Time dependent estimates of delays and delay costs at major airports

January 1975Includes bibliographical references (p. 35)Two queuing models appropriate for estimating time dependent delays and delay costs at major airports are reviewed. The models use the demand and capacity profiles at any given airport as well as the number of runways there to compute bounds on queuing statistics. The bounds are obtained through the iterative solution of systems of equations describing the two models. This computational procedure is highly efficient and inexpensive. The assumptions and limitations of the models are discussed. Common characteristics and properties of delay profiles at major airport are illustrated through a detailed example. Potential applications to the exploration of the effect of air traffic control innovations on congestion and to the estimation of marginal delay costs are also described

Locating Mobile Servers on a Network with Markovian Processes

The median problem has been generalized to the case in which facilities can be moved, at a cost, on the network in response to changes in the state of the network. Such changes are brought about by changes in travel times on the links of the network due to the occurrence of probabilistic events. For the case examined here, transitions among states of the network are assumed to be Markovian. The problem is examined for an objective which is a weighted function of demand travel times and of facility relocation costs. It is shown that when these latter costs are a concave function of travel time, an optimal set of facility locations exists solely on the nodes of the network. The location-relocation problem is formulated as an integer programming problem and its computational complexity is discussed. An example illustrates the basic concepts of this paper

Congestion Mitigation through Schedule Coordination at JFK: An Integrated Approach

Most flight delays are created by large temporary or long-term imbalances between demand and capacity at the busiest airports. Absent large increases in capacity, airport congestion can only be mitigated through improvements in the utilization of available capacity and the implementation of demand management measures. This paper presents an integrated approach that jointly optimizes the airport’s flight schedule at the strategic level and the utilization of airport capacity at the tactical level, subject to scheduling and capacity constraints. The capacity utilization part involves controlling the runway configuration and the balance of arrival and departure service rates to minimize congestion costs. The schedule optimization reschedules a selected set of flights to reduce the demand-capacity mismatches while minimizing interference with airline competitive scheduling. We develop an original iterative solution algorithm that integrates airport stochastic queue dynamics and a Dynamic Programming model of airport operating procedures into an Integer Programming model of flight rescheduling. The algorithm is shown to converge in reasonable computational times and is thus implementable in practice. Extensive computational results for JFK Airport suggest that very substantial delay reductions can be achieved through limited changes in airline schedules. It is also shown that the proposed integrated approach to airport congestion mitigation performs significantly better than the typical sequential approach where scheduling and operational decisions are made separately

Endogenous Control of Service Rates in Stochastic and Dynamic Queuing Models of Airport Congestion

Airport congestion mitigation requires reliable delay estimates. This paper presents an integrated model of airport congestion that combines a tactical model of capacity utilization into a strategic queuing model. The model quantifies the relationships between flight schedules, airport capacity and flight delays, while accounting for the way arrival and departure service rates can be controlled over the day to maximize operating efficiency. We show that the model estimates well the average and variability of the delays observed at New York’s airports. Results suggest that delays can be extremely sensitive to even small changes in flight schedules or airport capacity

Decentralized and Tactical Air Traffic Flow Management

This project dealt with the following topics: 1. Review and description of the existing air traffic flow management system (ATFM) and identification of aspects with potential for improvement. 2. Identification and review of existing models and simulations dealing with all system segments (enroute, terminal area, ground) 3. Formulation of concepts for overall decentralization of the ATFM system, ranging from moderate decentralization to full decentralization 4. Specification of the modifications to the ATFM system required to accommodate each of the alternative concepts. 5. Identification of issues that need to be addressed with regard to: determination of the way the ATFM system would be operating; types of flow management strategies that would be used; and estimation of the effectiveness of ATFM with regard to reducing delay and re-routing costs. 6. Concept evaluation through identification of criteria and methodologies for accommodating the interests of stakeholders and of approaches to optimization of operational procedures for all segments of the ATFM system

