NextGen for Airports: A Primer (2016)

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4 NextGen Airport Impacts Two of NextGen’s principal goals are to increase the efficiency and capacity of the NAS, including both the en route airspace and airports. Efficiency is usually defined in terms of reduced aircraft operating times and fuel burn, which result from NextGen operational improvements such as PBN that have the potential to provide shorter flying distances and more fuel-efficient flight profiles. These flight efficiencies are of greatest interest to aircraft operators and may not offer appreciable capacity benefits to airports. As described later in this document, improvements designed to improve efficiency could result in both favorable and adverse impacts to the communities underneath these new flight paths. Efficiency and Capacity for Congested Airports

5 Efficiency can also be increased on the ground through NextGen Surface Operations and Data Shar- ing improvements, which are designed to hold aircraft awaiting departure at their gates in “virtual queues” with engines off rather than in actual queues on taxiways with engines running. These surface operational improvements have been achieved by coordination of de- partures using data sharing and cooperative decision making among airports, airlines, and FAA air traffic management to reduce taxiway queues while preserving the equitable sequencing of departures. Capacity at airports is usually defined as the maximum number of landings and takeoffs that can be handled in an hour under a given set of operating conditions (e.g., runway use and weather). Many Next- Gen technologies are intended to recover the current losses of airport capacity in instrument conditions (bad weather). Enhancements that could increase arrival and departure capacity are expected to come from NextGen operational improvements that reduce minimum aircraft separations or enable reductions in the runway spacing required for multiple runway operations. Some large airports will welcome these increases in capacity and service reliability during instrument conditions, which could come without any airfield capital costs. However, if such airside capacity increases also raise the good weather capacity of the airport, it could result in increased requirements for passenger terminal facilities, aircraft parking positions, and landside roadway and parking facilities. Recent NextGen high-priority activities, such as PBN and Surface Operations and Data Sharing, have focused on programs that provide near-term efficiency improvements. These two near-term programs may result in better efficiency for the aircraft operators in terms of reduced fuel burn, and may have some effect on airport capacity by enabling improved use of the airspace. NextGen activities such as wake turbulence recategorization (RECAT) (see Figure 1), and closely spaced parallel runway opera- tions are intended to increase runway capacity at the airport, especially in instrument conditions. Figure 1. RECAT could create capacity at an airport without airport investment. One-page summaries of PBN, Multiple Runway Operations, Data Sharing, and other programs can be found in ACRP Report 150: NextGen for Airports, Volume 3: Resources for Airports, Chapter 3. Given the statements in the press regarding NextGen improvements to aircraft operations and the environment, opponents to airport growth may argue that these improvements obviate the need for additional new or expanded runways at an airport in order to increase capacity and/or reduce aircraft delays. In response, airports should note that NextGen all-weather capacity improvements may not be on the scale as those from a new runway, and new runways may still be required to handle future increases in demand.

6 Benefits for Uncongested Airports Environmental Issues Ground-based instrument landing systems (ILSs) support operations in low-visibility instrument con- ditions and enable air service providers and aircraft operators to maintain reliable air service. Ground- based ILSs are expensive and require extensive surface areas to enable the associated localizer and glide-slope antennas to function properly and to provide unobstructed straight-in approaches to the runway. NextGen satellite-based area navigation (RNAV) and required navigation performance (RNP) instrument approach procedures can support low-visibility operations at airports that cannot use an ILS due to lack of suitable space on the ground for the ILS critical areas or terrain that precludes straight-in approaches. In some cases where the traffic level at the airport may not meet the benefit/ cost criteria for an FAA sponsored ILS, the relatively low capital costs of a NextGen-enabled instrument approach may offer a feasible alternative. NextGen satellite-based automatic dependent surveillance-broadcast (ADS-B) and local transponder interrogation-based wide-area multilateration (WAM) can provide ATC surveillance in areas not cov- ered by radar. Together, these NextGen navigation and surveillance technologies can support significant increases in bad weather capacity at airports that lack radar coverage and have severe site constraints. Any airport included in the National Plan of Integrated Airport Systems (NPIAS) and its users can embark on the steps to gain an instrument-capable runway by requesting that FAA implement a localizer performance with vertical guidance (LPV) approach, which requires aircraft operators to have a wide-area augmentation system (WAAS) global positioning system (GPS) receiver. LPV approaches are the highest precision RNAV (GPS) instrument approach proce- dures available without specialized aircrew training requirements. Airport operators should understand, though, that air carrier aircraft are not routinely equipped with WAAS receivers that permit the lower LPV minimums. Beyond WAAS, a ground-based augmentation system (GBAS) can provide increased navigation accu- racy, and potentially enable approaches down to ILS Category II/III-level ceilings and visibilities. Other services, such as traffic information service and weather information service broadcasts associated with ADS-B could provide pilots improved information at all airports regardless of ground services. To an airport executive, NextGen environmental impacts may be multifaceted and politically compli- cated. As described below, improvements in one area could create adverse impacts in another. Noise exposure and emissions are the two environmental issues affected by NextGen, especially by PBN, because PBN results in a redistribution of flight tracks, and noise levels may either improve or Note that other existing technologies using head up displays, synthetic vision, and enhanced vision, which are not normally associated with NextGen, also could enhance low-visibility operations. These technologies also could enhance future NextGen- enabled flight procedures.

