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In the Operation

On any given day, FAA air traffic management specialists and controllers see to it that roughly 50,000 flights, performing a diverse set of missions through a wide variety of weather, get to their destinations safely and on time. A suite of tools, managed under the Program Management Organization Decision Support Systems (DSS) office, help them efficiently manage what would otherwise likely be a tangled web of delays.

DSS programs and products generally, cover air traffic management for strategic flow, en route flow, terminal flow and airport surface movement.

DSS tools combine modeling and analysis with traditional data access and retrieval to enable traffic managers to make decisions in rapidly changing environments. The tools alert operators to conditions that require a decision and help to develop and analyze possible courses of action.

The primary tools for strategic flow, en route flow and terminal/surface flow are Traffic Flow Management System (TFMS), Time Based Flow Management (TBFM), and Terminal Flight Data Manager (TFDM). These systems are often referred to as the "3Ts."

Strategic Flow

Traffic Flow Management System (TFMS), a strategic flow product, is available around the clock to support strategic and tactical Traffic Flow Management (TFM) at the Air Traffic Control System Command Center (Command Center) and other locations. The system becomes especially important when external factors such as adverse weather reduce NAS capacity, requiring proactive planning, coordination, and adjustments to mitigate impacts — missed connections, canceled flights, and increased fuel consumption. The Command Center uses TFMS to model and implement NAS-wide Traffic Management Initiatives (TMI) to make the most efficient use of available capacity to avoid gridlock and minimize delays. When delays are necessary, TFMS assigns departure times equitably and gives flight operators the opportunity to submit trajectory options and departure slot substitutions.

En Route Flow

The FAA's en route flow management tool suite, known as Time Based Flow Management (TBFM), uses time instead of distance to efficiently manage traffic flow. The TBFM tool suite includes departure and arrival management.

An air traffic manager at the Washington En Route Center

An air traffic manager at the Washington En Route Center uses Time Based Flow Management to schedule departing East Coast aircraft into the stream of arrivals into the New York City area.

TBFM helps air traffic managers in en route centers to plan efficient flight trajectories from takeoff to touchdown. En route centers are the facilities that control air traffic between the end of an aircraft's departure procedure and the beginning of its arrival procedure. TBFM has the ability to sequence and schedule aircraft, taking into account aircraft types and flight characteristics, in order to maximize capacity at select airports and terminal radar approach control (TRACON) facilities. TRACON controllers handle a flight between the en route segment and the departure and final approach phases. TBFM scheduling and scheduling-management tools enable en route controllers to deliver time-based metered aircraft in a smooth flow to TRACON controllers. TBFM provides a more efficient traffic flow that reduces fuel burn, lowers exhaust emissions, and increases traffic capacity. TBFM is operational at all 20 domestic en route centers.

Terminal and Surface Flow

Terminal Flight Data Manager (TFDM) is being developed by Leidos under an FAA contract. The system will help tower controllers better manage the flow of aircraft to and from the gate to the runway, eliminating the long conga lines of aircraft waiting to takeoff, and improving the overall efficiency of air traffic during the takeoff and landing phases of flight.

TFDM has four core objectives:

  • Improved electronic flight data distribution and electronic flight strips in the tower
  • Collaborative decision-making on the airport surface
  • Traffic flow management integration between TFMS, TBFM, and TFDM
  • Systems consolidation

The program will modernize control tower equipment and processes, streamline the sequence of aircraft scheduled to depart, reduce delays, improve situational awareness, and improve the air travel experience for the flying public. Equipped with TFDM, tower controllers will be able to assign airlines a "spot time" — the time when an aircraft must be at a certain location (called "the spot") on the ramp after pushback. Currently, an aircraft will often show up at the spot only to find out it may have to park and wait for its departure time. By knowing the spot time, the airline can manage boarding so that passengers have more time in the terminal rather than on the tarmac.

For controllers, TFDM reduces workload, particularly when it comes to eliminating the paper strips used to track an aircraft's progress through its flight. With paper, every time a flight plan changes, new strips have to be printed out. With electronic flight strips, that workload goes away. Transitioning to electronic flight strips will give more situational awareness to local and ground controllers who can see a full route, including departure fixes, and Data Communications clearances.

Screenshot of Electronic Flight Data

Electronic flight data have replaced paper strips in prototype Advanced Electronic Flight Strip (AEFS) installations at Phoenix, Charlotte and Cleveland towers.

TFDM will also replace multiple costly legacy systems, and enable data sharing and improved situational awareness among controllers within the tower, across other air traffic control facilities, and among other stakeholders. Elements of TFDM include the Electronic Flight Strip Transfer System in towers and TRACONs, AEFS prototype system in select towers, Airport Resource Management Tool, Surface Movement Advisor, and Departure Spacing Program.

Strategic Flow Today

Traffic Flow Management System (TFMS) supports traffic management personnel in providing efficiency-critical National Airspace System (NAS) services. Throughout each day, traffic managers use TFMS to maintain near real-time situational awareness and predict areas that may experience congestion due to volume or capacity reductions or unusual demand increase.

