Verification and Configuration Management for Avionics Systems

The performance of verification and configuration management is essential to the ARP4754A document and other avionics development documents. ARP4754A, officially titled Guidelines for Development of Civil Aircraft And Systems, is concerned with “the development of aircraft systems taking into account the overall aircraft operating environment and functions.”

It is a document that addresses the entire lifecycle of the development of aircraft and accompanying systems. Therefore, it is inevitable that it would also cover instructions for the validation of the requirements, even up to necessary post-certification activities. 

Note, though, that the use of the term ‘configuration management’ is not limited to the ARP4754A context. It is used across engineering. One of the five plans in DO-178C is a Software Configuration Management Plan. The plan covers the development team’s "strategy to control baselines, versions, changes, and ability to recreate software.” Likewise, there is a Hardware Configuration Plan under the partner document of DO-178C, DO-254. 

The configuration management process could be defined as the “application of administrative and technical procedures throughout the life cycle of the integrated on-board equipment complex (OBE), its components, and associated data.” The configuration management process plan often covers the following:

development of the configuration management environment (procedures, tools, methods, standards, responsibility, and interaction in the configuration management activities);

Let’s go over some documents where verification and configuration management is necessary for avionics development:

The full title of DO-178C is ‘Software Considerations in Airborne Systems and Equipment Certification’. It is the primary document that provides the framework for avionics software development, the global standards, as well as the certification requirements. With its supplements, this document stretches over 600 pages. It details airworthiness and safety requirements pertaining to avionics software development. This covers design, coding, testing, quality assurance, and so on.

DO-178C was introduced in 2011 to serve as both a replacement and clarification for the DO-178B.

The DO-254 is the hardware counterpart of the DO-178. It is fully titled, ‘Design Assurance Guidance for Airborne Electronic Hardware’. 

It was mainly introduced to set guidelines for the growing adoption of firmware in avionics. At the time, firmware was proliferating development and remained largely unregulated. Some of the avionics hardware systems that the document sets guidelines for, apart from firmware, are field-programmable gate arrays (FPGA), programmable logic devices (PLD), circuit boards, etc. as well as other complex electronic hardware systems. 

Guidelines for Development of Civil Aircraft and Systems (ARP475A) is a set of guidelines by the Aerospace Recommended Practices. Unlike DO-178C and DO-254, ARP4754A places a greater emphasis on safety practices. Also, it is not restricted to either aspect of the hardware-software divide. Instead, it contains principles for safety-critical systems in aircraft development, both hardware and software. ARP4754A is like a personal health handbook, but for aircraft, this time. 

Configuration management is usually performed with a tool, though it could work manually as well. 

DO-178C, for example, does not demand special tools for avionics configuration management, even though a tool may be helpful. The tool you use depends on what features you desire and what you want to achieve. Basic configuration management tools, for instance, include software version control, document management, as well as check-in/check-out. The advanced configuration management tools, which are certainly more expensive, provide statusing, problem tracking, version branching, etc. as well as greater automation of the management process. 

Alternatively, you can always perform configuration management for avionics software manually, with paper and a pen. Keep in mind, though, that this may be less efficient and more prone to errors compared to dedicated configuration management tools.

More importantly, you should note that there are certain configuration management steps that are not usually covered within a dedicated avionics configuration management tool. For processes such as data security, offsite backups, continuous peer reviews, and so on, you must perform them separately. 

The performance of configuration management is important to the development of safety-critical aircraft systems. It is always worth the effort to ensure that all the components of aircraft are working appropriately. Verifying that the right configurations have been used is only one step in this regard. But it is critical and must not be ignored.