7 worsen. In contrast, NextGen emissions changes are nearly always positive. Airport executives and their planning staffs need to be aware of which of these effects apply to each proposed improvement at their airports. NOISE EXPOSURE NextGen PBN flight track changes can improve performance for some noise abatement procedures, such as a precise arrival or departure path designed to go over vacant or compatible land or water to avoid populated areas. With PBN those tracks should be flown with improved accuracy, potentially reducing the dispersion over adjacent areas that may be noise sensitive. However, in some cases the improved accuracy may concentrate the PBN tracks that had previously been more widely dispersed; thus reducing the noise exposure for many, while significantly increasing the exposure for a smaller group. Alternatively, PBN techniques to distribute flight tracks, similar to traditional fanning departures, could help mitigate excessive departure noise exposure over a narrow noise-sensitive area. It is import- ant for airports to recognize that in designing a PBN procedure, FAA will not normally include multiple tracks to spread out the noise unless specifically requested to do so by the airport. (See Figure 2.) Actions to consider to prepare for PBN changes: Have you reached out to and engaged with NextGen planning specialists located in your FAA Regional Office and/or ADO (or Headquarters)? Have your local coordination procedures with FAA air traffic, users, and surrounding communities been updated to include consideration of the effects of NextGen operational improvements and technologies? Have you assigned responsibility to a qualified airport staff person for keeping you informed about the possible impacts on the local airport community? Figure 2. PBN flight route adjustments (arrivals from East and departures to the West). Previous paths, shown in blue, are dispersed. New paths in green are more concentrated, and in some cases over areas not used to aircraft noise. (Source: Phoenix Aviation Department)

8 EMISSIONS Fuel savings and corresponding emissions reductions are a potential NextGen benefit. Enabled en route arrival and departure profiles are intended to reduce fuel burn aloft, while NextGen surface operations and departure-metering programs are intended to reduce fuel burn and emissions on the airport surface. The surface emissions reductions are of primary interest to airport operators. Figure 3 shows how optimized profile descents (OPDs) reduce fuel burn on arrivals; Figure 4 shows the poten- tial impact of surface management operations. Figure 3. OPD profiles. Figure 4. Comparison of JFK departure queues pre/post surface congestion management. (Source: Nakahara & Reynolds, MIT Lincoln Lab, “Estimating Current and Future System-Wide Benefits of Airport Surface Congestion Management,” 10th USA/Europe ATM R&D Seminar - ATM 2013) Environmental Review and Community Outreach Process In most cases, PBN procedures are developed and reviewed by the FAA’s Air Traffic Organization (ATO). Smaller scale PBN development projects involving limited numbers of procedures may be developed locally, but larger scale procedure development efforts—including region-wide “Metroplex” initiatives—have been handled by staff at the FAA headquarters. Unlike airport development projects, where environmental reviews follow processes established by the FAA’s Office of Airports, the environ- mental reviews of PBN projects are governed by much less stringent processes and procedures estab- lished by the ATO. Public notification and participation processes can be truncated or absent if the FAA

