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This article presents an assessment of the inefficiency of airborne aircraft traveling in the U.S. airspace. The authors define excess flying time for each flight examined and finds an average of 5.5 to 7.5 minutes per flight. Given the average cost of $45.30 per minute of flight, potential savings are great if inefficiencies in the air are eliminated. Topics outlined in the research include the mean excess flying time throughout the NAS as a pool of benefits. The analysis of the datasets is described, using Enhanced Traffic Management System data, filtered to include only flights whose origin and destination airports are both in the coterminous U.S. (CONUS). Selection of data is described, along with methods of calculation and adjustments for elements such as weather and wind. Additional study is needed on further understanding how weather affects excess flying time, the routes that are more efficient, identifying the airlines that are more efficient and attempting to isolate practices that contribute to those savings, determining if fluctuations occur and focusing on effects that NAS enhancements could have.

Traffic Management Specialists within the Air Traffic Control (ATC) system strategically manage the flow of air traffic to minimize delays and congestion due to system stressors such as heavy volume, weather, and equipment outages. ATC facilities are required to log all Traffic Management Initiatives (TMIs), coordinate the implementation of some initiatives with the Air Traffic Control System Command Center, and communicate TMIs to Traffic Management Specialists at all affected facilities and to the controllers within their facility. The Federal Aviation Administration developed the National Traffic Management Log (NTML) to provide a single system for automated coordination, logging, and communication of TMIs throughout the National Airspace System. This report describes the results of an empirical comparison of TMI processing with and without the NTML. Researchers observed benefits in completion times, potential for user error, and workload. Furthermore, the completion time and potential for error remained relatively unaffected by TMI complexity. These results suggest that the NTML will continue to provide benefits as ATC complexity increases in the future.

An Eulerian network model for air traffic flow in the National Airspace System is developed and used to design flow control schemes which could be used by Air Traffic Controllers to optimize traffic flow. The model relies on a modified version of the Lighthill-Whitham-Richards (LWR) partial differential equation (PDE), which contains a velocity control term inside the divergence operator. This PDE can be related to aircraft count, which is a key metric in air traffic control. An analytical solution to the LWR PDE is constructed for a benchmark problem, to assess the gridsize required to compute a numerical solution at a prescribed accuracy. The Jameson-Schmidt-Turkel (JST) scheme is selected among other numerical schemes to perform simulations, and evidence of numerical convergence is assessed against this analytical solution. Linear numerical schemes are discarded because of their poor performance. The model is validated against actual air traffic data (ETMS data), by showing that the Eulerian description enables good aircraft count predictions, provided a good choice of numerical parameters is made. This model is then embedded as the key constraint in an optimization problem, that of maximizing the throughput at a destination airport while maintaining aircraft density below a legal threshold in a set of sectors of the airspace. The optimization problem is solved by constructing the adjoint problem of the linearized network control problem, which provides an explicit formula for the gradient. Constraints are enforced using a logarithmic barrier. Simulations of actual air traffic data and control scenarios involving several airports between Chicago and the U.S. East Coast demonstrate the feasibility of the method

Multivariate statistical analysis is used to estimate the impacts of a major capacity expansion at Dallas-Fort Worth International Airport. The model relates the Daily Flight Time Index (DFTI) to demand, weather, origin airport congestion, and the expansion itself. The effect of the capacity expansion on DFTI is found to depend strongly on visibility. On average, the index in the post-expansion period is 1.3 min less as a consequence of investment. This change includes a larger reduction in departure delay that is offset by an increase in taxi time. Moreover, the reduction caused by the expansion has been more than offset by increases in the DFTI resulting from other factors, notably increased demand and worse weather.

Traditionally, models used in air-traffic control and flow management are based on simulating the trajectories of individual aircraft. This approach results in models with a large number of states, which are intrinsically susceptible to errors and difficult for designing and implementing optimal strategies for traffic flow management. This paper outlines an innovative approach for the development of linear-time-variant dynamic traffic flow system models based on historical data about the behavior of air traffic. The resulting low-order, linear, robust models can be used both for the analysis and synthesis of traffic flow management techniques for current and future systems.

In Part I of this paper, we presented a large-scale airspace-planning and collaborative decision-making (APCDM) model that is part of a Federal Aviation Administration (FAA)-sponsored effort to enhance the management of the National Airspace System (NAS). Given a set of flights that must be scheduled during some planning horizon, along with alternative surrogate trajectories for each flight, we developed a mixed-integer programming model to select a set of flight plans from among these alternatives, subject to flight safety, air-traffic control workload, and airline equity considerations. The present paper offers insights related to, and a detailed description of, implementing this APCDM model, including the development of a comprehensive cost model, a study for prescribing a set of appropriate parameter values for the overall model, and an investigation on incorporating a suitable set of valid inequalities in the model formulation. Computational results are presented based on several test cases derived from the Enhanced Traffic Management System (ETMS) data provided by the FAA. The results indicate that under plausible probabilistic trajectory error assumptions and with the incorporation of star subgraph convex hull-based valid inequalities, the model offers a viable tool that can be used by the FAA for both tactical and strategic applications.

