connector after months or years of regular maintenance.

Every year, Lectromec creates a video to celebrate the holiday season. This year, we decided to utilize some of the lab’s high voltage test equipment. This year’s holiday video titled, “A Spark of Holiday Cheer” showcases the how far AC arcs can be drawn out at different voltages. Starting at just over 15kV, the arcs […]