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New RTCA Committee to Begin Work on Wireless Avionics MOPS

By Woodrow Bellamy III  | July 25, 2016
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[Avionics Today 07-25-2016] A new committee formed by the Radio Technical Commission for Aeronautics (RTCA) is preparing to develop a standard to define the future concept of operations for Wireless Avionics Intra-Communication (WAIC). The International Telecommunications Union (ITU) formed the new committee, Special Committee 236 (SC-236), at the request of the FAA, as well as the result of a major approval of a new frequency band for WAIC last year. 

Wireless aircraft depiction. Photo: Aerospace Vehicle Systems Institute (AVSI).

At the 2015 World RadioCommunication Conference (WRC), ITU approved the use of the 4,200 MHz to 4,400 MHz frequency band for wireless avionics communications. Until then, the industry could not achieve wireless communications for onboard safety-related aircraft functions because international regulations did not permit the use. The aviation industry effort toward obtaining approval for the use of the band began as far back as 2008, according to a February 2016 report on the approval released by the Airbus Group. Coordination for the joint effort to obtain the approval last year was overseen by the Aerospace Vehicle Systems Institute (AVSI), and included researchers from Embraer, Honeywell and United Technologies Aerospace Systems, with support from BAE Systems, Bombardier, GE Aviation, Gulfstream, and Texas A&M University.

WAIC consists of short-range radio communications occurring in distances of less than 100 meters between two or more points of a single aircraft, according to a presentation on the subject given by AVSI Director David Redman at the Passive Wireless Sensor Technology Workshop following the ITU’s approval of the WAIC band last year. Wireless sensors used for monitoring aircraft cabin pressure, fuel tank levels, and structural health, are examples of potential applications for WAIC technologies. Redman also believes wireless avionics communications can help to reduce OEM reliance on miles of redundant wiring required for aircraft integration of software intensive systems on today’s aircraft that add performance and safety functionality.

The European Organization for Civil Aviation Equipment (EUROCAE) Working Group 96 started working on Minimum Operational Performance Standard (MOPS) for WAIC in 2015, and the new RTCA committee was formed as the result of a request from the FAA as well as several industry organizations expressing interest in establishing a joint committee between EUROCAE and RTCA on the WAIC MOPS. 

RTCA Program Director Rebecca Morrison, also a former Rockwell Collins engineer, told Avionics Magazine the committee's initial goal will be to define how this new pipe will be used onboard the aircraft. After that, the industry can move on to concentrating on what type of hardware or applications can start communicating in the newly available frequency band.

"What this committee is going to do first is define a stable pipe that will be used for wireless communications on the aircraft for avionics. Once that has been defined from radio frequency level, it won’t matter to the pipe what gets transmitted over it. So, our first job is to make that pipe definition and to address as part of it how WAIC systems do not interfere with each other and how they do not interfere with existing avionics, particularly radio altimeters since they share a frequency band," Morrison said. 

According to the Terms of Reference (TOR) for SC-236, the MOPS will allow WAIC systems to share the 4,200 to 4,400 MHz band with radio altimeters and other WAIC systems. The committee is also looking to allow the worst-case performance of a WAIC system to be determined, as these two aspects are major prerequisites for proof of airworthiness for future WAIC systems. 

As an engineer, Morrison is well aware of the future use cases and clear benefits that the WAIC MOPS will provide to aviation industry system integrators, manufacturers and suppliers once achieved. 

"I think for the committee members, they are excited about defining the standard and making sure there is no interference with other systems or radio altimeters. But from an operational point of view, allowing wireless communication for avionics is going to have a significant impact on aircraft performance and efficiency. Any time you can do a wireless bus instead of 429, which is a very heavy bus to implement because it’s one-way point-to-point, that leads to less wiring, which leads to less weight on the aircraft, which can lead to a reduction in fuel burn and CO2 emissions. Even with [Avionics Full-Duplex Switched Ethernet] AFDX, which is an avionics routed bus, less wire is used, but you still have the Ethernet wiring throughout the plane. This has the potential to change a lot about how communications occur inside the aircraft,” said Morrison. 

Michael Franceschini, a senior engineer with Honeywell Aerospace, will serve as the chair for SC-236. While the newly formed RTCA committee already has 37 members from 19 different industry organizations, Morrison said the committee is still welcoming new members who are interested in helping to develop the MOPS. SC-236 expects to complete the MOPS requirements by 2019.

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