At the world’s busiest airport, air traffic controllers are using technology and new procedures to get more flights in and out each hour.
Jets now can take off in four parallel flight paths departing from Hartsfield-Jackson International, up from three in the past. They can fly closer together as they approach the airport for landing.
At peak the airport handles about 112 to 134 departures an hour, up from 96 to 130 before the changes, which are part of a multi-billion modernization program known as NextGen.
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The Federal Aviation Administration, working with Delta Air Lines, has used Hartsfield-Jackson as a proving ground for NextGen technology to allow more flights per hour, reduce delays and fuel burn, cut costs and save time.
“Atlanta is a very complex airport to operate in,” said FAA administrator Michael Huerta in an interview with the Atlanta Journal-Constitution. At the same time, with its simple layout of five parallel runways, he said, “the airport lends itself to trying out a lot of things.”
NextGen’s rollout has been dogged by delays, cost overruns and other challenges. It is expected to take until 2025 to phase in the series of systems and technology upgrades.
“Transitions are difficult,” said Steve Dickson, senior vice president of flight operations at Delta. “We’re changing the tires on the car as it’s going down the road.”
A U.S. Department of Transportation Inspector General report last year found that the FAA “faces significant risks and challenges” in taking NextGen nationwide. The importance of the modernization and the challenge of pulling it off makes NextGen a key issue as the FAA seeks reauthorization from Congress — and puts a spotlight on its performance in Atlanta.
Dickson said Delta has seen better efficiency and lower fuel costs so far.
“Atlanta has been a great place to start a lot of these initiatives,” he said.
Master plan movement
Some of the improvements may enable Hartsfield-Jackson to complete a key part of its master plan for future expansion: placing a sixth runway between existing runways.
That location wasn’t the plan 15 years ago when the airport was looking at additional runways. Back then, a sixth runway was expected to eventually be built north or south of the existing airfield, in areas currently occupied by residents and businesses.
Criticism from the community prompted the airport to table the idea of a sixth runway, though it moved forward with a fifth runway opened in 2006.
Now, airport officials say NextGen improvements could allow runways to be spaced closer together than was feasible in the past and still be used frequently. That’s expected to open the option of putting a sixth runway between the original four and the fifth, keeping such an expansion mostly on existing airport property.
Four paths of planes
The foundation of NextGen is the switch from ground-based to satellite-based navigation and monitoring of planes. The use of GPS-based systems in control centers and onboard aircraft enables more precise tracking. That in turn enables more direct routes and reduced spacing requirements — though officials say ample safety margins will remain.
A key example of what’s enabled with more precise navigation is a system the FAA is now using in Atlanta called ELSO, for Equivalent Lateral Spacing Operations, which allows for planes to take off in four simultaneous paths instead of three. That enables up to 12 more departures per hour and saves $20 million in fuel costs, according to the FAA.
More precise routing reduces the amount of buffer required, meaning planes departing at the same time don’t have to turn as sharply away from each other just after takeoff.
“By dealing with lateral spacing, we could get more takeoffs,” Huerta said.
After years of testing at Hartsfield-Jackson, the FAA now plans to expand it beyond Atlanta in the future.
Air traffic controllers have worked with the FAA and pilots on testing the new procedures to maintain a high level of safety, said Paul Rinaldi, president of the National Air Traffic Controllers Association. “There are a lot of the older procedures we’re using were set a very long time ago, when we didn’t have the modern aircraft we have today,” Rinaldi said.
Studying wake turbulence
Through another new standard, air traffic controllers have increased the number of arrivals Hartsfield-Jackson and other airports can handle by allowing a string of planes to come into the airport in closer succession.
The FAA determined that could be safely done by more closely analyzing the nature of wake turbulence.
Wake turbulence — vortexes of air formed behind a plane’s wingtips — can be hazardous for planes behind another aircraft. FAA standards have historically required plenty of space behind each plane.
But the FAA said closer analysis showed greater detail on how wake turbulence and its effects differ depending on the type of plane and other factors like wingspan.
“We’ve learned more about how these wakes interact with other airplanes,” Huerta said.
Re-categorizing different types of wake turbulence allows an incremental 5 percent increase in arrivals at Hartsfield-Jackson, reduced taxi times and $13 to $18 million in savings for Delta.
Future runway
The Atlanta airport doesn’t need another runway just yet.
Delta is using larger planes with more seats and retiring small regional jets. Southwest Airlines, the second-largest carrier in Atlanta, replaced AirTran’s Boeing 717s with larger Boeing 737s. The moves have reduced the number of flights per day at Hartsfield-Jackson, while still carrying more passengers.
But eventually, as the population and demand increases over time, the sixth runway idea will be back on the front burner.
“The capabilities that NextGen will enable will allow us to put the runway in the existing airport footprint,” Dickson said, “which I think would be good for everybody.”
