NextGen Performance Snapshots
Deconflicting Flight Paths with NextGen Procedures
Deconflicting Flight Paths with NextGen Procedures
Air traffic controllers are using NextGen procedures to keep aircraft safely separated on new precision flight paths, even as the weather does its best to thwart arrivals and departures. The benefits are especially evident in busy areas with airports so close to one another that they use the same airspace.
Such is the case with Las Vegas McCarran International and Henderson Executive airports in Nevada. Henderson handles about 7,800 flights per month, most of which are small, general aviation aircraft. Only 13 miles south of Las Vegas McCarran, Henderson is a reliever airport for its larger neighbor, which has more than three times as many flights each month. Because of their close proximity, the arrival and departure paths for these airports overlap. Aircraft may have to wait to arrive or depart while flights at the other airport complete their procedures.
To address this issue, the FAA introduced new NextGen procedures, known as Area Navigation (RNAV), that enable aircraft to fly along tightly constrained and precise paths that keep the Henderson and McCarran flights safely separated and able to operate simultaneously. The increased navigational accuracy of the flights using these decoupled routes results in more predictable flights. That translates to more on-time flights for passengers and lower fuel bills for aircraft operators. Less fuel use also means fewer aircraft exhaust emissions are released into the atmosphere.
RNAV operations have proven promising in the Las Vegas metropolitan area. Flights at Las Vegas and Henderson that used the RNAV routes experienced better flight efficiency, spending about 10 minutes less in the airspace within 200 miles of the airport.
Overall interactions between Las Vegas and Henderson air traffic fell 4 percent following the implementation of RNAV procedures. Specifically, interactions between McCarran traffic and Henderson arrivals experienced a greater improvement – a 14 percent reduction.
A similar situation exists in Chicago. During periods of bad weather, departure operations at O’Hare International Airport have to slow down to accommodate arrivals at nearby Chicago Midway Airport. Here, the FAA has developed an RNAV procedure with Required Navigation Performance (RNP), which includes an onboard performance monitoring and alerting capability to ensure that the aircraft is contained in a tight corridor of airspace.
Without the RNP procedure, air traffic controllers at O’Hare had to reduce the hourly arrival rate to 68 aircraft per hour from the normal rate of 92-112. But when the RNP procedure was used, O’Hare retained its regular arrival rate and neither airport incurred delays or lost capacity. Additionally, within the 40 miles of the airport, RNP flights going to Midway were more than two minutes shorter on average than conventional Midway arrivals.
Decoupling routes has also racked up benefits for operators flying into the Dallas-Fort Worth metropolitan area where Dallas/Fort Worth International and Dallas Love Field airports are within 20 miles of each other. Prior to the implementation of NextGen procedures, airlines flew in a single stream to land at either airport. Now the airports have separate arrivals flows, which means arriving aircraft need to do fewer speed changes and spend less time in holding patterns, said Captain Brian Will, director of airspace modernization and advanced technologies for American Airlines.
In addition to deconflicting traffic between airports, NextGen procedures have also eased intra airport congestion. For example, American Airlines has been able to increase flight operations during the heaviest traffic periods by 10-20 percent by using RNAV departure routes, Will said. This ability to increase the number of departures is especially helpful following severe weather, such as a thunderstorm. By having multiple new RNAV departure paths, American Airlines is able to get more aircraft off the ground quickly after a storm passes than before, he added.
