If you’re new to DO-254 or DO-178C compliance requirements – maybe you’re working on a UAV or military project – and you’re just starting to look at this, you might thing “Wow, this looks like a lot of work! What’s the point?”
For those who have had to comply already, many times I hear engineering teams and their management complain that DO-254 or DO-178C has cost them a lot of time and a lot of money. And they can – on both accounts. But usually, when I get to review the work that these teams have done to comply with DO-254/DO-178C, I realize they’ve made a lot of mistakes due to their misunderstanding about why they are applying this design assurance standard in the first place. They have done a lot of work but essentially missed the point.
Always remember that the reason DO-254 or DO-178C is being required is as a means of compliance to the CFRs (or EASA CSs) in order to demonstrate that the hardware or software item being developed “performs its intended function under all foreseeable operating conditions” for its intended use on the aircraft, engine or propeller it is to be installed on. The Design Assurance level (DAL) is established based on the item’s possible functional impact given its intended use on the aircraft, engine or propeller. The DAL adjusts the amount of rigor required under DO-178C or DO-254 in order to demonstrate this functionality is correct.
Keeping the primary goal and understanding of the Certification regulation in mind will help guide you, so you spend your time and effort on what is important: producing a design that functions as intended in the aircraft.
There are a lot of tips that can help keep you on track during DO-254 and DO-178C programs. I’ve provided a lot of information addressing common questions, problems, things to do, and things to avoid, in these blogs. So enjoy them, internalize them, and use them to help reduce both the time and money required for your next program.