FAA has pursued several different modernization efforts for air traffic control (ATC) since FAA’s creation by the Federal Aviation Act of 1958. These efforts to upgrade the air-traffic control system included the installation of a semi-automated air-traffic control system beginning in the mid-1960s and an air traffic control modernization program beginning in 1981. The 1981 modernization program was intended to replace and upgrade the equipment and facilities of the NAS to meet an expected increase in traffic volume, enhance the margin of air safety, and increase the efficiency of the air-traffic control system. The centerpiece of the program was the Advanced Automation System, which would replace computer hardware and software and controller work stations at tower, terminal, and en-route facilities. FAA restructured the automation program in 1994 after the estimated cost to deploy it had tripled, capabilities were shown to be significantly less than promised, and delays were expected to run nearly a decade. In 1995, we placed FAA’s air traffic control modernization efforts on our watch list of high-risk federal programs due to the cost, complexity, criticality to FAA’s mission, and problematic history. By 2003, the estimated cost of FAA’s air-traffic control modernization efforts had grown from $12 billion to $51 billion. In the early 2000s, the U.S airspace system was experiencing significant congestion and delays, with about one in every four flights delayed. Additionally, forecasts called for a possible tripling of air traffic by 2025, which raised concerns about the air-traffic control system’s ability to handle demand. In December 2003, Congress passed the Vision 100— Century of Aviation Reauthorization Act, which created the JPDO within FAA to plan for and coordinate a transition to NextGen by 2025. Congress’s goals for NextGen were to improve the level of safety, security, efficiency, quality, and affordability of the NAS and aviation services; take advantage of data from emerging technologies and integrate data streams from multiple sources; and accommodate and encourage substantial growth in domestic and international transportation, among other things. Congress assigned the JPDO the responsibility to develop an integrated plan for NextGen and facilitate collaboration between FAA and other federal agencies on NextGen efforts. Since passage of the Vision 100 Act, NextGen has evolved from a high-level vision developed by the JPDO to detailed plans currently being implemented by FAA. See appendix II for more detail on FAA’s planning and implementation documents for NextGen. NextGen is a system of systems designed to improve operations in all phases of a flight, through the replacement of the legacy radar-based air traffic control system with a satellite-based system that includes digital communications, among other improvements. NextGen includes a variety of programs that deliver specific improvements to the NAS. See figure 1 below for some of the improvements to the phases of flight that NextGen is expected to deliver. For example, under enhanced-surface-traffic operations, a service provided by FAA’s Data Communications program allows an air traffic controller to send flight-departure clearance instructions to aircraft electronically, which can expedite clearances and reduce communication errors. Under an improvement to streamline arrival management, performance-based navigation allows aircraft equipped with appropriate technology to fly precise paths at reduced power, which saves time, conserves fuel, and reduces exhaust emissions. In addition, FAA is deploying some programs that are necessary to implement NextGen programs. For example, the En Route Automation Modernization (ERAM) program replaced the computer system used by air traffic controllers at en route centers, a step that was necessary to deploy some NextGen programs. FAA is implementing NextGen incrementally through six NextGen-related areas—communications, automation, navigation, surveillance, weather, and foundational programs. FAA has faced challenges in including stakeholders and in measuring and reporting on NextGen progress. In response, FAA has encouraged the formation of groups of stakeholders to advise it on implementing NextGen and measuring its progress, and has worked to incorporate industry preferences into its implementation of NextGen. For example, FAA is deploying new navigation procedures in “metroplexes”— geographic areas covering several airports that serve major metropolitan areas—following a recommendation from a government and industry task force. FAA has also developed a website that reports on outcome-based performance metrics for NextGen. FAA plans to implement the concepts that will transform the NAS to a NextGen system by 2025, and current total cost estimates for NextGen are within the JPDO’s 2007 estimates. In the late 1990s, building on lessons learned from previous air traffic control modernization efforts and recommendations from stakeholders, FAA shifted its strategy for air traffic control modernization. In contrast to previous modernization efforts, in which FAA sought to build highly complex software-intensive systems all at once, FAA adopted a phased approach to modernization that allowed FAA to make mid-course corrections and avoid costly late-stage changes. JPDO later adopted this approach for developing and refining its enterprise architecture—a technical description of the NextGen system that was designed to provide a common tool for planning the complex, interrelated systems that would make up NextGen. According to FAA officials we interviewed, the development and implementation of NextGen is an iterative and evolutionary process. However, some stakeholders told us that FAA had originally described NextGen as a transformative initiative. A report from a 2015 National Academy of Sciences study commented that NextGen meant different things to different people, from a wide-ranging transformational vision to a much more concrete set of phased incremental changes to various parts of the NAS, and recommended resetting expectations. The study committee concluded that NextGen today is primarily an incremental modernization effort. The report also noted that given the continuing rapid pace of technological evolution and ongoing changes in what is demanded of the NAS, the NextGen effort is properly seen as an ongoing process, punctuated by particular efforts focused on particular capabilities. According to FAA officials, NextGen can be both incremental and result in a transformation. FAA has begun developing and deploying elements of many NextGen communications, automation, navigation, surveillance, and weather programs, as well as foundational programs on which NextGen improvements depend. A short overview of these six NextGen-related program areas can be found below. See appendix III for further information about select NextGen programs. Foundational programs to provide the infrastructure necessary to deploy NextGen programs. For example, the Terminal Automation Modernization and Replacement (TAMR) program includes updates to air traffic control systems to help controllers manage air traffic. Communications programs to enhance communication and information sharing in the NAS. This area includes programs such as Data Communications, which will supplement the voice communications currently used to relay information between air traffic controllers and aircraft with pre-scripted email-like messages. Navigation programs that use more efficient routes and procedures to save fuel, reduce flight times, increase traffic flow and capacity, and reduce exhaust emissions. This area includes programs such as Performance-Based Navigation (PBN), which provides new, more efficient aircraft flight routes and procedures that primarily use satellite-based navigation. Surveillance