budget. As discussed earlier, a decision to be less conservative and staff for the 50th percentile (median) traffic day rather than for the 90th percentile day would result in an 8 percent reduction in staffing (about 1,200 controllers) but only a 1.6 percent reduction in FAA’s budget. The impacts of such a reduction in controller staffing on safety are unknown, as are the impacts on the performance of the NAS. Economic costs and inconvenience to travelers as a result of delayed and canceled flights appear likely, but the extent of such disruptions is unclear.
Other ways of reducing the cost of FAA’s controller workforce are to contract out more low-activity towers and consolidate ATC facilities. Both these options face challenges, as discussed in Chapter 6. ANSPs in other countries are also exploring ways to reduce costs and put controllers to work more flexibly. Ideas being discussed by Deutsche Flugsicherung, for example, include increasing the number of positions each controller is able to work at centers so that staff can be moved around more easily, providing new controllers with part-time rather than full-time contracts, and working smaller towers remotely out of a “tower-center” (Hoefel 2013).
If receipts to the AATF are less than anticipated, Congress could consider increasing fees charged to the consumers of air traffic services, rather than focusing exclusively on ways of reducing the cost (and size) of the controller workforce. The AATF is effectively losing tax revenue—on the order of $248 million annually—because of airline practices with regard to charging ancillary fees for baggage handling that were formerly included in overall ticket costs and covered by the ticket tax. In addition, general aviation is a large consumer of ATC services requiring considerable ATC staffing at lightly used airports. In 2012, general aviation contributed less than 2 percent of taxes to the AATF but accounted for 38 percent of ATC operations. Commercial aviation contributed more than 98 percent of taxes to the AATF and accounted for 62 percent of ATC operations. Thus, the cost of controllers serving general aviation is currently borne by taxpayers and air carrier passengers rather than by general aviation users.
The committee was unable to determine whether FAA’s current controller staffing model is the most cost-effective, as required by its task statement. Such a determination requires safety and performance metrics that remain to be defined, and there are no conclusive methods for relating safety to controller staffing levels. Commercial aviation in the United States is now the safest it has ever been, a feature that needs to be maintained in the face of pressure to reduce the costs of ATC services. As noted earlier, care is needed before major changes in controller staffing levels or practices are implemented, given the current limited understanding of the relationships between staffing and ATC-related accidents and incidents.
There are also different perspectives on the meaning of cost-effectiveness. From a budgetary perspective, the most cost-effective controller staffing could be defined as the minimum number of controllers needed to meet expected air traffic demand, but commercial air carriers and general aviation pilots are likely to have different views about the types and levels of service that ATC should provide. Commercial carriers need ATC services that allow them to keep to flight schedules with minimal delays, even when these schedules involve short periods of high activity at hub airports interspersed with quiet periods en route. General aviation pilots, on the other hand, often lack the sophisticated equipment routinely available on commercial aircraft and so require controllers to provide weather and other advisories on an as-needed basis. General
aviation is typically the industry segment most concerned about which small towers provide services and at what hours.
The committee’s ability to assess the cost-effectiveness of FAA’s overall staffing process, rather than only the staffing standards (mathematical models), was limited further by a lack of information about and clear documentation of some of the methods and criteria, particularly those used by ATO.
The following major recommendations target areas where the committee identified important opportunities for FAA to improve its staffing processes. In each case, the numbers in braces at the end of the recommendation refer to related recommendations in preceding chapters.
Recommendation 1
FAA should explore the relationships between controller staffing and safety by
• Analyzing the wide range of data that can identify relationships between staffing and safety, including accident and incident reports, voluntary reports by controllers from the Air Traffic Safety Action Program, and other databases that, if properly integrated, can relate safety to staffing concerns (e.g., records of actual shifts worked); and
• Involving the controller workforce in staffing decisions, particularly as knowledge concerning relevant safety issues emerges.
