NextGen for Airports, Volume 3: Resources for Airports (2016)

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8 | RESOURCES FOR AIRPORTS NextGen Architecture2 NextGen encompasses both communication, surveillance, and navigation technologies (CNS) and a wide range of other related initiatives. Defining and tracking individual NextGen pro-grams can be difficult, in part because NextGen is so large and many of the technologies are unfamiliar to airports. For instance, one program with a noticeable airport impact is the wake vortex recategorization (Wake RECAT) program, which reduces the required wake turbulence separations between certain aircraft pairs. Wake RECAT has been the subject of ongoing research by the FAA, International Civil Aviation Organization (ICAO), and commercial aircraft operators for several years. As a result of this collaborative work, the FAA has implemented a change in the required wake turbulence separations between landing and departing aircraft at certain participating airports, and has made this change a part of its NextGen program. The lack of an obvious technical relation between programs makes defining “NextGen” an organizational rather than logical grouping. The content of NextGen is not static. From time to time, new programs are added to NextGen, as when a NASA air traffic management program that shows the promise of benefitting users demon- strates an adequate level of technical maturity is handed off to the FAA, and becomes a part of the FAA NextGen portfolio. The FAA also discontinues NextGen programs in favor of newer or better alterna- tives, such as cancellation of precision runway monitor (PRM) radar installations at airports in favor of parallel runway separation reductions under MRO without high update radar but with advanced controller monitoring displays.16 As NextGen technologies are implemented the FAA will discontinue redundant installations to manage its operational maintenance burden. Programs in NextGen also evolve in name, reach, or technology. For instance, Data Communications (or “Data Comm,” as it is often called) has been in development for many years under many different program names, including “Aeronautical Data Link” and “Controller-Pilot Data Link Communications” (CPDLC). Finally, the budget available to the FAA for NextGen is subject to change. When the budget for NextGen is cut, some programs have to be delayed. If budget cuts are sustained and deep enough, programs may be canceled. This budget variability affects NextGen plans and programs each year.17 As shown in the simplified schematic of Figure 2-1, NextGen represents a complex set of interrelated programs that require community-wide collaboration to achieve success. The next section summarizes the four groups of programs—the major players in NextGen implementation—that affect airports most directly. 16Advanced controller monitoring displays are high-resolution color monitors with alert algorithms (e.g., a Final Monitor Aid or FMA). 17Top Management Challenges for Fiscal Year 2015, Office of the Inspector General, Department of Transportation, Nov. 2014.

NextGen Architecture | 9 Major NextGen Programs NextGen consists of nearly 100 different modernization programs.18 To identify the NextGen capa- bilities that render the highest value to pilots, aircraft owners, and travelers, the FAA established the NAC—a federal advisory committee consisting of aviation industry and FAA experts, overseen by standards-making body RTCA, Inc., to review FAA modernization plans and recommend priorities for development and implementation. The committee recommended the following four major NextGen priority focus areas. PBN, Surface Operations and Data Sharing (SWIM), MRO, and Data Comm. 18For current NextGen programs, brief descriptions, and the expected time frame for implementation, see FAA, , www. faa.gov/nextgen/. Figure 2-1. NextGen is a set of complex, interrelated programs that require pilot, aircraft owner, airport, com- munity, and FAA collaboration.