The National Institute of Standards and Technology has proposed using the common criteria and system-level protection profiles (SLPPs) to specify security requirements in large systems, such as those used in air traffic management. This article summarizes experience with SLPP and security targets for the US Federal Aviation Administration's National Airspace System. The authors review the FAA efforts, highlight the problems encountered, and offer suggestions for future work, calling for more research on linking systems, software, and security requirements engineering with SLPP; clearer ties between security specifications and system certification; and better guidance on the appropriate use of SLPP as a prerequisite to widespread use

Eulerian models are used to represent the air traffic environment as traffic flows between interconnected control volumes representing the airspace system. While these models can be manually derived for simple air traffic patterns, computer-based approaches are essential for modeling realistic airspaces involving multiple traffic streams. A computer- aided methodology for deriving large-dimensional Eulerian models of air traffic flow is described here. Starting from the specification of a few airspace parameters, and traffic data, the modeling technique can automatically construct Eulerian models of the airspace. The synthesis of air traffic flow control algorithms using the model predictive control technique in conjunction with these models is given. It is shown that the flow control logic synthesis can be cast as a linear programming problem. The flow control methodology is illustrated using air traffic data over two regions in U.S. airspace.

The general aviation airport choice model is used to estimate general aviation (GA) person trips and number of aircraft operations through a set of airports given initial trip demand (GA person trips) from a set of counties. A pseudogravity model embedded in the model is used to distribute the intercounty person trips to the set of airports. The interairport person trips are then split into person trips by aircraft type (single, multiple, or jet engine). To split the trips, an attractiveness factor is developed on the basis of average occupancy, level of use, a distance distribution factor, and number of operations of each aircraft type. The person trips by aircraft type are then converted to aircraft operations with the use of occupancy factors for each aircraft type. The final model output is the number of aircraft operations by each aircraft type, in the form of three interairport trip tables. The estimated GA operations provide a means of assessing the impact of GA activities on the National Airspace System. The model output may also be used to assess the viability of GA aircraft as a competitive mode of transportation for intercity travel.

The collaborative routing coordination tools concept demonstration and evaluation prototype is a tool to help the Federal Aviation Administration detect traffic flow problems in advance, generate reroute-based problem resolutions, and evaluate the resolution strategies. The tool does this by modeling four-dimensional aircraft trajectories and using them to predict demand for sector usage. The predictions are affected by various sources of uncertainty in the national airspace system. Therefore, it is useful to understand the contribution of this uncertainty to the tool's predictive error. A methodology was developed and used to assess the impact of predeparture uncertainty on the prototype tool's prediction performance. The tool's trajectory modeling and sector load prediction are described, the methodology used to assess the tool's prediction performance is presented, and the results of the predeparture uncertainty analysis are discussed. The analysis is based on tool predictions made for two air route traffic control centers. Tool runs were made against recordings of actual air traffic data on two good weather and two bad weather days. Analysis of run data showed that predeparture uncertainty is a greater contributor to sector prediction error than en route uncertainty. Because predeparture uncertainty is reflected in departure time estimate, research is recommended to identify methods to improve the accuracy of this estimate.

Effective communication in the National Airspace System (NAS) is an essential safety component of successful air travel. As the NAS migrates from its current ground infrastructure and voice communications system to one that encompasses both ground and airborne systems, digital data transmission may become the principal communication medium. As technological advances lead to innovations in communications system development, these emerging systems will be evaluated against the existing legacy system's performance parameters such as setup delay, voice streaming, pause duration, and message propagation. The data presented here are but a first step in providing objective and quantifiable communications system performance metrics that may prove valuable to communication systems developers and personnel charged with evaluating, certifying, and deploying the next generation of communications systems. The authors analyzed nearly 8,000 transmissions that represented the busiest air-ground communications from the five terminal radar approach control facilities with the highest number of operations in the contiguous United States. Typically, setup delays lasted 81 ms, voice streaming 2568 ms, pause duration 127 ms, and message propagation 73 ms for a total of 2849 ms per transmission. On average, transmissions were separated by 1736 ms of silence. Disruptions to efficient information transfer can result from blocked, stepped-on, and clipped transmissions - but they are rare events and occurred in only 1.16% of the sampled transmissions. A comparison between aircraft with and without disruptions revealed that when a disruption was present, an average of 14.54 messages were transmitted, compared with an average of 9.90 messages when no disruption was present. Even so, there appears to be some type of a detection mechanism in place to alert the controller to the presence of blocked transmissions. The source of this detection system is unclear; however, systems developers may want to exploit and expand this capability to include stepped-on and clipped transmissions.

