Analysis of Excess Wake Vortex Separation on Arrival Delay

Abstract

n analysis is performed to estimate the delay in the terminal area due to excess leading/trailing aircraft wake vortex spacing. This analysis makes use of a large database of recorded traffic from early 2010 at several of the busiest Terminal Radar Approach Control Facilities (TRACONs) in the United States. To facilitate delay estimates, two arrival compression models are developed and applied to the recorded arrival traffic. A key feature of the compression modeling is the use of just two discrete points in the trajectory: TRACON entry and runway threshold crossing, eliminating the need for the resource intensive procedure of trajectory reconstruction. The analysis has two parts and each part focuses on two runways that are dedicated entirely to arrivals: KATL 27L and KDEN 35R. The first part is a sensitivity study exploring two strategies for compressing the arrivals: path reduction with original average true airspeeds and path reduction with (often times) faster average true airspeeds. This sensitivity study results in a range of delay savings on the order of tens of seconds per flight. The rest of the analysis uses the path compression model (original average true airspeeds), showing the uneven variation of daily delay savings at KATL 27L. Cumulative distribution functions capture the excess spacing reductions. They show a 10% increase (relative to the observed excess spacing) in arrivals landing with an excess spacing of 0.5 nmi or less at KATL 27L and a 25% increase at KDEN 35R.