Airport quotas and peak hour pricing : theory and practice

Work performed by the Flight Transportation Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts; and sponsored the Office of Aviation Policy, Federal Aviation Administration, Department of Transportation, Washington, D.CMay 1976Includes bibliographical referencesThis report examines the leading theoretical studies not only of airport peak-hour pricing but also of the congestion costs associated with airport delays and presents a consistent formulation of both. The report also considers purely administrative measures, such as quotas, and hybrid systems which combine administrative and economic control techniques. These are all compared to the real-world situation and problems of implementation discussed. The actual experiences of the Port Authority of New York and New Jersey at the three major New York area airports and the British Airports Authority at Heathrow are then presented. Both organizations administer hybrid quota/ peak-hour pricing systems in conjunction with their respective air traffic control authorities. Their experience is compared with the theoretical analyses.Prepared under NASA Ames Research Cente

Locations of Medians on Stochastic Networks

The definition of network medians is extended to the case where travel times on network links are random variables with known discrete probability distributions. Under a particular set of assumptions, it is shown that the well-known theorems of HAKIMI and of LEVY can be extended to such stochastic networks. The concepts are further extended to the case of stochastic oriented networks. A particular set of applications as well as formulations of the problem for solution using mathematical programming techniques are also discussed briefly

International aeronautical user charges

February 1985Includes bibliographical referencesIntroduction: 1.1 BACKGROUND AND MOTIVATION Very few issues relating to the international air transportation industry are today as divisive as those pertaining to user charges imposed at international airports and enroute air navigation facilities. In recent years, this general subject has led to acrimonious arguments, heated confrontations and even legal proceedings involving airlines (and the entire airport user community), airport authorities and national and local governments. Moreover, the end is nowhere in sight: should the current economic difficulties of many of the world's international airlines persist -- as well they might -- it is possible that disputes related to user charges will intensify further and reach critical proportions at some future time. The general label 'user charges" comprises a variety of fees which are employed by providers of aeronautical facilities and services as a means of recovering (partially, fully, or more-than-fully) the costs that they incur. A listing of the various kinds of user charges in existence is given in Table 1.1. Any given Airport Authority or organization that offers air navigation and aeronautical services may impose some or all of these charges. It is possible to state several facts that help explain why the subject of user charges is such a controversial one. At the same time, these facts provide the motivation for studies such as the one reported here: Fact 1: User charges have gone through a period of rapid increases in absolute and, in many cases, relative terms as well, over the last decade. A confluence of factors have contributed to these increases. Perhaps the foremost among them is that, during the 1970's, the aviation industry Table 1.1 TYPES OF USER CHARGES AIRPORT CHARGES:- Aeronautical Charges: Landing and/or take-off charges, Parking and hangar charges, Passenger service charges, Security charges, Airport noise charges, Ground (ramp and traffic) handling charges, Concession fees for aviation fuel and oil, Rentals of air terminal space, premises and equipment, Non-Aeronautical Charges: Rentals of airport land, premises and equipment (for purposes other than servicing traffic), Concession fees for commercial concerns catering to the public, Fees derived from airport's own operation of shops and services, Fees charged for tours, admission to reserved areas, etc. ENROUTE CHARGES Air navigation charges * The International Civil Aviation Organization (ICAO) recommends that where fuel charges are imposed, they should be recognized by airport authorities as being concession charges of an aeronautical nature and that fuel concessionaires should not add them automatically to the price of fuel to aircraft operator [ICAO, 1981d]. began to be treated as a "mature" one, in most of the world. Until then, many countries were content to subsidize the industry through provision of aeronautical facilities and services at no cost or at much-below cost. (It is a remarkable fact, for instance, that no enroute air navigation charges were collected by someWest European nations until 1971, the year when Eurocontrol began collecting charges designed to recover only 15% of costs.) However, as the industry grew "above critical size" and stabilized during the 1960's and 1970's, government attitudes toward it generally changed and a "users-pay" principle was increasingly being applied to the setting of user charges by the 1970's. (By 1981, Eurocontrol was recovering 100% of enroute air navigation costs on behalf of its 11 member states.) A second factor is that, during this period, some new types of charges, notably security charges and noise