The Federal Aviation Administration (FAA) forecasts that U.S. airline passenger volume will increase two percent per year, on average, reaching one billion passengers in 2029. To accommodate this growing increase in demand, airports may pursue two common solutions. The first is to undertake a capital improvement project, such as expanding or creating new runways and facilities. While effective, physical expansion may be a short-lived answer to passenger growth challenges unless the second tactic is also employed: eliminating underlying inefficiencies and aircraft traffic flow bottlenecks.
Increasing efficiency is a much more feasible undertaking thanks to advancements in data-capture, analysis and decision support technology deployed by the FAA. The data analytics tools, currently delivering actionable insight to air traffic managers across 20 air route traffic control centers, 30 terminal radar approach control facilities and 37 airport traffic control towers, help airports maximize capacity, improve schedule predictability and proactively assist onboard pilots. In addition, information captured and analyzed by this technology is shared with stakeholders inside and outside the national airspace system (NAS), and is already empowering airlines to optimize their scheduling and operational strategies.
While streamlining aircraft traffic flow is a crucial efficiency goal, automated decision support also improves the passenger experience through fewer delays, smoother flights and more accurate estimated arrival and departure times. After all, most airport leaders would agree that cost savings and operational efficiencies are important, but passenger safety and satisfaction are the ultimate goals.
Commonly faced air traffic challenges
Because miles-in-trail restrictions are established by an airport’s departure tower, unforeseen circumstances such as weather or traffic congestion may occur while the aircraft is en route. This means pilots may not have adequate time prior to a delay notification to adjust the aircraft’s speed for a fuel savings and smoother optimized profile descent (OPD) at the arrival airport. Consequently, pilots must enter holding patterns or delay arrival by stepping through several intermediate levels until they receive clearance for final descent. Not only can this result in unnecessary delays and lead to backups for both arriving and departing aircraft, it also can increase fuel consumption, which is an air carrier’s top cost.
Time-based metering offers dividends
Though distance-based metering presents several limitations, there are advanced decision support tools that air traffic managers can leverage to maximize runway capacity and flight efficiency. One of these is time-based flow management (TBFM) technology, which has made significant strides in flight planning capabilities in recent years. This technology allows controllers to visualize the predetermined sequence of aircraft to help coordinate arrivals. Time-based metering can help ensure adequate spacing of arriving aircraft, without having to rely on airport controllers’ ability to manually set miles-in-trail restrictions.
With time-based metering enhancements, air traffic control centers can deliver much earlier notifications to pilots to adjust their speeds. For example, an aircraft en route to Phoenix can begin to adjust its speed in Denver Center airspace. Since aircraft can begin an OPD hundreds of miles away from the airport, pilots can make smaller, less disruptive adjustments that result in a more pleasurable flying experience for passengers, less fuel consumption and more consistently accurate arrival time estimates — all of which also positively impact the passenger experience. In fact, at Phoenix Sky Harbor International Airport, just one type of OPD saves a total of 945 minutes for all flights that use that particular approach during the course of a day, enabling the airport to efficiently and safely maximize its daily traffic.
Speed-advisory decision support in traffic control centers around the country makes this type of streamlined arrival and departure process possible. One speed advisory tool uses an algorithm to present a four-dimensional view (latitude, longitude, altitude, time) of the predicted location of each aircraft, at each metered point in time. With this enhanced situational awareness, traffic managers can adjust routes and spacing to manage air traffic flows more effectively.
Similar technology was utilized at the Fort Lauderdale-Hollywood International Airport to better accommodate its 1.2 million passengers during busy winter travel seasons in 2012 and 2013, just as the airport was shrinking to one runway due to a capital improvement project. Despite the substantial runway challenge, 2.5 percent more flights arrived on time compared with the same time-period during the season before construction started. Overall arrival delays declined by 10.7 percent; with 1,037 fewer delayed arrivals, passengers benefitted from five fewer delayed flights on a daily basis. At the same time, average gate arrival delays decreased by 10.6 percent and gate departure delays decreased by 8.7 percent.
Time-based metering can also help safely fill open slots in the runway, which create opportunities to increase the number of flights per day using existing facilities. Improving estimated time of arrival accuracy also positively impacts the passenger’s experience and their perception of the airport.
Enabling performance-based navigation
Another benefit of time-based flow management is that it enables airports to adhere to performance-based navigation (PBN) standards the FAA has championed to make air traffic flow more efficient. Integrating and automating the data flow between air traffic control centers and towers for greater communication and collaboration is crucial to achieving PBN. Many airports still rely on a phone call-driven process to approve departures, which can be time-consuming and contribute to increased workload. Longer delays on the runways also impact an airport’s ability to safely maximize capacity.