programs to provide more precise tracking of aircraft, vehicles, and other objects to air traffic controllers and pilots. This area includes programs such as Automatic Dependent Surveillance- Broadcast (ADS-B), which uses Global Positioning System (GPS) satellites to determine an aircraft’s location, speed, and other data. Automation programs to enhance air traffic control efficiency, reduce costs, and provide traffic flow management solutions. This area includes programs such as Time Based Flow Management, which is designed to optimize the flow of aircraft as they arrive in or depart from congested airspace and airports. Weather programs to manage and disseminate weather information, help identify safety hazards, and provide support for strategic traffic flow management. This area includes programs such as Common Support Services-Weather, which will enable access to standardized weather information. Some NextGen improvements have already been deployed. For example, Data Communications departure clearance services have been deployed at 55 airports—all of the locations for the first phase of the Data Communications program, including 39 of the 40 busiest commercial airports in the United States. FAA has segmented the implementation of some of its NextGen programs into time frames during which FAA will implement certain portions of the programs. By segmenting implementation, FAA divides each program into defined parts that require less funding than the entire program. In many cases, achieving the desired NextGen outcomes depends on the successful implementation of multiple programs or capabilities. For example, more efficient air traffic control routes may provide limited benefits if air traffic controllers do not have access to tools to better manage airborne traffic. To help manage the implementation of NextGen improvements across programs, FAA has organized the operational improvements—specific operational changes to the NAS, such as the implementation of improved air traffic control procedures—into portfolios. This portfolio-based approach views NextGen as an integrated effort rather than a series of independent programs. See table 1 below for a list and description of FAA’s 11 implementation portfolios. In 2008, many of the aviation stakeholders we interviewed told us that while they felt they were provided the opportunity to participate in NextGen’s planning, many were not satisfied with the impact or outcome of their participation. Some of these stakeholders expressed concern that their input was not included in the development of planning documents and other products, and that issues were not addressed or incorporated in NextGen plans. This participation is critical to NextGen’s implementation because NextGen depends heavily on airlines’ and other stakeholders’ investments in NextGen technology and training. The need for stakeholder buy-in and investment led FAA in 2009 to request RTCA to form a task force of government and industry stakeholders. This task force —called the NextGen Mid-Term Implementation Task Force—was asked to recommend NextGen improvements that could be implemented with existing technologies in the “midterm,” which was defined as lasting through 2018. In 2009, this task force issued its recommendations to FAA; they prioritized operational capabilities in six areas: surface, runway access, metroplex, cruise, access to the NAS, and cross-cutting—recommendations that cut across the previous five areas (see table 2). FAA accepted the Task Force recommendations and incorporated them into its annual NextGen implementation plans. In response to the task force recommendations, FAA has focused its operational improvement efforts on key airports and metropolitan areas. Specifically, through the Optimization of Airspace and Procedures in the Metroplex (Metroplex) initiative, which began in fiscal year 2010, FAA has focused on airspace redesign and deploying PBN procedures— procedures that primarily use satellite-based navigation and equipment on aircraft to navigate with greater precision—in metroplexes. These metroplexes have a large effect on the overall efficiency of the NAS, because congestion or delays at one metroplex can affect NAS operations in other parts of the country. These metroplexes are shown in figure 2. In fiscal year 2013, FAA planned to complete projects at 10 metroplexes by fiscal year 2016, but as of March 2017 FAA had completed projects at only 4 metroplexes. FAA considers a metroplex “completed” when, among other things, it deploys new PBN procedures and when all air traffic controllers are trained on the new procedures. According to FAA, several factors caused the delay. FAA decided to implement ERAM before addressing metroplexes because ERAM is required for some NextGen operations. As a result, some Metroplex projects were delayed until ERAM was implemented. For example, the Charlotte and Atlanta metroplexes were delayed from April 2014 until August 2015 while the Atlanta Air Route Traffic Control Center implemented ERAM. In addition, FAA changed the Metroplex program in 2015 to include enhanced community involvement and outreach activities in Metroplex projects. This change further contributed to delays. For example, according to FAA, the introduction of the community involvement initiative caused a 15 month delay in the Cleveland/Detroit Metroplex project. Under FAA’s current community involvement strategy, a new Metroplex project would take about 7 months longer to complete because of community involvement activities. Further, according to FAA, sequestration and the 2013 government shutdown caused some delays due to employee furloughs and travel restrictions. In addition to the 4 completed projects, 8 other Metroplex projects are in various stages. While FAA plans to complete the current set of 12 Metroplex projects by fiscal year 2019, FAA “paused” work at one metroplex—Phoenix—in October 2015, due to legal action brought by the City of Phoenix over noise created by new PBN procedures. As of March 2017, FAA did not have plans to resume that work. At completed metroplexes, not all aircraft are flying PBN procedures. Although PBN procedures generally provide more efficient flight routes, controllers may continue to route air traffic on conventional routes for a number of reasons. For example, some aircraft may not have the proper equipment to use the new procedure. Further, some airline officials we interviewed reported receiving fewer benefits than expected from FAA’s implementation of PBN. For example, officials at one airline told us that, at one metroplex, FAA’s changes have led to that airline’s flying a less efficient route into one airport, a route that requires its aircraft to use more fuel and time to land at that airport. Some stakeholders have called on FAA to include New York in its Metroplex plans, due to its congestion and impact—such as flight delays—on the rest of the NAS, as we have previously reported. In 2013, we reported that FAA chose to exclude the New York/Philadelphia metroplex because FAA did not want to initiate a new environmental review process. FAA told us in 2017 that the agency plans to focus on the northeast in the future, but does not have a current plan to implement Metroplex improvements there. At FAA’s request, RTCA established the NAC to provide advice on NextGen implementation issues. FAA designated the NAC to develop aviation stakeholder priorities for NextGen implementation. These priorities included both the national implementation of NextGen as well as specific locations (such as airports) for NextGen improvements. In 2012, the Integrated Capabilities Work Group of the NAC developed priority operational improvements for major airports and metroplexes in the midterm. These priority improvements included capabilities such as deploying PBN procedures that allow aircraft to take