NextGen for Airports, Volume 5: Airport Planning and Development (2017)

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4Applicability of NextGen to Medium- and Large-Airport Planning and Development | 61 This section will clarify the traditional airport size classifications with respect to the types of NextGen capabilities and issues that are likely to be of most import to the larger facilities. The guidance for medium and large airports will consider the typically greater availability of staff and consultant resources at medium and large airports. As summarized in Appendix C, the impact that NextGen will have on a particular airport will depend upon its size and complexity, location, layout, type and level of air service, and role in the NAS. Be- cause NextGen technologies and operational improvements are designed to increase system capacity, reduce aircraft delays, reduce aircraft emissions, and enable more reliable flight schedules, the biggest beneficiaries of NextGen are likely to be the users and operators of busy medium and large airports. For medium and large airports, much of the focus of near-term NextGen improvements has been on reducing aircraft emissions, reducing aircraft separations, reducing the required spacing between parallel runways for conducting independent and dependent instrument approaches, and reducing congestion on the airport surface and in the surrounding airspace. This chapter identifies the various NextGen capabilities that could enhance operations at medium and large airports and how these capabilities may influence planning and development initiatives at these airports. It differentiates between the NextGen initiatives that have global application at most me- dium and large airports from those that have application only under certain operating conditions and environs. Definition of Medium and Large Airports The National Plan of Integrated Airport Systems (NPIAS) categorizes public use airports by type of activities, including commercial service, primary, cargo service, reliever, and GA.1 For purposes of this guidebook, medium and large airports generally include the following NPIAS Classifications: • Large Hub Primary Commercial Service (1% or more of annual passenger boardings). • Medium Hub Primary Commercial Service (at least 0.25% but less than 1% of annual passenger boardings). While medium and large private-use and military airports could benefit from NextGen technologies, their application is excluded from these discussions. Table 4-1 presents the overall NPIAS airport clas- sifications. The opportunities to enhance the NAS through the implementation of NextGen technolo- gies and operational improvements can vary significantly among airports, regardless of an airport’s size, role, and classification. There are numerous factors that will influence the direct and indirect ben- 1 Federal Aviation Administration, National Plan of Integrated Airport Systems, http://www.faa.gov/airports/planning_ capacity/passenger_allcargo_stats/categories, accessed January 7, 2016. Applicability of NextGen to Medium and Large Airport Planning and Development

62 | AIRPORT PLANNING AND DEVELOPMENT efits associated with each of the various NextGen initiatives for any given airport or system of airports. Therefore, the application of NextGen technologies and operational improvements, and the resulting benefits, will be unique for each airport. While each airport’s ability to leverage NextGen operational improvements is unique, the information contained herein is intended to distinguish the NextGen initiatives that are most likely to be applied at the various airport types and sizes, based on, but not limited to, the following criteria: 1Medium and Large Airports generally include the following NPIAS Classifications: • Medium Hub Primary Commercial Service (at least 0.25% but less than 1% of annual passenger boardings). • Large Hub Primary Commercial Service (1% or more of annual passenger boardings). Small Airports generally include the following NPIAS Classifications: • Nonhub Primary Commercial Service (>10,000 annual passenger boardings, but less than 0.25% of total passenger boardings in the United States). • Non-primary Commercial Service (no more than 10,000 annual passenger boardings). • General aviation/reliever airports. Source: NPIAS, Federal Aviation Administration. Table 4-1. FAA airport classifications.

