Comparison of Strategies for Continuing Time-Based Metering during Inclement Weather

Abstract

This report describes a comparison of miles-in-trail (MIT) and time-based metering (TBM) as modes of delivery for inbound traffic from center to terminal Air Traffic Control (ATC) facilities during periods of reduced landing capacity. Using a validated computer simulation of arrival operations, MIT and TBM delivery are evaluated in three contexts. The first context is steady operations with MIT and TBM delivery over a range of high and low airport landing capacities. The second is a comparison between MIT and TBM delivery as a method for immediately reducing the delivery rate, as would occur when field conditions degrade unexpectedly. The third is a comparison between strategies within TBM for responding to a forecast weather event which may cause a drop in the airport acceptance rate. It was found that during steady operations implementing TBM delivery requires less en route delay than MIT delivery, while also smoothing the diurnal peaks of delay inside terminal airspace. During a sudden drop in arrival capacity, it was found that using TBM as a means to adjust to a reduced delivery rate requires less rippling and holding than implementing a MIT constraint.