Air Traffic Controller Workload as a Factor in Multi-criteria Arrival Sequencing within the Point Merge System

Abstract

Gate-release strategy in the Point Merge System is crucial for reliable arrival sequencing and separation assurance in terminal areas. In this study, we examine three aggregation policies for the exit decision from the radius-to-fix arc conjunctive (AND), disjunctive (OR), and majority (MAJORITY) implemented with a non-compensatory safety barrier and S* speed-control variants. The objective is to assess each policy’s ability to regulate headways, maintain time-based separation, limit low-altitude level-offs, manage advisory demand, and mitigate environmental impact under varying weather conditions, and to identify their strengths and weaknesses. As an example, we conduct an experimental evaluation on the published geometry of Dublin (EIDW) RWY 28L, parameterising arrivals with realistic kinematics and stratifying by METAR; performance metrics include headways at arc/gate/final, spacing error relative to S*, a time-based loss-of-separation proxy, level-off time, and coarse terminal-area fuel / CO₂. Human factors are incorporated through a Human Workload Index combining expected speed-advisory count, level-off time, short-headway alarms, and weather difficulty markers. Alternatives are ranked using TOPSIS with AHP-like weights over Safety, Efficiency, Human, and Environment. The results show that policy choice is the primary driver of headway regularity, advisory load, and low-altitude behaviour; moreover, treating workload as a first-class criterion can overturn rankings obtained from an efficiency-only view. This evaluation helps practitioners select and gate-release policies to site-specific tolerances within an auditable framework.