ATC feasibility of potential near-term wake turbulence procedures

This paper documents the results of controller (human-in-the-loop, HITL) simulations to evaluate a proposed change of standards involving the wake turbulence separation required for closely spaced parallel runways with center line separation less than 2500 feet. Under current rules, dependent, diagonal separation between arrivals on adjacent parallel runways can be used when runway center line separation is at least 2500 ft. The Federal Aviation Administration is investigating the reduction of this required minimum runway separation value to 1000 ft. when the leading airplane is in the large or small weight category. If the lead aircraft is a B-757 or heavy then standard wake turbulence separation would apply. This change would enable continued operation of dual arrival streams in instrument conditions, increasing airport capacity and reducing delay. Real time simulations were conducted with controllers from a busy U.S. ATC facility to determine if such a change in standard would be acceptable and feasible. Both approach control and tower control positions were simulated. Results indicate that ATC operations with the proposed new standards were feasible, controller workload was acceptable as measured in the simulation environment, and that significant capacity benefits may be achieved both for arrivals and departures in instrument meteorological conditions (IMC) for such runway geometries. The paper includes a discussion of the procedures and strategies developed by the controllers in implementing the proposed change in standards, and presents results regarding controller workload, achieved arrival and departure rates, and various spacing values of interest on final approach relevant to a safety analysis of the procedure. The paper also suggests some steps that may help develop authorization of such a procedure.