Tracing Threads of Safety-Critical Functions for Certifying Airworthiness of Military Aircraft

It is important for certifying the airworthiness of military aircraft to be supported with complete tracing of safety-critical function (SCF) threads, because the analysis of every SCF thread requires to identify all of its elements, components and interfaces whenever they are newly developed, modified, or updated. Unfortunately, existing work on such complete tracing of SCF thread has been performed only by manual activities, being hard to allow for the repeatability and expandability of SCF thread analysis. To solve the problem, this paper presents a novel software tool that associates every SCF with a hierarchical tree of its safety supporting elements and traverses this tree wholly, partially, and bi-directionally. This tool allows of the thread tracing to be repeatable by systematically traversing the tree and to be expandable by transforming each abstract node as a subtree of safety supporting elements or components.