NextGen is an ambitious undertaking that is meant to modernize the national airspace system of the United States to accomplish a number of goals. It has several technology components that we hear about as we all strive to stay informed in our industry. It is my hope that this article will provide some useful information that helps you better understand the overall program and how individual technology components will contribute benefits along the way.
There is a lot of history in how the U.S. National Airspace System has advanced in complexity and performance. Some of the most dramatic changes came about over the past decades, as the result of accidents that created public concern which motivated the government to implement changes. One of the most significant examples is the Grand Canyon accident in 1956 when two air transport aircraft collided. The public demanded action and after a series of Congressional hearings, the Federal Aviation Act of 1958 created the Federal Aviation Administration (FAA).
The FAA was given full control of U.S. airspace, and large organizational and technology investments began to provide more assurance of aircraft separation. A key challenge to the task of providing aircraft separation at that time was that flight crews did not have the means of precisely defining their position in real-time during instrument conditions. World War II had expedited the development of radar that was an available technology to solve this problem, so air traffic separation functions were fundamentally ground-centric from then until the present. Over time, as traffic densities and aircraft speeds increased, additional technologies such as secondary surveillance radar and air traffic automation improved the overall system performance. In parallel with the ground infrastructure developments were advances onboard aircraft such as autopilots, altitude-encoding transponders, digital air data systems, and satellite-based navigation, to name a few. The tremendous improvement in aircraft flight guidance and navigation performance has not been well utilized in the management of air traffic, which set the stage for some ambitious new plans for the future.
The Origins of NextGen
In 2000, another crisis developed in the public mind that the media termed “gridlock” of the nation’s skies. A particularly tough summer storm season in the eastern United States rippled throughout the system and brought commercial air travel woes to passengers across the nation. Congress acted on the growing public concern and through a series of hearings and actions, the Joint Planning and Development Office (JPDO) was created “to develop a unified vision of what the U.S. air transportation system should deliver for the next generation and beyond, to develop and coordinate long-term research plans, and to sponsor cross-agency mission research.”
The JPDO coordinated activities across multiple government agencies, including the Department of Transportation and FAA, NASA, the National Weather Service, the Department of Defense, and the Transportation Security Administration. This multi-agency initiative developed a “Concept of Operations for the Next Generation Air Transportation System” that was intended to drive long-term research and detail planning and was released to the aviation community in 2007.
The scope of this JPDO “ConOps” was a “curb-to-curb” air transportation system with a completion goal of the year 2025 and an end state being an Air Traffic Management (ATM) system founded on an aircraft’s ability to fly precise paths in time/space and the Air Navigation Service Provider’s (ANSP) ability to strategically manage and optimize trajectories throughout the operation.
In 2011 the FAA published their “NextGen Mid-Term Concept of Operations for the National Airspace System” which focused on the areas of the air transportation system, from “gate-to-gate,” for which the FAA is responsible. This FAA ConOps was intended to drive NextGen implementation and had the same timeframe and end state as the original JPDO ConOps.
NextGen Planning and Implementation
In parallel to these government initiatives was a substantial amount of industry input and collaboration. The most notable of these activities was the RTCA NextGen Mid-Term Implementation Task Force (RTCA Task Force 5), which was organized in early 2009. This Task Force represented unprecedented collaboration of more than 300 members of a broad aviation consortium that included representatives from commercial airlines, general aviation, the military, manufacturers and airports. A key interest of the Task Force members was NextGen benefits that could be achieved in the near and mid-term, while efforts continued to build toward longer-term capabilities. By the end of 2009, the Task Force presented the FAA with a unified set of priorities for the following five years of NextGen. The FAA responded in early 2010 with an action plan for each of the Task Force “Tier 1” priorities.
In addition, the RTCA NextGen Advisory Committee (NAC) was established in 2010 as a Federal Advisory Committee. The NAC is made up of high-level representatives from throughout the aviation community and is the FAA’s principal source of stakeholder advice on NextGen issues and is tasked to provide recommendations that help “fine-tune” the agency’s plans. The interests and perspectives of King Air owners and operators are represented on the NAC by the chief executives of NBAA, AOPA, and GAMA. The NAC has proved to be very successful in bringing the industry and FAA together with sustained engagement and focus of many aviation stakeholders across the industry and government.
The Committee recognized in mid-2013 that the many industry requests and recommendations in combination with the FAA budget pressures of sequestration demanded that the NAC help the FAA set clear NextGen implementation priorities in combination with transparent plans. By 2014, after a significant amount of prioritization effort by the industry in close consultation with the RTCA Task Force recommendations, the FAA accepted the recommendation to focus NextGen implementation in four focus areas with the establishment of the NextGen Implementation Work Groups (NIWG).