a more direct route into and out of airports, which FAA expects will save both time and fuel. In 2014, FAA and the NAC issued a Joint Implementation Plan in which FAA and industry described a set of activities that FAA and the aviation community were committed to accomplishing within the next 3 years. These activities covered four focus areas: data communications, multiple runway operations, PBN, and surface operations and data sharing. According to FAA, by the end of 2016, FAA had implemented 124 of 128 NextGen commitments it made for 2014 through 2016. For example, FAA had deployed the System Wide Information Management (SWIM) Surface Visualization Tool at five terminal radar-approach control facilities. This tool provides air traffic controllers—who are not located in the airport tower—with a real-time picture of airport surface traffic. FAA and the NAC have agreed to update the Joint Implementation plan annually and develop rolling plans every 2 years to re-examine the needs of the NAS and its users and to add milestones. FAA had an additional 57 commitments for 2017 through 2019 as of the beginning of 2017, and industry had an additional 17 commitments for the same time period. In addition to these commitments, in February 2017, the NAC voted to make the Northeast Corridor – which stretches from Washington, D.C to Boston, MA and includes the New York area – the fifth area of NAC focus. Concurrent with the work and recommendations of the RTCA’s Mid-Term Implementation Task Force and the NAC, the DOT OIG and we conducted reviews of NextGen. As a result of those reviews, from fiscal year 2008 through fiscal year 2016 the DOT OIG and we issued 137 and 47 recommendations, respectively, aimed at improving the implementation of NextGen. Our analysis shows that FAA has implemented most of the recommendations related to NextGen programs from us and DOT OIG since fiscal year 2008. More specifically, FAA has implemented 39 of our 47 recommendations (83 percent), 6 recommendations are in process (13 percent), and 2 remain open (4 percent). Additionally, DOT OIG has closed as implemented 103 of its 137 recommendations (75 percent) that we determined to be related to NextGen. See appendix IV for an overview of the status of recommendations DOT OIG and we made related to NextGen. FAA has faced challenges in consistently communicating the status of NextGen’s implementation. In 2010, we found that while FAA had broad goals for NextGen, such as increasing capacity and reducing noise and emissions, it had not developed specific goals and outcome-based performance metrics to track the impact of and benefits realized from the entire NextGen endeavor. At that time, we recommended that FAA develop an action plan to agree with stakeholders on a list of specific goals and outcome-based performance metrics for NextGen. FAA developed a set of performance metrics, which were used as a starting point with industry collaboration, and aligned them with NextGen and agency-wide goals. Additionally, FAA launched the NextGen Performance Snapshots (NPS) website to compare key NextGen initiatives with performance outcomes at locations where NextGen technologies have been deployed. For example, with some NextGen initiatives already deployed, FAA tracks the measures and reports on airport performance at the Core 30 airports—a set of airports in major metropolitan areas with the highest volume of traffic–where NextGen technologies have been implemented. The agency plans to continue to update the NPS with additional metrics as they mature. Further, the NAC created a Joint Analysis Team which has developed outcome measures for deploying certain NextGen capabilities. For example, the team has measured the effect of efforts to update standards for separation between and among aircraft on the efficiency of operations at airports in Charlotte, Chicago, Indianapolis, and Philadelphia. The objective of this capability is to decrease the separation between and among aircraft and thereby allow more takeoffs and landings and greater efficiency and capacity for airports. FAA officials told us that FAA continues to work with industry partners to ensure that FAA is validating and verifying implementation progress of NextGen technology and reporting successes and beneficial effects. However, some stakeholders told us that FAA continues to focus on outputs, such as the number of ADS-B ground stations deployed, instead of outcomes, such as improvements in safety, capacity, or efficiency. According to FAA officials, current segments of NextGen programs are generally on schedule, and FAA documents indicate that FAA plans to implement the concepts that will complete the transformation of the NAS to a NextGen system by 2025. According to FAA, these timeframes are updated at least annually. FAA also has an Integrated Master Schedule for key NextGen activities; this schedule is updated at least every 3 months. In describing these concepts, FAA does not state that NextGen will be implemented or completed by 2025. Rather, FAA describes several interim milestones that are scheduled to occur between now and 2025. Taken together, the completion of these milestones—such as deploying Data Communications and expanded PBN—will result in the implementation of NextGen concepts, according to FAA. According to MITRE Corporation, the aviation industry has been able to leverage current ground-based and aircraft-based navigation capabilities to realize initial benefits of NextGen at key metroplex areas. For more information on the current status of implementation of select NextGen programs and future implementation plans, see Appendix III. After 2025, FAA plans to continue enhancing technology and implementing advanced NextGen applications as part of its ongoing efforts to improve the NAS. In August 2017, FAA estimated that NextGen had delivered $2.7 billion in benefits through 2016. According to FAA, these benefits were realized by airlines, the FAA, and the general public, and included benefits derived from fuel savings, reductions in crew and maintenance costs, additional airline flights, FAA efficiencies, safety improvements, passenger time savings, and reductions in carbon dioxide emissions. In addition, FAA and industry team and the MITRE Corporation have conducted studies to determine the benefits from the NextGen improvements FAA has already deployed. For example, a November 2015 MITRE Corporation analysis found that Metroplex procedural improvements resulted in fuel savings at one metroplex, although less than anticipated. Specifically, the analysis of the impact of new Metroplex procedures in the Houston Metroplex projected an annual benefit of $5.3 million in fuel savings to operators at two airports in Houston; however, the analysis also noted that these benefits were lower than the predicted savings of $8.3 million annually. Similarly, June 2016 and February 2017 assessments of the effect of revised wake separation standards by the Joint Analysis Team showed positive results. These standards specify the required distance between aircraft due to the turbulence created by the air behind aircraft. The Joint Analysis Team’s assessments found cost savings at four of five airports. Specifically, the studies found savings for flights on congested runways, and airports could increase the frequency of takeoffs and landings. The studies found a decrease in separation for arrivals at all five locations, and a decrease in separation for departures at four of the five locations, leading to increased capacity and projected cost savings of over $4.3 million annually. However, the studies also found that the effects at individual airports would depend on the type and number of aircraft at each airport. According to FAA, some airlines and shipping companies have also reported benefits from revised wake-separation standards. FAA reports