charges, have been added for the first time to the array of other charges that airlines traditionally faced. The fact that many aeronautical services are labor-intensive ones -- notably ground handling, enroute and terminal-area air navigation and security -- was a third contributing factor, as labor costs are particularly sensitive to inflationary pressures such as those experienced worldwide during the period in question. Yet another factor is that since the mid-1960's many countries have been investing large amounts of capital toward improving their aeronautical infrastructures (new or improved airports, modernization of ATC systems). As these new or improved facilities came into service, the cost-base on which user charges are computed grew rapidly. While one can expand this list of factors considerably, the point is that airlines and users of aviation facilities have felt the impact of such rapid increases. This, moreover, happened at a time when many of them were experiencing significant economic pressures. For example, IATA contends that, during the period of the dramatic fuel-price increases (1973-1981), the only other component of their costs that grew nearly as rapidly as fuel costs were aeronautical user charges (see Table 1.2). Fact 2: There are large differences from country to country and from location to location in the ways user charges are computed and in the magnitude of user charges. This is amply demonstrated by Table 1.3, which shows the size of typical landing fees and passenger service charges in a number of selected countries for three important aircraft types. Similar or even larger differences exist in the magnitudes of other charges imposed (especially for ground handling and enroute air navigation services), as will be shown in many parts of this report. Such differences - coupled with the unfortunate tendency of many aeronautical authorities to provide inadequate or minimal documentation in explaining their user charges -- have led to accusations of "unfairness", "predatory behavior", or "discrimination" against several specific countries or airports' (e.g., London/Heathrow, Tokyo/Narita, Australia). It is not surprising that such accusations are usually directed toward those that impose the highest charges. However, locations that impose much-lower charges, but have the benefit of a lower cost-base as well, are just as susceptible to adopting such practices. Fact 3: In many cases, user charges may absorb a sizable fraction of an international commercial flight's gross revenues. This is illustrated in Tables 1.4 and 1.5 for the case of flights by a real, but anonymous, Airline X between its home base (XXX) and New York (JFK International), London/Heathrow and Amsterdam. Table 1.4 shows all the charges imposed for each route/equipment combination for load factors of 100%, 1We do not imply here that such accusations are necessarily justified. Landing Fee at destination includes parking charge 4-hour stay-over in NYC; 2-hour in LON, AMS Peak-hour use in summer ... The specific assumptions made are listed at the bottom of Table 1.4. Table 1.5 estimates what percentage of total revenues (true one-way yields on the routes were provided by Airline X) is absorbed by user charges. (For example, for a B747 flight to NYC at 100% load factor, the total user charges of $18,378 -- see Table 1.4 - amount to 5.74$320,000). It can be seen that user charges in these examples vary from 6% to 22% of gross revenues, depending on destination, aircraft involved and load factor. It is also important to note that the total user charges (last line of Table 1.4) are largely determined by the type of aircraft flown on any given route and are quite insensitive to the load factor -- a characteristic that is quite vexing to the airlines. While this example is given for illustrative purposes only, the range of percentages it indicates in Table 1.5 is not atypical. IATA estimates that the sum of enroute charges and landing and other airport fees (not including ground handling charges and passenger service costs at airports) amount to approximately 6% of the total (direct and indirect) costs of the international scheduled services of its members. West European airlines contend that these same charges amount to 11.2% of their total costs for intra-European services and an even-higher percentage for airlines specializing in short-haul routes.(cont.) The Association of European Airlines (AEA), in fact, often blames high user charges in Europe as one of the main reasons for the higher European operating costs and therefore higher fares per mile.2 Most of the recent complaints of AEA carriers have centered in particular on enroute air navigation charges collected through the Eurocontrol agency. Pan Am has reported that whereas user charges of various kinds accounted for 4% of its costs on international routes in 1970, they now account for 9%. For domestic trunk carriers in the 2This view is not necessarily endorsed here. United States, user fees account for 4.2% of their costs. However, this percentage does not include the 8% tax on domestic fares, which is collected on behalf of the Aviation Trust Fund and which can be viewed as an aeronautical user charge. Up to a few years ago, U.S. airlines were among those most vocal in protesting the magnitude of and lack of uniformity in international user charges. Partially as a result, the International Air Transportation Fair Competitve Practices Act that became law in the United States