Impacts of technology on the capacity needs of the US national airspace system

A review of the U.S. air transportation system is undertaken, focusing on airspace and airport capacity. Causes of delay and congestion are investigated. Aircraft noise is identified as the fundamental hindrance to capacity improvement. Research areas for NASA are suggested to improve capacity through technology

Commuter airlines at Boston Logan International Airport: 1973-1981

January 1981Introduction: The adequacy of air transportation in New England has been the subject of intermittent debate-over the last twenty years-, culminating in the Civil Aeronautics Board's 1970-1974 "New England Service Investigation" (Docket 22973). Spurred on by Senate hearings on the "Adequacy of Northern New England Air Service" (1971) in particular and by Senator Norris Cotton of New Hampshire in general, in 1974 the Board certificated Air New England as a local service carrier. It was the first certification of a commuter airline by the Board. The certification contradicted the advice of the Board's own Bureau of Operating Rights and the U.S. Department of Transportation and overturned the initial (1973) decision of Administrative Law Judge Greer M. Murphy, who held that existing commuter airlines could provide adequate service in New England without certification. A potentially successful commuter ("Air New England 1970-1974 ," MIT-FTL Report R75-9), millions of subsidy dollars later, Air New England is struggling financially and operationally and is now giving up many subsidized points to replacement commuter carriers. Logan Airport, the major hub of New England, has one of the largest concentrations of commuter carriers in the U.S. During the last seven years, it has ranked in the top three. Some twenty commuters (including all cargo carriers) land at Logan, serving over fifty markets. However, of the passenger-carrying commuters, only four (including Air New England) have remained steady customers since 1973. The others are Command, Pilgrim, and Provincetown-Boston Airlines. This report is an attempt - 2 - to analyze the pattern of commuter airlines operations at Logan. Since the events prior to 1973 are well documented, the emphasis is on the years 1973-1981. In Section 2, the theoretical background to analyze the commuter industry Is provided. Section 3 gives the Boston market analysis. In Section 4, a brief description of the aircraft used by commuters is provided as well as a look ahead to the aircraft that will be available to the commuter industry in the 1980s. Finally, in Section 5 some recommendations are made to monitor the commuter activities at Logan airport

Air freight : the problems of airport restrictions : final report on the Conference of Air Cargo Industry Considerations of Airport Curfews

April 1979Conference held in Jupiter, Fla. in January 1979Includes bibliographical references (p. 36)Noise due to aircraft was considered to be a potential problem as far back as 1952, when the Doolittle Commission established by President Truman urged that a major effort be made to reduce aircraft noise. With the 'advent of the jet age in the late 1950's and the concomitant spread of suburbs towards airports in major cities such as New York, Denver, and Minneapolis-St. Paul, many more people became exposed to noise, and concern and anger intensified. Although only a small percentage (estimated at about 2-3%) of the total population of the U.S. is affected by high noise levels, these people and their representatives have been quite vocal about their dissatisfaction with noise abatement progress, even though technological advances have reduced the noise emanating from aircraft engines. As a result, the airports, the communities, and the federal government are seeking additional measures that will further diminish the noise impact of aircraft and airport operations. The dilemma is to decrease noise with the minimum economic disruptions to commerce, the community, and the aviation industry. Since very few people like to travel during the night hours (approximately 10 p.m. - 7 a.m.), and indeed very few aircraft operations take place (less than 5% of total operations at most airports), an environmentally and politically appealing option to diminish the effect of aircraft noise is to ban airplane operations during nighttime hours. However, a disproportionate number of operations at night are dedicated to cargo (about 50% of scheduled domestic all-cargo flights), and it is upon the air cargo industry and those users dependent upon nighttime flights that the major burden of a curfew would fall. The benefits of curfews are apparent; the economic penalties associated with them are not. To address this issue, the Flight Transportation Laboratory of the Massachusetts Institute of Technology hosted a week-long conference at Jupiter, Florida, in January, 1979, on the impact of airport use restrictions on air freight. This conference was sponsored by the Federal Aviation Administration and the Port Authority of New York and New Jersey. More than 70 participants, including some 50 panelists and speakers, represented various viewpoints of the air cargo industry: the users, the airlines, the airports, the communities, and various governmental agencies