FAA should use insights gained from these activities to inform decisions about controller staffing levels associated with the transition to NextGen and any other policies likely to result in changes in historically safe staffing levels. {2-5, 5-5}
Recommendation 2
FAA should reassess its approach to developing an improved staffing model for en route facilities and make any necessary changes, potentially including the adaptation or formulation of a new model likely to be developed and validated in a timely manner and at reasonable cost. Any new model should be constructed in such a way that it can be updated as NextGen operations are implemented. {3-2}
Recommendation 3
FAA should take steps to ensure that the planning and execution of its air traffic controller staffing process are clear, consistent, and transparent to a range of stakeholders. Stakeholders include but are not limited to the following:
• The controller workforce, which needs to engage with FAA in the collaborative development of improved staffing plans and their execution to ensure overall cost-effectiveness; and
• Congress, which needs to make informed decisions about future budgets for controller staffing. {3-3, 4-2, 4-3}
Recommendation 4
FAA should, as a matter of priority, continue its efforts to develop an improved scheduling tool capable of creating efficient controller work schedules that incorporate fatigue mitigation strategies. The agency should collaborate closely with the National Air Traffic
Controllers Association in implementing this improved scheduling capability, notably in adopting schedules that reflect science-based strategies for managing the risks associated with controller fatigue. {2-3, 3-1, 4-9}
REFERENCES
Abbreviations
| FAA | Federal Aviation Administration |
| OIG | Office of Inspector General, U.S. Department of Transportation |
| TRB | Transportation Research Board |
FAA. 2013. A Plan for the Future: 10-Year Strategy for the Air Traffic Control Workforce, 2013–2022. http://www.faa.gov/air_traffic/publications/controller_staffing/media/CWP_2013.pdf.
Hoefel, N. 2013. Air Traffic Controller Staffing at DFS. Paper prepared for the committee, June 13. Available on request from the Public Access Records Office of the National Academies, e-mail paro@nas.edu.
OIG. 2013. FAA’s Controller Scheduling Practices Can Impact Human Fatigue, Controller Performance, and Agency Costs. Audit Report AV-2013-120, Aug. 27. http://www.oig.dot.gov/library-item/6195.
OIG. 2014. FAA Made Limited Progress in Implementing NextGen Provisions of the FAA Modernization and Reform Act of 2012. Audit Report AV-2014-027, Jan. 28. http://www.oig.dot.gov/node/6298.
TRB. 1997. Special Report 250: Air Traffic Control Facilities: Improving Methods to Determine Staffing Requirements. National Research Council, Washington, D.C.
TRB. 2010. Special Report 301: Air Traffic Controller Staffing in the En Route Domain: A Review of the Federal Aviation Administration’s Task Load Model. National Academies, Washington, D.C.
This appendix summarizes the methodological approach of the Federal Aviation Administration (FAA) in preparing the terminal area forecasts (TAF) of demand for aircraft operations at terminal facilities. The approach is undergoing significant changes. Up to 2013, the TAF were prepared under an approach (referred to as Legacy TAF) that forecasts passengers and operations at individual airports. The approach applied in 2014 and beyond, called Terminal Area Forecast Modernization (TAF-M), focuses on forecasting passengers and operations at a finer level of granularity—at the level of origin–destination pairs, of routes serving specific airport pairs, and of flight segments connecting pairs of airports directly.
For commercial traffic, the Legacy TAF approach uses “passenger enplanements” as the starting point. For the 30 busiest airports (which together accounted for more than 70 percent of national enplanements in 2012), locally originating enplanements are forecast by coupling historical data with local-level forecasts of such input variables as personal income (or, more recently, disposable income), employment, population, and local fares. Enplanements of connecting passengers and of international passengers are forecast separately by considering the status of an airport (hub, nonhub, international gateway) and historical trends.
Forecasts of enplanements at second-tier airports (approximately 80) are obtained through a less detailed procedure relying primarily on econometric models. For the remaining roughly 390 towered airports, forecasts rely primarily on projections of historical trends and reviews of local conditions.
To convert enplanement forecasts to estimates of commercial air traffic activity, the number of aircraft departures is estimated on the basis of projections of aircraft characteristics (e.g., seating capacity, range) and of load factors. Short-term (1- to 1.5-year) forecasts of commercial aircraft operations are prepared for the busiest airports. They are strongly influenced by detailed information concerning recent-month and near-term projected flight schedules, aircraft mix, and so forth at the subject airport.
