A framework of indicators for the potential influence of Air Navigation Services on air traffic safety in Europe

This paper outlines a proposal for a framework of indicators developed with the aim to improve European safety performance monitoring of Air Navigation Services. The extension of scope from the usual choice of Air Traffic Management to Air Navigation Services has been made to address the complication that Air Traffic Management is a different service from Communication, Navigation, and Surveillance, but intimately connected with it. The framework considers the potential influence of Air Navigation Services on air traffic safety, and it uses accidents, their causal/contributing factors, and incidents related to these services as source data for the indicators. Those occurrence categories are considered for which Air Navigation Services have the potential to improve risk. This approach is independent of the notion of a service's contribution to occurrences, which is normally used, but which suffers from a considerable degree of subjectivity. In the data flows from air traffic operations to safety performance indicators, weak links are human incident reporting, varying proportions of incidents actually investigated sufficiently well plus different ways to perform the investigations, and differences in interpretation in providing overviews of the resulting safety data on the level of States. In view of these weaknesses, conditions are developed to prevent data of insufficient quality from being used. The paper mentions a number of aspects to consider when using the indicators. Before drawing conclusions, statistical significance and the existence of reporting bias need to be assessed. The paper finishes with a discussion of the relation of the framework with existing targets and indicates how the framework could support deriving appropriate targets and performance of safety assessments.