Search

Results for: wire system certification

SAE Wire and Cable Committee Meeting Update – Fall 2019

November 3, 2019 Michael Traskos

The SAE wire and cable committee held their fall 2019 meeting in San Diego this year. As with every committee meeting, a lot of technical areas were discussed, progress was made, and some new ideas/problems are emerged. As we do after all these meetings, we put together a highlight of some of the talking points from the meeting.

Wire Diagnostic Equipment

September 17, 2019 Michael Traskos

Finding wire faults/damage is not an easy task; now consider that problem across an entire aircraft. In-situ testing of wires/cables has always been viewed as something of a challenge to the industry. Given the branching that most harnesses undergo, the various wire lengths, splices, and numerous termination conditions, it can be difficult. Attempts to automate some of the testing has come to the development of Automatic Wire Test Sets (AWTS [pronounced “Eh-Wits”]).

Because there are so many ways to test a wire harness, the US military sought to create a performance standard to cover the general ideas and best practices of this equipment. Here, we review the standard and some of the performance features that can be expected when using equipment in compliance with the standard

Wires and Fuel Compatibility

August 7, 2019 Michael Traskos

Whether by design or by accident, some wires in an aircraft will be exposed to jet fuel. Because of this, it is necessary to be prepared and select wires/cable types that will not suffer adverse effects of the exposure. Considering the impact of fuel on wiring is not idle musing about wiring systems; to quote the FAA AC120-97A, “Since 1959, there have been 18 fuel tank explosions on transport category airplanes”. Read more

New Guidance for Wiring System Inspection

June 21, 2019 Michael Traskos

Back in November 2018, the US Navy released the second revision to the military handbook on “Guidelines for inspection of aircraft electrical wiring interconnect systems” (MIL-HDBK-522). This handbook is a guide for the aircraft EWIS inspection and provides a lot of detailed examples of wiring evaluation from beginning to end of the EWIS. Read more

Common Questions About Kapton® Wire

June 12, 2019 Michael Traskos

Love it or hate it, the fact is that Kapton® insulated wires will be on aircraft for at least another couple of decades, and because of this, we should learn to live with the insulation type. Part of living with it is understanding it. If you have questions that you would like to see answered, please send them to Lectromec or add them to the comments section below. We plan to add to this article as the questions arise. Read more

Principles of EWIS System Safety (25.1709)

June 4, 2019 Michael Traskos

Of the regulations encapsulating the 25.17XX EWIS group, none is more complicated than 25.1709. This regulation, consisting of only 31 words, can be the result of thousands of hours of labor, hundreds of pages of documentation, and requiring inputs from just about every system group working on the vehicle. If you step back from the regulation and ask, “What is necessary to show compliance?” it comes down to several factors. Here, we review some of the basic principles of 25.1709, where it impacts and interacts with other systems in the vehicle. Read more

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

Latest Developments in Wire and Cable (Spring 2019)

May 14, 2019 Michael Traskos

Wire and cable standards are never proactive, but reactive to industry needs, and as the aviation world moves to high power systems, wire and cable must catch up to ensure the products are available for long reliable service life. Twice a year the SAE wire/cable community comes together to slowly push the standards and industry guidance forward; this year, New Orleans was the setting.

During this three-day meeting, several topics were discussed impacting the next generation of aircraft designs. Here, we cover a couple of these developments.

High Voltage Impact the Aircraft Wiring System

March 18, 2019 Michael Traskos

For aerospace applications, high-voltage power is a rapidly growing interest and being addressed across several industry technical committees. The basic idea is that the power generation is increasing the supplied voltage and creating a need for the electrical wiring interconnects systems (EWIS) to have components designed to sustain these higher voltages for the entire length of the aircraft life. Just as it should not be expected for a connector to operate in a 300°C environment if it is only rated to 150°C, a connector should not be expected to perform perfectly with voltages exceeding its voltage rating. 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