Applicability of NextGen to Medium- and Large-Airport Planning and Development | 63 • Benefit/Cost, • Aircraft Equipage Limitations, • Aircraft Fleet Mix and Performance Characteristics, • ATC and Flight Crew Training Requirements, • Airfield Configuration, • Airspace Constraints and Airport Dependencies, • Surrounding Terrain and Obstacles, and • Operational Needs. Each of these criteria is discussed in greater detail in Appendix C. FAA NextGen Technologies and Initiatives Applicable to Medium and Large Airports The deployment of FAA’s NextGen initiatives and supporting technologies has been, and will continue to be, mainly focused on medium and large airports. This section provides an overview of the appli- cability of the FAA’s NextGen initiatives and support technologies at medium and large airports and describes the factors that may determine the applicability and benefits of their deployment. It also describes direct and indirect effects on planning and development at medium and large airports. While the basic approach and reference sources are the same for all sizes of airports, this section will emphasize those NextGen issues affecting efficiency and capacity, long-term infrastructure needs, surface management, noise concerns, and other interests typical of airport planning practitioners at medium and large commercial service airports. For each of the NextGen technologies affecting these issues, this chapter will discuss the following airport implications: • Facility impacts, • Operational impacts, • Environmental impacts, and • Financial/business impacts. PBN and Improved Landing Systems Because PBN procedures can take many forms, this chapter will concentrate on those PBN procedures of greatest interest to airport planning practitioners at medium and large airports: (1) RNAV SIDS and STARs, (2) RNAV and RNP instrument approach procedures, and (3) RNAV-enabled departure separa- tions such as ELSO, EDO, and UDOS. Facility Impacts RNAV SIDS and STARs—RNAV SIDS and STARs have no direct impact on-airport facilities. RNAV and RNP Instrument Approach Procedures—RNAV and RNP instrument approach procedures are satellite-based approach procedures and do not rely on ground-based navigation aids such as the

64 | AIRPORT PLANNING AND DEVELOPMENT ILS localizer and glide slope antennas. At most medium and large airports that already have RNAV and RNP approach procedures, ILS approaches still exist. Ultimately, FAA is planning that RNAV and RNP approach procedures may replace many ILSs, in which case there would be no need to have the associated localizer and glide slope antennas on the airfield. Some ILS installations may continue to serve as backups to guarantee adequate instrument approach procedures, but the transition away from ILS could take many years. However, other components of low-visibility ILS approaches, such as approach lights, obstacle-free areas, or touchdown zone lighting would continue to be required, depending on the desired minimums. RNAV-Enabled Departure Separations—In order to maximize the effectiveness of RNAV-enabled departure procedures, there may be a need to provide additional facilities such as hold pads or parallel taxiways. ELSO, EDO, and UDOS all require adequate holdpads and parallel taxiways to facilitate the departure staging and sequencing necessary to achieve the benefits of multiple divergent headings provided by these PBN-enabled departure separation procedures. Operational Impacts RNAV SIDS and STARs—The implementation of RNAV SIDS and STARs may provide the ability to en- hance the operational throughput at a medium or large airport that is constrained by the capacity of its surrounding terminal airspace. For example, with the increased precision provided by RNP, coupled with the benefits associated with RNAV, additional independent arrival and departure routes to and from medium and large airports may be established, thereby increasing airspace capacity by allowing greater segregation of arrivals and departures by origin/destination and reducing conflicts with flight paths to and from nearby airports in the region. RNAV and RNP Instrument Approach Procedures—RNAV, RNP, and GBAS-based instrument ap- proaches could increase operational capability and reduce landing minimums at airports that currently cannot accommodate ILS approaches because they can’t meet the critical-area siting requirements for either the ILS localizer or glideslope antenna. In addition, if these PBN-based instrument approaches could replace ILS approaches, there could be operational improvements at medium and large airports that currently have operational constraints to prevent aircraft from encroaching upon localizer or glideslope critical areas. GBAS is not currently programmed by FAA at any airport. At the request of airlines, FAA is conducting a benefit/cost to investigate investing with facilities and equipment (F&E) funds in GBAS, but there has been no determination yet. RNP approaches are implemented primarily at medium and large airports unless there are specific airspace where terrain constraints justify implementing the RNP approach at a smaller airport. The FAA has been implementing the LP, LPV, and LNAV/VNAV approaches to enhance operations dur- ing inclement weather at medium and large airports that have a substantial volume of GA and region- al aircraft operations to supplement existing instrument approaches and/or to provide redundancy. RNAV-Enabled Departure Separations—ELSO, EDO, and UDOS all are designed to provide additional departure throughput at airports with limited departure headings (e.g., at airports at which departures from different parallel runways must fly to the same waypoint for noise abatement purposes). These NextGen programs provide the benefits of multiple departure headings by either (1) requiring less divergence between departure headings off the end of the runway or (2) moving the point where divergence occurs out from the runway end to the nearest waypoint.