Aviation safety analysis

April 1984Includes bibliographical referencesIntroduction: Just as the aviation system is complex and interrelated, so is aviation safety. Aviation safety involves design of aircraft and airports, training of ground personnel and flight crew members' maintenance of aircraft, airfields, en route and terminal area navigation and communication facilities definition and implementation of Federal Aviation Regulations (FARs)l air traffic control procedures and much more. Ultimately, every part of aviation has a safety aspect. No other transportation mode has its safety record so rigorously scrutinized. In part this is due to the general societal (and media) fascination with infrequent large disasters in part because U.S. legislators have a personal interest in air safety, as they rely upon aircraft for their seasonal commutes to Washington, and in part because people in the industry are aware that their paychecks ultimately depend on their customers' perception that travel by air is as safe as possible. (Various airlines still conduct aircraft familiarity classes for travelers who have a fear of flying, although as the younger generation of Americans gains experience with airlines, this particular phobia should become less prevalent.) Aside from the industry's self-enforcement attempts, the Federal government tries to assure safety of the traveling public through regulation. The National Transportation Safety Board (NISB) investigates all major air carrier accidents and subsequently makes safety recommendations to the Federal Aviation Administration (FAA) - which the FAA may or may not choose to accept. One of the long lasting standoffs in aviation safety is between the NPSB (backed by Congressional committees), whose sole concern is safety,and the FAA, which must also take the economics of safety regulations into account-unless it wishes to run into a buzzsaw of industry reaction every time it changes (or issues) a FAR. On the international side, the International Civil Aviation Organization (ICAO) issues technical rules affecting aviation safety, although such decisions as its upcoming ruling on twinjet aircraft over-water flights may be tinged with economic considerations as well. But for safety regulations, whether external or internal to the aerospace industry, to make any sense, they must be grounded, to some degree, in reality, i.e. they must be backed up by some technical, statistical, or economic factors which people can address on their own merits. The more quantitative the supporting data are for rule justifications or changes, the greater the likelihood is that the regulations will be successfully promulgated and accepted by industry. Thus aviation safety analysis came into existence. Most broadly stated, the purpose of safety analysis is to improve safety. The spectrum of analysis ranges from the investigative to the predictive. At one end of the spectrum is the after-the-fact investigation of accidents and a search for causes at the other end is the attempt to seek out likely causes (or, more typically, combination of causes) of system failure before the system is put into operation. However, the great quandary of aviation system analysis is the lack of sufficient data to make probabilistic statements - even while the goal of this analysis is the elimination of the very accidents that provide the data. Practitioners of classical statistics, who have grown up considering probability as the likely outcome of an event based on a large number of repeated trials, face a mental hurdle when asked to accept the concept that an event which has never taken place can nevertheless be assigned a 0.95 probability of success. This is essentially the dichotomy between the investigative and the predictive ends of safety analysis - one is based on few accidents (but real accidents nonetheless), the other is based on more subjective probabilities of system (and subsystem) failures.