on January 3, 1975 directs the Secretary of Transportation to survey foreign user charges and to report to the Secretary of State and the Civil Aeronautics Board any charges that unreasonably exceed comparable U.S. charges or are otherwise discriminatory. The latter are then to negotiate with the foreign country involved to reduce such charges or eliminate such discrimination [Pogue and Davison, 1979]. The Act also gives to the Secretary of Transportation, in consultation with the Secretary of State, the right to impose compensatory charges on foreign carriers, should such negotiations fail. It should be noted that, as a result of the rapid increase of the exchange value of the U.S. dollar during the 1981-1984 period, U.S. international carriers have been protected, to a large extent, from "internalizing" the further increases in international user charges that have taken place during these years. (For example, although the costs, as computed in local currencies, of enroute air navigation in Western Europe (Eurocontrol) nearly doubled between 1980 and 1983, the cost to U.S. carriers when computed in U.S. dollars has not changed appreciably.) Should however, the current trend concerning exchange rates be reversed, it is likely that the international-user-charges issue will receive renewed prominence in the United States. Fact 4: Limited guidance on setting user charges is provided by multilateral or bilateral international agreements and by the International Civil Aviation Organization. The multilateral Convention on International Civil Aviation (Chicago, Decemer 7, 1944) which provides the legal framework for many aspects of international air transportation is vague on the subject of user charges. The relevant provision of the Convention is contained in Article 15 of Chapter II, which calls for non-discriminatory charges for international aviation, without being more specific on what this means. Bilateral agreements, e.g. Bermuda II, are equally non-specific, usually calling for: "just and reasonable" charges; equal treatment for the contracting states' carriers with regard to user charges; user charges that "may reflect, but should not exceed, the full cost" of providing facilities and services "including a reasonable rate of return on assets, after depreciation"; and continuing consultations and exchange of information between "the competent charging authorities" and airline representatives. The ICAO has also struggled repeatedly with the issue of user charges, notably in special conferences on the subject held in 1967, 1973 and 1981, all of which met with limited success. The principles and recommendations endorsed by the ICAO on the assessment and allocation of user charges are contained in ICAO Doc. 9082-C/1015 (Statements by the Council to Contracting States on Charges for Airports and Route Air Navigation Facilities). The ICAO Statements are not binding on member countries, but offer guidelines that charging authorities are encouraged to(cont.) follow. The Statements are reproduced here as Appendix 1A, because they will be repeatedly referred to and discussed in Chapters 2-6. (The reader who is unfamiliar with them is encouraged to review them.) For now, two points need to be made: First, that the ICAO Statements do endorse the concept that, in principle, international users should bear the full and fair share of costs of the aeronautical facilities and services they use. And, second, that, as is natural for a document that attempts to establish a common ground among many conflicting views and interests, the Statements are often ambiguous, subject to conflicting interpretations and, in a number of instances, even self-contradictory, as will be pointed out later in this report. As noted earlier, Facts 1-4 in addition to providing a background on the problem of international user charges, also constitute motivations for this report. Indeed the aim here is to attempt to present a systematic and integrated discussion of relevant issues and to contribute to an improved understanding of the range of options and approaches that exist worldwide with regard to setting user charges. 1.2. OUTLINE OF THIS REPORT We now present an outline of the contents of Chapters 2-6. Chapter 2 contains a brief survey of most types of aeronautical charges: landing fees; parking and hangar charges; passenger service charges; fuel throughput charges; noise and nuisance charges; security charges; and enroute air navigation charges. Discussion of ground handling charges is left to Chapter 6. For each one of the types of charges covered, the following are addressed: (i) Ways in which the charges are specified, as well as typical magnitudes and ranges of the charges (ii) Principal issues concerning the charges, including the positions of users (mostly the airlines) (iii) Summaries of the findings of recent ICAO surveys on the charges, as well as tabulations of charges in individual countries based on information collected by these surveys. Chapter 3 deals with the approach needed to determine whether, in the context of the conditions under which an aeronautical service or facility is provided, the resulting user charges are reasonable and fair. The emphasis in the preceding sentence is intended to underscore the point that comparisons among user charges in different countries or locations should not be undertaken without a full understanding of the particular circumstances and assumptions that underlie each of the systems of charges being