IMPROVING FLIGHT SAFETY THROUGH ANALYSIS OF SPATIAL DISORIENTATION INCIDENTS

INTRODUCTION: Spatial disorientation (SD) represents a real risk to flight safety; accident research shows that although the overall military aircraft accident rate has fallen over the past twenty years, the rate of accidents involving SD remains unchanged. Analysis of disorientation incidents can provide critical insights into causal factors; many incidents could readily have become accidents given slightly different circumstances or any further delay in recognition of the true situation. In order to inform flight safety and mitigate the risk of accidents, the UK MOD has collected and analysed aircrew incident reports. METHODS: An orientation incident survey was developed, allowing military aircrew anonymously to describe in their own words occasions in flight when they had either become confused about their aircraft attitude or had suddenly become aware of an unintended aircraft attitude i.e. occasions when they had been disorientated. This approach recognised the fact that the most dangerous form of disorientation arises insidiously without any experience of an illusion. These aircrew descriptions were then analysed by subject matter experts to determine the factors underpinning the incident. The survey has accumulated over 300 recorded incidents, enabling detailed analyses of causal factors to be undertaken. RESULTS: Stepwise logistic regression analyses and categorical analyses have found several strong correlations (p< 0.001) between factors and unrecognised disorientation. These results provide a rich picture of the conditions involved in disorientation incidents, including fatigue, distraction and combat flying. Results are being used to inform flight safety and training, moving away from a traditional emphasis on 'illusions'; in the survey, only one aircrew used the word 'illusion' to describe their understanding of what had happened in their incident. DISCUSSION: This data set is a unique and valuable source of aircrew experiences of SD. Information booklets have been produced, using aircrew descriptions to illustrate critical factors such as distraction, workload and aircraft manoeuvring.