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

Can the EWIS be Safe After a Modification?

April 11, 2017 Michael Traskos

The days of ‘fit and forget’ EWIS are at least a decade behind, the aircraft industry’s understanding of the implications of wiring as a system continues to evolve. New aircraft have gone through EWIS evaluations to ensure that the EWIS complies to regulations – not an easy task. Obviously, as the OEM design choices remain […] Read more

EWIS Considerations for UAVs

February 13, 2017 Michael Traskos

Many of the Unmanned Aerial Vehicles (UAVs) built have been for military applications. As this technology has matured so has the reliability. The improvements in reliability have made it a viable consideration to support civilian applications. Right now, the FAA has not certified a UAV, but undoubtedly this will occur. This video provides a cursory […] Read more

EWIS Design Changes – How to Achieve a Safe Separation Distance

November 6, 2016 Michael Traskos

Those familiar with aircraft wire system design know the limited available space in which wiring is usually routed. Often in tight quarters with other wire harnesses, redundant systems, and hydraulic lines, it can be very difficult and intimidating to identify safe separation distances in design and for retrofits. Adding to the complexity, a wire harness […] Read more

Aircraft wire systems: Bent pin analysis

January 29, 2016 Michael Traskos

Previous Lectromec articles have focused on certain parts of system design such as the physical separation between systems. In particular, the articles have focused on the wiring. In this article, we will switch our attention to a different, but no less important, area: the Electrical Wiring Interconnect Systems (EWIS) connector assessment. Specifically, we will examine […] Read more

Taking a look at aircraft wire testing and evaluation

July 15, 2015 John Gilroy

For the past thirty years, Lectromec has been a leader in the area of aerospace wire testing and evaluation. In order to provide aerospace professionals with information to increase their knowledge of this complex topic, we began creating educational materials. Accordingly, Lectromec has published almost two-hundred articles, distributes a monthly newsletter, has a podcast, and […] Read more

EWIS regulatory compliance: 25.1703, Part II

June 16, 2015 Michael Traskos

Aerospace wiring requirements like the FAA regulation §25.1703 can be difficult to comprehend in one sitting. Lectromec has taken this complex document on EWIS regulatory compliance and divided it into some logical categories. In our last podcast titled An EWIS Perspective, we examined concepts in expected life and discussed how to select components designed for […] Read more

Aircraft EWIS regulations in China

October 2, 2014 Michael Traskos

There have been significant developments in the Chinese aerospace industry over the last couple of years. The largest of these developments is the design commencement of the Comac C919 narrow-body aircraft. It is a huge undertaking with the projected introduction into service in 2018. It has been necessary to standup an infrastructure capable to support […] Read more

7 considerations for aircraft wire separation

March 30, 2014 Michael Traskos

The development of a safe, reliable, and easy to maintain Electrical Wire Interconnection System (EWIS) is a challenging task. The considerations range from selecting each EWIS component, to matching the load and Electromagnetic Interference (EMI) requirements of the connected devices, to ensuring your design can maintain performance across multiple zone environments. EWIS design takes a […] Read more

Physical and functional EWIS issues included in Rule 25.1709

January 1, 2008 Lectromec Team

The recent set of FAA rules deal with physical and functional EWIS issues. The rules were released for the Enhanced Airworthiness Program for Airplane Systems/Fuel Tank Safety (EAPAS/FTS) places new requirements on system safety and certification of aircraft Electrical Wiring Interconnection Systems (EWIS). These new rules were effective as of December 2007. They are the culmination […] Read more

FAR 25.1709