The four focus areas were:
- Closely Spaced Parallel Runways – Multiple Runway Operations
- Surface and Data Sharing
- DataComm – Controller Pilot Data Link Communications (CPDLC)
- Performance Based Navigation – Time Based Flow Management
In 2017, a fifth NIWG focus area was added by the NAC in response to concerns about the poor airspace performance in a key region of the United States:
- Northeast Corridor
Each of these NIWGs developed implementation planning items that were approved by the NAC, recommended to and subsequently accepted by the FAA. Regular reports on progress to the NAC, and updates every three years, keep this work relevant and aligned with industry and agency needs. The FAA communicates the current NextGen implementation plans and progress in these five focus areas on their NextGen website as “performance snapshots” at: https://www.faa.gov/nextgen/snapshots/priorities/ .
The following is a brief description of each of the focus areas and a more in-depth explanation in a couple of the areas that have some exciting potential for the
King Air community.
Closely Spaced Parallel Runways – Multiple Runway Operations NIWG
Multiple Runway Operations recommendations identify capabilities to improve access to runways including closely spaced parallel runways that will enable more arrivals and/or departures in less than visual approach weather conditions. This is primarily of interest to air transport operations as their hub airports are under increasing demand as traffic increases faster than the ability to add new runways.
Surface and Data Sharing NIWG
Surface and Data Sharing recommendations provide greater predictability to airport surface operations and the NAS with plans for abundant information input among the FAA, Flight Operators and Airport Operators. The enhanced data sharing proposed in the recommendations will lead to more accurate predictions of capacity/demand imbalances and improve overall traffic management efficiency while also reducing taxi-out times and associated emissions. This is also primarily of interest to air transport operations to more completely connect and coordinate the uncontrolled ramp and gate operations with the air traffic operations of the airport surface
Northeast Corridor NIWG
In February 2017, the NextGen Advisory Committee (NAC) voted to make the Northeast Corridor (NEC) the fifth NextGen focus area. This action was taken in recognition that improvements to airspace operation in the Northeast brings benefits to the entire U.S. aviation system. Some primary themes for the NEC planning items are deconflicting arrivals into the New York area, improving arrival and departure throughput, easing congestion points, and addressing community noise. For King Air operators at Teterboro and other NEC regional airports, the emphasis on deconflicting operations between airports will be of particular interest. The final set of recommended planning items are currently being finalized and are expected to be presented to the NAC in June 2018.
DataComm – Controller Pilot Data Link Communications (CPDLC) NIWG
NextGen requires the implementation of advanced DataCommunications (DataComm) between flight crews and air traffic controllers to meet the stated goals. Voice communication between pilots and controllers is labor intensive, time consuming, has a propensity for miscommunication and human error and limits the ability of the NAS to meet future traffic demand. The DataComm NIWG reviewed the FAA implementation plans for DataComm and developed a consensus on timelines, locations and services to which both industry and the FAA would commit.
Early work focused on the deployment of tower DataComm services at 56 airports on an accelerated deployment schedule beginning in 2015. In addition, an agreement was reached to deploy a set of initial enroute services at all 20 Air Route Traffic Control Centers beginning in late 2018. This initial set of enroute services include transfer of communication, initial check-in, altimeter setting, simple airborne reroutes and crossing restrictions. The graphic on page 4 illustrates the complete DataComm plan that is the focus of this NIWG.
These DataComm services are accessed by aircraft that are equipped with Controller Pilot Data Link Communications (CPDLC) that were originally developed as part of the Future Air Navigation System (FANS) for deployment in oceanic operations. It is understandable that the King Air community would not be that familiar with a capability that is viewed as only applicable for oceanic airspace, but it is important to consider the current and imminent operational benefits of DataComm. For operations at airports with the DataComm services, departure clearances are delivered direct to the aircraft and more importantly, re-routes are “pushed” to the aircraft for upload into the nav system. This is particularly important when the clearance delivery or ground frequency is overloaded during the peak demand caused by significant weather events, etc.
In late 2018, Memphis and Kansas Centers will implement the initial set of enroute data services. Other Air Route Traffic Control Centers (ARTCCs) will follow and by the end of 2019, all 20 ARTCCs in the U.S. NAS will provide this service. NavCanada implemented this capability several years ago and for those of us that operate CPDLC-equipped aircraft in that airspace, the transition from voice to digital communications with ATC is pretty amazing.