Applicability of NextGen to Medium- and Large-Airport Planning and Development | 65 Environmental Impacts The possibility of significant environmental impacts could arise from implementation of RNAV SIDS and STARs, RNAV and RNP instrument approach procedures, and/or RNAV-enabled departure separa- tions. There could be significant concerns over increased noise exposure at some medium and large airports because of the associated concentration of flight paths over a narrow geographic area char- acteristic of all three of these PBN procedures. The ATO environmental screening process does not normally consider noise impacts below the FAA threshold of significance [day-night average noise level (DNL) 65]. However, even noise impacts below that DNL 65 value can provoke significant adverse community reaction. On the plus side, these PBN procedures following precise flight paths can be designed to avoid noise sensitive areas and possibly provide multiple departure headings. In addition, RNAV and RNP ap- proaches also have the potential to reduce aircraft emissions and aircraft noise exposure. The FAA’s plans call for PBN procedures to be implemented at many if not most medium and large air- ports. The FAA has also undertaken the implementation of PBN procedures through its Metroplex ini- tiative. Airport planners at airports affected by these Metroplex implementations should be aware that PBN procedures implemented as part of a Metroplex project will entail a full EA and public process, while single-site PBN procedures adopted as local initiatives may not be afforded that level of public process unless the airport intercedes and requests an EA by citing the potential for significant adverse public opposition on environmental grounds [CEQ regulations at 40 CFR 15056(c) 1 and 2]. Financial/Business Impacts RNAV SIDS and STARS—Because RNAV SIDs and STARs do not require additional infrastructure at an airfield, they have no impact to an airport’s capital expenditures. RNAV and RNP Instrument Approach Procedures—Because RNAV and RNP approaches do not require additional infrastructure on the airfield, the primary increases in expenditures would be for the costs of surveying obstacles, obstacle removal, lighting, visual guidance, and weather systems. How- ever, as with traditional ground-based instrument approaches, the establishment of RNAV and RNP instrument approaches requires an evaluation of obstacles to ensure adequate obstacle clearance for aircraft utilizing these procedures, which may require capital expenditures for obstacle removal. If the approaches allow lower landing minimums, installation or upgrade of runway or approach lighting may be required. RNAV-Enabled Departure Separations—Because ELSO, EDO, and UDOS all require adequate hold- pads and parallel taxiways to be effective, they could have an impact on an airport’s capital expendi- tures if additional holdpads and parallel taxiways would be required to optimize their operation. Surface Operations and Data Sharing The key elements of the FAA Surface Operations and Data Sharing NextGen program are (1) advanced electronic flight strips, (2) surface departure management, (3) surface surveillance event data distri- bution to users via SWIM, (4) the SWIM Surface Visualization Tool, and (5) traffic flow management system, and (6) TBFM. The sharing of data is intended to enable the establishment of CDM efforts between FAA and industry stakeholders and between stakeholders at medium and large airports. CDM is enabled through the dissemination of traffic flow data management and other SWIM data to the CDM group to support improved real-time decision making, tools and procedures to more easily respond to changing condi- tions, and advanced technological solutions and decision making for all stakeholders.

66 | AIRPORT PLANNING AND DEVELOPMENT Surface operation and CDM data sharing technology could track the movement of surface vehicles and aircraft at medium and large airports, incorporating the movement data into the airport sur- veillance infrastructure and sharing the information with controllers, pilots, and airline operations managers. As such, at constrained airports, improved surface operations could substantially increase facility requirements on the airfield, or at the terminal if new gates are required. Facility Impacts One of the key elements of improved surface operations is surface departure management, more widely known as “departure metering,” which is intended to reduce the departure queue and thereby fuel burn, emissions, and surface congestion. However, effective departure metering requires ample apron areas, gates, and hold pads, which some space-constrained medium and large airports may have difficulty providing. At such constrained airports, improved surface operations could substantially increase facility requirements on the airfield. Ramp control towers are also an important means of improving surface operations and data sharing. At some airports, ramp control towers are operated by the lead carrier. Recently implemented ramp control towers have been operated by the airport rather than the airlines. Las Vegas McCarran Inter- national Airport was one of the first airports to take over the management of its gates and the ramp operations, which has resulted in significant efficiencies in terms of common use of the gates and centralized management of ramp operations. Surface movement data may also be useful to track the exact usage of any pavement area on the air- field as part of pavement management systems enabling calculations of pavement wear and useful life. Operational Impacts Improved surface operations will improve safety, efficiency, and flexibility on the airport surface by implementing new traffic management capabilities for pilots and controllers using shared surface movement and en route data. The capabilities address surface movement and the exchange of infor- mation between controllers, pilots, and air traffic managers that occur from before the aircraft pushes back from its gate up to the departure of the aircraft from the airport and, for landing traffic, from exiting the runway to arriving at the terminal gate. Surface operations and data sharing at medium and large airports also provide opportunities to improve airport and airfield operational monitoring and vehicle operational data analyses. These data could facilitate facility planning studies, such as detailed traffic studies and defining vehicular staging and storage requirements. EAs could also leverage the data to conduct air quality analyses and assess- ments of movement area activity to support SMS analyses. Environmental Impacts Surface departure management or departure metering has the objective of reducing fuel burn and carbon emissions by holding departing aircraft at their gates with their engines off as long as possible without losing their sequence in the departure queue, or allowing the departure queue to dry up, which could result in the loss of departure slots. In addition, improved surface operations may reduce the number of aircraft taxiing stops and starts, which could further reduce fuel burn and emissions.