(cont.) But safety analysts cannot throw up their hands and say that there is insufficient data after only one accident occurs and simply wait for the next one to happen. They must combine forces with their predictive brethren and attempt to head off the next accident. Only when this becomes the rule will aviation safety analysis rest on a sound base. Until this millennium, however, much remains to be done to improve safety analysis at each end of the analysis continuum, and also where the two occasionally intersect by chance. The investigative techniques depend on data: of incidents, accidents, near misses, and the like. The FAA, NASA, NSB, ICAO, aircraft manufacturers, airlines, etc., all maintain various types of data bases, most of which are incompatible (in the sense that they keep track of slightly different variables). A further complication is that some bases are computerized (different data base management systems are usually involved) and some are manual. The safety analyst, attempting to establish broad trends, is immediately faced with this incompatibility problem. Still, if the focus of the investigation is narrow enough (for example, a failure of a mechanical part on a specific aircraft), it may be possible to extract enough information from the various data bases to find a definitive cause. This is especially true when the cause of the incident is, in fact, mechanical - it is here that repeated failures should be noticed, isolated, and corrective action taken. Flight International (1984) provides a typical example that an alert safety analyst (or system) should have anticipated and caught: "Mis-rigging of the baggage door operating mechanism and the failure of the door warning arrangements to give adequate warning of door safety led to the fatal crash of a Dan-Air BAe 748-2A in June 1981, according to the official report. The baggage door at the rear end of the cabin, blew out and became fixed on the tailplane, thus making the aircraft uncontrollable. Subsequently, the wings were overstressed and suffered structural failure. The condition of the door operating mechanism, says the report, made it impossible to lock the door fully using the outside handle. But it was probably by the outside handle that the door had last been closed. Crew checks failed to discover the fault because of "a combination of shortcomings in the design, construction, and maintenance of the door warning systems and the appearance of the visual indications". The report notes that there have been 35 instances of the 748 baggage door malfunction reported in the past". Very rarely do accidents have such obvious design-induced crew error precursors. Most accidents result from interactive causes, rather than one specific factor, and one of the causes is, invariably, a human being - the pilot, the air traffic controller, or the maintenance worker. These acts of human beings do not fit readily into data banks, there to be identified by a specific parts number, and the safety analyst must now switch to the other end of the spectrum and try to isolate the sequence of events that lead to "pilot error". These accidents involving human performance usually turn out to be oneof- a-kind events - and it should be the aim of the safety analyst to ensure that they remain so. Data unavailability and incompleteness, however, are always present and it is up to the skill (and luck) of the analyst to uncover the sequence of events leading to the accident. If a procedural error is found, it can be immediately correctedy more difficult are those amorphous incidents where it is not at all clear why there was human error. (If it were possible to obtain quantitative estimates of human performance, such as human error rates per task, it would be a simple matter to incorporate them into operational reliability equations to determine system reliability.) Just as the role of analysis of incident and defect reporting systems should be to find mechanical failures before they become accidents, the human incident reporting systems should be designed to cause humans to "confess" their incidents so that the analyst can isolate potentially dangerous trends and practices before they too become accidents. (The Aviation Safety Reporting System (ASRS) managed by NASA is a step in the right direction.) It is the purpose of this report is to discuss various aspects of aviation safety analysis, ranging from general aviation to the public transportation system, and then to make some recommendations for improving the methodology of safety analysis.*Supported by Dept. of Transportation, Transportation Systems Cente

