Development Assurance process requirements verification

Titled Guidelines for Development of Civil Aircraft and Systems , this document addresses the development process of aircraft systems and the Development Assurance processes of (a) validation of requirements and (b) verification of the design implementation. 

Commensurate levels of assurance are required for each part of the development process. Therefore, whilst verification of code by static analysis, for example, meets a clear need, it does not address systems issues at all. Experience has shown that, particularly with real-time or reactive systems, that the difficult design issues do not arise in the software itself the complexities of synchronisation and interference exist... 

Abstract. Modern safety-critical systems are increasingly reliant on software. Software safety is an important aspect in developing safety-critical systems, and it must be considered in the context of the system level into which the software wiU be embedded. STPA (System-Theoretic Process Analysis) is a modern safety analysis approach which aims to identify the potential hazardous causes in complex safety-critical systems at the system level. To assure that these hazardous causes of an unsafe software s behaviour cannot happen, safety verification involves demonstrating whether the software fulfills those safety requirements and will not result in a hazardous state. We propose a method for verifying of software safety requirements which are derived at the system level to provide evidence that the hazardous causes cannot occur (or reduce the associated risk to a low acceptable level). We applied the method to a cruise control prototype to show the feasibility of the proposed method. 

The D0178 inspired the ARP 4754 and D0254. Essentially, this is a classic approach of process assurance planning development activities (design, validation and verification, configuration management, as well as safety) to a certain quality standard and demonstrating that the process and the product meet the requirements stated in these documents. 

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