10 | RESOURCES FOR AIRPORTS The RTCA Committee’s recommendations are documented in the RTCA NextGen Integration Work- ing Group Final Report, October 2014. The FAA is currently implementing the RTCA recommendations. The FAA NextGen Priorities Joint Implementation Plan, Executive Report to Congress, 2014, describes the technologies being pursued, and the FAA NextGen Priorities October 2015 Joint Implementation Plan, Revision 1 contains status information. The FAA NextGen Implementation Plan 2015 addresses the priority areas plus other key NextGen programs. All these reports are available online for review and download. The following websites provide useful information on the priority programs. NAC_Description (https://www.faa.gov/nextgen/update/collaboration/advisory_committee/) contains description of the NAC, descriptions of the priority groups and links to relevant documents Priority_Snapshots (https://www.faa.gov/nextgen/snapshots/priorities/) contains current updates on the four focus areas. Priority_Completion (V) contains information on program completion history. NextGen_Airports (https://www.faa.gov/nextgen/update/operator_investments_and_airports/airport_ enhancements/) includes information specifically focused on airports. This chapter describes the four priority focus areas and their potential impacts on airports. FAA provides extensive online information describing NextGen programs and their progress, includ- ing programs not in the four priority focus areas, but the information is often distributed among several websites. For example, the website NextGen_Progress_&_Plans (https://www.faa.gov/ nextgen/update/progress_and_plans/) includes links for the priority programs PBN and SWIM plus enabling technologies such as ADS-B and NAS Voice System, but does not include MRO. A web search for MRO uncovers additional sites, such as MRO_Portfolio (https://www.faa.gov/nextgen/ snapshots/portfolios/?portfolioId=9) and MRO_Snapshot (https://www.faa.gov/nextgen/snapshots/ priorities/?area=mro), containing different types of information on technical content, schedules, and progress. An interested researcher needs to examine several sites and associated links to gain a full pic- ture of a particular program or technology. This guide provides basic information about each program and suggests links. PBN A key enabler for NextGen is the shift from solely ground-based radar and navigation aids to include the use of navigation data based on the Global Navigation Satellite System (GNSS). GNSS includes po- sition and timing signals from U.S. GPS satellites, error correction/accuracy improvement to GPS signal provided by WAAS and local area ground-based augmentation systems (GBAS), and aircraft GNSS receivers including signal integrity monitoring. The use of GNSS increases both navigation accuracy and flexibility. PBN refers to en route and terminal operations that take advantage of the improved navigation performance available from automation using either or both space-based or ground-based sources. As described by the FAA, Performance-Based Navigation (PBN) is comprised of Area Navigation (RNAV) and Required Navigation Perfor- mance (RNP) and describes an aircraft’s capability to navigate using performance standards. RNAV enables aircraft to fly on any desired flight path within the coverage of ground or space-based navigation aids, within the limits of the capability of the self-contained systems, or a combination of both capabilities. RNP is RNAV with the addition of onboard performance monitoring and alerting capability. A defining charac- teristic of RNP operations is the ability of the aircraft navigation system to monitor the navigation performance

NextGen Architecture | 11 it achieves and inform the crew if the requirement is not met during an operation. The performance require- ments of PBN are conveyed to the operators through navigation specifications. PBN navigation specifications include Advanced RNP (A-RNP), RNP 0.3, RNP 1, RNP 2, RNP 4, RNAV 1, RNAV 2, RNP 10 (RNAV 10), as well as RNAV (GPS) and RNAV (RNP) approaches.19 In the above description, RNAV 1 and RNP 1 refer to navigation performance criteria where the aircraft will be within 1 nautical mile of the assigned track with 95% confidence. The other RNAV and RNP values represent the 95% confidence for their respective nautical mile performance criteria. RNAV/RNP values of 4, 5, and 10 apply to oceanic en route operations; values of 1 and 2 refer to domestic en route and terminal area operations, and values of 0.3 and 0.1 apply to terminal instrument approach procedures. To understand the benefits of PBN, it helps to understand air traffic management history. Navigation History En Route Phase Aircraft navigation across the United States has evolved from dead reckoning with compass, map, stars, and visual landmarks, first based on revolutions in radio, and more recently, on advances in aircraft electronics (avionics), digital computers, and space-based navigation systems. Bonfires and rooftop arrow markers were early ground references, replaced in the early-20th century first with radio direction finders that homed in on radio stations, and then with dedicated aviation, non-directional, radio beacons and very high frequency (VHF), directional, radio beacons. The directional VHF omnidi- rectional range (VOR) radio beacons emit signals that identify the beacon, and generate radio signals that transmit radial rays around the beacon. The aircraft VOR radio receiver decodes the signal and displays the directional radial from an emitter. Crossing two radials from two different VORs (with two radios) allows precise lateral position determination by triangulation. The other current primary radio navigation element is the VHF distance measuring equipment (DME), which is often co-located with a VOR. The DME provides precisely timed responses to aircraft interrogations enabling determination of slant range between the aircraft and the DME location. With range and bearing data, aircraft position can be determined with single VOR/DME radio and site. The non-directional and directional radio bea- con systems are collectively referred to as navigational aids (NAVAIDs). Use of these NAVAIDs by the aircraft required only relatively simple aircraft radio equipment. Navigation “fixes” could be defined by either intersections of VOR radials or the physical location of individual NAVAIDs. Published flight routes based on these fixes, often called “highways in the sky,” are used to manage air traffic. Flight plans listing the names of NAVAIDs as waypoints along the flight plan are loaded in aircraft flight management computers and filed with ATC. Flight plans can be altered during flight, particularly to avoid weather, turbulence, and adverse winds. NAVAIDs are often about 50 miles apart to maintain good frequency reception. Navigation based on flying from one geographically fixed NAVAID to another provided a major safety improvement but has disadvantages. First, following the zigzags from NAVAID to NAVAID adds time and distance to a route as shown in Figure 2-2, increasing fuel costs. Second, the limited number of routes can become congested due to traffic or weather. On the other hand, a limited list of fixed NA- VAID waypoints can be more easily memorized by pilots and controllers, enabling them to maintain a mental picture of the traffic in their airspace. Modern aircraft navigation systems with RNAV avionics are capable of navigating with virtual way- points defined by relative distances from ground NAVAIDs or on GPS-based latitude and longitude. These RNAV routes can be constructed to reduce distances, spread traffic demand, or follow more efficient routes. The FAA has established RNAV routes defined by NAVAID intersections and distances. 19FAA Performance Based Flight Systems Branch PBN Information sheet, https://www.faa.gov/about/office_org/headquarters/avs/ offices/afs/afs400/afs470/pbn/.