FAA's Traffic Situation Display

The intensity of daily air travel in the U.S. is captured by the FAA's Traffic Situation Display, one of the many decision support tools available to controllers and others.

TFMS is a core analysis tool used in Command Center bi-hourly planning teleconferences to plan impact mitigation strategies between the Command Center, traffic management units at all 81 major air traffic control facilities, and flight operators.

TFMS functions include:

  • Receiving data on planned and active flights from various sources, forecasting demand for monitored NAS elements
  • Processing information on flights within the continental United States and inbound/outbound international flights
  • Providing information and alerts to FAA users and other NAS stakeholders
  • Providing information to flight operators participating in Collaborative Decision Making (CDM)
  • Providing flight information to the public
  • Providing subscription capability for non-sensitive feeds to industry vendors

The TFM Production Center at the FAA William J. Hughes Technical Center in Atlantic City, NJ, performs the core data processing and distribution of flight data functions. There is also a backup Disaster Recovery Center in northern Virginia to maintain operations. Wide area network services are provided via the FAA Telecommunications Infrastructure and System Wide Information Management (SWIM) services.

En Route Flow Today

Time Based Flow Management (TBFM) departure management tools include En Route Departure Capability (EDC) and Integrated Departure Arrival Capability (IDAC). EDC allows the managers to adjust departure times for more efficient integration of flights into the en route stream. On a typical day at the Washington En Route Center, managers use EDC to create smooth flows into New York area airports from departure airports as far away as Charlotte. Their tools include a vertical "ladder" display that shows the stream of aircraft heading toward an arrival fix to a runway. Towers typically use phone lines to call the managers to request a certain departure time. Managers can see on their displays if there is room in the overhead stream for the new entrant to fit in. If the overhead stream is saturated, a manager will offer a later departure time, meaning the airline can hold off on boarding passengers.

photo collage

Controllers depend on Decision Support Systems to manage aircraft throughout the National Airspace System.

A growing number of airports are receiving IDAC, which uses electronic messaging — rather than a voice call — from the tower to the en route center to request a departure time. IDAC automates the process of monitoring departure demand, identifying departure slots, and assigning them to aircraft. The tool coordinates the departure times between airports and provides situational awareness to air traffic control towers so they can select from available departure times and plan their operations to meet those times. FAA analysis shows that flights under an IDAC approval request/call-for-release have shorter taxi-out times, shaving 2–5 minutes off each departure time. As part of the Northeast Corridor initiative, IDAC was operationally introduced in December 2017 at:

  • New York John F. Kennedy
  • New York LaGuardia
  • Newark
  • Philadelphia
  • Teterboro
  • Westchester County

TBFM has several arrival management tools. Ground Based Interval Management–Spacing (GIM-S) is an interface between TBFM and the En Route Automation Modernization platform. The tool calculates speed advisories so controllers can efficiently manage flow. Controllers can place each aircraft at the correct place and time to initiate a Standard Terminal Arrival with an Optimized Profile Descent (OPD) more than 100 nautical miles from arrival airports that support this navigation procedure. Aircraft on an OPD descend at near-idle speeds from cruise flight almost all the way to the airport. GIM-S boosts the use of these Performance Based Navigation arrival procedures.

GIM-S uses metering tools to "pre-condition" the arrival flow prior to the top of descent. This results in fewer course changes requested by controllers (also known as vectoring) and a reduction in the variation in flight times.

Extended metering creates additional metering points over longer distances for the arrival stream. Meter points can be coupled to other meter points. Longer distances between meter points reduce timing accuracy, so multiple shorter distances between meter points improve predictions of aircraft arrival times. Delay can be allocated further upstream, prior to the top of descent, which can create a better opportunity for an OPD. Coupled scheduling is similar to extended metering but is tailored to shorter distances within a single en route center.

Speed advisories are a key function of GIM-S, helping to achieve scheduled time of arrival (STA) and reduced vectoring. TBFM provides speed advisories to En Route Automation Modernization controllers who transmit the information to pilots in order to meet targeted meter fix times.

The FAA implemented GIM-S for arrivals at Phoenix and adjacent center metering at the Denver En Route Center. Analysis at Phoenix showed that 80.1 percent of flights that accepted a speed advisory arrived within 30 seconds of the STA, compared to 57.4 percent of flights that declined an available speed advisory. Denver experienced a 6 percent increase in flights arriving within 1.5 minutes of the STA.

Terminal and Surface Flow Today

Terminal Flight Data Manager (TFDM) will provide electronic flight strips as well as improved surface management tools that will enable streamlined operations in the air traffic control towers for busy airports. In June 2016, the FAA awarded Lockheed Martin (now Leidos) a $344 million contract to develop and deploy the TFDM system.

Precursor applications in operation are paving the way for TFDM once deployments start in 2020. Included are the Surface Visualization Tool (SVT), AEFS, and NASA's Airspace Technology Demonstration-2 (ATD-2) at Charlotte.

