En Route Descent Adviser

The National Airspace System relies on a complex set of actions with thousands of variables. If one aircraft is so much as 5 minutes out of position as it approaches a major airport, the error could trigger a dom­ino effect that results in traffic congestion in the air, too many airplanes on the ground needing to use the same taxiway at the same time, late arrivals to the gate, and missed connections. One specific tool created by NASA to avoid this is the En Route Descent Adviser. Using data from CTAS, TMA, and live radar updates, the EDA software generates spe­cific traffic control instructions for each aircraft approaching a TRACON so that it crosses an exact navigation fix in the sky at the precise time set by the TMA tool. The EDA tool does this with all ATC constraints in mind and with maneuvers that are as fuel efficient as possible for the type of aircraft.[269]

Improving the efficient flow of air traffic through the TRACON to the airport by using EDA as early in the approach as practical makes it possible for the airport to receive traffic in a constant feed, avoiding the need for aircraft to waste time and fuel by circling in a parking orbit before taking turn to approach the field. Another benefit: EDA allows controllers during certain high-workload periods to concentrate less on timing and more on dealing with variables such as changing weather and airspace conditions or handling special requests from pilots.[270]