Impact of displaying of RA Downlink information to the controller - empirical study

Kurzfassung

If the Airborne Collision Avoidance System (ACAS) identifies an imminent collision, it issues a Resolution Advisory (RA). The RA takes precedence of Air Traffic Control (ATC) instructions and the air traffic controller should not interfere with the according collision avoidance manoeuvre. To date, the only source of information for the controller to know about the RA is the pilot report. However, pilot reports of RAs are often incomplete, delayed, incorrect or even missing. This introduces ambiguity about tasks and responsibilities of pilots and controllers. One option to address this problem consists in downlinking RAs for display at the controller working position (CWP). The present paper gives an overview of EUROCONTROL’s Feasibility of RA Downlink Study (FARADS) and describes the results of one of the experiments that have been conducted to determine the impact of RA downlink on the controller’s performance, situational awareness and workload. The results of the experiment point to operational benefits of RA downlink. Contradictory clearances to aircraft involved in an RA were exclusively observed in the absence of RA downlink. Controller’s recollection of RA events caused by pilot or controller error was superior if RA downlink was provided. Furthermore, there was no evidence for negative effects of RA downlink, such as cognitive tunnelling on the RA event and a lower ability to separate other traffic in the sector.