Gregg G. Fleming

Modeling of Terminal-Area Airplane Fuel Consumption

DOI: 10.2514/1.42025 Accurate modeling of airplane fuel consumption is necessary for air transportation policy-makers to properly adjudicate trades between competing environmental and economic demands. Existing public models used for computing terminal-area airplane fuel consumption have been shown to have substantial errors, potentially leading to erroneous policy and investment decisions. The method of modeling fuel consumption proposed in this paper was developed using data from a major airplane manufacturer. When compared with airline performance/operational data, this proposed method has been shown to accurately predict fuel consumption in the terminal area. The proposed method uses airplane performance data from publicly available environmental models supported by the Federal Aviation Administration and others. The proposed method has sufficient generality to protect the proprietary interests of the manufacturer, while still having adequate fidelity to analyze low-speed airplane operations in the terminal area. This improved methodology will enable more informed decisions by policy-makers seekingtoaccountfortheeffectsoffuelconsumptionandairplaneemissionsonplansforfutureairspaceandairport designs.

Analysis of Departure and Arrival Profiles Using Real-Time Aircraft Data

The quantity and rate of fuel burned during aircraft operations forms the basis of all emission inventories at airports. The international standard for calculating fuel burn and emissions produced is the landing and takeoff cycle of the International Civil Aviation Organization and forms the basis for many emission inventory models and emission charging schemes at airports. The acquisition of real-time aircraft flight data recorder information provided a unique opportunity to compare actual operational fuel flows and times in mode to the International Civil Aviation Organization standard. For departures, there is tremendous variety in fuel flow patterns, rates of fuel flow, and times in mode. Only 67% of the flights analyzed show a classic transition from takeoff to climbout. Most of the remaining flights showed essentially flat-line fuel flow profiles. All aircraft showed some fuel flow rates indicative of reduced-thrust departures. The certificated values for departure fuel burn matched favorably to the real-time totals for four-engine aircraft. However, for the twin-engine aircraft in this study, total departure fuel burn was grossly overpredicted, due to shorter observed departure times in mode. The average approach times in mode were slightly higher than the International Civil Aviation Organization norm, but approach fuel flow rates were significantly lower, yielding lower total fuel burn values. In general, total fuel burn for both departures and arrivals is overestimated by the International Civil Aviation Organization method.

Impact of the Reduced Vertical Separation Minimum on the Domestic United States

Aviation regulatory bodies have enacted the reduced vertical separation minimum standard over most of the globe. The reduced vertical separation minimum is a technique that reduces the minimum vertical separation distance between aircraft from 2000 to 1000 ft, for cruise altitudes between 29,000 and 41,000 ft It was first introduced over the North Atlantic in March 1997, and, more recently, over the domestic U.S. in January, 2005. Previous studies by EUROCONTROL and the Federal Aviation Administration have found that, by allowing for more efficient flight trajectories, the implementation of reduced vertical separation minimum can reduce fuel burn and related emissions by 1.5%-3%. However, the modeling techniques used in these prior studies did not directly include weather or the influence on changes in engine-specific fuel consumption with throttle setting, Mach number, or altitude. Because of the influence that these factors may have on accurately predicting changes in fuel burn with small changes in aircraft operations, we sought to assess the influence of these assumptions, to develop improved modeling methods, and to use these improved methods to make a new estimate of the impacts of the reduced vertical separation minimum. This document estimates the impact of reduced vertical separation minimum within the continental U.S. for a sample of 100,000 radar-based flight trajectories. We incorporated meteorological conditions resolved along the individual flight trajectories. Computer flight data recorder archives from 2800 flights were statistically analyzed to develop an improved model for estimating changes in aircraft fuel burn with changes in Mach number, throttle setting, and ambient conditions. Using these methods, we estimate that fuel burn and nitrogen oxide production per distance traveled decreased by about 2% and 3%, respectively, with the implementation of reduced vertical separation minimum over the continental U.S. Although our estimate for the benefits of reduced vertical separation minimum is similar to previous studies, we also show that the use of detailed meteorological conditions, and the advancements in aircraft fuel burn estimation described in this paper, are important for analyzing small changes in efficiency related to the implementation of reduced vertical separation minimum. In particular, if these advancements were not incorporated, the estimated benefits of reduced vertical separation minimum for this sample of 100,000 radar-based flight trajectories would be approximately 0%.

Lateral attenuation of aircraft sound levels over an acoustically hard water surface : Logan airport study

During the summer of 1999, in order to examine the applicability of currently available mathematical models of lateral sound attenuation, a noise measurement study was conducted at Logan International Airport in Boston, Massachusetts. It was revealed through analysis of the data collected that lateral attenuation is a function of the location of the engines on the aircraft, i.e., tail-mounted versus wing-mounted. In addition to that included in existing aircraft noise models, attenuation for aircraft with tail-mounted engines was found to agree with the published literature. For wing-mounted engines, attenuation was found to be less than that documented in the literature. A general under-prediction of side-line noise by the existing noise models is the result of this lower lateral attenuation for aircraft with wing-mounted engines.

Aircraft noise dose-response relations for national parks

An analysis of visitor survey responses and concurrent noise exposure was performed using data from ten sites in four scenic U. S. National Parks. Data collection was structured to learn the effects of air-tour aircraft noise and high-altitude jet noise on the experience of park visitors at scenic overlooks and on short hikes. The analysis utilized multilevel logistic regression and resulted in six dose-response relations: two responses (annoyance and interference with natural quiet), paired with three response dichotomizations (slightly or more, moderately or more, and very or more). Each of those six relations retained the same set of regression predictors. Individual-visitor Leq from all aircraft (averaged over the visitor duration at the site) proved to be the most reliable/accurate predictor of all noise dose metrics tested. The relation with visitor Leq was significantly strengthened by inclusion of three additional dose-related predictors: the energy-percentage due to tour helicopters for each visitor, the same due to fixed-wing tour aircraft, and the interaction of these two percentages. In addition, the relation was also strengthened by inclusion of the following context variables: Scenic overlook or short hike, natural quiet very important (or not) to that visitor, visitor group includes only adults (or not), and first-time visit at that site (or not). For a given noise exposure, visitors expressed more negative response regarding interference with natural quiet than regarding annoyance. In addition, visitor response to a given dose of air-tour noise was less severe when there were low-to-moderate levels of high-altitude jet noise present.

