Challenges for an open and evolutionary approach to safety assurance and certification of safety-critical systems

Safety assurance and certification are amongst the most expensive and time-consuming tasks in the development of safety-critical embedded systems. The increasing complexity and size of this kind of systems combined with the growing market demand requires the industry to implement a coherent reuse strategy. A major problem arises as typically a safety-critical product and accompanying safety evidence is monolithic, based on the whole product, and evolutions to the product become costly and time consuming because they entail regenerating the entire evidence-set. Another key difficulty appears when trying to reuse products from one application domain in another, because they are constrained by different standards and the full safety assurance certification process is applied as for a new product, thus reducing the return on investment of such reuse decision. This paper describes the current state on safety assurance and certification of embedded systems in the avionics, railway and automotive domains and then proposes some future directions for work in the area. In particular, we describe the need for a common certification framework that spans these different markets to improve mutual recognition agreement of safety approvals. We then discuss the need for new strategies focused on a compositional and evolutionary certification approach with the capability to reuse safety arguments, safety evidence, and context information about system components, in a way that makes certification more cost-effective, precise, and scalable.