Field test results of an airline based en route sequencing and spacing tool

This paper describes the results of a field test of the ground-based Airline Based En Route Sequencing and Spacing (ABESS). The main objective of this field test were the conditions of successful long look-ahead trajectory modeling. Longer look-ahead trajectory modeling consists of predicting movement of flights over 60 to 90 min in the future and to determine metering fix crossing times with sufficient quality and little variability. Requirements and feasibility of longer look-ahead trajectories were assessed in a test at the UPS AOC in Louisville Kentucky during April and June of 2009. During this test the trajectory models for sets of UPS flights were compared with their actual flight behavior. However, no operational evaluation with human operators was performed. It was found that though accuracy and stability of trajectories approached levels that appeared usable for spacing flights on some days, accuracy was found to be insufficient on many test days as errors exceeded on average of 1 min on about 50 % of the test days. These results indicate that while the available accuracy of the used trajectory modeler seems sufficient under best case conditions, it seems yet insufficient to support en route ground based spacing for daily use. This paper proposes potential solutions that could address such shortcomings and describes next steps.