12 | RESOURCES FOR AIRPORTS RNAV avionics also allows use of “direct” routes where the aircraft can fly from an arbitrary staring point to a real or virtual waypoint. The use of RNAV operations enabled by modern avionics has been supported by upgrades to the air traffic management computers and displays. ATC computers and displays could not accept GPS-based latitude and longitude position reports until the en route automation modernization (ERAM) computer hardware and software upgrades were accomplished nationwide. On the human side, NextGen ATC decision support tools are intended to aid the human controller in maintaining situational awareness with the more complex en route airspace. Transition to Terminal Airspace and Airport Leaving cruise, a pilot executes a planned descent to the airport airspace. The descent from cruise—a controlled and planned change in altitude—dissipates both speed and altitude; if done efficiently, it is smooth and burns very little fuel. Due to traffic and spacing requirements, current approaches are often not efficient and involve radar vectoring instructions for both step downs with level flight seg- ments and lateral excursions, both of which add time and burn extra fuel. A major goal of the FAA is to use NextGen PBN technologies to support more of the efficient optimized profile descents (OPDs). In order to manage arrival traffic in high traffic airspace, to minimize communication errors, and to reduce communication workload, the FAA has produced for major airports standard terminal arrival routes (STARs) which prescribe a flight route defined by a series of NAVAIDs extending from the last en route fix, approximately 100 miles from an airport, to a terminal airspace fix in the vicinity of the air- port. Because aircraft approach from many directions, each airport has many STARs. The basic Stan- dard Terminal Automation Replacement System (STARS) is based on aircraft navigation using standard NAVAIDS, and the resulting aircraft position accuracy limits the number of STARs and waypoints one can have in a given section of airspace. Sometimes, several airports in the same vicinity share a STAR; aircraft follow the same arrival path up until the final waypoint when they join the airport approach. This can result in congestion, with delays propagated across nearby airports. Figure 2-3 is an example STAR for the Dallas-Ft. Worth Metroplex that terminates at the FINGR fix and serves several airports. Along with increased flexibility in establishing waypoint location, RNAV/RNP flight precision enables establishing multiple closely spaced flight paths, allowing individual and non-overlapping STARs for airports in the same vicinity. Figure 2-4 shows an RNAV STAR in the Dallas-Ft. Worth Metroplex. Us- ing RNAV/RNP technology with more flexible waypoints along an approach enables shortening flight Source: Erzberger, Heinz, and McNully, David. 2001. Method and System for an Automated Tool for En Route Traffic Controllers. U.S. Pat- ent 6,314,362 B1, filed February 2, 2000, and issued November 6, 2001. Figure 2-2. Typical NAVAIDs-based routes are circuitous.

NextGen Architecture | 13 Figure 2-3. Conventional STAR for Dallas-Ft. Worth. Figure 2-4. RNAV STAR for Dallas-Ft. Worth.

