Spacing Instructions in Approach: A Stepwise Design

Abstract

A new allocation of tasks between controller and flight crew is envisaged as one possible option to improve air traffic management, in particular the sequencing of arrival flows. It relies on a set of new spacing instructions. The flight crew can be tasked by the controller to maintain a given spacing with respect to a designated aircraft. To assess feasibility, benefits and limitations of these instructions, after an initial air-ground experiment, two streams of independent air and ground experiments were conducted with a unified perspective. This paper only reviews the ground experiments. They initially focussed on upstream sectors highlighting a positive impact on controller activity and on control effectiveness. However, the application to downstream sectors appeared as an issue. The paper shows how this issue was addressed, in particular how the organisation of roles, working method and airspace have been gradually refined for the effective use of spacing instructions. The proposed working method, though implying significant changes as compared with today, seemed easy to use and assimilate. Overall feedback from controllers was positive. The analysis of instructions and eye-fixations shows a positive impact on controller activity (relief from late vectoring and earlier flow integration). The analysis of inter aircraft spacing on final approach shows more regular spacing than with current day operations. Next step will consist in investigating interactions between upstream and downstream sectors.