9 determines that the proposed PBN procedures qualify for a categorical exclusion (CatEx). The specific criteria necessary for a project to qualify for a CatEx include reductions in fuel consumption, carbon dioxide emissions, and noise on a per-flight basis. In these cases, and barring “extraordinary circum- stances,” the FAA Administrator can issue and file a CatEx. This eliminates more extensive review with public notification—either in the form of an environmental assessment (EA) or an environmental impact statement (EIS). The use of a CatEx for the Phoenix (PHX) PBN im- plementation resulted in significant adverse public response, which could have been better handled if there had been public notification as part of an environmental review process. It was only after the significant public protest that consideration of community views was considered. Other more successful PBN implementations (e.g., in Denver) have used National Environmental Policy Act (NEPA) EA procedures to provide public process and input. On March 29, 2016, the FAA issued FAA Memorandum on Order 1050.1, Guidance Memo, “Guidance for Implementation of the Categorical Exclusion in Section 213(c)(2) of the FAA Modern- ization and Reform Act of 2012,” which states that public notification provisions apply to use of the CatEx. The memo states that “Collaboration with air- port operators and public notification should include provision for appropriate community outreach that not only informs the affected public of the FAA’s proposal, but also allows the public to provide feedback on community concerns.”2 It is in the airport executive’s interest to (1) be aware of any plans being considered to change airspace procedures at his/her airport, (2) make an independent assessment of the potential for public contro- versy, and (3) formally notify the FAA in writing of any concerns that the proposed procedures would be likely to be controversial on environmental grounds. Regular contact with appropriate FAA organi- zations is the best way to find out if any procedural changes impacting an airport are planned. ADO staff that airport executives normally interact with are often unaware of advanced procedure develop- ments occurring in the ATO. Likewise, local FAA air traffic control tower personnel are also unlikely to be aware of advanced development of airspace procedures until shortly prior to implementation. Hav- ing staff routinely monitor PBN Implementation Plans through at the FAA’s Aeronautical Information Services, Instrument Flight Procedures Gateway (https://www.faa.gov/air_traffic/flight_info/aeronav/ procedures/) can assist with this task. In addition to community outreach, effective communications with aircraft operators and the pilot community are also necessary, as has been demonstrated by NextGen procedures that have been successfully implemented at airports such as Seattle and Dallas. In both cases, the affected airport and the operators were both sensitive to and involved with community concerns, resulting in processes that generated less controversy and were perceived as both inclusive and successful. Committing to an EA at the beginning of the process is more likely to result in a process whereby the airport executive and surrounding community understand the trade-offs of the benefits and possible negative impacts related to NextGen capabilities. Recently, the FAA has tasked the RTCA NAC to recommend procedures for improving the PBN implemen- tation process by incorporating community outreach considerations early in the implementation process.3 NextGen environmental review processes are different. There are multiple originators of NextGen pro- cedures, each with different environ- mental processes. Use of categorical exclusions (CatEx) that limit public involvement are authorized by public law for certain NextGen operations, but are not being used due to experi- ence with adverse public response.

10 Financial Issues Potential airport financial impacts from NextGen vary with the technologies being considered. In many cases the greatest costs will be borne by the FAA through their purchase of ATC hardware and assumption of operating and maintenance costs, and by aircraft owners through airplane equipage investments. The FAA may seek navigational aid leases from airports. Airport executives may choose to fund non-federal equipment, such as the ground-based augmentation instrumentation for CAT II/ III approaches. Obstacle clearance costs associated with reduced minimums may be eligible for Airport Improvement Program (AIP) or passenger facility charge (PFC) funding (similar to new non-NextGen approaches like ILS). AIP funds may also be used for projects such as GIS mapping and to remove ob- structions to support PBN approaches, surface management operations, and potentially GBAS. The implementation of PBN procedures does not guarantee their efficient use. Aircraft operators, air traffic controllers, and airport personnel also must equip and train to facilitate their effectiveness. In some cases, such as use of PBN approaches in low-demand operations, a benefit will accrue on an individual flight basis. In other cases, including PBN in high-demand operations, benefits will require a high fraction of participating aircraft in the fleet, and appropriately trained controllers to achieve the timing, control, and coordination necessary to achieve a significant fraction of efficient descents and corresponding fuel savings. NextGen multiple runway operations programs may provide a benefit for airports. The ability to use higher capacity instrument procedures on closely spaced parallel runways can reduce the amount of additional real estate needed to satisfy runway separation requirements for increased airport capacity in instrument conditions.

11 Infrastructure and Capital Planning to Prepare for or Adapt to NextGen Airports may wish to, or in some cases be required to, take action related to NextGen implementation: Obstruction clearance may be needed for new approach procedures with lower minimums and obstacle clearance surfaces. If your airport’s obstruction map is not up to date, it can delay implementation of new procedures. Additional land around runway ends may need to be obtained to meet more stringent obstruction clearance and design standards associated with new NextGen procedures. Digital maps in an airport master plan will need to be updated for any enhancements, replacements, or additions that use AIP money. Airports may choose to invest in holding pads and bypass taxiways in order to make surface operations work optimally. An airport plan establishing the need and feasibility of future runways should incorporate projections for conducting multiple runway operations (e.g., dependent or independent parallel approaches). An airport may want to consider installing GBAS itself in order to realize improved navi- gation access during low-visibility conditions. (GBAS is just one element. In order to re- alize the improved low-visibility access, procedural changes, additional navigational aids such as approach light systems, runway protection zones, weather reporting systems, as well as improved aircraft capabilities are also required.) An airport may need to assume the liability of maintaining GBAS if the airport purchases one. Airport executives should consider how potential delay reductions could change gate holding requirements, and impact gate and terminal capacity. Delay reductions are not likely to be significant, but are worth considering. Airports seeking to develop surface management capabilities may need to invest in soft- ware, data subscriptions, and enhanced surface surveillance sensors.