that Delta Air Lines estimated that revised separation standards at Atlanta increased Delta’s average daily operations by 6.8 percent, among other benefits, resulting in $13.9 to $18.7 million in annual savings. Similarly, FAA reports that United Parcel Service, Inc. estimated 1.5-million gallons in annual fuel savings from revised standards at Louisville, and FedEx Corporation estimated 4.1-million gallons in fuel savings from revised standards in Memphis. While some cost savings have already occurred, not all NextGen activities are being implemented. According to FAA officials, they have identified six NextGen activities that FAA had previously planned to complete by 2025, but has now deferred until after 2030 due to technical or operational infeasibility or changed operational needs. FAA officials explained that these applications are not in progress, and may be continually deferred, redefined, or never implemented. For example, in 2011 FAA planned to implement automated conflict-resolution aids—a mechanism to enable air traffic controllers to manage more aircraft while maintaining safety—by 2018. However, FAA’s revised plan for NextGen has deferred implementation of these applications until after 2030. According to FAA, FAA deferred them for reasons such as costs outweighing prospective benefits, a lack of sufficient air traffic to justify implementation, or deployment of other capabilities that provide similar benefits. See appendix V for more information about these deferred programs. FAA’s current total cost estimate for implementing NextGen through 2030 is within the JPDO’s 2007 estimates. In 2007, JPDO projected that through fiscal year 2025, FAA’s total NextGen cost would be between $15 billion and $22 billion and that costs to the aviation industry would be between $14 billion and $20 billion. In 2016, FAA estimated the agency’s cost through fiscal year 2030 at $20.6 billion—within the range of JPDO’s 2007 estimate of $15 to $22 billion. FAA also estimated $15.1 billion in costs for the aviation industry—also within the range of the 2007 estimate. Of the $20.6 billion in estimated costs, FAA indicated that the agency had already expended $5.8 billion through fiscal year 2014— approximately 28 percent of the estimated cost of NextGen—and projected NextGen costs of $14.8 billion from fiscal year 2015 to 2030. Assessing prior NextGen cost estimates against current estimates is difficult because the NextGen program has changed since 2007. As previously discussed, six NextGen activities were removed for reasons such as costs outweighing benefits or insufficient air traffic to justify implementation (see appendix V). Other programs, such as PBN, were added to the NextGen program after 2007. As a result, FAA officials stated that it is somewhat coincidental that the 2016 estimate is within the range of the 2007 estimate. We recently found that NextGen cost estimates have evolved, but not increased markedly since 2004. According to FAA, NextGen cost estimates have changed in part because earlier estimates considered the cost of upgrades and enhancements, but over time estimates have also considered the cost of sustaining systems, PBN procedures, and recently, the costs associated with integrating unmanned aircraft systems (UAS) (commonly known as “drones”) into the NAS. FAA officials explained that FAA’s current estimated total cost for the aviation industry to equip for NextGen-capable avionics—electronic equipment found in modern aircraft—is lower than earlier estimates in part because smaller aircraft are being replaced by new, larger, and better equipped aircraft, reducing the number of aircraft in the commercial fleet. According to MITRE representatives, several factors have contributed to the lower aviation industry’s cost estimates, including changes in assumptions for the expected volume of commercial traffic, modifications to the cost of equipage, and reduction in uncertainty about what equipment aircraft would need. Based on an analysis of FAA budget documents and data, we recently found that FAA received approximately $7.4 billion for NextGen from fiscal year 2004 through fiscal year 2016. According to FAA officials, operational costs of fully implemented NextGen programs are not included in these funds. Congress appropriates most of the funding to FAA from the Airport and Airway Trust Fund, which receives revenues from a series of excise taxes on airline tickets, aviation fuel, and cargo shipments paid by users of the national airspace system. See figure 3 for an overview of federal funds FAA has received for NextGen programs and activities. In addition to funds for NextGen, FAA has also invested in other programs on which aspects of NextGen are dependent. For example, according to FAA, the deployment of the core ERAM program cost $2.58 billion when completed in 2015, and FAA estimates that all completed and current TAMR programs will cost $3.082 billion. FAA faces several remaining challenges as it continues to implement NextGen, such as uncertainties regarding future funding, leadership stability, aircraft equipage, and cybersecurity issues. FAA is taking some actions to address these challenges by, for example, prioritizing and segmenting NextGen improvements into smaller pieces that each require less funding. While it is not possible to eliminate all uncertainties, FAA is adopting Enterprise Risk Management (ERM) as a tool to help it anticipate and manage risks across NextGen programs, and plans to use ERM to mitigate future risks. Most of the aviation stakeholders we interviewed (22 of 34) told us that uncertain funding has been a challenge and has affected FAA’s efforts to implement NextGen. FAA officials told us that sequestration and “continuing resolutions” have had an impact on FAA’s ability to plan and implement NextGen. Uncertain funding includes not knowing the amount of funding that will be appropriated to NextGen or when the funding will become available. From fiscal year 2011 through fiscal year 2016, Congress has passed 25 continuing resolutions that impacted funding for FAA, ranging from 1 day to 365 days, with an average of approximately 46 days. In 2014, we reported that some stakeholders told us that stops and starts associated with continuing resolutions make it difficult for FAA to carry out long-term planning and strategic development of future technologies. We found that operating under continuing resolutions can also complicate agency operations and cause inefficiencies, such as leading to repetitive work, limiting agencies’ decision-making options, and making trade-offs more difficult. Uncertain funding was also cited by some stakeholders as a major reason for Congress to consider restructuring the FAA, which is discussed later in this report. FAA has taken steps to mitigate challenges resulting from uncertain funding. Specifically, it has prioritized NextGen improvements in collaboration with the NAC and has segmented some NextGen programs into smaller pieces that each requires less funding. In 2012, we found that FAA broke large, complex programs, such as SWIM, into smaller segments to reduce risk. We previously found that this approach can improve program management by positioning FAA to make any necessary corrections earlier in development, and thus help FAA avoid costly late-stage changes. However, we also found that this approach can increase the duration and possibly the total cost of the program. For example, in 2015 we found that FAA had divided capital investments for Data Communications into small segments, raising questions from the aviation industry about when FAA will fully implement Data Communications. A related funding challenge is the need for FAA to have funding sufficient to support both existing legacy system maintenance and the implementation of NextGen capabilities. As we reported in November 