Data concerning the growth and utilization of regional jets between 1998 and 2003 are presented and analyzed. During this period, daily regional jet operations increased by 356%. These additional flights were primarily used to enter new midrange markets that were previously too far to serve efficiently with a turboprop and too small to warrant a traditional jet. Analysis of aircraft situational display to industry operational data also shows an increase in the stage length of regional jet flights; for example, at Dallas‐Fort Worth, the regional jet catchment basin increased from 299 n mile to 868 n mile. To better understand the reasons for the rapid growth of regional jets, an analysis of the economics of regional flight was performed. This analysis shows that airlines benefit from regional jets primarily because of the fee-per-departure payment structure and their current utilization patterns. HE number of regional jets in the national airspace system (NAS) has grown significantly over the past 10 years. Regional jets are small, 30‐100 seat aircraft capable of flying up to 1000 n mile and have been growing in number at a nearly exponential rate since 1994 (Ref. 1). This increase represents a major change in the composition of the national fleet and may affect the efficiency of the air traffic control system, as well as the dynamics of the airline industry. This paper examines the evolution of regional jet utilization to better understand their growth and operating patterns, as well as possible future trends. The goal just outlined was reached in two steps. The first was to analyze flight track data and develop methods to visualize and quantify any changes in the flight patterns of regional jets. Once this was accomplished, the second step was to analyze aircraft economics, aircraft utilization, airline scope clause agreements, and other factors to develop an understanding and explanation of the observed patterns. II. Methodology A. Data Sources To perform an analysis of emerging regional jet trends and compare them to those of other aircraft, this study made use of actual flight data from the aircraft situational display to industry (ASDI) feed. The ASDI feed provides aircraft position and speed information during flight, in addition to the flight origin, destination, and departure/arrival times. The ASDI feed is compiled from the Federal Aviation Administration’s (FAA’s) Enhanced Traffic Management System (ETMS) and is made available to vendors, who can then pass the data on to other interested parties. This study used ASDI data for one Thursday in January, between 1998 and 2003, resulting in a total of 6 days. Each data sample is from the same month and weekday to eliminate the effects of seasonal and weekly variations in airline operations. The specific dates were chosen to represent typical January days. In particular

Given the current accident rate, the number of fatal accidents is projected to increase in the next several years emphasizing the need for advanced aviation safety research. An initial attempt to d...

We offer a conceptual and empirical framework to predict future aviation timetables. Future timetables are critical for simulating the national airspace system. In the past, timetables have been derived by iteratively scaling up an observed origin and destination trip distribution matrix to match forecasts of airport terminal operations into individual flights. This allocation mechanism has a few shortcomings. Furthermore, it does not use rich data that are presently available. Using an econometrically estimated demand driven passenger flow model, combined with forecasted values of economic and demographic variables for local metro areas, we derive forecasts for origin and destination passenger flows. Passenger itineraries are then assigned using the existing allocations as a guide for predicting the future network. Aircraft type and the number of operations between airports have been derived by using a multinomial aircraft choice model that ties enplanements to aircraft choices. Once flight counts have been forecast, we calibrate the model to align with the baseline OAG. Following this calibration, we use the forecasted values of O&D flows to derive the future aviation timetables

This paper presents a capacity enhancing, gateto-gate air traffic management (ATM) operational concept for the US National Airspace System (NAS) in 2020. The concept defines five core services for ATM: airspace, flow, traffic, separation and information management. Flow, traffic and separation management are the services that directly influence air traffic movement, while airspace management determines the physical resources available to accommodate traffic demand. Information management is a new service that provides the collection, storage, and dissemination of information throughout the system. The planning and control authority of flow, traffic and separation management is determined using a partitioning of planning time horizons to each service. This paper also outlines a method for assessing the benefits of these and other operational concepts.

Introduction: Adverse weather conditions have a major impact on National Airspace System (NAS) operations. They create safety hazards for pilots, constrain the usable airspace for air traffic control (ATC), and reduce the overall capacity of the NAS. A system-wide dissemination of weather information to controllers could theoretically improve safety and efficiency. Problem: However, it is currently unclear what weather information would be beneficial for tactical operations. Furthermore, no previous research has empirically evaluated optimal presentation designs for ATC weather displays. Ill-designed weather displays can cause safety hazards by presenting redundant information (i.e., by increasing the cognitive load) and display clutter (e.g., by interfering with the visual extraction of traffic data). Method: In the present paper, we outline our use of cognitive work analysis (CWA) techniques for the assessment of weather information needs for terminal controllers. Results: Specifically, we describe how the CWA modeling tools helped us reveal instances in the terminal domain where weather information is lacking or insufficiently disseminated. We used our CWA results to drive the development of weather display concepts and to set up a high-fidelity simulation capability. Impact on Industry: By means of high-fidelity simulations, we can empirically evaluate controller weather information needs in order to propose weather displays for increased aircraft safety and efficiency of terminal operations.

Scientific methods can describe the National Airspace System (NAS) in ways that provide intuitive insights into its operation and performance. One such method is classification and analysis of hist...