With greater integration, controllers in the tower can electronically notify the air traffic control centers about a departure request. A notification can then be approved with the simple push of a button instead of through a phone call. Manual processes, like phone conversations, would only be needed when the control center feels they are necessary.
Some tower controllers also have greater visibility into approaching traffic thanks to integrated decision support. Historically, tower controllers have only been able to see that a certain number of aircraft are scheduled to land, but do not have any guidance in regard to the arrival sequence. In some airports, controllers can now better coordinate arrivals through visualization of the aircraft sequence as calculated by time-based flow management technology. This situational awareness helps controllers maintain the sequence and adequate runway spacing, which can prevent holding patterns near the airport and increase flight schedule predictability.
For example, take a scenario in which a controller must advise three flights heading to a certain airspace at 11 a.m. Time-based flow management might determine that flight No. 1 should arrive at 11 a.m., but flight No. 2 should arrive at 11:05 a.m. and flight No. 3 at 11:10 a.m. The en route controllers feeding the terminal radar approach can then delay flights No. 2 and No. 3 by assigning them a slower speed or a different altitude.
This feature is especially advantageous in busy airports where air space is at a premium and tower controllers want to maximize capacity by limiting the open runway slots. With integrated systems and data access, controllers have visual evidence of why they might need to leave a slot open to maintain a certain sequence. By adhering to the technology’s pre-calculated flight plan, towers can help maximize the number of arriving and departing flights.
Pilots are also better able to follow PBN procedures with decision support. Traditional approach protocols, for example, involve flying past the runway to position the aircraft for arrival based on wind direction. By utilizing onboard performance monitoring and alerts, pilots can enhance their situational awareness to follow procedures for a more efficient runway approach.
On the whole, PBN standards can contribute to greater safety, capacity, predictability, environmental impact and operational efficiency. At Hartsfield-Jackson Atlanta International Airport, for example, flights are 48 percent faster from gate to departure and into en route airspace using PBN procedures — saving Delta Airlines alone $10 million to $12 million per year.
Sharing information among stakeholders
Despite the numerous decision support tools available to airports to improve efficiency and capacity, it is collaborative efforts between the FAA and carriers that promise the greatest continuous improvement opportunities. The same technology that enables more efficient air traffic operations, for instance, can also capture data useful to air carriers and airports.
Through a single interface and a standard data format, different producers and users of data can communicate and exchange intelligence to guide tactical and long-term strategic decisions. For NAS stakeholders such as the FAA and other air traffic managers, this information sharing should enhance coordination between multiple FAA systems to maximize efficiency and decrease delays.
Enhancing and expanding communication
Collaborative communication is essential for both those in the air and on the ground. Digital communication technology in aircraft now allows pilots to update route information on their own with support from tower controllers.
Consider the scenario in which tower controllers determine prior to takeoff that a route adjustment is necessary due to a weather event. Currently, in most airports, this requires a controller to read the new route over the radio to the pilot, who repeats the instructions and manually enters them into the aircraft’s avionics system. Depending on route complexity, this process is error-prone and can be highly time-consuming. A departure clearance using voice communications can take two to three times longer than a departure clearance with digital text communication; it becomes even slower in high-traffic situations. At some airports, the process of providing navigation instructions can occur multiple times before takeoff.
With the improved digital communication technology already implemented in some airports the route adjustment automatically uploads into the avionics system and is accepted by the pilot with the push of a button. This technology will be available for airborne aircraft in en route airspace through the En Route Automation Modernization (ERAM) system in 2019. Once this capability is deployed, airborne, data communication will also include text-based messaging capability between air traffic control centers and the aircraft to offer visual guidance in addition to radio instruction. This will be especially constructive information when re-routing becomes necessary due unexpectedly dense airspace. As with time-based metering, the earlier an aircraft receives the guidance, the sooner the pilots can make adjustments to more closely adhere to the aircraft’s estimated time of arrival in a safe, fuel-efficient manner.
Smart, sustained growth
Airports are building new facilities and expanding runways all over the United States. Physical expansion alone, however, is only one option for airport leaders faced with limited space but increasing passenger demand. A more long-term and sustainable solution is to increase operational efficiencies to improve passenger flow — not only inside the airport terminal, but through streamlined aircraft traffic flow on the runways.
By leveraging data capture, analysis and decision support technologies, airports in collaboration with the FAA and air carriers can help safely increase the volume and predictability of flights arriving and departing their facilities. With the next generation of automation, it is possible for airports to serve more passengers per day while delivering a more satisfying flight experience.
Paul Engola is the Senior Vice President of Transportation and Financial Solutions and Fran Hill is Vice President of Air Traffic Programs, both at Leidos, formerly Lockheed Martin Information Systems & Global Solutions.