2015, according to FAA officials, NextGen implementation in future years is dependent on the timing and amount of future appropriations. Specifically, any funding delay in one NextGen program can lead to increased costs for FAA, even if the delay does not result in a direct cost increase to a program. These cost increases occur because FAA staff must continue to manage program implementation and maintain any legacy system that the program is replacing. In addition, NextGen programs are interdependent, so a schedule delay in one program can also affect how and when other programs will be implemented. In response to the challenge of maintaining the legacy system while also implementing new systems and capabilities, FAA officials told us that funding has been allocated to account for the “technical refresh” of existing systems and other maintenance related issues, and that FAA will continue to monitor and prioritize the delivery of NextGen capabilities while maintaining existing systems. According to FAA officials, approximately 55 percent of FAA’s current budget is used to maintain the current air traffic control system. The longer that legacy systems are maintained, there is a greater likelihood that they will continue to require increasingly large shares of the FAA budget and reduce the amount of funds available to implement NextGen. In 2011, we concluded that FAA will have to balance its priorities to ensure that NextGen implementation stays on course while also maintaining the current infrastructure that is needed to ensure the safety and reliability of the NAS. NextGen program leadership has undergone significant changes that are likely to continue. Specifically, while the FAA administrator is appointed to a 5-year term, there have been four administrators since a previous administrator’s term ended in September 2007, including no confirmed administrator for all of 2008 and 2012. The Deputy Administrator-Chief NextGen Officer left the position in June 2016 after 3 years in the position, and a new Deputy Administrator was sworn in in June 2017. Furthermore, since the position of Assistant Administrator for NextGen was created, in late 2011, three assistant administrators and one interim assistant administrator have filled the position. Additionally, a new Secretary of Transportation was sworn in in January 2017, and the current FAA administrator’s term expires in January 2018. We previously found that programs benefit from having experienced program managers who provide consistent leadership through major phases of a program. Additionally, we found that leading practices of successful organizations indicate that programs can be implemented most efficiently and effectively when managers are empowered to make critical decisions and can be held accountable for results. Conversely, the absence of stable and consistent leadership may have the opposite effect on project implementation. For example, continued uncertainty about the FAA’s leadership of NextGen could affect FAA’s ability to manage the various efforts needed to achieve full implementation of NextGen. As we have previously reported, industry stakeholders have expressed concerns about the fragmentation of authority and lack of accountability for NextGen, two other factors that could delay its implementation. Legislation introduced in June 2017 would establish a separate not-for- profit corporate entity outside of FAA to operate the nation’s ATC system. This proposal could affect the implementation of NextGen. For example, the change could result in more certain funding, as funding would not be subject to the federal budget process. However, other challenges could develop. In October 2016, we reported that subject area experts, aviation stakeholders, and FAA officials identified issues that will need to be considered if such a transition were to occur. Some of those issues directly affect NextGen implementation. Specifically, stakeholders told us that one issue would be the amount of time and costs required to complete a transition from FAA to another ATC operator. This transition time would include the time it could take to terminate or revise current contracts between FAA and companies that produce NextGen technologies. Another issue that stakeholders identified is how management and workforce roles and responsibilities would be defined within the new entity and FAA. For example, selected experts identified the importance of clearly delineating each organization’s roles and responsibilities to ensure a smooth transition. According to FAA, the transition could create some uncertainty among some employees over future workforce or organizational changes. While it is uncertain how a transition would affect NextGen implementation, the legislation includes a requirement for FAA to prioritize and track progress on some NextGen programs before the transition occurs. To achieve desired benefits, NextGen requires system users such as aircraft owners and operators to equip their aircraft with new avionics that provide aircraft capabilities needed for the planned NextGen operational capabilities and services to be used effectively. For example, ADS-B uses Global Positioning System (GPS) satellites to determine an aircraft’s location, speed, and other data, rather than traditional radar. ADS-B Out uses avionics installed in an aircraft to broadcast the aircraft’s position, air speed, and altitude to other aircraft equipped with ADS-B and to ground stations, which transmit the data to air traffic control facilities. FAA has mandated that, starting January 1, 2020, aircraft must be equipped with ADS-B Out to fly in most controlled airspace. This deadline applies to all aircraft in the applicable airspace, including commercial aircraft, general aviation, and military aircraft. In discussing challenges to implementing NextGen, 27 of the 34 aviation stakeholders we interviewed told us that factors related to equipage are a challenge for NextGen implementation. For example, officials from an aviation association told us that the primary barrier to installation of ADS-B Out when the Equip 2020 working group was created in 2014 was the cost of purchasing and installing the equipment. These officials said that the price of ADS-B Out was too costly for general aviation and that the cost to equip was not declining as the deadline approached. Additionally, representatives from two airlines and two aircraft manufacturers told us that they are hesitant to equip due to concerns that FAA could change equipage standards. FAA has worked with industry and academia through the Equip 2020 working group to identify and mitigate barriers to owners equipping their aircraft and, according to FAA, has not changed equipage standards for 7 years. FAA estimates that more than 100,000 aircraft still need to equip with ADS-B Out before the January 1, 2020 deadline. As of December 2016, FAA reported that 787 U.S. air carrier aircraft were equipped with ADS-B Out, representing between 13.1 percent and 15.7 percent of all U.S. air carrier aircraft. However, FAA reported that it has received equipage plans for meeting the 2020 requirement from airlines that account for 88 percent of the projected fleet. According to FAA, it continues to work with airlines to address the remaining aircraft, which include new deliveries, additional retrofits, and aircraft that may be shifted outside the U.S. market. FAA also reported that 18,292 U.S. general aviation aircraft were equipped with ADS-B Out, which represents between 11 percent and 18 percent of all U.S. general aviation aircraft. To encourage aircraft owners and operators to equip with ADS-B Out, prior to the January 1, 2020, deadline, FAA announced a $500 rebate in September 2016 for 20,000 general aviation aircraft owners and operators who equip with ADS-B Out. According to FAA, a minimal rule- compliant