AIR7502 and Future Implications for Aviation

July 8, 2022 Laura Wishart

The AIR7502 defines voltage levels for HV aircraft and components. The extent to which AIR7502 is incorporated into the aerospace industry remains unsure, but the implications of the document are worth considering even before the document’s use is determined. Read more

EWIS High Voltage Certification

April 14, 2022 Michael Traskos

With the gradual industry implementation of high voltage EWIS systems in aviation, the demand for HV-specific safety standards is rapidly growing. High voltage OEMs currently use available industry standards, as applicable, but are still left with the task of developing and justifying their own system requirements. The SAE’s AS50881 standard, often considered the ‘go-to’ standard for OEMs, could benefit from proposed updates made to address the gaps for high voltage systems. Read more

ICA Guidance for HIRF and Lightning Protection

February 21, 2022 Laura Wishart

The advisory circular 33.4-3, issued by the FAA offers guidance for developing adequate ICA for an aircraft’s HIRF and lighting protection functions. Read more

S&T 2021 Meeting Report

January 20, 2022 Laura Wishart

A discussion covering the topics of interest presented at the FAA’s annual S&T meeting in 2021. Read more

Verification and Validation

November 1, 2021 Devon Gonteski

Amidst the manufacturing process, a structured system of quality assurance is of utmost importance; implementation of a standardized evaluation system is key to ensuring that whatever is being made is up par for its certain usage. In the world of technology and manufacturing, the evaluative journey of a product from start to finish is broken up into multiple segments.

Relative Thermal End Point Time and Temperature Index

The chemical composition of a wire’s insulation degrades at elevated temperature; this test provides data to establish curves describing the rate of degradation with respect to the exposure temperature. Samples are divided into four groups; each group is exposed to a selected temperature for defined time intervals. The time intervals are determined by an estimate […] Read more

A New Revision of MIL-HDBK-522

October 20, 2021 Laura Wishart

A new version (Revision C) of MIL-HDBK-522 was released on May 11, 2021. This article examines many of the changes made between Revision B and Revision C. Read more

Environmental Stress Crack

Environmental stress crack tests a sample ethylene plastic’s susceptibility to cracking as a result of environmental stress and the presence of selected chemicals (soaps, oils, detergents, etc.). Pre-damaged samples are mounted into the test fixture and submerged in a selected reagent (may depend on standard/ application) at a specified temperature. Specimens are inspected for evidence […] Read more

In Consideration of Backshells

September 1, 2021 Michael Traskos

The backshell of a connector is an item that perhaps does not get the attention that it should. Often the discussion of EWIS focuses on the wiring, the connectors, or managing the risk of EWIS failures, but the connector backshell is ignored. The simple connector backshell (that is anything but simple) is designed for support and protection of wires and cables physically and, in the case of signal cables, support and protect electrically too. The following is a brief introduction to backshells, their use, associated standards, and research that has been performed to determine what to look for when performing maintenance.

Addressing the Big Questions of Partial Discharge

June 11, 2021 Michael Traskos

In this high-voltage present, wires and cables must address new challenges, perhaps the most notable is partial discharge (also referred to as corona). This article discusses the fundamentals of partial discharge, its impacts on wiring design, and test methods used to assess a component’s partial discharge performance. The PD may occur between (1) the conductor and insulation, (2) within void in the insulation, (3) between insulation layers, or (4) between the insulation surface and shield. Read more

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