Modeling Operational Errors at Air Traffic Control Facilities

This paper focuses on the occurrence of aircraft separation minimum violations as documented in the form of operational errors (OEs) at two types of air traffic controller facilities, terminal radar approach control (TRACON) facilities and air route traffic control centers (ARTCCs). Poisson regression was used to analyze the daily count of OEs at various facilities of both types. The occurrence of OEs was found to increase approximately with the square of daily traffic at TRACON facilities and slightly higher than the square of traffic at ARTCC facilities. At TRACON facilities, where separation violations are not automatically reported, an increase in reporting was seen after a new severity metric was introduced in 2007. It was also found that large, consolidated TRACON facilities tend to behave like a sum of several smaller facilities rather than a single larger facility with respect to the occurrence of OEs vs daily traffic. Weather effects such as visibility and wind were found to influence the occurrence of OEs as well. The model prediction for TRACON facilities is very good for the most severe OE types and very poor for the least severe OE types, indicating many unobserved factors contributing to the reporting of the least severe OE types in the terminal environment. Model prediction for the ARTCC facilities is very good for about half the facilities.