system costs approximately $2,000, plus installation costs. The Equip 2020 working group performed a survey of aircraft owners and found that getting costs below $2,000 would encourage many price- sensitive owners to equip. As such, the FAA chose $500 as an amount that would get the price down to that more-attractive range, and according to FAA, this amount also maximized the total number of rebates the agency could distribute, based on total funding approved for the program. FAA officials said it could be a problem if owners wait until 2019 to get equipped since there are a limited number of facilities and technicians available to equip airplanes. Additionally, once aircraft are equipped with new avionics technology, FAA must ensure that the avionics were properly installed and meeting performance standards. Similar to ADS-B, before aircraft owners and operators can benefit from the capabilities of Data Communications, their aircraft must be equipped with Data Communications avionics equipment. FAA has achieved its 2019 goal for equipping 1,900 domestic air carrier aircraft with Data Communications avionics. For example, according to FAA, as of August 2017, more than 3,150 domestic air carrier aircraft were equipped for Data Communications. As with ADS-B Out, FAA established an incentive fund to encourage early adoption of the technology, and eight airlines signed agreements to equip their aircraft under the incentive program. According to 16 of 34 aviation stakeholders we interviewed, the need to integrate new entrants—UAS and commercial spacecraft—into NextGen efforts is a challenge to implementing NextGen. Integrating new entrants could have both budget and program implications. When the original planning for NextGen was developed, UAS were not generally included in the planning. In June 2016, FAA finalized the first set of federal aviation regulations that established the regulatory framework for small UAS operations and allowed routine commercial use of small UAS at 400 feet and below and within the operator’s line-of-sight. This regulation went into effect in August 2016. FAA statistics indicate that there are more than 770,000 registered drone operators in the United States. Applying lessons learned about the importance of early and continued involvement of stakeholders, FAA established the Drone Advisory Committee (DAC). The DAC consists of government officials and predominantly industry stakeholders and advises FAA as it works to expand small UAS operations in the NAS. This expansion could include operations over people, at night, and beyond the visual line-of-sight of the operator, and the transportation of persons and property. The increased use of drones has resulted in an increase in the number of UAS sightings, which occur when pilots, law enforcement, and others report a possible encounter with a UAS, many of which FAA is concerned pose a safety hazard to manned aircraft. The number of reported sightings increased about five-fold from 233 in 2014 to 1,218 in 2015 and increased by about another 50 percent in 2016 to 1,837 (see fig. 4). FAA must also integrate commercial space launches into the NAS. The commercial space industry delivers cargo to the International Space Station as well as launching satellites. In recent years, U.S. companies have conducted a number of licensed launches and reentries. According to FAA data, the first licensed reentry occurred in October 2014, and FAA has licensed a total of seven entries through June 2017. During this same time period, FAA has licensed 33 commercial space launches. As companies develop the capability to conduct other types of launches, such as delivering crew for the National Aeronautics and Space Administration’s commercial space programs and conducting space tourism, the number of launches and reentries affecting U.S. airspace is expected to grow. If the expected growth occurs, NextGen will need to accommodate spacecraft launches and re-entries as they go through the national airspace system. Through PBN, FAA uses satellite-based guidance to route aircraft and to improve approaches at airports, which can result in changes to flight paths. Specifically, aircraft using PBN can begin to fly a more direct and predictable path into or out of an airport. As a result, parts of a community that may not have experienced aircraft noise in the past may begin to experience noise. (See fig. 5 for an illustration of these procedures.) This new noise can also be more prevalent for some parts of a community as airplanes fly a more direct and predictable path into or out of an airport and are therefore overhead more frequently. Consequently, aircraft noise has resulted in some public opposition to NextGen. FAA officials have acknowledged that, in some locations, there is significant public resistance to redesigning airport arrival and departure routes to take advantage of PBN. FAA has enhanced community outreach efforts to help address concerns about aircraft-related noise. For example, in February 2016, FAA completed the development of its Community Involvement Manual to give FAA staff an understanding of the value of community involvement. The manual also describes practices and effective techniques for engaging in dialogue and collaboration with communities affected by FAA actions. Additionally, in June 2016, a NAC task group made recommendations to FAA for community outreach to assist FAA and industry with the growing environmental challenges associated with PBN implementation. For example, the task group recommended that FAA should form a specialized Community Outreach Team trained to conduct outreach both from the aspect of retaining conformity with legal and regulatory requirements as well as communicating in an effective manner. FAA must ensure that its NextGen programs are compatible with programs in other countries. This compatibility is known as “international harmonization.” Other countries are in the process of updating their air traffic control systems, and international coordination is necessary to ensure that systems and procedures are interoperable. In July 2015, we reported that as such modernization efforts proceed worldwide, collaboration—both within FAA and with domestic and international aviation stakeholders—will be critical to developing modernized systems and procedures that allow aircraft to seamlessly transition from one system to another, help enhance safety, and ensure the greatest operational and performance benefits to aviation users. We found that FAA has taken positive steps to better coordinate its NextGen interoperability efforts across the agency. These steps include the development of an international strategic plan and establishment of two internal bodies to guide and monitor international activities. However, we also found that FAA lacked a process for routinely and comprehensively assessing potential NextGen interoperability risks. As a result, we recommended that FAA implement a more effective international strategy for achieving NextGen interoperability with other nations. FAA is in the process of addressing this recommendation. In April 2015, we reported that FAA faces cybersecurity challenges in at least three areas: (1) protecting air-traffic control (ATC) information systems, (2) protecting aircraft avionics used to operate and guide aircraft, and (3) clarifying cybersecurity roles and responsibilities among multiple FAA offices. Through NextGen, FAA is shifting the ATC system from a point-to-point communications system to an Internet-based, interconnected system; a process of changeover that increases cybersecurity risks. We found that FAA is making strides to address these risks, including implementing an enterprise approach for protecting its systems from cyber-attack by both internal and external threats in accordance with standards of the National Institute for