‘ Systemic Failures ’ and ‘ Human Error ’ in Canadian TSB

This paper describes the results of an independent analysis of the primary and contributory causes of aviation accidents in Canada between 1996 and 2003. The purpose of the study was to assess the comparative frequency of a range of causal factors in the reporting of these adverse events. Our results suggest that the majority of these high consequence accidents were attributed to human error. A large number of reports also mentioned wider systemic issues, including the managerial and regulatory context of aviation operations. These issues are more likely to appear as contributory rather than primary causes in this set of accident reports. INTRODUCTION Reason [1] has recently distinguished the 'person' from the 'system' approach to accident analysis. Each of these perspectives implies a radically different view of causation. The 'person approach focuses on the errors of individuals, blaming them for forgetfulness, inattention, or moral weakness'. In contrast, the system approach 'concentrates on the conditions under which individuals work and tries to build defenses to avert errors or mitigate their effects'. Similarly, Cook and Woods [2] argue that accidents occur through the concatenation of multiple small failures. Each of these causes is necessary. However, they are each insufficient to cause the failure unless they occur in combination with other potential causes. Often these small failures have roots that extend well back from the moment when the accident is triggered. This analysis is careful to distinguish between the operators who often trigger an incident 'at the sharp end' and the managers and regulators who often create the latent conditions for a failure 'at the blunt end'. In particular, managerial and regulatory problems often make it possible for