Systems theoretic accident analysis of an offshore supply vessel collision

Abstract

This thesis uses Dr. Leveson's Systems-Theoretic Accident Model and Process (STAMP) model of accident causation to analyze a collision in late July 2014 between two Offshore Supply Vessels equipped with software-intensive Dynamic Positioning Systems. The Causal Analysis based on STAMP (CAST) is compared with the Root Cause Analysis, a traditional chain of events based model, used by the original investigation team after the collision. Linear chain of event models like the Root Cause Analysis often look for a broken component or incorrect action within the proximal sequence of events leading to the accident. CAST examines a system's entire safety control structure to assess why the system constraints, control loops, and process models were either inadequate or flawed. This thesis aims at identifying how the safety control structure of the Offshore Supply Vessel operations could be improved by identifying the systemic factors and component interactions that contributed to the collision. The primary objective of this thesis is to demonstrate the use of a systems theory-based accident analysis technique in analyzing a complex accident. The secondary objective of this thesis is to compare and contrast the outcomes of the Root Cause Analysis conducted by the Navy Programs organization, with the findings of the CAST analysis. Finally, this thesis examines STAMP's underlying new assumptions regarding the need for new safety analysis in the context of the findings from the CAST analysis of the collision.