compared. In fact, it is believed here that such comparisons should normally be avoided and that user charges at international airports and enroute air navigation facilities should be reviewed individually on a case-by-case basis. Chapter 3 presents what could be described as a normative model* for conducting such a review. Specifically, on the basis of the insights gained during this research, we shall review the steps that must be carried out by a provider of aeronautical services in order to determine and specify a system of user charges. These steps include: (a) Postulating the policy guidelines that should be followed (b) Developing a cost base (c) Allocating costs in the cost base among the various cost and revenue centers of the aeronautical facility (d) Allocating costs associated with each center among the users of that center (e) Arriving at a methodology for computing charges to be paid by each specific user (f) Setting up a framework for interacting with users and soliciting user comments and general inputs. Each of the above steps is discussed in Chapter 3 in some detail, with emphasis on: (i) Identifying the range of(cont.) practices that exist around the world with respect to each of these steps (ii) Discussing some of the principal options available at each step (iii) Highlighting a few important points that the prospective reviewer of user charges should be aware of, including common pitfalls (iv) Identifying certain areas where there may exist some room for improvement in prevailing international practices (v) Illustrating the discussion through a number of brief examples. In Chapter 4, four selected case studies are reviewed. Each of the cases has been selected for two reasons: (1) It helps illustrate one or more of the principal concepts that were discussed in Chapter 3 (2) In itself, the case offers one or more interesting aspects (important airport, innovative approach, controversy, etc.). The first example discussed is Boston's Logan International Airport. We examine in detail the procedure used to determine the unit-rate (charge per thousand pounds) for computing landing fees at this major United States airport. This, in turn, offers an opportunity to explain why airside user charges at U.S. international airports are usually considerably lower than those elsewhere in the world. The controversial case of Tokyo/Narita International Airport is brought up next. It illustrates how a combination of poor site and planning choices and of often-unreasonable cost-allocation practices has led to what seems to be a system of unfair and excessive user charges. A study aimed at helping the Board of Civil Aviation of Sweden ("Swedish CAA") determine an appropriate system of user charges is summarized next. This study is especially important, because of the several innovative concepts that it contains, principally regarding the practical application of shortand long-term marginal-cost approaches to the setting of user charges. Finally, cost allocation in the Commonwealth of Australia is reviewed. User charges in Australia have become a matter of considerable controversy in recent years. Moreover, the Australian cost-allocation approach is quite typical of the "traditional" kind of rationale and methodology generally used in efforts of this type. Chapter 5 deals in its entirety with the Eurocontrol system of user charges. This represents the principal case study reported herein. In its first part, Chapter 5 examines in detail the distribution of Eurocontrol charges among users. The second part concentrates on the cost-base which these charges are designed to cover. Some of the points which are addressed include: (a) The extent to which the Eurocontrol "formula" for computing user charges truly reflects the costs that individual users impose on facilities and services (b) The effects of changes in this formula on the distribution of costs among the various types of users: much quantitative evidence is provided in this respect (c) The composition of the cost-base and differences among memberstates in this respect (d) Possible explanations for the large differences in the unit rates that the eleven individual member-states specify for computing user charges. Chapter 6 represents a first attempt to examine in a systematic way the subject of costs of ground handling services at international airports. It is noted that, due (i) to vast differences among airports as to who the provider of these services is, and (ii) to lack of uniformity in the type and quality of services provided, it is difficult to develop general conclusions in this area. Nevertheless, several preliminary but highly-interesting observations are made on the basis of previously-unpublished data provided to the author by the International Civil Airports Association (ICAA) and by a major U.S. trunk carrier. The data in question deal with ground handling costs at many European and a few U.S. airports. An extensive list of references on the subjects of airport economics and of airport user charges is also provided at the end of this report. Finally, as already indicated in the Foreword, two companion reports, based on the thesis work of D. Lippera and E. Ch'ng, cover much related ground, especially with regard to a more-formal analysis of alternative costallocation methodologies. These two reports also include many additional examples, especially several concerning the British Airports Authority and the setting of user charges at London/Heathrow Airport