Forecasts of all-cargo flights rely primarily on projections of historical trends. They have been exhibiting a slow growth rate at an aggregate level during the past decade and account for a small percentage of air traffic activity in the United States.
Because of a relative paucity of data, forecasts of general aviation (GA) air traffic activity are primarily based on time-series models that are less advanced than those used for forecasting commercial traffic. In addition, GA, which is typically associated with smaller aircraft and recreational flying, has exhibited a high degree of volatility and has been hit particularly hard by the various economic downturns of the past dozen years. Business GA activity, especially activity involving jet aircraft, has been more stable, but even this segment was strongly affected by the financial crisis of 2008–2009 and has been recovering at a slow rate.
The TAF also play a critical role in forecasting en route traffic, that is, traffic handled by air route traffic control centers (ARTCCs). The number of commercial aircraft operations handled at each ARTCC is estimated by (a) multiplying by two the number of forecast commercial (air carrier plus commuter and air taxi) instrument flight rules (IFR) departures from airports located within the region covered by the ARTCC and (b) adding to this a forecast of the number of IFR itinerant operations (overflights) for that ARTCC. The forecast of IFR itinerant operations is based on analyses and projections of historical data at each ARTCC. Forecasts of GA aircraft handled are based on historical trend modeling. Military aircraft handled are assumed to remain at their most recent annual level throughout the forecast period.
In the course of preparing each year’s TAF, the team from the Office of Aviation Policy and Plans consults with the regional and local facilities of FAA to obtain additional data, insights, and feedback based on local developments. For example, the establishment of a new flight school near an airport is likely to increase the number of local operations there. Consultation with airlines and GA organizations may also take place.
TERMINAL AREA FORECAST MODERNIZATION
TAF-M adopts an approach different from that of Legacy TAF by focusing on origin–destination pairs and segment-level forecasts. As in the case of the Legacy TAF, the TAF-M process begins by projecting numbers of passengers. Econometric models are used to forecast the number of passengers flying between origin–destination airport pairs in major markets. Inputs to the models include fares, demographics (e.g., populations of end cities), forecast income levels, distance between origin and destination, competition on the segment, season, and so forth. Assignment algorithms are used to allocate passengers among the alternative routes available between origin–destination pairs. In this way, estimates of passenger flows are obtained for individual flight segments. As a result, TAF-M provides forecasts of passenger flows in individual major markets (e.g., Miami–Los Angeles), specific routes (e.g., Miami International Airport–Atlanta International Airport–Los Angeles International Airport), and flight segments (e.g., Atlanta International Airport–Los Angeles International Airport). Such route- and segment-specific outputs are better suited for use as inputs to typical studies of the National Airspace System (e.g., traffic simulations) because of their finer granularity.
Commercial aircraft operations at the segment level are estimated next by combining (a) the route- and segment-level passenger demand forecasts, (b) historical information about the aircraft fleet and airline schedules on the segment, and (c) econometric models that project aircraft fleet choices by the airlines. Inputs to the econometric models include number of passengers, distance between the end airports of the segment, performance characteristics of candidate aircraft types (e.g., seating capacity, range), aircraft operating costs, end airport characteristics (e.g., size, hub or spoke), and season when the flight takes place.
TAF-M is limited at this time to forecasting commercial passengers and commercial aircraft operations. In the TAF published in January 2014, the forecasts of passenger and commercial aircraft operations at the 141 busiest airports will use the TAF-M approach; Legacy TAF will be used for the remaining FAA-towered airports and for forecasts of GA and military traffic everywhere.
Tests indicate that the use of different growth rates in each year at each airport by TAF-M generates slightly lower passenger forecasts (by 2 to 3 percent) for 2030 for the 141 hub airports
in the aggregate than the forecasts prepared with the Legacy TAF approach. The difference may vary from airport to airport.