Applicability of NextGen to Medium- and Large-Airport Planning and Development | 67 Financial/Business Impacts To leverage the benefits of surface operations and data sharing applications, medium and large airports would need to include the acquisition costs of these technologies into their airport capital, operating, and maintenance budgets. Ground vehicle tracking and the associated traffic display and analysis systems will also require investment into the associated technologies, including GPS receivers/ transmitters, graphics, and database systems. Two-vehicle tracking methodologies are available to airports. AC 150/5210-25 describes GPS-based tracking through a Runway Incursion Warning System. AC 150/5220-26 describes vehicle tracking at airports served by multilateration and vehicles equipped with ADS-B transponders. If either method is chosen, additional capital and operating costs would be required. Wake Turbulence Recategorization As previously described, the FAA’s recategorization of wake turbulence separation standards is being implemented in three phases. Prior to the implementation of Phase I in 2014, aircraft wake turbulence classifications were based strictly on aircraft weight. The FAA’s Wake RECAT efforts are now focused on actual wake turbulence characteristics generated by each specific aircraft type. Phase I included the classification of each aircraft type into one of six wake turbulence categories and adjusted the minimum separations between aircraft arrivals and/or departures accordingly. Phase II will ultimately establish wake turbulence separate criteria for individual aircraft-type pairs, in lieu of the six-category classification system established for Phase I. Due to the complexities associated with the planned establishment of aircraft wake turbulence separa- tions by individual aircraft types, it is anticipated that Phase II would be adopted at more congested airports that need to optimize the capacity of the airfield and/or airspace. When considering such implementation at an airport, FAA will evaluate whether Phase I or Phase II Wake RECAT is the better option given the fleet mix at the airport. Phase II is not necessarily better, but rather it’s a different ap- proach that may be a better fit at some airports depending on the makeup of their fleet mixes. Facility Impacts Wake RECAT should have no significant effect on medium and large airport facilities. The expected increase in capacity with the implementation of Wake RECAT could possibly defer the need to increase the capacity of the airfield through capital improvements such as new runways and/or taxiways. On the other hand, increasing the capacity of the airport in all weather conditions may affect the capital planning for airside or terminal infrastructure. Operational Impacts These new separation minima could result in significant improvements in maximum arrival and depar- ture throughput at medium and large airports that have significant numbers of Heavy jets and B757s in their aircraft-fleet mix. For example, FedEx has experienced an increase in airfield capacity of 20% at Memphis. However, airport planners should be cautioned that the benefit of increased throughput is heavily dependent on the fleet mix at their individual airports. At many medium and large airports the capacity increase due to Wake RECAT is expected to be on the order of 2%–4%. One factor that could limit the achievable benefits of Wake RECAT at medium and large airports is the presence of departure airspace restrictions. These departure airspace restrictions could be due either to noise abatement procedures, conflicts with nearby airports, or surrounding obstacles or mountainous terrain.