Wide-body aircraft demand potential at metropolitan Washington airports

May 1976Includes bibliographical references (leaf 24)Introduction: At present there is concern regarding the feasibility and future impact of allowing service by wide-body aircraft into National Airport in Washington. Some of the important issues are: (i) To what extent would the air carrier traffic change at Dulles and National Airports if wide-bodies were allowed at National? In addition, would this reduction in the quality of service (i.e. trip convenience and time) result in diversion of passengers to other modes of transportation in short-range markets? (ii) Could airlines maintain a high level of service to Metropolitan Washington and still make a profit serving their Washington markets? (iii) What would be the effect of changing the existing quota of 40 operations per hour at National Airport? FA-7, an air transportation simulation model developed in the Flight Transportation Laboratory at M.I.T. is well suited for analysis of these policy-oriented questions and was used to obtain answers to a series of hypothetical scenarios regarding wide-body aircraft use at the two Metropolitan Washington airports.

Impacts of technology on the capacity needs of the U.S. national airspace system

December 1991Includes bibliographical references (leaf 57)Introduction: Air passenger traffic in the United States showed remarkable growth during the economic expansion of the 1980's. Each day a million and a quarter passengers board commercial flights. The boom coincided with the advent of airline deregulation in 1978. This drastic change in the industry has inspired professional and newspaper articles, graduate student theses, and books which have discussed the causes, effects, costs, and benefits of deregulation with predictably mixed conclusions. Economists, who like to predict the future by exercising econometric models, are finding that conditions in air transportation have become too dynamic (chaotic?) for their models to cope. Certainly the future of the air transportation industry is unclear. There has been, however, an unmistakable trend toward oligopoly, or, as industry spokesmen describe it, "hardball competition among the major airlines." This trend has been accompanied by formations of hub fortresses owned by these survivors. Air traffic has always been concentrated in a few large cities; airplanes will go where there is a demand for them. But airline (rather than traffic) hubs have created artificial demand. Up to seventy percent of travellers boarding airplanes in the hub cities do not live anywhere near these cities - in fact, they may have no idea at which airport they are changing planes. Most passengers do not care, while travel cognoscenti soon learn to avoid certain airports (and airlines which frequent these airports). A hub airport is a frenzy of activity for short periods of time during the day, as complexes of airplanes descend, park and interchange passengers, and take off. Then the airport lies quietly. If observers were to arrive at a major hub between times of complexes, they would be perplexed to hear that "this is one of the most congested airports in the world." Thus congestion and its evil twin, delay, are not constants in the system. Rather, they appear only if a number of conditions conspire to manifest themselves simultaneously, or nearly so. First, the weather must deteriorate from visual flight conditions to instrument flight conditions. Then, this must occur near peak demand conditions at the airport. Of course, some airports in the Unites States are always near peak conditions, among them the so-called slot constrained airports: New York's La Guardia and Kennedy, Washington's National, and Chicago's O'Hare. When weather goes bad at these airports or other major hubs during complexes, ripple effects start nearly all over the country, because some airlines have now designed schedules to maximize utilization of their airplanes. Very little slack time is built into the schedules to account for potential delays, although "block-time creep" exists: the phenomenon that travellers discover when they arrive at their destinations ahead of schedule (if they happen to leave on time). This "creep" protects the airlines from being branded as laggards by the DOT's Consumer On-Time Performance Data hit list. Thus a combination of management practices by airlines (which place great demand on terminal airspace over a concentrated period of time) and mother nature (which provides currently unpredictable behavior of weather near the airport) conspire to limit the capabilities to handle arrivals and departures at various airports below the numbers that had been scheduled. Travellers complain that the schedules aren't being met, and if enough people complain to Congress, or if the travellers themselves happen to be members of Congress, a national problem appears. How much of a problem is this? In 1988 there were 21 airports, according to the FAA, which exceeded 20,000 hours of annual