Federal Aviation Administration air traffic operations utilize several types of Decision Support Tools (DSTs) to provide for separation and management of air traffic in the National Airspace System...

To ensure the safety of the national airspace system, the Federal Aviation Administration (FAA) oversees surveying programs with the goal of geolocating vertical features that penetrate 3D Obstruction Identification Surfaces (OIS) around airfields. These OIS are defined mathematically and are based on the layout of the runways, the types of electronic navigation equipment used for each runway, and other factors. Under a series of interagency agreements, the National Geodetic Survey (NGS) is tasked with supplying obstruction survey data to the FAA. Airport obstruction surveys have traditionally been conducted using a combination of photogrammetry and conventional field survey techniques. In this study, we investigate the use of airborne laser scanning technology for this application. Specifically, we examine the effects of varying the forward look angle, laser footprint, flying height, flying speed, scan angle, scan frequency, transmitted power, and receiver sensitivity, as these parameters relate to the detection and measurement of vertical obstructions. We present results of test flights over the Gainesville Regional Airport (GNV) using fourteen different configurations of an Optech ALTM 2050. The results are compared to field-surveyed obstruction data obtained by NGS. Our analysis shows that certain configurations of the airborne laser scanning system notably improve the detection of obstructions. In this study, the best results were obtained using a 20° forward tilt angle and a 0.2 milliradian beam divergence from a flying height of 750 m. With this configuration, all obstructions were detected and the vertical accuracy (RMSE) was 0.88 m when compared to the field-surveyed obstructions.

An Eulerian approach to modeling air traffic flow is advanced. This modeling technique spatially aggregates air traffic to generate models of air traffic flow in a network of interconnected, one-dimensional control volumes. The approach simplifies the problem of characterizing the air traffic flow because the order of the corresponding airspace model depends only on the number of spatial control volumes used to represent the air traffic environment and not on the number of aircraft operating in it. Under a quasi-steady-state assumption, this process results in linear models of the air traffic environment. It is shown that analysis and design methods from linear control theory can be applied to this model to yield useful approaches for characterizing and controlling the air traffic flow.

The Surface Management System (SMS) aims to increase airport capacity and decrease surface gridlock, which are goals consistent with the Federal Aviation Administration's (FAA) National Airspace System Operational Evolution Plan (FAA, 2002). An operational trial was conducted to evaluate the initial design of the SMS traffic management tools. Although the dataset was small, participant responses were positive on four dimensions (usefulness, frequency of use, perceived accuracy, and ease of use) for nearly all of the six traffic management tools. Participant debriefs highlighted additional issues including the effects of SMS on coordination between Air Traffic Management facilities. This paper outlines the conduct of the operational trials and explores two of the major issues raised by the observations made during the trials.

This paper presents deterministic models for estimating airspace and airport capacity and delays during equipment outages. The National Airspace System (NAS) is very complex and consists of almost 48,000 reportable facilities and services that support air traffic control with very diverse functions and technologies. To better understand NAS performance and develop a methodology for estimating degraded capacity, previous studies about equipment outages and about airspace and airport performance are first reviewed. A deterministic aircraft separation model is used to estimate degraded capacity. It is useful for quick estimates of the number of aircraft operations per facility under some predefined conditions (i.e., mile-in-trail separation and aircraft mix), but does not estimate delays. A deterministic queuing approach is used for estimating delays due to single outages for a hypothetical airport and terminal airspace area. It can also estimate the number of aircraft experiencing queuing and the queue duration, while considering arrival and service rates that vary over time.

Capacity constraints in the United States national airspace system (NAS) have coupled with the growth in air traffic to increase congestion in airways, terminal areas and on the airport surface. In this paper, we discuss the growth in aviation emissions from ground operations in the United States from 1995 to 2000 and investigate the potential for emissions reductions under 3 scenarios: improved operations, single-engine taxiing, and use of tow trucks to move aircraft to and from runways. Emissions estimates, unlike with previous models, are based on actual mission times and aircraft types from the Airline Service Quality Performance (ASQP) data, compiled by the US Department of Transportation (DOT) from information provided by the ten largest US carriers. Results indicate that surface emissions have been growing faster than airborne operations or total mission time in domestic US aviation, and may therefore become a constraint on airport expansion. The potential for emissions reductions through improved ...