68 | AIRPORT PLANNING AND DEVELOPMENT Environmental Impacts Wake RECAT is not expected to have significant adverse environmental effects even at airports where it could result in a significant increase in arrival and departure capacity. On the contrary, the potential reduction in in-trail separation between aircraft, and the corresponding reduction in aircraft delays, could shorten aircraft traffic patterns on arrival and reduce aircraft hold times for departure, which could ultimately (1) reduce aircraft noise exposure over certain communities caused by arrivals, and (2) reduce aircraft emissions caused by departures. Financial/Business Impacts For medium and large airports that may benefit from Wake RECAT, the capacity of the airfield could be enhanced, thereby reducing aircraft operational delays and potentially deferring the need for other capital improvements necessary to enhance the capacity of the airfield. Otherwise, Wake RECAT is not expected to have any financial/business impacts at medium and large airports. Closely Spaced Parallel Runway Operations NextGen offers the ability to enhance the airfield capacity of airports with multiple runways through wake turbulence avoidance and/or potential changes in the minimum separation standards for aircraft landing on parallel runways during IMC. Wake turbulence avoidance procedures could benefit medi- um and large airports with either intersecting or closely spaced parallel runways (<2,500 feet of lateral separation). As with Wake RECAT, however, the application of wake turbulence avoidance procedures would be limited to medium and large airports that serve substantial numbers of Heavy jet and B757 aircraft operations. Similarly, closely spaced parallel runway operations are of greatest interest to airport planning practi- tioners at medium and large airports that have sufficient land area and traffic volumes to justify such procedures. Medium and large airports with dual parallel runways and a lateral separation between 2,500 feet and 4,300 feet would have the best opportunity to improve arrival capacity during IMC. Through the use of high-resolution color monitoring displays with alert algorithms (i.e., the final monitor aid or FMA), and without HUR, the minimum lateral spacing between dual parallel runways required for simultaneous independent approaches can be reduced to (1) 3,600 feet for straight-in instrument approaches, and (2) 3,000 feet for 2.5 degree-offset instrument approaches. Under current ATC rules, aircraft arrivals to parallel runways with a lateral separation between 2,500 feet and 3,600 feet would still be dependent, although the diagonal spacing between such depen- dent parallel instrument approaches was recently reduced from 1.5 nautical miles to 1.0 nautical mile. Other instrument approach enhancements, such as triple dependent/independent parallel operations, dual independent operations with offset approaches, and RPAT, are candidates for application at me- dium and large airports. Facility Impacts The recent and potential changes in the rules for the minimum spacing between parallel runways required for dependent or independent approaches, and the types of instrument approach procedures that can use such parallel runways, could open up new opportunities at medium and large airports that previously would not qualify for such approaches. Therefore, new alternatives could be consid- ered in the airport planning and development process for such airports. Such alternatives would have to be evaluated in terms of how the spacing between the parallel runways could facilitate the develop-

Applicability of NextGen to Medium- and Large-Airport Planning and Development | 69 ment of airport facilities between those runways and also how the new capabilities could affect noise exposure in the surrounding communities and operations at other nearby airports. For example, with the reduction in spacing between parallel runways required to accommodate si- multaneous independent parallel instrument approaches, medium and large airports considering such operations will have less difficulty fitting such parallel runways on their existing property or acquiring additional property for a new runway. For long-term planning, the spacing between the inboard-most parallel runways for independent ap- proaches may be insufficient to accommodate the planned terminal and landside facilities for meeting future demand. At best, a spacing of 3,600 feet between two parallel runways limits the options for developing passenger terminal and landside facilities between those runways. Therefore, for long- term planning of a new airport at a “greenfield site” (i.e., undeveloped land in a city or rural area) for example, airport planning practitioners should consider providing wider-than-the-minimum spacing between the parallel runways to accommodate the needed passenger terminal gates and landside (roadways and parking) facilities, in addition to planned air cargo and GA facilities. Having such facili- ties between the runways greatly reduces the risk of runway incursions due to aircraft having to cross one or more active runways to get to or from their parking position. Operational Impacts For medium and large airports that may benefit from wake turbulence avoidance procedures or reduced aircraft and/or runway separation standards for instrument approaches to closely spaced parallel runways, the capacity of the airfield could be increased. Such procedures would reduce aircraft operational delays and potentially defer the timing of the need for other capital improvements neces- sary to enhance the capacity of the airfield. The NextGen CSPO