Measured Impact of ADS-B in Approach Applications

The Federal Aviation Administration’s (FAA) Automatic Dependent Surveillance – Broadcast (ADS-B) In Retrofit Spacing (AIRS) evaluation is demonstrating the operational feasibility and value of ADS-B In capabilities using a retrofit avionics solution. As part of this project, American Airlines has equipped their Airbus A321 fleet with avionics necessary to perform multiple applications. The avionics include an ADS-B Guidance Display (AGD) that can be used to designate surrounding traffic and obtain information on relevant distance, speed, and altitude. Two of the proposed applications have the potential to provide benefits on approach. American started using the Cockpit Display of Traffic Information (CDTI) Assisted Visual Separation (CAVS) application in May of 2021 and this application can be used wherever they operate. The CDTI Assisted Separation on Approach (CAS-A) application involves new air traffic controller procedures. It began evaluation in March 2023 at the Dallas Terminal Radar Approach Control (TRACON) for arrivals into Dallas-Fort Worth International Airport (DFW). The paper presents recent analyses and results for both CAVS and CAS-A. When pilots designate traffic on the AGD, they tend, on average, to achieve more consistent and smaller interarrival distances at the runway threshold. Furthermore, when pilots using an AGD are controlled by TRACON controllers who can recognize the equipped traffic and use a procedure like CAS-A, the result is flight time and distance savings in the terminal area.