U.S. airspace is reaching its capacity with the current air traffic control (ATC) system. The number of flights is constantly rising and it is estimated to be over 58 million per year by 2005. The FAA has undertaken several projects to modernize the National Airspace System (NAS) to ensure the safety of the increasing number of flights. Of special importance is the modernization of the air-ground communications infrastructure, which is the heart of the ATC. The current plan in the modernization of the air-ground communications is to migrate from analog voice only system to integrated digital voice and data system. The next generation satellite systems can be an alternative to the terrestrial air-ground systems by their low propagation and transmission delays, global coverage, high capacity and free flight suitable characteristics. In this paper, we give an overview of the current and the future ATC architectures, describe the systems and the communications issues in these systems and develop a framework in which next generation satellite systems can be integrated to the future ATC systems.

ver the past several years there has been a steady increase in space launch operations and forecasters conservatively predict slight growth in future launch rates. New technologies, national security, and the development of new markets in the commercial space transportation industry could further accelerate this growth. Although the September 11, 2001 attacks have reduced the current level of operations, the FAA expects the longterm growth in air travel to resume in the 2004 to 2013 timeframe. These trends will require a safe and efficient integration of both air and space transportation vehicles operating in shared airspace. The Federal Aviation Administration (FAA) and NASA are developing operational concepts that will seamlessly integrate air and space launch/reentry operations while ensuring that the highest levels of safety, security, and efficiency are maintained. The current procedure for ensuring aircraft are safely distanced from the spacecraft during a launch is to restrict all air traffic from flying in a very large region of Special Use Airspace (SUA) and/or Altitude Reservations (ALTRV) within the range. Figure 1 presents a debris hazard zone within a hypothetical SUA/ALTRV. During a launch, aircraft that would normally fly through this airspace simply take a longer, alternate route to their destination. This procedure accommodates today’s launch rates and the air traffic around the launch site. However, this procedure will probably not be acceptable if launch rates significantly increase, or when

The En Route Controller-Pilot Data Link Communications (CPDLC) program is designed to enable digital data communications between controllers and pilots. CPDLC Build 1A has been proposed as the first step in the nationwide rollout of this program to en route airspace by implementation in eight air route traffic control centers. Because CPDLC will automate several routine air-ground communications tasks, one potential benefit is reduced controller workload, which could lead to increased sector capacity and thus reduced flight times for flights traversing busy sectors. To quantify the workload reduction, a comparison has been made of the time currently required to perform communications tasks, as determined from recordings of actual air-ground communications, and the time required to perform the same tasks with CPDLC, as determined by a controller-in-the-loop simulation. This comparison indicated the potential for a significant reduction in the time spent on controller-pilot communications. A model was constructed to relate the reduced controller communications workload to increased sector capacity. The National Airspace System Performance Analysis Capability (NASPAC) model was used to estimate the reduction in flight times associated with the modeled sector capacity increase. NASPAC was run for both an idealized good weather day and a sample actual bad weather day. By 2017, the last year of the projected economic lifetime of CPDLC, average flight time savings from CPDLC-related capacity increases were estimated to exceed 9, 400 min/day.

Jet:Wise is an agent-based model that explores the evolution of the airline industry and its interactions with the National Airspace System (NAS). It models competitive decisions airlines make, such as setting fleet mix, itineraries, schedules, and fares and responding to delays and missed connections. The model addresses questions of the form, “How would a specific, quantifiable change in one aspect of the NAS affect the entire NAS?” Examples include changes in operational costs, passenger demand, and flight times; removal of certain Federal Aviation Administration restrictions; improvements in technology; new facilities; congestion pricing; mergers; startup airlines; and the expansion of low-cost carriers. Understanding their complex interaction is beyond the ability of traditional modeling tools and has not been attempted until now. Validation evidence is presented: Jet:Wise is shown to produce a close correlation between simulated and observed leisure passenger counts both by origin-destination city pairs and for individual flights.

This paper summarizes both the vision and the early public-private collaborative research for the Small Aircraft Transportation System (SATS). The paper outlines an operational definition of SATS, describes how SATS conceptually differs from current air transportation capabilities, introduces four SATS operating capabilities, and explains the relation between the SATS operating capabilities and the potential for expanded air mobility. The SATS technology roadmap encompasses on-demand, widely distributed, point-to-point air mobility, through hired-pilot modes in the nearer-term, and through self-operated user modes in the farther-term. The nearer-term concept is based on aircraft and airspace technologies being developed to make the use of smaller, more widely distributed community reliever and general aviation airports and their runways more useful in more weather conditions, in commercial hired-pilot service modes. The farther-term vision is based on technical concepts that could be developed to simplify or automate many of the operational functions in the aircraft and the airspace for meeting future public transportation needs, in personally operated modes. NASA technology strategies form a roadmap between the nearer-term concept and the farther-term vision. This paper outlines a roadmap for scalable, on-demand, distributed air mobility technologies for vehicle and airspace systems. The audiences for the paper include General Aviation manufacturers, small aircraft transportation service providers, the flight training industry, airport and transportation authorities at the Federal, state and local levels, and organizations involved in planning for future National Airspace System advancements.

Making greater use of smaller airports is one way that has been proposed to increase the capacity of the National Airspace System. A major difficulty is that many small airports do not have control towers, and thus capacity is severely limited during poor visibility. The authors consider a proposed system in which airplanes self-separate, so they are able to land at higher capacities without a control tower. Before such a system is implemented, it must first be shown to be safe. Safety is a difficult metric to measure and predict because accidents are so rare. Even computer simulation can be slow because of the long time to observe accidents. One methodology that has been successful in assessing aviation safety through simulation is TOPAZ (Traffic Organizer and Perturbation AnalyZer). In this study, the authors apply the methodology to assess the safety of the proposed nontowered system.