The forecast of IFR aircraft handled for en route traffic (ARTCC) takes advantage of the fact that TAF-M generates segment-level forecasts of the number of commercial aircraft operations for each of the principal individual markets (city pairs). Thus, the number of aircraft handled is estimated as the sum of (a) twice the number of forecast commercial IFR departures from airports located within the region covered by the ARTCC, (b) the number of commercial aircraft operations on all the flight segments that traverse the ARTCC (overflights), and (c) a historically based forecast of GA aircraft handled. As with the Legacy TAF, the number of military aircraft handled is assumed to remain at its most recent annual level throughout the forecast period.
Study Committee Biographical Information
Amy R. Pritchett, Chair, is the David S. Lewis Associate Professor of Cognitive Engineering in the School of Aerospace Engineering, Georgia Institute of Technology. She holds a joint appointment in the School of Industrial and Systems Engineering. Dr. Pritchett received bachelor’s, master’s, and ScD degrees in aeronautics and astronautics from Massachusetts Institute of Technology (MIT). She has led numerous research projects sponsored by industry, the National Aeronautics and Space Administration (NASA), and the Federal Aviation Administration (FAA). She has served as Director of NASA’s Aviation Safety Program. Dr. Pritchett was responsible for planning and execution of the program ($75 million to $82 million per year), which was conducted at four NASA research centers and sponsored about 200 research agreements. In that role, she served on the Aeronautics Science and Technology Subcommittee of the Office of Science and Technology Policy and on the executive committees of the Commercial Aviation Safety Team and the Aviation Safety Information Analysis and Sharing program. She has published more than 170 papers in conference proceedings and in scholarly journals such as Human Factors, Journal of Aircraft, and Air Traffic Control Quarterly. She has won the William H. Jackson Award of the Radio Technical Commission for Aeronautics (RTCA) and, as part of Commercial Aviation Safety Team, the Collier Trophy, and the American Institute of Aeronautics and Aviation has named a scholarship for her. Dr. Pritchett is the Editor-in-Chief of the Journal of Cognitive Engineering and Decision Making. She is a member of FAA’s Research, Engineering, and Development Advisory Committee (REDAC) and chairs REDAC’s Human Factors Subcommittee. She is a licensed pilot.
Mathias Basner is an Assistant Professor of Sleep and Chronobiology in Psychiatry at the University of Pennsylvania Perelman School of Medicine. Dr. Basner received a degree in medicine and a PhD in research from the University of Bochum, Germany, and a master of science degree in epidemiology from the University of Bielefeld, Germany. He trained at the Institute for Applied Physiology at the University of Bochum and worked as a Research Associate at the German Aerospace Center (DLR), Institute of Aerospace Medicine, Flight Physiology Division from 1999 until 2006 before moving to the United States to pursue his research interests in the neurobehavioral consequences of sleep loss as a research associate. He returned to DLR in 2008 to head the Flight Physiology Division for 2 years. At that time, he was coinvestigator on a Deutsche Flugsicherung (German Air Traffic Control) study investigating workload effects in Croatian air traffic controllers. In January 2010, Dr. Basner assumed the position of Assistant Professor of Sleep and Chronobiology in Psychiatry at the University of Pennsylvania. He was awarded the German Aerospace Center Science Award in 2007 and the Science Award of the German Academy for Aviation and Travel Medicine in 2010. He is a member of the American Academy of Sleep Medicine and its sleep deprivation steering committee. He is also a member of the Sleep Research Society and the German Sleep Research Society. Dr. Basner is Deputy Editor of the journal Sleep, on the editorial boards of Noise and Health and PLOS ONE, and ad hoc reviewer for 40 scientific journals. He has reviewed proposals for the National Institutes of Health, the U.S. Department of Veterans Affairs, the European Space Agency, the Australian Antarctic Science Program, and the German Research Foundation.
Peter J. Basso retired as Chief Operating Officer and Business Development Director of the American Association of State Highway and Transportation Officials (AASHTO) in February 2013. Before joining AASHTO in 2001, he served as Assistant Secretary for Budget and Programs and as Chief Financial Officer of the U.S. Department of Transportation. Mr. Basso’s 34 years of service as a career official included assignments as Deputy Assistant Secretary for Budget and Programs of the Department of Transportation, Assistant Director for General Management of the Office of Management and Budget, Deputy Chair for Management of the National Endowment for the Arts, and Director of Fiscal Services for the Federal Highway Administration. He received a BS in business administration from the University of Maryland.