Reducing the Impact of Environmental Noise on Quality of Life Requires an Effective National Noise Policy

The focus here is on the impact of environmental noise on the quality of life. After reviewing the terms of The Noise Control Act of 1972 (NCA 72) related to quality of life, the authors explore the following issues: (1) the desire for an acceptable quality of life; (2) the absence of an effective national noise policy; (3) changes in the noise exposure of the United States population; (4) changes in the population (numbers, locations and desires); (5) changes in sources (numbers, locations and noise characteristics); and (6) inadequacy of knowledge about the effects of noise. The conclusion is drawn that a more effective national noise policy is required to achieve an acceptable quality of life for all Americans.

GROUND EFFECTS IN FAA'S INTEGRATED NOISE MODEL

The Federal Aviation Administrations Integrated Noise Model (INM) has used a lateral attenuation algorithm based on the two regression equations described in the Society of Automotive Engineers Aerospace Information Report 1751 since 1981. These equations, which together represent a single relationship developed from measured data for 1960s and 1970s aircraft with low-bypass ratio jet engines, are applied equally in the INM to the entire fleet and do not take into account the effects of propagation over acoustically hard terrain such as water. For these reasons, the INM development team initiated the task of revising the lateral attenuation algorithm within the model in 1997. An entirely new methodology for considering ground effects is the primary component of the revised algorithm. The methodology, which is based upon a newly-compiled spectral data base, along with the physical acoustics model documented by Tony Embleton, Joe Piercy and Giles Daigle of the National Research Council of Canada, will exist in INM as a library of regression equations. As such, this approach will offer the accuracy and flexibility of a pure physical acoustics model, coupled with relatively modest computer runtimes. The methodology summarized in this paper will result in an improvement in the INMs predictive accuracy, especially at small reflection angles. It also provides the INM user with the ability to take into account the effects of an acoustically hard surface, including the effects of mixed, acoustically soft and hard ground surfaces, a capability never before available in this model. Recent field studies have shown the approach to agree well with measured data.

Development of a tool for modeling snowmobile and snowcoach noise in Yellowstone and Grand Teton National Parks

The National Park Service (NPS) develops winter use plans for Yellowstone and Grand Teton National Parks to help manage the use of Over-Snow Vehicles (OSVs), such as snowmobiles and snowcoaches. The use and management of OSVs in the parks is an issue because of potential environmental impacts and because of actions by environmental, recreational, and commercial groups. The U.S. Department of Transportation, Research and Innovative Technology Administration, John A. Volpe National Transportation Systems Center (the Volpe Center) supported the NPS by modeling the acoustical environment in the parks associated with potential modeling alternatives as well as current and historical conditions. The modeling considered a number of alternatives for inclusion in the NPSs winter use plans. These alternatives affect the type and number of OSVs that are allowed to operate in the parks and where they are allowed to travel. The acoustical modeling was performed by using the Federal Aviation Administrations (FAA) Integrated Noise Model (INM), adapted for use with OSVs. INM adaptation included the development of an over-ground sound propagation model to account for propagation over snow-covered terrain. The Volpe Center also developed a new OSV noise database, which defined OSV noise as a function of speed and source-to-receiver distance, based on previously published OSV acoustical studies and winter 2005-2006 measurements. Vehicle types modeled included two- and four-stroke snowmobiles as well as two- and four-track snowcoaches

Lateral attenuation of aircraft sound levels due to engine installation effects: Wallops study

In September of 2000, the National Aeronautics and Space Administration’s (NASA) Langley Research Center, with assistance from the John A. Volpe National Transportation Systems Center conducted a controlled aircraft noise measurement study at NASA’s Wallops Island Flight Facility on the northeast coast of Virginia. The broad objective of the study was to obtain the data necessary to support an update/replacement to SAE AIR 1751, which addresses the lateral attenuation of aircraft noise. The specific focus of the study was the engine/installation effects, or directivity characteristics of various types of civil transport aircraft. Included in the study was a 767‐400, a DC‐9, a Falcon 2000, and a King Air turboprop. Measurements were conducted with a 20 microphone array deployed on a combination of two construction cranes and a set of 30 ft. poles. Precision aircraft tracking data were collected using a differential global positioning system, as well as a video tracking system. This presentation will overvi...

Highway traffic noise measurements compared to predictions from FHWA’s Traffic Noise Model

In 1998, the United States Federal Highway Administration (FHWA) released a new tool for highway traffic noise prediction and noise barrier design, the Traffic Noise Model (TNM). In order to assess the accuracy and make recommendations on the use of TNM for the FHWA, the Volpe Center Acoustics Facility performed numerous roadside measurements, obtaining over 100 h of traffic noise data from highways around the country. For each site, acoustical, meteorological, and traffic data were collected simultaneously throughout the measurement period. Spectrum analyzers were used to collect 1/3‐octave band A‐weighted equivalent sound levels, and the microphones were deployed at distances from 50 to 1300 ft from the roadway and at two heights off the ground, the number of microphones used being site dependent. In comparing the measured and TNM‐predicted sound levels, results indicate that TNM is, on average, within 1 dB of the measured data for all types of sites combined. Grouping the data by site types shows how w...