Standards and Technology and other cybersecurity leading practices. However, FAA had not developed a threat model that would describe the landscape of security risks to FAA’s information systems. We recommended that FAA, as a first step to developing an agency-wide threat model, assess the potential cost and timetable for developing such a model and the resources required to maintain it. In January 2016, FAA issued FAA Threat Model Schedule and Cost Estimate, Report of Finding, which stated that FAA is developing an Enterprise Threat Model that will be a holistic approach to the identification and assessment of cybersecurity threats, hazards and vulnerabilities. The report included a detailed schedule and cost estimate for developing the model. FAA has adopted ERM as a framework to manage risk across NextGen programs. ERM is a forward-looking management approach that allows an agency to assess risks and opportunities that could affect the achievement of its goals and the agency’s ability to achieve results. The Office of Management and Budget (OMB) considers ERM to be an effective agency-wide approach to addressing the full spectrum of an organization’s risks by understanding the combined impact of risks. In July 2016, OMB issued an update to its Circular A-123 that required federal agencies to implement ERM to better ensure their managers are effectively managing risks that could affect the achievement of agency strategic objectives. While this requirement is only at the department level, FAA has established ERM for NextGen in addition to any DOT-wide efforts. ERM is intended to yield an “enterprise-wide,” strategically-aligned portfolio view of organizational challenges that provides better insight about how to most effectively prioritize resource allocations to ensure successful mission delivery. Three organizations within FAA have established risk management efforts that, taken together, would manage risks at each of the program, portfolio, and enterprise levels. The efforts constitute a three-tiered structure for managing risks to NextGen. Program risks are elevated to the portfolio level if they cannot be effectively managed by a program, and portfolio risks are elevated to the enterprise level if they cannot be effectively managed by the portfolios. Risks are also transferred to a lower level if they can be managed at that level. Each level also seeks to identify, assess, and manage risk at its own level. In December 2016, we issued a report that identified essential elements and good practices for ERM. These and other documents provide guidance for agencies seeking to implement ERM which can assist agencies in managing risks and challenges related to delivering the organization’s mission. In this review, we found that it was too early to assess FAA’s efforts against our identified good practices. We provided a draft of this report to the Department of Transportation for review and comment. The Department provided technical comments, which we incorporated, as appropriate. As agreed with your office, unless you publicly announce the contents of this report earlier, we plan no further distribution until 30 days from the report date. At that time, we will send copies to the appropriate congressional committees, Secretary of Transportation, and other interested parties. In addition, the report will be available at no charge on the GAO web site at http://www.gao.gov. If you or your staff have any questions about this report, please contact me at 202-512-2834 or dillinghamg@gao.gov. Contact points for our Office of Congressional Relations and Public Affairs may be found on the last page of this report. GAO staff who made major contributions to this report are listed in appendix VI. Our objective was to assess the status of the Federal Aviation Administration’s (FAA) efforts to implement the Next Generation Air Transportation System (NextGen). For our review, we addressed (1) how FAA has implemented NextGen and addressed implementation challenges; and (2) the challenges, if any, that remain for implementing NextGen, and FAA’s actions to mitigate these challenges. To address both of these objectives, we reviewed FAA’s planning documents for NextGen and FAA reports, briefings, and other documents related to ongoing NextGen efforts. To determine how FAA has implemented NextGen and addressed challenges to its implementation, we reviewed FAA implementation actions for developing and deploying elements of NextGen programs, including programs in the areas of communications, automation, navigation, surveillance, and weather. We also assessed FAA’s efforts to address commitments it made in 2014 to implement actions in four focus areas—data communications, multiple runway operations, PBN, and surface operations and data sharing—over a 3-year period. FAA and the aviation industry identified these commitments as part of a collaborative effort between FAA and the NextGen Advisory Committee (NAC), which includes representatives from industry and FAA’s senior leadership and advises FAA on the implementation of NextGen. Additionally, we reviewed reports issued by GAO, the Department of Transportation’s (DOT) Office of Inspector General (DOT OIG), and NextGen advisory groups. We also reviewed NextGen-related recommendations made by GAO, the DOT OIG, and NextGen advisory groups such as the NAC, RTCA, and MITRE’s Center for Advanced Aviation System Development, and assessed FAA’s efforts to address these recommendations. We then conducted a detailed analysis of NextGen-related recommendations made by GAO and the DOT OIG from fiscal year 2008 to fiscal year 2016 and determined the status of each individual recommendation. We also assessed the current cost estimates for implementing NextGen through 2030, and compared them to earlier estimates provided by the Joint Planning and Development Organization (JPDO) in 2007. In addition, we interviewed FAA officials from the NextGen Office and its Interagency Planning Office, the Office of Aviation Safety (AVS), and the Air Traffic Organization (ATO). To determine the challenges, if any, that remain for implementing NextGen, and FAA’s actions to mitigate these challenges, we interviewed FAA officials from the NextGen Office, AVS, and ATO. Additionally, to determine actions FAA is taking to address risks to NextGen, we reviewed FAA’s risk management documents and interviewed FAA’s NAS Systems Engineering Services Office, an organization within the Office of NextGen responsible for designing and maintaining the FAA’s NAS Enterprise Architecture and providing systems engineering related to NextGen, which has established a process to manage risks to NextGen. To obtain aviation stakeholders’ perspectives on NextGen challenges and FAA efforts for both of our objectives, we interviewed a non-probability sample of 34 aviation stakeholders (see table 3). We created an initial list of stakeholders using internal knowledge of the aviation industry. We further developed the list of stakeholders by identifying industry stakeholders that have made NextGen-related recommendations to FAA, conducting a literature review of NextGen issues. We also included stakeholders based on interviewee responses to our question on whom else they thought we should speak with, as well as stakeholders that experienced the effects of changes from NextGen. Specifically, we wanted to obtain perspectives from individuals and organizations with direct experience, as users, or knowledge, through research or study of NextGen. We divided stakeholders into the following eight categories: airlines, airports, aviation experts and other relevant organizations, former FAA officials, research and development organizations, general aviation, labor unions and professional associations, and manufacturers and service providers. We used a semi-structured interview format with open- ended questions