aircraft delay, perhaps 50,000 hours per year, or 140 hours per day. (One, Chicago's O'Hare, exceeded 100,000 hours.) These airports, in turn, averaged 1,000 operations (arrivals and departures) per day, so that each operation would have averaged about 8 minutes of delay. At O'Hare, for example, 6% of all operations experienced in excess of 15 minutes of delay. (In excess means just that - there is no knowledge of how much "in excess" is.) Conversely, this means that at that most congested airport in the United States, 94% of all airplanes arrive or depart with less than 15 minutes of delay. However, airline delay statistics may be similar to the apocryphal story of the Boy Scout troop which drowned wading across a creek which averaged two feet in depth. There are estimates that on a dollar basis, delay accounts for a $3 billion cost to airlines, or a net societal cost of$5 billion if travellers' wasted time is included. Since in their best years U.S. airlines make about $3 billion in profit, reducing delay is a sure-fire way for airlines to climb out of their all too frequent financial morasses, as well as diminishing their passenger frustrations. Even though all of the numbers mentioned in the paragraphs above are subject to substantial caveats, it is indisputable that on certain days during the year the air transportation system seems to come to a crawl, if not a halt. Travellers either find themselves sitting at airport lounges observing cancellation and delay notices appearing on the departure and arrival screens, or sitting in airplanes (on runways or at gates) being told that there is an "air traffic delay." Old-timers grumble that the only difference twenty years of technology improvements has made to the U.S. airspace system is that the wait is now on the ground instead of circling in the air near their destinations. To the casual observer, it would appear that a number of solutions exist to solve this problem. The most obvious is to pour more concrete: more airports, more and longer runways, more taxiways, more gates and terminals. This is analogous to widening highways and building more interstates for ground transportation congestion. The concrete solution, alas, runs into both financial and citizen roadblocks. It is very expensive - the latest airport coming off the drawing boards (Denver International) carries a tag of some$2 billion, with about $400 million of that in bonds being backed by a new funding creature, the Passenger Facility Charge (a head tax of up to 3 dollars assessed to every passenger enplaning at an airport - voluntary or not). The citizen roadblock is community objections to airport noisiness. The bill creating the PFC in 1990 also carried with it a mandate for the FAA to create a national noise policy so that individual airports would not wreak havoc with the whole system by creating their own local operational rules, such as curfews. The bill also attempted to pacify airport neighborhoods by setting a deadline for all U.S. aircraft to be quiet(er) - complying with Stage 3 regulations by the year 2000. More damaging than financial difficulties are the anti-noise sentiments, and the concomitant not-in-my-backyard syndrome, that are at the forefronts of protests of either an alert citizenry, or New Age Luddites, when any expansion plans are made public. Whatever one's view, it is a crowd vocal and seemingly powerful enough in local political circles to stop any large- scale progress to ground solutions of the congestion problem. That, then, leaves the air. It is intuitive that if airplanes were closer spaced than they are now, much more traffic would move through a given area in the same amount of time, and consequently airplanes would land (and take off) quicker, reducing any waiting (queue) time. This obviously increases airport noise levels. There are two problems with this approach. The first trick is to accomplish this safely. Safety has at least two dimensions: there is the physical, i.e., airplanes should not run into each other (or the ground, as a result of weather disturbances and wake vortices); and pilots (and controllers) should feel they are still in control of the situation, even after separation standards are reduced. The first aspect is mostly a matter of technology, the second mostly a matter of human factors. But if traffic moved quicker and noise of the aircraft is not reduced, the same citizens who had vehemently opposed the construction of additional ground facilities would once again rise in righteous anger and demand a stop to the more efficient techniques of flying airplanes which have caused an increase in the noise levels in their neighborhood. They, too, must be considered. This report will attempt to address some of the issues outlined above. The focus will be on technology and where it is best suited to provide an equitable and efficient expansion of capacity in the air transportation system. Ultimately, the discussion will be centered on NASA's potential contributions to solving the capacity problem

