The Next Generation Air Transportation System, or NextGen, is the ongoing transformation of air traffic control. This transformation includes the transition from primarily ground-based to primarily satellite-enabled surveillance and navigation, from analog voice to digital communication, and from limited data exchange to fully integrated information management. NextGen is improving how we see, navigate and communicate in our nation’s skies.
Ultimately, we are moving the U.S. system of air traffic control away from one based on knowing where an aircraft is to knowing where an aircraft is going to be at critical points along its flight path. This system of time-based management, known as Trajectory Based Operations (TBO), will increase predictability and efficiency throughout the National Airspace System. NextGen is already improving safety, capacity and efficiency on runways and in our skies while reducing fuel burn, carbon emissions and noise.
This fact sheet explains NextGen through the different phases of flight, describing some of the major technologies and procedures that are supplementing or replacing those currently in place.
Phases of Flight
Based on previous lessons learned, the agency determined that the best way to upgrade its services was to begin with a new infrastructure that could accommodate state-of-the-art enabling technologies and advanced capabilities.
The FAA has been investing in ongoing FAA modernization programs, including En Route Automation Modernization (ERAM), Terminal Automation Modernization Replacement (TAMR), Traffic Flow Management System (TFMS), and Time based Flow Management (TBFM).
ERAM is fully operational at the 20 en route centers across the country where controllers handle high altitude traffic. It processes flight and radar data, enables NextGen communications and generates other data for controllers' screens. The technology is helping to advance the transition of air traffic control to air traffic management by allowing controllers to track up to 1,900 aircraft at a time – an increase from 1,100 under the previous system.
TAMR is a similar technology advancement to ERAM. It replaces multiple automation systems with one platform – the state-of-the-art Standard Terminal Automation Replacement System (STARS). Controllers use STARS to provide air traffic control services to pilots in terminal airspace, which is the airspace immediately surrounding major airports. STARS now operates at the 11 Terminal Radar Approach Control Facilities that control 80 percent of U.S. air traffic.
TFMS serves as the FAA's primary system for planning and implementing traffic management initiatives. Its suite of automation tools help to optimize overall airspace capacity and fleet performance as well as efficiency of individual flights. The FAA is collaborating with airlines, business and general aviation, vendors, government, research groups, academia and the military to develop TFMS updates.
TBFM uses time instead of distance to help controllers sequence air traffic. Compared to the traditional distance based process to separate aircraft, TBFM provides a more efficient traffic flow that reduces fuel burn, lowers exhaust emissions, and increases traffic capacity. It is operational at all 20 domestic en route centers, the facilities that control air traffic between the end of an aircraft’s departure and the beginning of its arrival procedure.
Data Comm, a NextGen technology that is evolving communication between air traffic controllers and pilots, is now helping to enhance safety and reduce departure delays at 62 airports nationwide.
The new technology supplements radio voice communication, enabling controllers to transmit typed digital departure clearances that pilots then read, accept, and – with the push of button – load into the aircraft’s flight management system. They can do this as many times as necessary from the gate until before takeoff.
Voice communications can be time consuming and labor intensive. For example, controllers issuing new routes to pilots awaiting takeoff to help them avoid bad weather must do so through two-way radio. This process, which can take 30 minutes or more depending on how many aircraft are in line for departure, can be further slowed by miscommunication known as “readback/hearback” errors.
Planes with flight crews using Data Comm can keep their spots in the takeoff line – or may even be taken out of line and sent ahead – enabling them to depart on time. It’s safer because revised routes can’t be missed or mistaken through congested radio traffic, and it gives controllers and pilots more time to focus on other tasks.
One of the most important – and least visible – keys to a safe and efficient flight is to give the people responsible for that flight the right information at the right time.
A NextGen technology called System Wide Information Management (SWIM) provides near real-time, accurate flight, traffic flow and weather information in a flexible, secure digital architecture. SWIM is the data-sharing backbone of NextGen. It receives information collected independently, combines it and distributes it as data to authorized users in the aviation community. Putting the right information in the right hands at the right time provides for common situational awareness and facilitates collaborative decision making. SWIM provides the tools for airline operators, air traffic managers and controllers, the Federal Air Marshal Service, and the Department of Defense to share information such as route availability and weather conditions in near real time.
Wake Recategorization(Wake Recat) enables the FAA to safely reduce the distance between various aircraft based on wingspan, weight and stability instead of relying mainly on weight. FedEx reported in 2013 that it experienced a 17 percent capacity gain in Memphis, a 3-minute reduction in taxi-out time, and a
2.5-minute reduction in approach time. The airline saved 10.7 million gallons of jet fuel and reduced its carbon dioxide emissions by more than 100,000 metric tons.
A NextGen standard called Equivalent Lateral Spacing Operations (ELSO) is increasing capacity by safely enabling more aircraft to take off from the same runway during the same time period. Atlanta is the first airport to adopt ELSO, which will be implemented in Cleveland, Denver, Detroit, Fort Lauderdale and Miami over the next few years.
