  A key goal of the System-Theoretic Process Analysis (STPA) hazard analysis
technique is the identification of loss scenarios - causal factors that could
potentially lead to an accident. We propose an approach that aims to assist
engineers in identifying potential loss scenarios that are associated with
flawed assumptions about a system's intended operational environment. Our
approach combines aspects of STPA with formal modelling and simulation.
Currently, we are at a proof-of-concept stage and illustrate the approach using
a case study based upon a simple car door locking system. In terms of the
formal modelling, we use Extended Logic Programming (ELP) and on the simulation
side, we use the CARLA simulator for autonomous driving. We make use of the
problem frames approach to requirements engineering to bridge between the
informal aspects of STPA and our formal modelling.