Lawrence M. Cole is an aviation professional with 38 years of experience in the field of air traffic control (ATC). He began his career in 1968 as a U.S. Air Force radar air traffic approach controller. This was followed by 18 years in positions of increasing responsibility at operational FAA terminal radar approach control facilities and towers and as an instructor at the FAA Air Traffic Control Academy. During his last 17 years with FAA he served at the agency’s national headquarters, where his responsibilities included managing the ATC Human Factors (HF) Research Program, the Technical Operations HF Research Program, and the Runway Safety HF Program in support of long-term agency plans and objectives. For the past 6 years, Mr. Cole has been self-employed as an aviation and HF consultant affiliated with Aloft Aviation Consulting, LLC. He has a master of business administration degree from Western New England College and a bachelor of arts degree in psychology from West Virginia Wesleyan College.
Mary (Missy) L. Cummings received her BS in mathematics from the U.S. Naval Academy in 1988, her MS in space systems engineering from the Naval Postgraduate School in 1994, and her PhD in systems engineering from the University of Virginia in 2004. A naval officer and military pilot from 1988 to 1999, she was one of the Navy’s first female fighter pilots. She is an associate professor in the Duke University Department of Mechanical Engineering and Materials Science and the Duke Institute of Brain Sciences, and she is the director of the Humans and Autonomy Laboratory. Her research interests include human–unmanned vehicle interaction, human–autonomous system collaboration, human–systems engineering, public policy implications of unmanned vehicles, and the ethical and social impact of technology.
Francis T. Durso is Professor of Psychology, Georgia Institute of Technology. His areas of recent and current research include (a) an exploration of how the HF consequences of the Next Generation Air Transportation System and related automation of some tasks could affect air traffic controller strategies for managing workload, situation understanding, and performance and (b) development of a taxonomy of human–automation coordination strategies and the consequences of those strategies for the development of new technologies. Dr. Durso is the current President of the Human Factors and Ergonomics Society and a member of the National Research Council (NRC) Board on Human–Systems Integration. He has coauthored several articles dealing with aviation safety; air traffic controller selection criteria; air traffic control; task analysis; and management of workload, performance, and situational awareness in aviation. He received a PhD in psychology from the State University of New York at Stony Brook.
John J. Fearnsides is CEO and Chief Strategist, MJF Strategies, LLC. Until 1999, he was Senior Vice President and General Manager of the MITRE Corporation and Director of its Center for Advanced Aviation System Development. He worked at the U.S. Department of Transportation from 1972 to 1980, serving as Deputy Under Secretary and Chief Scientist, Executive Assistant to the Secretary, and Acting Assistant Secretary for Policy and International Affairs. He was a National Science Foundation Fellow and is a Fellow of the Institute of Electrical and Electronics Engineers and the National Academy of Public Administration. He has served on numerous NRC and Transportation Research Board committees, including the Committee for a Review of the En Route Air Traffic Control Complexity and Workload Model and the Committee for a Study on Air Passenger Service and Safety Since Deregulation. Dr. Fearnsides received his BSEE and MSEE from Drexel University and holds a PhD in electrical engineering from the University of Maryland.
Andrew LeBovidge has been an ATC Specialist with FAA at the Houston Air Route Traffic Control Center (ARTCC) from 1992 to the present. He has also served as a representative for the National Air Traffic Controllers Association (NATCA) since 1998, area representative from 1998 to 2000, Principal Facility Representative at the Houston ARTCC (Local President) from 2000 until the present, and Alternate Regional Vice President for NATCA’s Southwest Region from 2003 until the present. He has worked on several national and regional committees focusing on staffing and placement within the ATC system. He is recognized by both management and labor for his expertise. Mr. LeBovidge received a bachelor of arts degree in history from the University of Pennsylvania.