Performance Based Navigation (PBN) – Time Based Flow Management NIWG
In 2016 the FAA published the PBN NAS Navigation Strategy in close collaboration with industry through an ad hoc committee of the Performance Based Aviation Rule Making Committee (PARC) and was endorsed by the NAC. The strategy describes a number of FAA goals and commitments that are necessary to transition to a “PBN-centric” NAS. The current work of the PBN NIWG is focused on bringing the Strategy to an operational level which requires a huge quantity of resources and planning.
A tremendous amount of PBN work has already been accomplished that is visible and useful to King Air operations across the United States. PBN routes and procedures have been deployed across all phases of flight. Each application has specifications that define the airspace and equipment requirements and operational procedures. The current inventory of all types of PBN routes and procedures published by the FAA in the U.S. NAS is over 15,500. Because of the nature of PBN, it is quite cost-effective to continue to expand the inventory of routes and procedures and as the FAA deployment plans continue to be defined, it is clear that will be the case.
Over the past decade, the FAA has deployed 133 high altitude “Q” and 101 low altitude “T” airways. These PBN airways augment the existing inventory of 274 high altitude “J” and 664 low altitude “V” airways that are organized around the ground network of VOR stations across the NAS. The deployment of PBN airways will intentionally be less than the conventional airways that have existed over the past several decades. This is in accordance with FAA airspace plans that embrace the PBN concept of route structure where beneficial and point-to-point flexibility elsewhere with RNAV navigation.
Conventional Standard Instrument Departures (SIDs) and Standard Terminal Arrival Routes (STARs) have been used for many decades to organize the flow of traffic to and from airports. The success of these types of procedures has been greatly expanded with the increased flexibility of PBN. In addition to the lateral flexibility provided by PBN for STARs, there has been a focused effort by the FAA to provide a vertical descent path along the lateral path.
The result has been that PBN SIDs and STARs have been deployed quite successfully in improving aircraft efficiency benefits in combination with community environmental improvements. The total number of PBN SIDs and STARs deployed in the U.S. NAS is over 900, which outnumbers the current inventory of conventional SIDs and STARs.
PBN has also been deployed to improve the quality of guidance for pilots in the event of an engine failure on departure. For these considerations, PBN can provide a contingency route that balances payload (performance) with flyability and better separation from obstacles and terrain.
PBN instrument approach procedures have been deployed extensively to runways across the NAS. The current inventory of RNAV (GPS) and RNAV (RNP) approaches in the U.S. NAS is over 14,400. This current inventory of PBN IAPs is less than the existing conventional instrument approach procedure counts by a few thousand, but it is significant to note that there are many airports that are only served by PBN instrument approach procedures. In addition, there are over 1600 PBN precision approaches to airports that are not equipped with an ILS. The U.S. General Aviation population has benefitted greatly from the U.S. WAAS program through the implementation of LPV approaches. These procedures have focused on the challenge of providing ILS-type guidance from the final approach fix to the runway. The benefit of Required Navigation Performance (RNP) approaches has been almost completely unavailable to this population of aircraft and is waiting for this capability to be provided by the avionics manufacturers. The benefits of this technology to address the more complex challenges of the complete set of approach, missed approach and departure operations has been widely recognized and implemented by air transport operators with Boeing and Airbus aircraft. A highly regarded example of this is the RNP operations in Queenstown, New Zealand as depicted in the graphic above, and as viewed from the cockpit in a YouTube video: www.youtube.com/watch?v=7mxmFCw-Dig .
The development and implementation of RNP is an outcome of navigation and guidance performance of our modern airplanes that far exceeds the assumed performance used in Terminal Instrument Procedures (TERPS) design criteria.
Trajectory Based Operations and the Future
All of these activities are preparing for a much larger vision than the benefits provided by the individual elements by themselves. The primary goal of NextGen is to transition to Trajectory Based Operations (TBO) and remain the same as first envisioned by the JPDO in 2007. TBO is the air traffic concept to operate the National Airspace System based on the aircraft’s ability to fly precise paths in time and space and the Air Traffic Management’s ability to strategically manage and optimize trajectories throughout the operation. Another way to describe this is to say that we are moving from a system based on knowing where an aircraft is (radar and ADS-B) to a system based on knowing where an aircraft is going to be at any given time.
With this in mind, it will be increasingly important for each aircraft to have a sophisticated flight management function to build a precise 4-D (time and space) plan. This onboard plan will be shared via DataComm with the ground systems to support the strategic management of airspace.
All of this seems quite far away now, but it is helpful to keep the bigger picture in mind as the individual components are being developed and brought together through many separate initiatives.