Modelling risk in ATC operations with ground intervention

Cover titleJuly 1991Includes bibliographical references (leaves 17-18)Preface: It was part of a continuing series of research work aimed at creating models for estimating Collision Risk for ATC operations which can be used by the Federal Aviation Administration and ICAO to establish safe criteria for separations between aircraft.Introduction: The purpose of this information paper is; a) to provide a document describing the problems of analyzing risk for ATC systems which have surveillance over air traffic and which allow ground controllers to intervene to avoid unsafe encounters; b) to propose a framework for future studies which attempt to solve these problems. The need for such methods of analyzing risk arises in justifying reduced ATC separation criteria which ensure safety for newer forms of ATC operations. The benefits of these new systems strongly depend on achieving a reduction in current ATC separations, and as a result, an increase in capacity and efficiency for aircraft operations. These benefits must be weighed against the costs of developing and operating the new ATC systems.Supported by the Volpe National Transportation Systems Center of the US Department of Transportatio

Maintenance cost studies of rotary wing commercial transport aircraft

December 1974Includes bibliographical references (p. 121-123)Introduction: The vertical take-off and landing (VTOL) aircraft market has had substantial growth in the period of the last ten years when one considers the overall number of aircraft in use. The military fleet has continued to increase, as have such operators as natural resource (petroleum and lumber) companies, and law enforcement agencies. (See Table 1.) In scheduled passenger service, however, the VTOL- market has not enjoyed sustained growth. Consider Table 2, the type and number of helicopters in passenger service during 1962-1972. Following the cessation of federal subsidies to helicopter operators in 1966 the number of aircraft (and total available seats) has been steadily declining. Table 3 shows the composition of the fleets of the certificated carriers since 1966. Los Angeles Airways has been in bankruptcy since 1969; Chicago Helicopter is now largely a charter operator, although retaining its certificate; New York Airways, after a period of experimentation with the fixed wing Twin Otter (DHC-6) in 1968-1969, finally made it into the black in 1973, flying Sikorsky S-61's; and SFO Helicopter has retrenched its passenger services severely, but is not yet profitable. Why is the state of scheduled passenger operations so bleak? Many answers to this question have been given. For example, it has been said that the aircraft used by the operators have been inadequate: that they have been designed for military use and are ill suited for civilians who have been used to a higher comfort level (especially since most flights taken on a helicopter are in conjunction with a ride on a large, comfortable jet transport). Alternatively, it has been said that the high cost of operating the current helicopter fleet has caused the ticket price to be too high to be attractive to the traveler. Sometimes the operators have been fingered as the culprits -- that they have not priced their product adequately and have structured their networks poorly, i.e., that the failure has been one of management and marketing. And from the purely technology minded, the answer has been that once the properly designed rotary wing aircraft arrives on the scene -- one designed for civilian use and having the proper payload-range configuration -- the market will boom as VTOL aircraft enter city-center to city-center service. Doubtless there is a kernel -of truth in all these explanations, and examples to sustain most of them can be found in the history of helicopter operations in the United States. The intent of the work described in this report was to explore one frequently cited cause of the problem of high operating costs of helicopters in scheduled service - to wit, high maintenance costs of rotary wing aircraft. This attempt was made to allow a look ahead and to predict trends in maintenance costs of future rotary wing aircraft.This work was performed under a NASA Contract for Ames Research Cente

Air New England (1970-1974) : a case study of a commuter air carrier

October 1975On cover, series statement "R75-9" is the correct numbering; t.p. has "75-7" and has been corrected to "75-9" by handIncludes bibliographical referencesThis is a brief account of research by CAB staff. The success of Air New England from the beginning of its corporate life to the summer of 1974, when it was offered a certificate of public convenience and necessity by the CAB, can be attributed to a number of factors. The foremost was capable management. The management team at Air New England had previous experience operating commuter airlines in the New England area and was aware of the two major pitfalls that would undermine profitability, excess capacity and high corporate overhead, and was careful to avoid them. Further, the regulatory environment in which the commuters operated was such as to allow various competitive marketing strategies to be tried by management, such as modifying fare structures, flying different routings, and changing frequencies on routes. Additionally, the area chosen for initial market penetration, the Cape and Islands, was dense enough to support a number of airlines during the peak season, and allowed Air New England to minimize its start-up losses. Air New England's management was, of course, aware of the financial situation at Executive, its major established competitor. Air New England realized that if it was able to control its own costs, the financial difficulties that had existed at Executive during previous years would eventually lead to the disappearance of that particular competitor. (Of course, the possibility always existed that new commuters could also appear.) Thus, the emergence of Air New England as the dominant commuter air carrier in New England was a combination of management skills in all areas of airline operations combined with mismanagement on the part of their competitors. In the summer of 1974 Air New England's future was bright.Sponsored by the Department of Transportation

Presentations from the 1995 MIT/industry cooperative research program annual meeting.

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