program includes a number of technologies and operational improvements that affect the operation and capacity of parallel runway layouts in IMC. The primary focus has been on reducing the spacing between parallel runways required for conducting either simultaneous indepen- dent parallel instrument approaches or dependent parallel (staggered) instrument approaches. These changes have enabled dual or triple approach procedures in IMC at airports that previously could not conduct such procedures. The rules for conducting simultaneous independent visual parallel ap- proaches, which are conducted in VMC, have not been affected. Enabling dual or triple approaches in IMC can significantly increase the arrival capacity of a parallel runway operation, sometimes by as much as 50%–100%. The actual capacity increase depends upon how many parallel runways an airport has and how those parallel runways are operated for arrivals and departures. One factor affecting the capacity increase is whether the parallel runways are dedicated to either arrivals or departures (i.e., “segregated operations”), or whether there are “mixed operations” (i.e., both arrivals and departures) on one or more of the parallel runways. A second factor that affects the capacity increase is whether the arrival and departure runways are dependent or independent. Environmental Impacts The recent CSPO-enabled reductions in the minimum parallel runway spacings and aircraft separations required for independent and dependent parallel runway operations could have significant environ- mental impacts in cases where (1) the change enables the construction of a new parallel runway not previously possible, or (2) the change enables a new or modified flight procedure that affects the arrival or departure paths over the surrounding community depending on runway or flight proce- dure locations. In either case, there could be significant environmental impacts due to overflights of neighborhoods that previously were not overflown. In such cases, airport planning practitioners would

70 | AIRPORT PLANNING AND DEVELOPMENT almost certainly have to undertake either an EA study or an EIS study in order to obtain the necessary environmental approvals for implementing either (1) a new CSPO-enabled parallel runway, or (2) op- erating independent or dependent parallel approaches on an existing pair of parallel runways in a way that was not previously possible without CSPO. In the case of existing parallel runways, the procedure change would be an ATO action. ATO would normally be responsible for NEPA, not the airport. The decision on the NEPA type in this case is com- plex. A CSPO procedure change (where that was the entire project) may not require a full EIS. While a new runway will almost certainly require an EIS, a CSPO change to existing runways might not trigger an EIS unless there is a significant change in flight procedures or runway use required to enable achiev- ing the benefit of the project. In some cases, the increased capacity afforded by the new CSPO could have a positive impact on the environment. For example, these enhancements could shorten aircraft flight paths on arrival and air- craft hold times for departure, which would ultimately reduce aircraft emissions and potentially reduce aircraft noise exposure to surrounding communities. Financial/Business Impacts At medium and large airports where a new parallel runway is enabled by the recent changes in requirements, there would be significant capital expenditures required for the planning, design, and construction of the new runway. At airports with existing parallel runways that would gain enhanced capability from the recent changes in requirements, there would be no capital expenditures required, and investment in additional capacity enhancements might be deferred by the enhanced capability of the existing layout. Multilateration MLAT systems are used for surface movement systems across the world. FAA incorporates MLAT sen- sors into the ASDE-X systems to provide ATC with surface movement information across an airfield. This system is deployed at 35 major airports in the U.S. and is used on a daily basis for operations. Both ASDE-X and ASSC include MLAT and ADS-B. ASDE-X is deployed at 35 hub airports, but it is not the top 35. ASSC is coming to eight airports. MLAT technology had been expected to replace the PRM radar system to refresh the aging technol- ogy. These systems have been beneficial in supporting simultaneous operations at airports with closely spaced runways. However, the FAA has not determined MLAT to be a replacement for PRM, although it is a likely technology candidate. Because ADS-B also provides 1-second position updates, it also was once considered as a replacement for PRM. Integration/fusion software of these various systems remains to be developed, at a later date. For now, FAA is not proceeding with a PRM replacement. MLAT is also anticipated to be the backup surveillance system for ADS-B Out. Facility Impacts An MLAT system consists of a transmitter, receiving antenna sensors, a central processor, and an optional interrogator system. The sensors and transmitters send out signals interrogating aircraft transponders which, in turn, transmit a response. The response from the transponder is interpreted by the computers to accurately locate an aircraft using triangulation by measuring the TDOA of the signal from the transponder at three or more synchronized receiver sites. The altitude of the aircraft is ob- tained directly from the required Mode C altitude-reporting transponder. En route and terminal config-