14 | RESOURCES FOR AIRPORTS routes to reduce time and fuel burn and also enables an increase in the potential number of flight routes. Approach and Landing Phase In the approach airspace, controllers vector the arrivals to intercept the final approach path or to a charted arrival procedure. A charted procedure consists of another set of NAVAID-based fixes with specified lateral and altitude requirements leading to interception of the final approach path. The ILS final approach consists of the localizer (lateral) and glide slope (elevation) radio beacons, which provide precision azimuth and elevation guidance to the runway. Because ILS approaches are based on radio beams, they require relatively long obstacle-free, straight arrival paths for aircraft to get estab- lished on the localizer course, and cannot be used when terrain or other obstructions do not permit such long paths. The ILS produced a revolutionary improvement in low-visibility operations; however, it only supports straight line approaches and requires several miles of clear distance leading to the runway, and the cost precludes implementing ILSs at smaller airports, and the required straight path precludes use where terrain does not allow a clear straight approach. NextGen RNAV/RNP technology supports efficient, continuous routes through the terminal airspace to the final approach, and can include curved flight routes to avoid terrain obstacles Figures 2-5a and 2-5b compare the basic ILS and the RNAV/RNP approaches to Runway 31L at Dallas Love Field. Figure 2-5a. DAL, Rwy 31L ILS approach. Figure 2-5b. DAL, Rwy 31L curving RNAV/RNP approach.

NextGen Architecture | 15 Raw GPS data are not sufficiently accurate to support low-visibility RNAV/RNP instrument approach procedures. The WAAS and the GBAS both provide corrections to the GPS position data. The WAAS corrections cover the entire continental U.S. and are adequate for near-ILS Category I approaches. The GBAS corrections are local and are expected to potentially support ILS Category III level approaches. The FAA work program is now focused on validating standards for a GBAS Approach Service Type–D (GAST-D) (Category-III minima) service. The program projects that a GAST-D can be available by 2018. Both straight and curved PBN approaches can be supported by WAAS and GBAS, allowing their use with terrain-challenged runways. GBAS has several advantages over traditional ILS. One GBAS station can support multiple runway ends and reduce the total number of systems at an airport. This reduces the radio frequency requirements and simplifies airport infrastructure. Unlike ILS, which requires one frequency per runway, a GBAS requires only one frequency assignment for up to 48 individual approach procedures. GBAS has more flexible siting criteria, enabling it to serve runways that cannot support an ILS because of insufficient space for conflict-free localizer and glide slope critical areas. A GBAS is sited to minimize NAVAID criti- cal areas, placing fewer restrictions on aircraft movement during ground taxi and air operations. The GBAS approach guidance is steadier than ILS approach guidance. Also, GBAS requires less frequent flight inspections than those required of ILSs. Despite these advantages, GBAS, so far, has only been applied to a “niche market,” because the majority of airports requiring Category II and III landing minimums already have adequate ILSs installed. Departures and Climb Out Standard instrument departures (SIDs) are charted departure paths analogous to STARs. Like STARs, their use reduces workload and communication requirements, and, as with STARs, the use of an SID can create a delay as aircraft wait for the pathway out of an airport to be clear before taking off. NextGen RNAV/RNP flight precision supports procedures to alleviate this delay by allowing more closely spaced and spatially separated SIDs. Spatially separated SIDs can allow non-airline operators to depart an airport near a major airline hub airport when previously the non-airline operators (such as business aircraft operators and GA) would have faced a delay. New SIDs can introduce noise to new areas, or re-distribute aircraft noise among the paths. Aircraft using RNAV/RNP SIDs have much more accurate navigation performance, and follow the defined SID much more closely than with conventional SIDs, which can concentrate flight paths and increase air- craft noise level under an existing departure route. Without sufficient advanced planning and commu- nity outreach, these changes can cause significant public controversy and increased noise complaints even with the implementation of single new RNAV/RNP SID. PBN Terminal Area Summary The FAA has bundled PBN implementation together for sets of airports. The FAA program name is Optimization of Airspace and Procedures in the Metroplex, or OAPM, but it is also commonly called Metroplex. The FAA PBN website, PBN_Progress_&_Plans (https://www.faa.gov/nextgen/update/ progress_and_plans/pbn/), contains a description of PBN, and links to information on Metroplex and single airport RNAV/RNP programs. Adjusting arrival and departure routes by even a few tenths of a mile can mean aircraft traffic, and noise, is introduced over a new area near an airport. This is particularly noticeable when the new pat- tern affects airport departures. Taking off and climbing uses most of an aircraft’s thrust, so the aircraft’s engine or engines are operating at a high pitch and generating the loudest noise of the entire flight.

