SPACING INSTRUCTIONS IN APPROACH: BENEFITS AND LIMITS FROM AN AIR TRAFFIC CONTROLLER PERSPECTIVE

A new allocation of tasks between controller and flight crew is envisaged as one possible option to improve the sequencing of arrival flows. It relies on a set of new spacing instructions where the flight crew can be tasked by the controller to maintain a given spacing with respect to a designated aircraft. The investigations initially focussed on upstream sectors (en-route) highlighting a positive impact on controller activity and on control effectiveness. However, the application to downstream sectors (approach) appeared as an issue. The paper shows how this issue was addressed, in particular the how organisation of roles, the working methods and the airspace have been adapted for the effective use of spacing instructions. It also presents the results from the latest experiment which involved six approach controllers over four weeks. Overall feedback from controllers was positive. The proposed working method, though implying significant changes as compared to today, seems easy to use and assimilate. The analysis of instructions and eye-fixations shows a positive impact on controller activity (relief from late vectoring and earlier flow integration). In terms of effectiveness, the inter aircraft spacing on final is more regular. Concerning aircraft, in addition to receiving fewer instructions, spacing instructions would enable to fly, in approach sectors, under lateral navigation mode (as opposed to fly open vectors). The next step will consist in investigating interaction between upstream and downstream sectors when using an arrival manager.