Modular Open Systems Approach - (MOSA)

In May of 2023, Avilution enjoyed a spotlight moment regarding its eXtensible Flight System (XFS) software for avionics and mission systems integration. We participated in the U.S. Army’s Experimental Demonstration Gateway Exercise (EDGE 2023), held at the Yuma Proving Ground, AZ, May 15-18, 2023. In the world of software engineering, it often seems that the gremlins conspire to appear at the worst possible times. This is a story of how a change in approach regarding the implementation of safety-critical software permitted the defeat of last-minute gremlins.

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U.S. Army Aviation is aggressively implementing modular open system approaches (MOSA) for avionics and mission systems to ensure its aircraft maintain peak combat capability. Avilution LLC, a Huntsville-based avionics software startup, showcased its innovative eXtensible Flight System (XFS) software at the U.S. Army EDGE 2023. The demonstration highlighted the company's unique approaches to leveraging effective MOSA for achieving rapid avionics upgrades to multiple Army aircraft.

In preparation for the demo, Avilution collaborated with the U.S. Army Program Executive Office–Aviation and the UH-60V Black Hawk avionics prime contractor, Northrop Grumman, to design and test the needed modifications. Utilizing the interoperability inherent in XFS’s reconfigurable software microservices, Avilution required less than four months to adapt and bench test its modular software for integrating the PRC-167 radio “under the glass” of the existing UH-60V cockpit display units. This short development time highlighted Avilution’s use of an efficient Continuous Integration/Continuous Delivery (CI/CD) cycle and the intrinsic flexibility of XFS software modules adapted from one use case to another by changing only the necessary parameter data items (PDI) in the associated configuration files. No source code changes or changes/retesting of the operating system (OS) or the aircraft’s operational flight program (OFP) were required. Northrop Grumman (NG) then completed an “All LRU Test” with the XFS configuration in its UH-60V system integration laboratory (SIL) and found 100% compatibility between XFS and the host NG mission computer. Similarly, Avilution coordinated with the avionics contractor on the CH-47F Chinook, Collins Aerospace, to allow PRC-167 radio control from its existing pilot display, as well.

Preparations complete, Avilution arrived at EDGE 2023 prepared to swiftly install and demonstrate the PRC-167 radio application in an actual Georgia Air National Guard UH-60V aircraft and the CH-47F simulator. After installation, however, we received from the pilots two heretofore unmentioned requirements: support for P25 public safety call groups and a continuous guard monitor function on the PRC-167 radio. Making relatively minor additions to the appropriate UH-60V and CH-47F configuration files, and aided by the 90-95% code reuse between the two platforms despite their significantly different avionics architectures, Avilution was able to make the necessary changes on-site and still complete both demonstrations the same day, appreciative of our new friends from the Georgia Guard for helping us underscore our point about XFS adaptability and responsiveness.

This interoperability was made possible by the generic design of XFS microservices around a constrained number of common avionics design patterns, customized for each use case by its configuration file, and by the powerful data protocol translation capabilities resident in XFS whereby all input is translated into the common XFS data bus protocol then all outputs re-translated back into the receiving component’s respective protocol.

On the second day, at the request of the Army’s Cargo Helicopter Project Office, Avilution took advantage of the last-minute availability of a PRC-158 radio to demonstrate its integration into both the CH-47F avionics simulator and the UH-60V aircraft. This off-the-cuff decision to add unplanned installations of the PRC-158 radio was part serendipity (the unexpected availability of the radio and its ICDs), and part well-reasoned opportunism. Having designed XFS microservices for rapid reconfigurability, and recognizing that the PRC-158 shared a common design pattern with the -167 that meant no source code changes would be required, we knew we had a potential opening to highlight XFS’s adaptability in a very dramatic way. Without the benefit of any preparation work beforehand (drum roll here), we were able to integrate and successfully demonstrate the PRC-158 operating in both aircraft architectures in one day of effort!

On day three, as a crowning achievement, we updated the XFS configuration files for dynamic reconfigurability, so both radios could be installed on both aircraft and have the avionics systems automatically support whichever radio was active, even if they were hot-swapped during flight. To our knowledge, no other COTS avionics and mission systems software has demonstrated such adaptive, automatic, real-time, reconfiguration capability.

We had bested the gremlins, three days in a row.

In total, these integrations—including the real-time additions—were completed and successfully demonstrated within just four months of contract award. Avilution's participation in EDGE 2023 provided back-to-back-to-back real-world examples of XFS’s ability to rapidly integrate the MOSA upgrades in legacy Army Aviation platforms necessary to counter today’s rapidly evolving threats.

J.T. Naylor, who led Northrop Grumman’s strategy for UH-60V avionics development, lauded the performance by saying, "This demonstrates exactly the kind of rapid capability development that the Army is seeking to address a highly dynamic environment. "This is the holy grail for Army Aviation—the ability to rapidly integrate operational capability without the onerous timelines, cost, and proprietary hurdles that have historically plagued our efforts. That’s why the Army initiated the UH-60V program: to break that paradigm. This demonstration shows that we really can implement new operational capability in weeks rather than years.”

For avionics software engineers, it doesn’t get much better than that.