Safety and efficiency are two of the most important goals of the national airspace system (NAS). However, these goals are typically viewed as competing or independent, rather than complementary. The complementary aspect of safety and efficiency is illustrated from the point of view of human factors and ergonomics. Statistical methods were used to analyze safety and efficiency performance measurements, operational errors, and daily flight time index (DFTI). Factors related to weather and complexity were found to be more likely on days with poor operational performance as measured by DFTI. The results indicate a positive relationship between NAS safety and efficiency and imply that NAS safety performance may be improved by increasing efficiency, and vice versa.

We present a large-scale, airspace planning and collaborative decision-making model (APCDM) to enhance the management of the U.S. National Airspace System (NAS). Given a set of flights that must be scheduled during some planning horizon, along with alternative surrogate trajectories for each flight as prompted by various airspace restriction scenarios imposed by dynamic severe weather systems or space launch special use airspaces (SUA), we develop a mixed-integer programming model to select a set of flight plans from among these alternatives, subject to flight safety, air traffic control workload, and airline equity constraints. The model includes a three-dimensional probabilistic conflict analysis, the derivation of valid inequalities, the development of air traffic control workload metrics, and the consideration of equity among airline carriers in absorbing costs related to rerouting, delays, and possible cancellations. The resulting APCDM model has potential use for both tactical and strategic applications, such as air traffic control in response to severe weather phenomena or spacecraft launches, FAA policy evaluation (separation standards, workload restrictions, sectorization strategies), Homeland Defense contingency planning, and military air campaign planning. The model can also serve a useful role in augmenting the FAA's National Playbook of standardized flight profiles in different disruption-prone regions of the national airspace. The present paper focuses on the theory and model development; Part II of this paper will address model parameter estimations and implementation test results.

This paper outlines the operational issues involved in using knowledge of wake turbulence behavior to develop candidate terminal approach procedures that would increase arrival capacity at a variety of United States airports. Later procedures build incrementally on the experience that would be gained with these initial procedures. The process by which the Federal Aviation Administration (FAA) and The MITRE Corporation’s Center for Advanced Aviation System Development (MITRE/CAASD) have been analyzing these candidate procedures will be discussed. This process is part of the broader effort to implement an FAA/National Aeronautics and Space Administration (NASA) Wake Turbulence Research Management Plan (RMP). Two candidate procedures, and their operational variations, are described in detail, along with expected capacity benefits at selected airports. The analysis methodology is described. The first procedure is a near-term proposed change to the 2500 foot separation minimum for dependent approaches to two parallel runways. The second procedure is a mid-term proposed change to reduce wake constraints for departures from parallel runways spaced closer than 2500 feet using a shor t-term prognosis of crosswinds at and near the area of aircraft rotation. Activities, such as additional wake data collection at a field site, that are planned during the current year to advance towards the specific design and implementation of the procedures are also briefly outlined.

A primary objective of the FAA’s ATM functions is to provide fair and equitable access to the National Airspace System. Traditionally, the FAA has interpreted fairness as prioritizing flights on a ...

Critical infrastructures, such as the National Airspace System (NAS), offer a challenging set of information security and systems engineering problems. In 1997, the President's Commission on Critical Infrastructure Protection made protecting critical infrastructures in cyberspace a part of the national agendai. Post 9/11, the flying public expects the Federal Aviation Administration (FAA) to apply the right level of focus to ensure safe air travel. Besides understanding the changing threat environment and managing wide-ranging vulnerabilities, progress depends on improving systems engineering approaches that unify cyber security in mammoth infrastructures such as the NAS. An important ingredient to the FAA's success lies not only in the technology, but also in the agility of corporate infrastructures that protect the NAS. Corporate security applies to the people and the processes that work behind the scenes to integrate appropriate technology and processes to obtain adequate and timely levels of security. As well, corporate security seeks sufficient funding to support the overarching goals for FAA “Information System Security (ISS) Protection Levels,” described here. The ISS Levels offer a strategy for achieving agile and survivable cyber protection for complex systems of systems.

Responsibility for the guidance of aircraft in the National Airspace System is currently given largely to the air traffic controller. This study investigated the benefits of having pilots more involved in guidance during two representative air traffic management operations: maintaining in-trail separation and arrival sequencing. This included 12 airline pilots flying arrival routes in a part-task, medium-fidelity simulator, during which they were responsible for attaining and maintaining a commanded relative position within the traffic flow. A variety of cockpit displays of traffic information and procedures were tested, and the pilots' performance was tracked during both nominal and off-nominal traffic situations. Results provide preliminary evidence of the benefit of pilot involvement in the guidance component of these operations. Suggestions are given for modifications to cockpit avionics systems. The need for established air traffic control procedures to provide foreknowledge to the pilots and a structure within which pilots can interact is also highlighted, illustrating that improvements to aircraft guidance within the National Airspace System may benefit from both technical and procedural changes.