Amedeo R. Odoni is a Professor in the Department of Aeronautics and Astronautics and in the Department of Civil and Environmental Engineering at MIT. He has served as codirector of the Global Airline Industry Center at MIT (1999–2009) and of FAA’s National Center of Excellence in Aviation Operations Research (1996–2002). Previously, he was head of the Systems Division of the Aeronautics and Astronautics Department (1991–1996) and codirector of MIT’s Operations Research Center (1985–1991). Dr. Odoni is the author or coauthor of three textbooks and about 100 professional publications, as well as coeditor of six books. He served as Editor-in-Chief of Transportation Science from 1985 to 1991 and is a current or past member of the editorial boards of many professional journals. Dr. Odoni is a member of the National Academy of Engineering, a Fellow of the Institute for Operations Research and Management Science, and the recipient of many awards for his teaching and research. He has served as consultant to national and international organizations and to many of the busiest airports in the world on projects related to practically every aspect of airport planning and design and of air traffic management.
Norman T. O’Meara is a Senior Fellow at the Logistics Management Institute, where over the past 20 years he has analyzed manpower, workforce planning, and resource allocation issues for a number of top-level governmental entities with emphases on the cabinet-level Departments of State, Defense, and Transportation. Dr. O’Meara served on a congressionally directed NRC committee to study FAA’s methods for estimating air traffic controller staffing requirements. He led the analytical team for the Department of Defense’s Joint Cross Service Group for Depot Maintenance in support of the department’s base realignment and closure recommendations and testimony before the commission. Dr. O’Meara served with the Army Science Board to identify
the resource alternatives necessary for Army transformation. He received a bachelor of science degree from the United States Military Academy, master of science degrees in mathematics and operations research and statistics from Rensselaer Polytechnic Institute, and a doctor of science degree from George Washington University.
Clinton V. Oster, Jr., is Professor Emeritus and former Associate Dean for Bloomington Programs at the School of Public and Environmental Affairs, Indiana University. His research has centered on aviation safety, airline economics and competition policy, energy policy, and environmental and natural resource policy. He has coauthored five books on various aspects of air transportation including Deregulation and the Future of Intercity Passenger Travel with John Meyer and Managing the Skies: Public Policy, Organization, and Financing of Air Navigation with John Strong. He is a coauthor of the Transportation chapter in Climate Change Impacts in the United States: The Third National Climate Assessment. He has chaired and served on numerous NRC committees. He was chair of the Committee for the Study of Traffic Safety Lessons from Benchmark Nations, chair of the Committee on the Federal Employers’ Liability Act, chair of the Committee on the Effects of Commuting on Pilot Fatigue, and cochair of the Committee on NASA’s National Aviation Operational Monitoring Service Project. He was a member of the Committee for Guidance on Setting and Enforcing Speed Limits and the Committee for a Study on Air Passenger Service and Safety Since Deregulation. He holds a bachelor’s degree in engineering from Princeton University, a master’s degree in public affairs from Carnegie–Mellon University, and a PhD in economics from Harvard University.
Roger Wall has more than 50 years of air traffic management (ATM) and control experience and has been self-employed as an independent consultant with the Washington Consulting Group since 2011. He has focused primarily on international efforts in China with the U.S.–China Aviation Cooperation Program, including teaching classes to Chinese transportation and civil aviation personnel on U.S. ATC policies and procedures. Mr. Wall retired from his position as FAA Coordinator and ATM Projects Manager for FedEx Corporation in 2008, having served 10 years with FedEx. Before joining FedEx, he was Director of Air Traffic Operations for FAA, having risen from air traffic controller. At FAA, Mr. Wall held management positions at ATC facilities, FAA regional offices, and FAA headquarters. He began his career as an air traffic controller for the U.S. Navy in 1959. From 1996 to 2008, he served as chairman of the Free Flight Select Committee of RTCA and the Air Traffic Management and Airport Systems Requirements and Planning Working Group. He was honored with RTCA’s Lifetime Achievement Award in 2008. He holds a private pilot, single-engine land rating. He served on the Committee for a Review of the En Route Air Traffic Control Complexity and Workload Model. He is a graduate of the Government Senior Executive Service Program.