16 | RESOURCES FOR AIRPORTS Airports for which noise is an issue should know that they may be able to influence the placement of new RNP routes and NextGen Metroplex routes if they engage in the planning process before a new route is finalized. Both RNAV SIDs and RNAV STARs can be designed to require an aircraft to operate over non-noise-sensitive areas and avoid noise-sensitive areas. Identifying the noise-sensitive areas and ensuring that RNAV/RNP flight routes are not placed over them would reduce subsequent aircraft noise complaints. More extensive and detailed discussion of PBN can be found in ACRP Report 150: NextGen for Airports, Volume 1: Understanding the Airport’s Role in Performance-Based Navigation: Resource Guide, ACRP Re- port 03-34. Surface Operations and Data Sharing The goal of the improved surface operations and data sharing is to increase efficiency and reduce air- craft delay through improved situational awareness and collaborative decision making (CDM). Airport operators could play a significant role in the implementation of both situational awareness and CDM. The FAA has published a concept of operations document (ConOps) for surface CDM which states: Surface CDM is the sharing of flight movement and related operational information among Airport Operators, Flight Operators, Flight Service Providers, and FAA Stakeholders to improve demand and capacity predictions, thereby enabling those who practice the Surface CDM concept to maximize the use of available airport and airspace capacity, while minimizing adverse effects on Stakeholders, passengers, and the environment.20 The ConOps includes situational awareness-related data requirements for airport operators including runway status, ramp operations, deicing operations, and security. Under the NextGen program the FAA is developing the Terminal Flight Data Manager (TFDM) system, which will enable greater sharing of data among controllers, aircraft operators, and airports so they can better stage arrivals and departures to improve efficiency in the terminal. TFDM operates through four functions:21 • Electronic flight data distribution, • Traffic flow management, • CDM on the airport surface, and • Systems consolidation. The near-term priority efforts are directed to converting to electronic flight strips under the Advanced Electronic Flight Strips (AEFS) program and sharing of surface traffic data among the towers and terminal radar approach control (TRACONs). The SWIM system is the backbone of the data distribu- tion system. SWIM is designed to provide the single point of access supported by standardized data formats for near real-time access to NAS data. SWIM will include a broad array of aeronautical, flight, and weather information. In accordance with the NAC surface operations priority, early SWIM imple- mentations have included surface visualization tool (SVT) and the SWIM Terminal Distribution System (STDDS) that supports airport surface data distribution to both the airport towers and TRACON, and the SWIM SVT that displays the terminal surface data in the Tower and TRACON. 20U.S. Airport Surface Collaborative Decision Making (CDM) Concept of Operations in the Near-Term, FAA Surface Operations Office, June 15, 2012, p1-2. 21NextGen Decision Support Systems at NextGen_Decision_Support_Systems (https://www.faa.gov/nextgen/update/progress_ and_plans/decision_support_systems/#tfdm).

NextGen Architecture | 17 General SWIM information and status can be seen at the FAA website “System Wide Information Management” SWIM_Progress_&_Plans (http://www.faa.gov/nextgen/update/progress_and_plans/ swim/). The websites Surface_Ops_Progess_&_Plans (https://www.faa.gov/nextgen/snapshots/ portfolios/?portfolioId=7) and Surface_Ops_Priorities (https://www.faa.gov/nextgen/snapshots/ priorities/?area=sops) contain general and status information on the surface operations. The website https://www.faa.gov/about/office_org/headquarters_offices/ato/service_units/pmo/proj/tfdm/ pro- vides information on the goals and status of TFDM. The decisions on surface data access are made by a CDM stakeholders group (CSG). As noted in the 2014 NextGen Priorities Joint Implementation Plan: The [Collaborative Decision Making Stakeholders Group] CSG provides oversight and governance of joint FAA/ industry CDM initiatives and provides the FAA with input on prioritization and tasking for possible technologies, tools, and/or procedures that will increase the efficiency of the NAS. The CSG includes representatives from the Airlines for America, National Business Aviation Association (NBAA), Regional Airline Association (RAA) and the current industry lead of the CDM program, Delta Air Lines.22 The October 2015 revision to the plan notes that: Several milestones were completed relative to the two-way data sharing agreement negotiated by the Col- laborative Decision Making Stakeholders Group (CSG). First, the CSG reached agreement to allow airport operators to participate in data exchange collaborative decision making related processes and procedures. Like flight operators, airports require real-time air traffic control and flight movement information to manage airside operations more effectively. This is especially true for airports that provide ramp control in the non-movement areas. More uses of real-time information include better gate management, forecasting of airport resource demands and preparing for irregular operations such as severe weather operations.23 Airport operators can get access to SWIM data through the NAS Enterprise Messaging System (NEMS). The data products available on SWIM and links to instructions on getting access to SWIM data are available at the FAA website “Data Products