ELSO allows the FAA to space routes more closely together and allows controllers to safely clear aircraft for takeoff more efficiently. This is possible because aircraft equipped for Performance Based Navigation are able to fly precise paths with pinpoint accuracy, giving controllers more certainty about the aircraft’s path. When controllers know the aircraft’s exact path on takeoff, they don’t have to build an extra cushion of airspace around the plane to account for variations in the flight path. Current air traffic rules require a 15-degree minimum angle between departure routes to provide that certainty. With ELSO, controllers can reduce the minimum to 10 degrees between departure headings in Atlanta, allowing four flights to depart in the same area that previously accommodated only three flights. This flexibility makes it possible for controllers to clear as many as eight to 12 additional departures every hour.
This innovative capability benefits air traffic controllers, airports, airlines and the flying public by freeing up airspace and reducing taxi time. Atlanta is saving nearly $20 million per year in fuel expenses. If demand increases just 10 percent, the savings will more than double to $50 million per year. For the passenger, the increased efficiency equates to nearly one-and-a-half years of cumulative savings in reduced taxi and departure times. It benefits the environment because aircraft spend less time on the ground with engines idling.
ELSO is just one of many innovative strategies under NextGen that will help to streamline our nation’s airspace and reduce complexity for air traffic controllers and airlines. Through the use of new separation standards with Multiple Runway Operations, the FAA and industry are working together to improve the efficiency of aircraft arrivals and departures, reducing taxi times and saving fuel.
When an aircraft leaves the ground it often uses another major NextGen capability called Performance Based Navigation (PBN), which enables aircraft to safely fly more directly from Point A to Point B. Pilots can fly flight paths not bound to the location of ground-based navigation aids. It delivers new routes and procedures that primarily use satellite-based navigation and onboard aircraft equipment to navigate with greater precision through all phases of flight. PBN also provides a basis for designing and implementing automated flight paths, airspace redesign and obstacle clearance. Aircraft flying RNAV procedures usually have GPS equipment capable of integrating and using the data to maintain flight paths, but can also fly RNAV routes using position information from ground-based navigation aids.
Safety is enhanced through repeatable and predictable flight paths when flying near obstacles and terrain, and with vertical guidance for more stable approaches to the runway. Increased efficiency improves airport arrival rates and reduces fuel burn.
Two types of PBN, Area Navigation (RNAV) and the more precise Required Navigation Performance (RNP), enable controllers to guide aircraft to and from runways simply by assigning one of these highly structured flight paths. There are RNAV and RNP procedures that define approach paths, and RNAV procedures that define arrival and departure flight paths. Similarly, thanks to more accurate tracking and navigation, along with better understanding of wake vortices, controllers may allow aircraft to operate simultaneously on closely spaced runways, either independently or with reduced separation. This translates into increased capacity for an airport’s existing runways.
Required Navigation Performance (RNP) increases the precision of RNAV through computer-based performance monitoring and alerting aboard the aircraft. A principal application of this capability is flying precise curved approach paths. This gives air traffic controllers more options and enables them to relieve or eliminate conflicts between approaches to airports that are located close to each other.
Climb and Cruise:
Controllers are now able to track and manage aircraft in flight through the use of Automatic Dependent Surveillance–Broadcast (ADS-B), the satellite-based system that is replacing ground-based radars as the primary means of aircraft surveillance. ADS-B is one of NextGen’s most important underlying technologies. ADS-B uses GPS signals in conjunction with aircraft avionics to transmit the aircraft’s location to ground receivers. The ground receivers deliver that information to controller screens.
The FAA completed the nationwide infrastructure for ADS-B in April 2014, meaning that the nation’s airspace system now has satellite-enabled coverage wherever radar coverage exists – as well as in some areas that lack radar coverage, such as the Gulf of Mexico and Alaska. On Jan. 1, 2020, aircraft operating in most controlled airspace will be required to have what is called ADS-B Out, which broadcasts aircraft position. ADS-B In, which is optional, gives pilots cockpit displays that show the position of nearby aircraft, bad weather and flight information. In several cases, ADS-B In has helped general aviation pilots avoid a mid-air collision.
Descent and Approach
NextGen capabilities improve aircraft operations around airports, minimizing the need for controllers to use traditional actions to absorb delays, such as holding patterns and vectors. This, in turn, increases the predictability of flights – a major advantage in managing flights – while reducing fuel burn. Enhanced traffic management tools analyze flights approaching an airport from hundreds of miles away to calculate scheduled arrival times, optimize performance and improve the flow of arrival traffic. Controllers receive automated information on airport arrival demand and available capacity, enabling them to improve sequencing and balance arrival and departure rates.
Properly equipped aircraft fly Optimized Profile Descents (OPD), a type of PBN arrival procedure that enables aircraft to smoothly descend from cruising altitude with engines at near idle, reducing carbon emissions and noise. Aircraft can fly longer at more fuel-efficient altitudes and eliminate the inefficient, stair-step descent that requires pilots to adjust engine thrust to maintain level flight at each altitude. Also, the transition from cruise to approach will be more efficient at high-density airports. Controllers will be able to use multiple precise paths that maintain flows to each runway through RNAV and RNP approach procedures.
Another PBN application that improves efficiency while enhancing safety is Initial Tailored Arrivals. These differ from OPDs because they are tailored to the characteristics of a limited number of aircraft types equipped with advanced avionics known as the Future Air Navigation System. Beginning hundreds of miles from the destination airport, these arrivals enable controllers to examine an aircraft’s flight path and substitute planned trajectories tailored to the make and model of the aircraft. In this way, the aircraft descends more efficiently and avoids conditions that might slow it down, such as bad weather and airspace restrictions.