SVT is deployed at several TRACONS, the Los Angeles and New York en route centers, and the FAA Command Center, where it provides a shared situational awareness of the airport surface. Input to SVT comes from the Airport Surface Detection Equipment–Model X and Airport Surface Surveillance Capability data sent through the SWIM network. The function of the SVT prototype will eventually be incorporated into the TFDM system.

AEFS replace traditional paper flight strips and manual tracking of incoming and outgoing flights with an electronic flight data display. The AEFS system can be updated through the swipe of a finger or the click of a mouse. Controllers no longer need to physically carry paper flight strips across the control room. This enables the controller to stay engaged with traffic at all times. The AEFS function, which has the FAA has implemented in the Charlotte, Cleveland, and Phoenix towers, will be incorporated in the production TFDM system.

ATD-2 at Charlotte integrates surface, departure, and arrival concepts and technologies to demonstrate the benefits of an integrated surface, departure, and arrival traffic management system for metropolitan areas with multiple airports, also called metroplexes. ATD-2 research and development will demonstrate the capabilities described in the concept of operations planned for the production TFDM system. NASA will transfer lessons learned and technologies developed for ATD-2 to the FAA for use in the TFDM system development and deployment. These technologies will increase predictability in the air traffic system and enhance operational efficiency while maintaining or improving throughput, leading to reduced environmental impact, greater predictability in airport surface resource allocation, and better coordinated scheduling across the NAS.

Strategic Flow Ahead

The FAA is developing major enhancements for Traffic Flow Management System (TFMS) through 2025 in part through its ongoing Collaborative Air Traffic Management Technologies (CATMT) work and through improvements introduced by the TFDM program. Along with better forecasting algorithms, CATMT will add the Integrated Departure Route Planning tool to TFMS. The tool uses weather and departure demand information to identify potential capacity and demand imbalances and recommend rerouting options.

TFMS Screenshot

The Traffic Flow Management System includes alerts that show air traffic managers when traffic is predicted to exceed capacity. In this picture of Kansas City En Route Center airspace, the top sector is shaded red to indicate that demand will be higher than capacity.

Beyond these enhancements, the FAA is researching how to improve TMI modeling by incorporating the what-if effects of multiple ground delays.

En Route Flow Ahead

The FAA will extend Time Based Flow Management (TBFM) metering capability into terminal airspace with Terminal Sequencing and Spacing (TSAS), set for introduction in 2019. TSAS will have the capability to merge multiple streams of incoming aircraft when used for metering arrivals to airports with closely spaced parallel runway operations. In short, TSAS will give a better picture of what's coming, in order to optimally control what's going out of an airport. In conjunction with en route metering, this capability reduces the time and distance flown by allowing runway assignments and sequencing information to be displayed to terminal controllers. Real-time updates consider factors such as meter points inside terminal airspace, previous arrival runway and sequence assignment, traffic, weather conditions, and runway spacing constraints. TSAS is the terminal analogy to GIM-S for en route; it provides speed advisories that terminal controllers relay to pilots.

TSAS Screenshot

With TSAS, controllers are provided with speed commands (yellow circles) that will help aircraft meet their optimized schedules.

Terminal and Surface Flow Ahead

Terminal Flight Data Manager (TFDM) is set to begin operating in Phoenix in January 2020, with 88 more sites to be completed by 2028. All 89 sites will feature electronic flight strips and the largest 27 will have departure metering capability. The TFDM development testing is planned to start in fall 2018, which will be followed by operational testing at the new purpose-built laboratory at the FAA Tech Center and at the first key site in Phoenix.

An increasing number of airlines and business aviation operators are providing the FAA with data elements they did not previously share. TFMS is distributing the additional surface operations information to TFDM and across the NAS when data become available from operators.

For airlines, this information will mark the times of aircraft events on the ground, including the earliest time the aircraft can leave the gate, the gate location, and the time the aircraft leaves the gate. The FAA will use these data to improve efficiency.

Knowing the earliest time an aircraft can leave the gate, for example, helps controllers reduce delays by sequencing departures while aircraft are still at the gate. Creating a virtual queue of departing aircraft minimizes the number of flights burning fuel on taxiways, and passengers can wait inside the airport instead of on planes. Knowing which gate an aircraft will use after landing can help the controller speed up the arrival process by assigning a runway with a shorter taxi time to that gate.

The new surface operations data, along with data exchanged through SWIM, will enable new applications for airport control towers, such as improved surface demand predictions, enhanced tactical departure scheduling, and runway balancing decision-support capabilities. Additionally, the surface situational awareness capability will expand to other facilities via SWIM.

The ATD-2 demonstration is underway in Charlotte. In Phase 1 (September 2017 to September 2018), the tools are being used offline to test concepts of operation and identify new enhancements to TFDM rather than to optimize surface traffic activity.

Surface traffic view of Charlotte airport

Surface traffic at Charlotte is available to air traffic managers at the Washington En Route Center as part of the ATD-2 project.

Phase 2 (September 2018 to September 2019) will include live air traffic control operations at Charlotte, and Phase 3 (September 2019 to September 2020) will include metroplex capability.

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