ACARS and the Uncertain Road to Obsolescence

2019-05-31  |  4 min read 

Aviation electronics (avionics) must improve performance and capabilities while ensuring lasting use in systems with long lifetimes. The Aircraft Communications Addressing and Reporting System (ACARS), for example, has been in use since 1978. This system, which enables messages to be sent between aircrafts and ground stations, originally used Telex – an early way to electronically send written messages. It continuously evolved with technology developments to increase its effectiveness, leveraging capabilities like satellite and broadband links. Yet some say ACARS will now fade into oblivion with the emergence of the Internet Protocol Suite (IPS).

IPS for Improved Communication Performance

The Airline Executive Engineering Committee (AEEC) IPS for Aeronautical Safety Services is currently developing a plan to define the future use of a new network infrastructure for aviation safety services communications. According to its working group, a strict aviation focus limits both the current ACARS network and the Aeronautical Telecommunication Network (ATN) infrastructure. What is needed, states the site, is a “modern, off-the-shelf, efficient, and robust network infrastructure common to both air traffic services (ATS) and aeronautical operational communications (AOC) safety service applications.”

IPS will be designed to provide better air-to-ground data communication performance than the legacy ACARS and ATN networks. By advancing data communication technologies used for NextGen and SESAR airspace initiatives, the working group says that the project will benefit airlines, airframe manufacturers, and avionics suppliers. Key to IPS is its use of line-of-sight and beyond-line-of-sight (BLOS) subnetworks, which will operate in dedicated spectrum.

Unanswered Questions & Timeline

Proponents of ACARS, however, point out how entrenched it is in the aviation industry, handling millions of messages globally. While some may assume that these messages are strictly air to ground, they are actually sent between aircraft, air traffic control (ATC), and airline operational control (AOC) centers. They are also transmitted from the ground out to other parts of the network.

Yet the question is not actually how much the aviation industry relies on ACARS, as that is a known fact. It is whether IPS will be able to replace all ACARS capabilities. The needs and corresponding roadmap for IPS in aeronautical safety services are still being defined. There will undoubtedly be a transition phase in which all three systems – ACARS, ATN/OSI, and IPS – will co-exist. The question is whether ACARS will still be in use after that transition.

The transition to IPS will be a long-term process carefully managed to accommodate both legacy and new aircrafts. Security and other considerations need to be worked out as well, with cybersecurity being a chief concern. At the end of it, however, the retirement of ACARS is broadly anticipated. Yet there is another fate discussed, in which ACARS evolves to become part of IPS. Only time will tell, but it will take at least a decade to standardize and validate a new technology for aviation safety services. Deployment must follow on a delay, which means ACARS is not going to be obsolete in the very near future.

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