In analyzing arrival predictability in the National Airspace System (NAS), it is essential to understand the complex relationships between the various processes involved. Taxi-out times, departure time, and delay propagation each have a compound effect on the actual arrival time of a flight. Arrival predictability is important to Traffic Flow Management (TFM) specialists whose responsibility it is to ensure maximum utilization of airport arrival capacity, which involves the accurate anticipation of future arrival demand. This paper presents a new visualization technique with which TFM specialists and Air Traffic Control Systems Command Center (ATCSCC) analysts will achieve a more detailed depiction of the variables that affect arrival predictability. This visualization technique supports three conclusions of our analysis. Foremost, arrival compliance depends heavily on the chosen definition for compliance. Secondly, when the control time of arrival (CTA) at departure is compared to the actual arrival time...

This research involved the evaluation of a multimodal asynchronous communications tool to support collaborative analysis of post-operations in the National Airspace System (NAS). Collaborating authors have been shown to provide different feedback with asynchronous speech based communications compared to text. Voice synchronized with pointing in asynchronous annotation systems has been found to be more efficient in scheduling tasks, than voice-only, or text only communication. This research investigated how synchronized voice and pointing annotation over asynchronously shared slide shows composed of post operations graphical and tabular data differs in its effect compared to text based annotation, as collections of flights ranked low by standard performance metrics are discussed by FAA (Federal Aviation Administration) and airline representatives. The results showed the combined problem solving and message creation time was shorter when working in the voice and pointing mode than the text based mode, without having an effect on the number and type of ideas generated for improving performance. In both modes the system was also considered useful and usable to both dispatchers and traffic managers.

The acceptance and implementation of advanced digital avionics and flight control systems is dependent on the successful integration of these systems into the current and future National Airspace System (NAS). This paper describes a digital avionics systems research facility known as the Digital Information Facility (DIF) developed to provide researchers with the ground systems and air-to-ground interfaces needed to conduct and document experiments involving a mix of new technologies within the existing NAS infrastructure. The DIF supports four NAS functions: Controller Pilot Data Link Communications (CPDLC), Flight Information Services (FIS), Differential Global Positioning System (DGPS) navigation, and Automatic Dependent Surveillance-Broadcast (ADS-B). The DIF also includes the capability to record pilot and air traffic management interactions and document research participant observations. The DIF capability includes connectivity to flight test and simulated aircraft in a fully immersive Communications, Navigation, and Surveillance (CNS) environment.

Air transportation, involving both passengers and cargo, is well recognized as having a disproportionate impact on the health of the nation’s economy. The anticipated future congestion at airports ...

This paper presents a practical perspective on the subject of airport demand management, primarily in the context of policies that might be viable for the United States. It first summarizes a surve...

With most of the recent delay in air travel caused by disruptions that limit capacity (versus crew scheduling and operational issues), this paper examines the practicality and effectiveness of using congestion pricing in conditions such as weather-related delays to allocate airspace in a way that reflects the value that the different airlines and airports place on the available capacity at any given time. Using a simple queuing model shows that as each user (aircraft) joins the queue, he adds to the time that subsequent users will have to wait (their cost) until they can make use of the airspace. Congestion pricing can impose the subsequent users' cost on the current user, which will discourage some users from entering the queue because the value to them is less than the cost. The paper analyzes institutions in the electric power industry that use similar short-term price fluctuations to ration power and suggests there is room in the aviation industry to adopt pricing schemes that would help rationalize capacity supply and demand during weather-related disruptions. It shows, too, some of the ways the system might evolve in order to accommodate such demand management techniques.

Demand on the air traffic management system continues to grow. The Federal Aviation Administration is faced with the challenge of increasing capacity to meet the rising demand. Several concepts are...

Free Flight Phase 1 (FFP1) is an FAA program for improving the performance of the National Airspace System (NAS) through the deployment of advanced technologies for air traffic management. In addition to the deployment activities, FFP1 includes a significant evaluation component, which faces a significant hurdle. A plethora of factors—weather, demand, enhancements to the NAS infrastructure not related to FFP1, facility outages, and so on—may also cause changes in NAS performance. It is necessary to normalize for these factors in order to determine the effect of FFP1. Normalization procedures to isolate the impact of the implementation of an FFP1 technology—the Terminal Area Traffic Management Advisor (T-TMA)—are documented at the Southern California TRACON, where it is used for controlling traffic into Los Angeles International Airport. Two examples of normalization are presented. One examines the effect of T-TMA on airport arrival capacity, and the other looks at arrival delay. The results, although preliminary given the short time since implementation, are consistent: it appears that capacities have increased and delays decreased as a result of the deployment of the tool. Moreover, the magnitudes of the delay reductions and capacity increases are consistent.