Available via SWIM,” https://www.faa.gov/nextgen/ programs/swim/products/. Surface traffic surveillance data are available at the 35 airports that are equipped with airport surface detection equipment—Model X (ASDE-X) and at the nine airports that are equipped with airport sur- face surveillance capability (ASSC). Data are provided by the ASDE-X and, for ASSC, the ASDE-3 radar supplemented by multilateration location information based on aircraft transponder responses. In the future ADS-B data may be used to provide more accurate surveillance data at additional airports. MRO As mentioned at the beginning of the chapter, MRO are included in NextGen, but are not based primarily on the use of improved navigation, surveillance, and communications. Rather they are based primarily on analysis aircraft performance data and analysis of aircraft wake generation and wake upset susceptibility data. Most of the MRO technologies apply to parallel runway operations; however, NextGen Wake RECAT, while not restricted to MRO, is included programmatically under MRO. The applicability of MRO technologies to an airport is a function of the runway configuration for parallel operations and the traffic weight class mix for Wake RECAT. Wake RECAT redefines the FAA aircraft wake vortex class structure. Current classes, including Small, Large, Boeing 757 (B757), Heavy and Super [Heavy] are based on weight only. Wake RECAT defines six classes, A–F, based on weight and wingspan to better reflect leader wake hazard and follower wake upset susceptibility. Wake RECAT classes and separation requirements are defined in FAA Order JO 22NextGen Priorities Joint Implementation Plan, 2014. 23NextGen Priorities Joint Implementation Plan, Revision 1, October 2015.

18 | RESOURCES FOR AIRPORTS 7110.659C, Wake Turbulence Recategorization. Practically, RECAT removes the additional wake vortex separation requirement that existed for Large class aircraft following Boeing 757 aircraft, and reduces the separation requirements for certain Heavy class aircraft following smaller Heavy class aircraft. It has the biggest impact at international and cargo airports that have significant heavy and B757 traffic. The removal of the additional separation requirement behind the B757 has been included in FAA Order JO 7110.65W as a general change independent of Wake RECAT. The use of full Wake RECAT with the new classes has been implemented at specific airports, including Memphis (MEM), Louisville (SDF), Atlanta (ATL), Houston (IAD), Cincinnati (CVG), Chicago (ORD), Charlotte (CLT), Newark (EWR), and New York (JFK and LGA). NextGen includes four significant impacts on parallel runway operations in instrument conditions. The first is the reduction of the minimum runway centerline separation for dual simultaneous independent approaches from 4,300 feet to 3,600 feet (3,000 feet with a 2.5–3.0 degree offset approach) with- out high update radar but with advanced controller monitoring displays. The second is the reduc- tion of the minimum runway centerline separation for triple simultaneous independent approaches from 5,000 feet (4,300 feet with advanced controller monitoring displays) to 3,900 feet (3,000 feet with 2.5-3.0 degree offset approaches to both outside runways) without high update radar but with advanced controller monitoring displays. The third is the reduction of minimum diagonal separa- tion for arrivals on parallel runways separated by 2,500 to 3,600 feet from 1.5 nautical miles to 1.0 nautical mile. These changes, based on analysis of aircraft performance, are generally applicable and are already included in FAA 7110.65W. The fourth is the ability to use dependent (staggered) ap- proaches with runway centerline separations from 2,500 feet to as low as 750 feet for specific airports and specific classes of aircraft. This procedure is airport specific, based on wind and wake data, and is governed by FAA JO 7110.308A. These improvements can have impact on airport runway construction options. NextGen wake turbulence mitigation refers to the use of wind data and sensing to determine if opera- tions on an upwind runway of a closely spaced pair can be operated independently from the down- wind runway. This is especially important for departures where extended wake separation require- ments on either runway affect operations on both. This wake turbulence mitigation for departures (WTMD) technology is most likely to provide benefits for airport such as SFO where there are persis- tent crosswinds on the departure runways. The most recent FAA position is that WTMD will remain at SFO for periodic testing, but will not be deployed elsewhere. In addition to the above, the need to increase capacity on very closely spaced parallel runways has re- sulted in the development of offset approaches. Under these procedures, aircraft conduct independent approaches as if they will land on widely spaced parallel runways, but one aircraft must be lined up on an offset angle to its actual runway centerline. During the final part of approach, the offset aircraft establishes visual contact with the runway and parallel traffic and moves inward to the real runway extended centerline.24 Data Comm Data Comm services will provide digital communications services between pilots and air traffic control- lers (Figure 2-6), as well as enhanced ATC information to airline operations centers. The capabilities will enhance safety by reducing communication errors, increase controller productivity, and increase airspace capacity and efficiency while reducing delays, fuel burn, and carbon emissions at 56 towers nationwide. 24San Francisco approach RNAV(PS) PRM X RWY 28R (Simultaneous Close Parallel) Terminal Approach Plate.

