US performance-based navigation takes off

The Federal Aviation Administration (FAA) is not only using performance-based navigation to improve efficiency around major metropolitan areas, it’s also connecting those areas with the most efficient and direct routes possible, reports ATO News.

The new Q-routes and T-routes take flights through en route airspace using Area Navigation — RNAV — guidance. They will eventually replace most of the current network of airways that rely on ground-based navigational aids, such as very high frequency omnidirectional ranges, known as VORs.

The FAA has designed 100 Q-routes — which are RNAV routes used at Flight Level 180 and above. That’s approximately 25 per cent of the high altitude PBN routes the FAA expects to have in place by 2020.

T-routes are RNAV routes used by aircraft flying below Flight Level 180. The new routes will create a much more integrated airspace structure, according to John Witucki, an air traffic controller who works for Airspace Services in ATO Mission Support.

That office is in charge of guiding the implementation of the Q-routes and T-routes. When the national airspace system was established in the middle of last century, it was built as a series of parts, Witucki explained.

Radial beacons were built in locations based on terrain and air traffic demand in the 1940s, 1950s and 1960s. Procedures and routes were created based on those beacons, and then the procedures and routes were connected to each other. Those parts worked well enough together, but moving aircraft from one part of the country to another was not entirely seamless, Witucki said.

Planes often had to fly dozens of miles out of their way to get to their destination. And the old routes have other downsides. The system was built when demand was much different than it is today. Airports in Los Angeles and Phoenix saw only a fraction of the amount of airplanes they now handle.

Demand and traffic flows have shifted, and the FAA has worked to keep up. But it could only do so much with a system that relied on equipment in fixed locations. “Now we’re smarter, we have more up-to-date information and better technology,” Witucki said. “We’re able to improve where the flight paths are going and deliver aircraft more efficiently.”

Performance-based navigation, which uses satellites to create waypoints, gives the FAA the ability to put a Q-route or T-route wherever it will create the most efficient path between two points. Waypoints no longer have to be a certain distance from a navigational aid on the ground.

“You have more leeway with Q and T routes because you’re not tied to ground-based navigational aids,” said George Davis, the manager of the En Route Products Group in AeroNav Products. “You get more efficiencies from going direct from point A to point B without the restrictions of following ground-based navigational aids.”

Using performance-based navigation will make the new system an integrated whole, not just be a series of connected parts, Witucki said. A big part of that is using Q-routes and T-routes to connect all the Optimization of Airspace and Procedures in the Metroplex projects.

OAPM is bringing performance-based navigation to several major metropolitan areas like Atlanta, Houston, North Texas and Northern California. It’s making the arrival and departure procedures in those areas as efficient as they can be. Each region is getting a generous dose of new RNAV or RNP — Required Navigation Performance — standard terminal arrival routes and standard instrument departures.

Mission Support’s Airspace Services is making sure those SIDs and STARs are connected with routes that are just as efficient, and that those connections are as streamlined as possible. They work with AeroNav’s En Route Products Group to make sure the Q-routes and T-routes meet current criteria for things like leg length and altitudes over mountainous terrain.

It’s required some adjustments to the Metroplex teams’ designs. But once they see the benefits to the entire national airspace, everyone is happy to fine tune procedures and routes to make sure they meet the needs of controllers and airspace users, Witucki said. That way, as the FAA implements the airspace of the future, it will create a fully integrated system.

One that will move a flight from San Francisco to Atlanta with little deviation from the most direct path. The ATO has already implemented 10 Q-routes and T-routes on the West Coast to connect OAPM efforts in Northern California and Southern California and the Greener Skies initiative in Seattle.

The effort is pushing eastward, as well. Nine routes connect Seattle with Denver, Houston and Chicago, and 13 connect Northern California with those same three metropolitan areas. And a Q-route extends nearly 1,600 miles from San Francisco to Atlanta. The effort is expanding use of performance-based navigation that has already proved capable of saving millions of dollars.

During the first three years of use, RNAV and RNP procedures in Atlanta, Dallas/Fort Worth and Las Vegas reduced delays by as much as 45 percent and saved system users $100 million. And increased efficiency is not the only way performance-based navigation routes and procedures will save money.

Since the Q-routes and T-routes don’t rely on VORs, their implementation will advance the process of decommissioning the aging navigational aids, which are expensive to maintain. Developers of Q-routes and T-routes will work with air traffic controllers and industry to replace or overlay existing conventional routes. That will create the network of performance-based navigation flight paths necessary to safely and efficiently guide air traffic with a reduced number of VORs, Witucki said.