A methodology is presented to quantify and minimize the effect of adverse weather on commercial and general aviation traffic. The method described uses two simple models, the Air Traffic Flow Model and the Adverse Weather Impact Model, to quantify the impact of adverse weather into regional airspace operations in the National Airspace System (NAS). The impact of adverse weather in aviation in system delays is well documented. Weather is a major source of delays in NAS. In the past 5 years, weather has accounted for 71.2% of all delays in NAS according to statistics compiled and published by the FAA. Adverse weather varies in extent from a few square miles to thousands of square miles. Besides causing delays, it affects the safety, comfort, and efficiency of aviation. Better models to manage air traffic under adverse weather conditions are needed. Ultimately, these models could be deployed as decision-support systems to aid air traffic personnel to divert traffic optimally in a real-time scenario.

The rate of occurrence of air traffic control operational errors is recognized as an important measure of the safety performance of the National Airspace System. As the volume of air traffic increases and new automated air traffic control decision support tools are introduced, there is a concern not only to increase the level of safety in the system by reducing the occurrence of operational errors but also to ensure that efforts to increase the capacity of the system do not adversely affect safety. Recent trends in air traffic control operational errors in the United States are analyzed. Factors that have been found to influence the rate of occurrence of these errors are discussed, and the relationship between the severity of operational errors in an en route environment and the traffic characteristics at the time are examined. The limitations of the information currently available to support the analysis of operational errors are described. Finally, the data requirements are addressed for future research to better understand the causal factors affecting the rate of occurrence of operational errors and to develop strategies to enhance the safety of the National Airspace System.

The technical column on verification presents an invited contribution by César A. Muñoz, Aaron Dutle, Anthony Narkawicz, and Jason Upchurch at NASA Langley Research Center titled Unmanned Aircraft Systems in the National Airspace System: A Formal Methods Perspective in the July issue of the SIGLOG newsletter. In the past few years we have seen a dramatic increase in the number of hobbyist unmanned aircraft systems (UAS). In addition we have seen a push by several companies including Amazon to use UAS as a package delivery mechanism. The increasing numbers of UAS in our current airspace have introduced a new safety challenge. There have been some high-profile incidents that were reported widely in the media. One example was a drone being 100 feet within an commercial airliner at the JFK airport in New York in Aug 2015, while another was a near miss at the Los Angeles airport between a Lufthansa passenger jumbo jet and a UAS in March 2016. These are however not isolated incidents. The Federal Aviation Administration (FAA) records shows that there are hundreds of close calls between airplanes and UAS in the US airspace. Similar reports have been documented in the UK and Europe. This safety concern has prompted the development of a detect and avoid capability for the UAS that is designed to avoid aircraft in its vicinity. The article presents the work being done at the NASA Langley Research Center Formal Methods group in Hampton Virigina. I am very excited for this article to appear in the SIGLOG newsletter. This article I believe will be of interest to people not only in the logic, formal methods, and verification community but a broader and more general audience as well.

Commercial space transportation is a rapidly developing industry worldwide. The expansion of the space transportation infrastructure creates additional challenges to the National Airspace System. New launch facilities have and are being developed some of which co-locate with commercial airports. Rocket launch community noise impact requires adequate assessment and mitigation. New space vehicles encompass a wide range of design, aircraft geometry, and flight parameters. A database of operational launch profiles for rockets does not exist at this moment. The acoustical characteristic of these new vehicles may also differ from that of existing rockets or conventional aircraft. Spacecraft ascent sonic boom signatures have higher overpressure, longer duration and a bow shock. There are no standard methodologies for the environmental assessment of launch vehicles and sites. Developing and validating these models is an emerging field. In addition, the metrics used for community noise assessment for commercial ai...

In terminal airspace, inefficient operations occur frequently due to constrained airspace and uncertainty. Choke points can easily form in the terminal area and therefore reduce the efficiency of the entire National Airspace System. Based on previous work on scheduling of aircraft arrivals and departures with shared fixes in terminal airspace and uncertainty in departure and arrival times, this work extends the previous stochastic scheduler with dynamic capability such that the scheduler can be sequentially applied to air traffic in terminal airspace with a much larger time frame through sliding windows instead of a static 30-minute traffic scenario. Results show that great delay savings can be achieved by using the dynamic stochastic scheduler relative to current air traffic control procedures. With a 30-minute time window, if an aggressive solution is chosen, on average 5.2 hours can be saved in a day in Los Angeles out of the 30% arrivals and 10% departures that are covered in the experiment. The expected value of annual fuel saving would be more than 10 million dollars. However, the cost of potential controller intervention, which results from the uncertainty of estimated departure and arrival times, will increase by 50% on average. If a moderate solution is chosen instead, with the same expected controller intervention as using current procedure, more than four hours delay saving can still be expected. When uncertainty of departure time increases with look-ahead time, experiments show that optimizations with large windows still find better solutions than the ones with small windows when delay saving is moderate. However, when delay saving is high, time-varied uncertainty plays a more important role than window size, where a small window is preferred for finding good solutions.