Safety and Performance Implications of Wake Vortex Buffers

Abstract

This paper presents a simulation-based study of the performance implications of spacing buffers in the United States’ Air Traffic Control System. A spacing buffer is used during instrument flight operations, when radar control is active. The buffer represents additional spacing between successive flights beyond what is required so that separation violations rarely, if ever, occur. In contrast, during non-radar visual operations, spacing at or near the minimum occurs when pilots request and are granted visual clearances. Using published data derived from multilateration surveillance systems, this study describes a simulation experiment created to understand the performance implications of actual separations for controlled flights when instrument flight rules are active. The results show, unsurprisingly, that there is a statistically meaningful increase in delays as the spacing buffer increases. These results also demonstrate how, during weather-triggered radar operations, the air traffic system at busy airports can become congested and delays escalate.