Avoiding EMI

April 17, 2018

William Kucinski

Aircraft produced and operated today increasingly rely electrical and electronic equipment to perform various functions. If one of these electronic functions were to fail, the impact felt by, say, a passenger jet could be as mundane, yet irritable, as a failure in the in-flight entertainment system.

Alternatively, it could result in the catastrophic system failure of the aircraft.

Regardless of the aircraft function, the equipment that powers it and the interconnecting wiring unavoidably generate and are exposed to various types of transient surges, electrical and magnetic fields, and spurious noise—all of which could occur over a wide range of frequencies and amplitudes.

If these anomalies are not mitigated or managed, they could lead to adverse electromagnetic interference, or EMI, to equipment and systems. While the term EMI is used when referring to undesirable electrical effects that occur on an aircraft, electromagnetic compatibility, or EMC, refers to the goal of aircraft system compatibility.

This past week, SAE International published a new technical standard that provides detailed information, guidance, and methods for demonstrating EMC on civil aircraft.

The standard, ARP60493: “Guide to Civil Aircraft Electromagnetic Compatibility (EMC) ,” describes civil aircraft regulations and provides guidance for achieving aircraft EMC compliance. It also details approaches for aircraft electrical and electronic equipment qualification testing and result analysis.

This wide-ranging document is specifically oriented to civil aircraft such as small general aviation aircraft, passenger airlines, and helicopters. The SAE International AE4 Electromagnetic Compatibility committee, which developed the standard, was established to provide a technical and advisory function specifically in the field of aerospace EMI. The group studies various electrical and electronic accessories in spacecraft, aircraft, and propulsion systems for compatibility with various communications media.

According to Mike Riley, co-chair of the SAE International AE4 Electromagnetic Compatibility committee (which developed the standard), it’s the first document to comprehensively address EMC demonstrations on aircraft and will become the standard for all EMC compliance demonstrations in the aerospace industry—both in the United States and Europe.

“What this means for the average air traveler is less chance of interference between the various aircraft systems, which means a safer flight,” said Riley.

And of course, a better passenger experience.

SAE International’s global reach resulted in ARP60493 being developed with contributions by more than 50 working group members from Belgium, Brazil, Canada, France, Japan, Spain, Germany, the United Kingdom, and the United States. The document (which also standardizes EMC demonstrations in Europe) was jointly rolled out by the European Organisation for Civil Aviation Equipment (EUROCAE) as ED-248 “Guide to Civil Aircraft Electromagnetic Compatibility (EMC).”