A Methodology for Airport Arrival Flow Analysis Using Track Data – a Case Study for Mdw Arrivals

Traffic flow in the Terminal Radar Approach Control Facilities (TRACON) is a significant factor in determining airport throughput capacity and airline operational efficiency. In recent years the availability of high fidelity terminal area track data has made it possible to increase the granularity of airport and airspace performance analysis. This paper describes a methodology for airport arrival flow analysis using National Offload Program (NOP) track data. The analysis provides insight into track distances flown and track time for alternate terminal arrival flows (i.e. from the final waypoint in the Standard Terminal Arrival Route (STAR) to the runway threshold via a type of approach). The methodology is applied to 35 days of NOP track data for Chicago TRACON (C90) for arrivals into MDW. Arrivals into MDW landing to the north-west on 31C and to the north-east on 4R exhibit the shortest average track distance (28.42 NM and 29.81 NM.). Arrivals landing to the southeast on 13C exhibit the highest mean track distance of 38.9 NM. Track distance/time is least for VFR approaches onto all runways. When IMC conditions exist, RNP approaches provide 6-10% savings in track distance/time over ILS approaches. One unexpected result is that RNP approaches exhibit the same variance in track distance/time as ILS approaches. The variance in RNP approaches occurs on the downwind and turn-to-base, while the variance on the ILS approach occurs by “tromboning” on the base leg and the turn to final.