NextGen Architecture | 19 Figure 2-6. Typical Data Comm display shows pre-departure clearance from tower. Pre-departure clearance allows tower controllers to give pilots complex taxi instructions in a text format. At large airports with complex taxiway layouts, having text displays of the routes by taxiway name decreases the possibility of error in taxiing and increases safety. Previously, pilots often wrote down taxi instructions as they were given and followed their handwriting. Pre-departure clearances can be granted using the commercial Aircraft Communication Addressing and Reporting System (ACARS). A different medium will be used for en route Data Comm. Air traffic controllers do not have ACARS terminals for transmitting ACARS-based messages. For this applica- tion, the FAA will use Future Air Navigation Systems (FANS) 1/A+ avionics and VHF Data Link Mode 2 (VDL-2) radios for en route Data Comm. FANS 1/A has been in use over the ocean for many years, so many large aircraft already have this equipment. The FAA has established NextGen equipage funds to provide interest-free financing for avionics equipage, prior to ground station implementation of the technology. Both the controller and the pilot need to have Data Comm equipment to realize the Data Comm benefits, so the FAA set up an incentive fund to encourage the aircraft side of the Data Comm investment. Data Comm will provide a means of two-way communication for ATC clearances, instructions, advisories, flight crew requests, and reports. Data Comm is critical to the success of NextGen, enabling efficiencies not possible with the current voice system. En route services will include airborne reroutes, controller- and pilot-initiated downlinks, altitude and altimeter settings, tailored arrivals, and issuing of crossing and holding restrictions, advi- sory messages, beacon codes, transfer of communications, and initial check-in. Data Comm implementation is scheduled in two stages: initial services (such as pre-departure clear- ance) and a much fuller implementation called full services. The Data Comm en route services will contribute to enhanced safety, more efficient routes, and a reduction in flight delays, resulting in lower fuel burn for operators. In accordance with NAC priorities, the FAA is planning to install Data Comm at 56 Airport Traffic Control Towers by the end of 2016. Data on the installation status can be found at the Data_Comm_ Progress_&_Plans (https://www.faa.gov/nextgen/update/progress_and_plans/data_comm/). Aircraft Equipment Mandate The FAA has mandated that every aircraft seeking access to Class A, B, and C airspace, and Class E airspace above 10,000 feet, must be equipped with GPS-capable ADS-B equipment that transmits a

20 | RESOURCES FOR AIRPORTS GPS-based position of the aircraft, by January 1, 2020. Broadcasting the aircraft’s position is commonly referred to as “ADS-B Out,” for outbound communication. For an aircraft equipped with the ability to receive the signals, receiving the broadcast is called “ADS-B In.” With both ADS-B Out and ADS-B In, suitably equipped aircraft can view all transmitting aircraft relative to their position on a cockpit dis- play. In is not mandated; only Out is mandated. Aircraft (usually GA) equipped with traffic information system–broadcast (TIS-B) will also be able to see the position of nearby aircraft. ADS-B Out is mandated because universal equipage provides the ability to track the position of all aircraft more accurately and independently of radar. The FAA explained that aircraft owners who saw the benefit of ADS-B In could choose to acquire it. The ADS-B Out mandate is triggering interest from GA aircraft owners in a broader range of avion- ics upgrades. The NextGen GA Fund was established to finance these installations, including WAAS– capable GPS, ADS-B (In and Out), RNAV/RNP avionics, transponders, Data Comm, SWIM displays, instrument panel modifications, antennas, other enabling electronic components, installation, and cer- tification