In the U.S. National Airspace System (NAS), there are more than 87,000 flights every single day, with approximately 5,000 of them in the air at any moment. The United States averages 64 million takeoffs and landings a year, or more than 7,000 every hour, carrying 660 million passengers annually as well as more than 37 billion cargo-revenue tons of freight – figures that foretell of an ever-increasing growth in air travel.
If this seems a massive undertaking, consider that by 2025 airspace demands are expected to multiply. Already, the construction of airports and runways is falling behind the increases in air traffic, and there are limits to the amount of land available to build them. Even if resources and land for airports were unlimited, the actual amount of airspace over those airports, the nation, and indeed the globe is finite. There is only so much airspace available, and it is becoming increasingly congested. This means not only jam-packed airports and more and longer delays, but an increasing strain on air traffic controllers as they provide safe operations in these crowded skies.
Through the development of tools, technologies, and programs like Traffic Management Advisor, Efficient Descent Advisor, Precision Departure Release Capability, and Terminal Sequencing and Spacing, and the subsequent transfer of these NASA development programs to the FAA, NASA has helped to establish the foundation for NextGen and enable it to fulfill its promise to revolutionize the safety and efficiency of air travel.
Over the last two decades, NASA engineers and program representatives within the Aeronautics Research Mission Directorate (ARMD) have helped enable a safer, more secure, efficient, and environmentally friendly air transportation system through supporting the creation of the Federal Aviation Administration’s (FAA) Next Generation Air Transportation System or “NextGen” transformation of the National Airspace. NextGen will transition the nation’s air traffic control network from a system centered on ground-based radars to an expanded space-based system of satellites, radars, and onboard systems and software.
“We’re a research house,” said Dr. John Cavolowsky, program director for ARMD’s new Airspace Operations and Safety Program (AOSP). “We do a lot of advanced development. We will build software tools. We will work in close connection with the FAA to verify that those tools work in real environments. What the FAA then does is take our algorithms, take our software, and they work with a contractor – an FAA contractor – to make sure that they are hardened for use by the organizations that fly, the FAA as well as airlines, and make sure they’re safe and integrated into the system. So we do a lot of the heavy lifting up front, but that implementation of the final piece is done by the FAA. That’s the way we’ve done this for decades now. That’s the way we’re going to continue to do it, because it’s not our job to implement, but it’s our job to bring attention to these capabilities that can benefit the operation the FAA provides for the flying public and for the airlines both nationally and internationally.”
Through the development of tools, technologies, and programs like Traffic Management Advisor, Efficient Descent Advisor, Precision Departure Release Capability, and Terminal Sequencing and Spacing, and the subsequent transfer of these NASA development programs to the FAA, NASA has helped to establish the foundation for NextGen and enable it to fulfill its promise to revolutionize the safety and efficiency of air travel.
Foundation: Traffic Management Advisor
According to Thomas Davis, Airspace Automation Technology Advisor at NASA Ames Research Center, the origins of NASA’s support of the FAA go back several decades.
“The whole thing really began back in the very late 1970s or early 1980s,” he said, identifying a key researcher behind the initial effort as Dr. Heinz Erzberger.
The Traffic Management Advisor (TMA) tool in operation at Denver TRACON (Terminal Radar Approach Control). The NASA-developed TMA has become the foundation for the Federal Aviation Administration’s (FAA) time-based traffic flow management system. NASA image
Erzberger saw that flight deck technologies were advancing at a brisk pace, and was part of the creation of concepts such as optimized descents on a flight path management system, Davis explained. “He believed that you could take that math and that modeling and put it on the ground to use it to the advantage of air traffic controllers.”
“So, by not just calculating the flight trajectory for the individual aircraft you’re flying as to what’s going to happen and what’s the most efficient thing to happen, you could put the capability on the ground in a ground system and compute that for all of the aircraft in the airspace,” Davis said. “From that you could add things like optimized scheduling of arrival traffic to create additional efficiencies. You could also build advisories that controllers could issue to pilots that would align with flight management system calculations – like descend at a specific speed at idle thrust; begin the descent at this point – so now there was a joining of what the controller was advising and what the pilot was able to execute in an efficient manner. Then, as you start to do that across all of the aircraft in a piece of airspace, you’re going to add efficiency to the system.”
Davis said that another young engineer on the team “had the idea that he could take Heinz’s algorithms and models, put them in a workstation, network it together, provide a graphical user interface, and now you’ve really got something. You had the computer science part of it joining up with the guidance and control system part of it.”
Team members began to implement some of the concept on a network of Sun workstations. The process included the early building of actual tools, like the Traffic Management Advisor (TMA).
TMA provides graphical displays and alerts, and generates statistics and reports about air traffic flow for controllers. TMA also computes the undelayed estimated time of arrival (ETA) as well as the sequences and scheduled times of arrival to the outer meter arc, meter fix, final approach fix, and runway threshold for each aircraft, to help controllers set and meet sequencing and scheduling schemes. The TMA also assigns each aircraft to a runway to optimize the scheduled time of arrival (STA), according to NASA. The NASA-developed TMA technology provided the foundation for the FAA’s time-based traffic flow management system and has become an ubiquitous part of the National Airspace.