Fort Hill Group developed a comprehensive taxonomy to promote the identification and mitigation of factors affecting air traffic control safety events.

Many human factors accident and incident investigation taxonomies have been developed over the years to assist in identifying and classifying the factors involved in near miss events, incidents, and accidents. These taxonomies exist at many levels of detail, from generalized taxonomies to domain-specific taxonomies – each with their own benefits and limitations. Generalized taxonomies, such as the Human Factors Analysis and Classification System (HFACS), are easy to understand and allow for trend analysis of broad factors, but can be limited in identifying domain-specific mitigation strategies. Domain-specific taxonomies, such as JANUS and Human Error ATM (HERA), may more accurately describe individual air traffic control events, but can have too many factors to provide meaningful systemic analysis and domain comparisons. In order to examine the various risk pathways and factor associations within the air traffic domain, an expansive, human factors taxonomy is needed to ensure various human performance modes and factors can be identified to allow for such a detailed analysis. 

The Air Traffic Analysis and Classification System (AirTracs) was developed to systematically and thoroughly examine the impact of human performance on air traffic near miss events, incidents, and accidents. The AirTracs framework promotes the identification of human factors trends by allowing factors from the immediate operator context to agency-wide influences to be traced to individual events while still being able to identify human factors patterns and trends.

The AirTracs taxonomy was developed utilizing subject matter experts from the air traffic, flight deck, and human factors domains. The AirTracs model follows a tiered approach, which allows for active factors at the operator and equipment levels to be identified in addition to latent factors throughout the various levels of an organization. The tiered approach allows for the development of risk pathways that trace the impact of high-level latent factors on operational human and system performance. A sample risk pathway from an assessment of near and actual loss of separation events can be seen below (Berry, Sawyer, & Austrian, 2013).


AirTracs has been used to assess over 2,000 air traffic and aviation safety events. AirTracs has been fundamental in understanding various risk profiles, including the process for controller transfer of aircraft identification, Area Navigation (RNAV) and Required Navigation Performance (RNP) operations, and local facility airspace redesign.

For more information on AirTracs, please refer to the Understanding Human Performance Workbooks.