costs. Pilots operating under Federal Aviation Regulation Parts 23, 91, and 135 are likely to be early adopters. Pilots and aircraft owners interested in the fund provisions should contact NEXA Capital Partners, LLC. Up-to-date information, including information on a $500 ADS-B rebate for single-engine aircraft, can be found at the FAA NextGen Equip ADS-B website, Equip_ADS-B (http://www.faa.gov/ nextgen/equipadsb/). Aircraft will lose access to certain U.S. airspace without timely equipage. In 2015, there were over 200,000 GA aircraft registered in the United States. Over 120,000 were single-engine piston, fixed-wing aircraft.25 Many are more than 40 years old. About 6,000 of these aircraft had been equipped with ADS-B Out as of July 2014.26 Equipping the entire fleet would require nearly 300 new installs per week until the deadline. Equipping to meet the mandate costs from $1,000 to $7,000 per aircraft, depending on how high the aircraft flies and how many functions the owner chooses. Not all GA aircraft will equip; some will choose to remain clear of the airspace requiring ADS- B instead. The cost and trouble of equipping aircraft to enable new services is one of the costs of NextGen, and some aircraft owners are not happy about the mandates. Also, the choice of equipment depends on what the aircraft owner wants to do with the new capabilities, and sometimes that is not straightfor- ward. Changing deadlines and changing program requirements at FAA in the past have made some users wary of NextGen promises and schedules,27 even though NextGen offers the benefits of fuel efficiency and reliable flight service. Geographic Information System (GIS) Mandate and Airport Improvement Program (AIP) The FAA Memorandum, “Airports Geographic Information System (GIS) Transition Policy for Non- Safety Critical Projects,” dated August 23, 2012, mandated immediate incorporation of safety-critical data into the GIS for all airports in the National Plan of Integrated Airport Systems (NPIAS) and phased incorporation of non-safety-critical data for specific airport classes in the NPIAS.28 Cost is recognized as a major issue; use of AIP funding is permitted for above-ground surveys. Several NextGen technologies specifically depend on airport geospatial data. Federal funding for specific airport improvements is available under the FAA AIP. Extensive informa- tion on the AIP, including the 3,345 eligible airports, types of projects, contacts, and much more, is 25FAA General Aviation and Part 135 Activity Surveys – CY 2014, Table 1.1. 26John Croft, “ADS-B Options Increase As Operators Resolve To Equip,” Aviation Week, Jul 30, 2014. 27Bill Carey, “American Airlines Awaits Fruit of NextGen Investment,” Aviation International News, September 16, 2013. 28FAA_GIS_policy_memo (http://www.faa.gov/airports/planning_capacity/airports_gis_electronic_alp/media/airportsGISTransition Policy.pdf).

NextGen Architecture | 21 available at the FAA website Airports_AIP (http://www.faa.gov/airports/aip/). AIP funding for GIS is addressed in the AIP handbook, FAA JO 5100.38D paragraph 3-82,29 and GIS-related information is on the following FAA websites. • FAA_Implementation_Guidance_for_Airports_GIS_and_eALP (http://www.faa.gov/airports/ planning_capacity/airports_gis_electronic_alp/). • FAA_GIS_Advisory_Circulars (http://www.faa.gov/airports/resources/advisory_circulars/index.cfm/ go/document.list/parentTopicID/187). • FAA_Airports_GIS_Survey (https://airports-gis.faa.gov/public/airportsSteps.html). • FAA_Airports_GIS_Public (https://airports-gis.faa.gov/public/). • FAA_GIS_Info (http://airports-gis.info/). • NPIAS_airports (http://www.faa.gov/airports/planning_capacity/npias/). • Part_139_airports (http://www.faa.gov/airports/airport_safety/part139_cert/). Much more information on GIS is included in ACRP Report 150: NextGen for Airports, Volume 4: Leverag- ing NextGen Spatial Data for Airports: Guidebook. 29FAA JO 5100.38D, September, 30, 2014, http://www.faa.gov/airports/aip/aip_handbook/.