No matter the industry or role, planning is a crucial part of any task’s successful completion. Well thought-out, SMART-goal driven plans help set the scene for activities, letting every stakeholder “see” the desired outcome, and how, when and even why that outcome will be achieved. When it comes to avionics, a great plan and “sticking to it” will invariably make or break your project.
In this article, we’re focusing on avionics software development and how to plan with DO-178C and related DALs in mind. We’ll start with a quick list of the primary components that every good DO-178C-related plan, and ultimately project, need:
1. Plan for Software Aspects of Certification (PSAC): Think of this as the parent plan to underlying child and sub sections of your plan. The PSAC should include a description of the software you plan to develop, the hardware environment it will be used in, the design assurance processes you will follow, and how you will demonstrate compliance, including implemented code verification and any commercial tools you will use in your verification.
2. Software Development Plan (SDP): This is a description of the software development processes and the software life cycle used to satisfy DO-178C objectives.
3. Software Verification Plan (SVP): SVPs detail the verification processes (Reviews, Analyses and Tests) used to satisfy DO-178C objectives. They can include project deliverables and responsibilities.
4. Software Configuration Management Plan (SCMP): The SCMP describes the methods and environment used to configure all of the design data and compliance evidence needed to achieve DO-178C certification.
5. Software Quality Assurance Plan (SQAP): A description of the methods and associated records that will be used to ensure that DO-178C quality assurance objectives are satisfied, SQAPs typically consist of the procedures, techniques and tools used to ensure that a product meets the project requirements.
For DALs C and higher, as well as producing the above planning documents, you will also need to establish and document the standards you will use for Requirements, Design, and Code, documenting the methods, rules, and tools you will use to ensure complete and consistent generation of these items in a way that will meet DO-178C and project objectives. It pays to put effort into writing your standards – having well thought out standards reduces the chance of incurring rework costs later due to issues that could be addressed through having better standards, such as producing unverifiable requirements.
As you need to describe the processes and tools you are going to use for verification during the Planning stage of a DO-178C project, you’ll need to ensure that what you plan to do for your verification is feasible and efficient before designing your code, let alone implement it. The earlier you invest in evaluating options for verification, the better. It pays to evaluate whether you will use manual processes or tools to satisfy each verification objective and evaluate the tools you intend to use while considering any tool qualification needs. The key thing to remember: any changes to your verification processes after the completion of SOI#1 would require renegotiation of your compliance strategy with your certification authority, which could add costs and delays to your project.
When your plans are complete and have been reviewed and signed off internally, it will be time to take the first step in the compliance process by having the SOI#1 review with your certification authority. The SOI#1 review is typically a “desk” review performed by the authority, who will thoroughly review all plans and standards to ensure that all applicable objectives of DO-178C and any relevant supplements will be satisfied if the development proceeds as documented in your plans. This review will result in either a report documenting any observations or findings that must be resolved, or acceptance that your plans and standards are compliant. Once your plans are accepted, the last step should be the easiest in the project’s lifecycle: follow the plan! Though avionics-related planning processes can be laborious, you can save countless time and energy by using a set of template planning documents as a starting point. However you prepare, make and execute your plan, it’s always worth the work. You’ll know the goals you want to achieve, have the record of milestones to reference throughout execution, and ultimately ensure your project has the best chance of success.