Applicability of NextGen to Medium- and Large-Airport Planning and Development | 71 urations supporting surveillance are referred to as WAM, whereas airport installations supporting surface movement, virtual air traffic control towers, and noise monitoring systems are referred to as MLAT. Operational Impacts The position information provided by MLAT and ADS-B is fused with existing radar systems, providing a “target” on the radar screen, enabling air traffic controllers to provide positive control of the aircraft and properly equipped surface vehicles. MLAT systems allow for the aircraft to receive its own posi- tions through ground station signals and could be a backup should the GPS system fail. No additional aircraft equipage is required for mode C equipped aircraft. Environmental Impacts MLAT systems are also used by airports as part of noise abatement systems. These systems are tailored for each installation providing aircraft tracking, noise, and other data services. In addition to enhanced operational safety, a benefit of MLAT used for WAM could be to reduce air- craft diversions, thereby reducing aircraft emissions and noise exposure in the region. The use of MLAT could also enhance the ability for an airport noise and operations monitoring system (ANOMS) to correlate aircraft noise exposure with actual aircraft operations. Implementation of ANOMS is normally feasible only at airports that have a significant aircraft noise exposure problem or noise abatement program that would justify the significant investment in manpower and equipment required to oper- ate such a system. Financial/Business Impacts MLAT systems are also used by airports as part of revenue tracking systems. These systems are tailored for each installation providing aircraft tracking and other data services. Airports can purchase new MLAT systems or expand existing MLAT systems through the acquisition of additional sensors. The same is true for ADS-B systems. To the extent that the MLAT sensors would be installed on the airport, there would still be a cost for installation and maintenance. ADS-B In and Cockpit Display of Traffic Information ADS-B In provides operators of properly equipped aircraft with weather and traffic position informa- tion delivered directly to the cockpit. ADS-B In–equipped aircraft have access to the graphical weather displays in the cockpit as well as text-based advisories, including Notices to Airmen and significant weather activity. ADS-B In and CDTI are intended primarily to improve operational safety in both flight and on the ground. However, they can be of benefit to airports by (1) ultimately enabling equivalent visual ap- proaches at lower minimums, thereby increasing capacity and reducing emissions and (2) reducing the risk of certain runway incursions between aircraft taxiing on the ground or between aircraft and ground vehicles. FAA has a mandated timetable for replacing most of its current radar aircraft surveillance systems with satellite-based systems utilizing ADS-B Out technologies. In particular, FAA is requiring all aircraft operating within controlled airspace to be equipped with ADS-B Out by 2020. However, there is no mandated timetable established for the implementation of ADS-B In procedures. Concepts and time-

72 | AIRPORT PLANNING AND DEVELOPMENT frame for ADS-B applications remain an active discussion between FAA and industry, through industry organizations such as RTCA. CDTI is an avionics system that, when combined with ADS-B In and Out, displays neighboring aircraft information, on the ground or in the air, to the flight crew as well as automation functions that, in some cases, provide speed or maneuver guidance to the crew. Facility Impacts There are no airport facilities required for ADS-B In. User requirements for ADS-B In include aircraft equipage and the development of cockpit systems to take advantage of all the capabilities available through the technology under which pilots of suitably equipped aircraft with proper training would be responsible for their own separation. Operational Impacts The primary benefit of ADS-B In is to enhance operational safety both in flight and on the ground. Air- craft equipped with ADS-B In equipment, and associated cockpit displays of traffic, weather, and other advisories, can maintain uniform separation from other aircraft, thus potentially increasing the capacity of the airfield at airports without radar surveillance systems. However, the capacity benefits would be marginal and difficult to quantify. In the past, there were projections that CDTI, when combined with ADS-B In and Out, would provide the capability to conduct “equivalent visual separations” in IMC, under which pilots with proper and operating suitably equipped aircraft would be responsible for their own separation, including wake tur- bulence separation, much like they are under current visual approach procedures conducted in VMC. Recently, however, this notion has not been promoted; instead, CDTI-enhanced visual approaches are a long-term possible concept, but there are other higher priorities that are more critical to fund and implement in the near term. Nevertheless, it is expected that with further advances and implementa- tion of enhanced vision and synthetic vision systems, that there will come a time when visual approach type procedures could be conducted with ADS-B In combined with enhanced CDTI displays. Environmental Impacts There should be no significant environmental impacts to airport operators from the implementation of ADS-B In and CDTI. Financial/Business Impacts There should be no significant financial/business impacts to airport operators from the implementation of ADS-B In and CDTI.