Airport Congestion Mitigation through Dynamic Control of Runway Configurations and of Arrival and Departure Service Rates under Stochastic Operating Conditions

The high levels of flight delays require the implementation of airport congestion mitigation tools. In this paper, we optimize the utilization of airport capacity at the tactical level in the face of operational uncertainty. We formulate an original Dynamic Programming model that selects jointly and dynamically runway configurations and the balance of arrival and departure service rates at a busy airport to minimize congestion costs, under stochastic queue dynamics and stochastic operating conditions. The control is exercised as a function of flight schedules, of arrival and departure queue lengths and of weather and wind conditions. We implement the model in a realistic setting at JFK Airport. The exact Dynamic Programming algorithm terminates within reasonable time frames. In addition, we implement an approximate one-step look-ahead algorithm that considerably accelerates the execution of the model and results in close-to-optimal policies. In combination, these solution algorithms enable the on-line implementation of the model using real-time information on flight schedules and meteorological conditions. The application of the model shows that the optimal policy is path-dependent, i.e., it depends on prior decisions and on the stochastic evolution of arrival and departure queues during the day. This underscores the theoretical and practical need for integrating operating stochasticity into the decision-making framework. From comparisons with an alternative model based on deterministic queue dynamics, we estimate the benefit of considering queue stochasticity at 5% to 20%. Finally, comparisons with advanced heuristics aimed to imitate actual operating procedures suggest that the model can yield significant cost savings, estimated at 20% to 30%

Decomposition Algorithms for Analyzing Transient Phenomena in Multi-class Queueing Networks in Air Transportation

In a previous paper (Peterson, Bertsimas, and Odoni 1992), we studied the phenomenon of transient congestion in landings at a hub airport and developed a recursive approach for computing moments of queue lengths and waiting times. In this paper we extend our approach to a network, developing two approximations based on the method used for the single hub. We present computational results for a simple 2-hub network and indicate the usefulness of the approach in analyzing the interaction between hubs. Although our motivation is drawn from air transportation, our method is applicable to all multi-class queuing networks where service capacity at a station may be modeled as a Markov or semi-Markov process. Our method represents a new approach for analyzing transient congestion phenomena in such networks. Airport congestion and delay have grown significantly over the last decade. By 1986 ground delays at domestic airports averaged 2000 hours per day, the equivalent of grounding the entire fleet of Delta Airlines at that tillie (250 aircraft) for one day (Donoghue 1986). In 1990, 21 airports in the U.S. exceeded 20, 000 hours of delay, with 12 more projected to exceed this total by 1997 (National Transportation Research Board 1991). This amounts to *School of Public and Environmental Affairs, Indiana University, Bloomington, Indiana tSloan School of Management, Massachusetts Institute of Technology, Cambridge, Massachusetts ;Department of Aeronautics and Astronautics, Massachusetts Institute of Technology, Cambridge, Massachusett