When Mike McKee of Denver International Airport discusses NextGen, the new Federal Aviation Administration system that represents the future of U.S. air travel, the word that keeps coming up is predictability. "They've built this network of procedures now that's much more predictable, to use the FAA's term," he says. "A lot of the things that used to be more up to the controller's discretion are built-in and hard-coded."
Denver International has been among the leaders in implementing NextGen. In the past year, the airport has adopted 51 satellite-based procedures that make flights smoother, reduce airspace and runway congestion, cut down on aircraft fuel emissions, and improve communication with other area control towers. The progress made in Denver — the fifth busiest U.S. airport — shows the larger promise of the NextGen system.
In simple terms, the difference between the old way of doing things and the NextGen way is the difference between flexibility and predictability. Before NextGen, flight management relied heavily on the knowledge and judgment of individual air-traffic controllers. By contrast, NextGen establishes strict, satellite-based flight procedures that use crowded airspace as efficiently as possible.
The clearest example of this shift may be a new procedure for landing into Denver International. Previously, aircrafts made a "stair-step" descent toward the runway. They would descend to certain altitudes, level off until they were cleared to go lower, and descend again — just like going down a series of steps.
"That's not very efficient," says McKee. "It increases emissions. It also probably increases time a little bit."
The improved procedure, called "optimized profile descent," begins when the plane is about 150 miles away from its destination. The NextGen system considers all the traffic in an area and issues a single procedure for a smooth descent. Unless a controller sees a potential conflict, the plane glides on a more or less straight path all the way toward the runway.
Behind these optimized descents, as well as the airport's many other upgrades, is a sophisticated new approach to navigation. Older aviation procedures allowed for a little "tolerance" on a flight track, meaning there was a bit of wiggle room in the sky. NextGen flight paths are much tighter, enabling controllers to monitor air traffic with unprecedented precision. McKee likens them to a "laser."
"It's much more important to design a system — which is what they've done with NextGen — where you know Aircraft A is going to be at this point at this time at this altitude at this speed every single time," he says.
The FAA says Denver's upgrades will save 3.2 million gallons of fuel a year and reduce go-arounds (when a plane is ready to land but must fly around before it gets clearance) about 35 percent. There's still room for improvement, says McKee. Some of the more advanced procedures are on hold until airlines that go through Denver International get new equipment and give flight crews special training.
And, of course, Denver is just one airport. America's entire commercial flight system won't operate at optimal efficiency until every airport has NextGen procedures up and running. "Once you get to the point of where all the major airports are using these procedures," says McKee, "then you're going to see end-to-end benefits."