to obtain aviation stakeholder perspectives on the status of NextGen implementation efforts, factors that have affected NextGen implementation, challenges that still remain, and FAA efforts to address such factors and challenges. We used open-ended questions to engage the stakeholders in a conversation about the challenges they considered most important and relevant. To determine the common themes that we are reporting on, we conducted a content analysis of each of the interviewees’ responses. The numbers reported for our open-ended questions represent those stakeholders who, during our interviews, identified a challenge to consider or suggested a change. The reported numbers do not mean that the remaining stakeholders agreed or disagreed with that challenge, change, or issue. In our discussion of stakeholder views obtained through our open-ended questions, we aggregated their responses and reported on stakeholders’ perspectives in general. The results of our interviews are not generalizable to the industry as a whole. Based on stakeholder responses, we identified a set of challenges and asked FAA to provide their perspective on each challenge and any actions FAA is taking to address it. We conducted this performance audit from November 2015 to August 2017 in accordance with generally accepted government auditing standards. Those standards require that we plan and perform the audit to obtain sufficient, appropriate evidence to provide a reasonable basis for our findings and conclusions based on our audit objectives. We believe that the evidence obtained provides a reasonable basis for our findings and conclusions based on our audit objectives. Since the passage of the Vision 100 Act in December 2003, the planning for NextGen has evolved from a high-level vision developed by the Joint Planning and Development Organization to detailed implementation plans currently being implemented by the Federal Aviation Administration. The following table provides an overview of these documents. Appendix III: Selected Programs in the Next Generation Air Transportation System (NextGen) This appendix contains information on selected NextGen programs, including the program’s purpose, the progress of each program, and the Federal Aviation Administration’s future plans for implementing the program. This appendix provides an overview of the status of NextGen-related recommendations that we and the Department of Transportation (DOT) Office of Inspector General (OIG) have made to the Federal Aviation Administration (FAA) from fiscal year 2003 to fiscal year 2016. FAA has implemented 39 of our 47 recommendations (83 percent), 6 are in process (13 percent), and 2 remain open (4 percent). Those recommendations that are “in process” include those for which FAA has provided information to GAO and asked GAO to close the recommendation as implemented. For these recommendations, the information had not been fully reviewed within GAO at the time of our review, or we had not yet determined that FAA’s information sufficiently addressed our recommendation. For an overview of the status of our recommendations, see figure 6 below. The two open recommendations are from our 2015 report on FAA’s efforts to ensure the global interoperability of NextGen. In that we report, we recommended that FAA (1) conduct a risk assessment to identify potential threats to NextGen interoperability and (2) identify and document actions FAA will take to mitigate these risks. Additionally, DOT OIG has closed 103 of the 137 recommendations (75 percent) that we determined to be related to NextGen. Of the 34 DOT OIG recommendations that remain open, 33 have been resolved, meaning DOT gave OIG a target action date and concurred or partially concurred with the recommendation, while 1 remains unresolved. For an overview of DOT OIG recommendations, see figure 7. FAA has identified six NextGen activities that it had previously planned to complete by 2025, but has now deferred until after 2030 due to technical or operational infeasibility or changed operational needs. FAA officials explained that these applications are not in progress, and may be continually deferred, redefined, or never implemented. The following table provides an overview of these deferred activities and reasons FAA gave for deferring them. In addition to the individual named above, John W. Shumann ( Assistant Director); Raymond Griffith (Analyst-in-Charge); Melissa Bodeau; Andrew Burton; Tobias Gillett; David Hooper; SaraAnn Moessbauer; Malika Rice; and Michelle Weathers made key contributions to this report.

Summary: FAA is leading the implementation of NextGen, which is designed to transition the nation's ground-based air traffic control system to one that uses satellite navigation, automated position reporting, and digital communications. Planning for NextGen began in 2003 and in 2007 the effort was estimated to cost between $29 and $42 billion by 2025. NextGen is intended to increase air transportation system capacity, enhance airspace safety, reduce delays, save fuel, and reduce adverse environmental effects from aviation. Given the cost, complexity, and length of the project, GAO was asked to review FAA's NextGen implementation efforts. This report examines: 1) how FAA has implemented NextGen and addressed implementation challenges; and 2) the challenges, if any, that remain for implementing NextGen, and FAA's actions to mitigate those challenges. GAO reviewed FAA documents, advisory group reports, and NextGen-related recommendations made to FAA by GAO and others. GAO interviewed a non-generalizable sample of 34 U.S. aviation industry stakeholders, including airlines, airports, aviation experts and research organizations, among others, to obtain their views on NextGen challenges and FAA's efforts to address them. Stakeholders were selected based on GAO's knowledge of the aviation industry and includes those that have made NextGen-related recommendations to FAA, among other things. GAO also interviewed FAA officials regarding NextGen implementation and stakeholders' views. The Federal Aviation Administration (FAA) is implementing the Next Generation Air Transportation System (NextGen) incrementally and has taken actions to address challenges to implementation. NextGen has enhanced surface traffic operations at 39 of the 40 busiest airports in the United States by providing electronic communications to clear planes for departure, technology that can expedite clearances and reduce errors. FAA has taken steps to address challenges such as limited stakeholder inclusion that affected early implementation of NextGen. For example, FAA established groups of industry stakeholders and government officials, who worked together to develop implementation priorities. By 2025, FAA plans to deploy improvements in all NextGen areas—communications, navigation, surveillance, automation, and weather. While specific NextGen initiatives and programs have changed over time, FAA's 2016 cost estimates for implementing NextGen through 2030 for 1) FAA and 2) industry—$20.6 and $15.1 billion, respectively—are both within range of 2007 cost estimates. FAA's challenges as it continues to implement NextGen include uncertainties regarding future funding; whether aircraft owners equip their aircraft to use NextGen improvements; potential air traffic control restructuring; FAA's leadership stability; and cybersecurity issues. FAA is taking actions to address challenges within its control by, for example, prioritizing NextGen improvements and segmenting them into smaller pieces that each require less funding. While it is not possible to eliminate all uncertainties, FAA has adopted an enterprise risk management approach to help it identify and mitigate current and future risks that could affect NextGen implementation. Moreover, FAA has implemented most of GAO's related recommendations.