A quick look at the relevance of avionics embedded cards and associated communication standards like MIL-STD-1553 and ARINC-429 in the field of avionics

The industry is continuously shifting, with aircraft manufacturers looking for the smallest and the lightest equipment for their upgrades. That puts the pressure on embedded systems suppliers to innovate and provide better solutions. While aviation and embedded systems are two fields that experience continued research and development, there are some systems and protocols that have passed the test of time.

The Relevance of Avionics Embedded Cards

Today, let’s take a look at the longstanding relevance of some of the most popular avionics embedded cards - from MIL-STD-1553 to ARINC-429 to PCI Express Interface boards.
Most equipment that is an essential part of an aircraft I/O was considered for this brief study. Starting with the most important ones.

MIL-STD-1553B is Still a Relevant Protocol

Data networking standards have undergone massive shifts in the industry, thanks to the continuous requirement of fast, reliable, and cost-effective equipment. But MIL-STD-1553B – the popular network standard that provides a data rate of up to 1 Mbps – is still regarded highly for its safety and reliability. Of course, it requires some changes – some of which are already ongoing – so as to align with the current requirements in the aerospace and avionics industries. But that hasn’t restricted it from being used across applications ranging from cockpit communications design and military communication systems.

But what really makes MIL-STD-1553B a relevant standard is its very long product life cycle. Some of the additional features of the MILBUS (MIL-STD-1553) that will continue to make it relevant for decades are:

• Its physical layer has high electromagnetic immunity, thereby providing extremely low rates in harsh conditions (extreme temperatures, for example)
• High synchronicity with support for acyclic messages in an aircraft
• A fast command overwrite function allows for better reaction to operational changes

MILBUS, in general, is still favored over enhanced models mostly because of its longevity that tends to reduce as features are upgraded.

ARINC-429 – An Integral Element of Modern Avionics

ARINC 429 is still an integral component of airplane protocol. It supports an aircraft’s avionics main data bus and local area network. And it has been around for decades. Thanks to its superior signaling and communication features.

Despite the enhancements in the field of data bus since the 1980s, ARINC-429 still remains relevant because of its ability to keep older, old-school systems in connection. The uniform language – used in the communication between different systems in an aircraft – helps the standard stay on top of the mind of engineers, suppliers, and manufacturers.

The problem with upgrading the electronics system of an aircraft is that if one element is upgraded, everything has to be upgraded. Unless manufacturers are ready to innovate and look at overhauling all of their systems, ARINC-429 is here to stay as well, as a universal interface to relay information in and out of aircraft systems.

It may be interesting to note the most recent update in enhancing the data bus interface. The United Electronic Industries (UEI) announced the launch of an updated interface – called DNx-429-516 ARINC-429 – that has 8 additional RX channels. This would naturally increase the possibilities in which aircraft systems contact each other.

PC/104-Plus – Increased Development

The rugged PC/104-Plus specification has quickly garnered attention from companies all over the world during its short introduction. Its small form factor, high speed, and self-stacking bus ability have placed it among the lines of its predecessor and other popular bus extenders. This earnest interest by companies makes it one of the important avionics embedded cards that are still relevant in the industry.

Some of its top applications other than in avionics are:
• High-performance single-board computers
• High-speed LANs
• Communications interfaces such as USB and IEEE-1394
• Full-motion video interfaces
• PCI adapters
• Control interfaces (including cockpit systems)

Such wide applications that are only going to expand in the next few years is a clear indication of its steady growth and relevance.

MACC and Other Connection Devices

A connector that binds all of these components discussed above together is the Miniature Airborne Communications Converter (MACC). Its main task is to build a communication line between integrating components that were not originally designed to work together. Naturally, as long as there is scope and demand for standards like MIL-STD-1553 and protocols like ARINC-429, MACC will continue to be in demand.

Other auxiliary devices such as MARC recorder (used in black boxes) and power supply components also are important in building or connecting these devices. The aircraft I/O is a very complex system that is only as good and rugged as the components it is made up of.

So, when standards as discussed above are still in use and will be in continuous use for at least the next decade, such auxiliary tools become important too.

A Steady Growth of Avionics Embedded Cards

In November 2008, Ed McKenna, writing for Avionics International, discussed about the upcoming trend of use of embedded systems and cards in avionics. He said that it would take some time for the industry to understand the true power of embedded systems which are helping fuel “the digital transformation of civil and military aircraft.” That was nearly 12 years ago and here his forecast has come true.

Two years before the article, it was claimed that nearly 4 billion embedded systems or devices were shipped for use in avionics. Anyone can only guess how the numbers have risen (gone beyond astronomical figures) for almost a decade and a half since then, further confirming the increasing relevance of avionics embedded cards.

“Developers are using embedded systems not only to address specific technology needs but also stiff challenges triggered by growing technology complexity and safety and security requirements,” McKenna starts the article and continues to talk about commercial-off-the-shelf (COTS) systems among others. It is not too surprising to see how the industry has embraced the incoming power of embedded cards and their versatile nature in the field of avionics.

With the internet and LAN only making communication easier for the components, it will remain to be seen how these embedded cards and their associated standards help the industry innovate and increase the power of avionics. As of now, one can only wish for the industry to come back to its feet post he epidemic and continue the innovation happening in the ongoing marriage between embedded systems and avionics.