Beyond Belief: Representing Knowledge Requirements For The Operation Of Safety-Critical Interfaces

Abstract

Human intervention has played an important role in many major accidents. The staff of the London Underground continued to allow trains to deposit passengers in Kings' Cross after the fire had started. The crew of the Herald of Free Enterprise left their bow doors open. One reason why human `error' is such a significant factor in major disasters is that companies frequently fail to consider the derailed requirements that must be satisfied by operator training. Accident reports often criticise the lack of structure and content in the courses that are provided for safety-critical applications. The following pages address this problem. A mathematical notation is used to represent knowledge requirements for off-shore oil production. This provides an explicit representation of the factual and procedural information that must be included in training courses. This approach also helps to document the standards by which an operator's performance will be assessed. The application of a formal notation is appropriate because a range of organisations, including the UK Ministry of Defence and NASA, are advocating these languages for large-scale development projects. Logic-based formalisms, therefore, provide a common language for systems engineering and human-factors development. This helps to ensure that training issues are not relegated to an after-thought in the design and implementation of safety-critical systems.