Showing papers on "Aircraft noise published in 2001"

Chronic aircraft noise exposure, stress responses, mental health and cognitive performance in school children.

Abstract: Background. Previous research suggests that children are a high risk group vulnerable to the effects of chronic noise exposure. However, questions remain about the nature of the noise effects and the underlying causal mechanisms. This study addresses the effects of aircraft noise exposure on children around London Heathrow airport, in terms of stress responses, mental health and cognitive performance. The research also focuses on the underlying causal mechanisms contributing to the cognitive effects and potential confounding factors.Methods. The cognitive performance and health of 340 children aged 8–11 years attending four schools in high aircraft noise areas (16h outdoor Leq>66dBA) was compared with children attending four matched control schools exposed to lower levels of aircraft noise (16h outdoor Leq<57dBA). Mental health and cognitive tests were group administered to the children in the schools. Salivary cortisol was measured in a subsample of children.Results. Chronic aircraft noise exposure was associated with higher levels of noise annoyance and poorer reading comprehension measured by standardized scales with adjustments for age, deprivation and main language spoken. Chronic aircraft noise was not associated with mental health problems and raised cortisol secretion. The association between aircraft noise exposure and reading comprehension could not be accounted for by the mediating role of annoyance, confounding by social class, deprivation, main language or acute noise exposure.Conclusions.These results suggest that chronic aircraft noise exposure is associated with impaired reading comprehension and high levels of noise annoyance but not mental health problems in children.

Optimization of Noise Abatement Departure Trajectories

Abstract: This paper describes the development of a new tool that offers significant capabilities for the analysis and design of noise abatement procedures at any given airport. The proposed tool combines a noise model, a geographic information system and a dynamic trajectory optimization algorithm. The optimization algorithm essentially modifies routings and flightpaths such as to minimize the noise impact in the residential communities surrounding the airport, while satisfying all imposed operational and safety constraints. Numerical examples, involving departure trajectories from Amsterdam Airport Schiphol, are included to demonstrate the effectiveness and flexibility of the developed tool. Although the results obtained to date are for departure flights only, the employed methodology tool holds out equal promise for application to approach trajectories. In the numerical examples the characteristics of a Boeing 737-300 aircraft are used.

An Updated Catalog of 521 Social Surveys of Residents' Reactions to Environmental Noise (1943-2000)

Abstract: This report describes all social surveys of residents' reactions to environmental noise in residential areas that have been located in English language publications from 1943 to December of 2000. A total of 521 surveys are described. The surveys are indexed by country, noise source, and date of survey. The publications and reports from each survey are listed in a bibliography.

Mitigating operational aircraft noise impact by leveraging on automation capability

Abstract: have been adopted and implemented. These measures include directing aircraft over unpopulated areas, phasing out noisier aircraft, enforcing nighttime curfews on the operation of certain aircraft, publicizing airlines noise mitigation efforts, and utilizing advanced engine technology to reduce source noise. While these measures have contained the impact of aircraft noise, the increased demand for air transportation has not been matched by increased capacity, thus resulting in greater delays and congestion at major airports during this past decade. Advanced approach noise abatement procedures enabled by flight guidance technologies such as GPS and FMS have been shown to reduce the impact of noise in communities near airports. The implementation of these procedures, however, is hindered by the inability of air traffic controllers to separate aircraft that are decelerating at significantly different rates. This is especially problematic when the traffic density is high or when atmospheric conditions are turbulent. This paper discusses the factors that limit the ability of air traffic controllers to separate aircraft without automation aids, and offers an automation infrastructure that utilizes flight operation uncertainties observed from an experimental pilot-inthe-loop simulation study to predict the initial separations necessary for aircraft to maintain the required minimum separation throughout the approach.

The influence of psychological factors on self-reported physiological effects of noise.

Abstract: We examine the possibility that physiological effects of noise may result not only from noise exposure per se, but also from people's beliefs about the noise. Due to widely publicised changes to the runway configuration at Sydney Airport, aircraft noise levels in nearby areas were expected to either increase, decrease or remain the same. As part of the Sydney Airport Health Study, residents in each of these 3 expected-change areas (N=1015) completed a structured interview which included indices of noise reaction (including annoyance) and physical and mental health, prior to the anticipated changes. Concurrent (pre-change) measures of aircraft noise levels were taken. Self-reported physiological/health effects differed across areas with the same aircraft noise level consistently with differences in psychological reaction across these areas. Expected change in noise level added to the level of self-reported physiological symptoms predicted by noise level in regression analyses. Dose-response functions differed across the expected-change areas. These results are consistent with the hypothesis that noise exposure produces physiological symptoms, but that expectations regarding future noise levels also contribute to the physiological impact of noise, which may be reduced by addressing psychosocial factors related to noise reaction.

Active control of fan tone noise from aircraft engines

Abstract: The noise reduction potential of different active noise control (ANC) configurations and control algorithms for the application to aircraft engines were studied. The work was done within the framework of the Brite/Euram research project RANNTAC (Reduction of Aircraft Noise by Nacelle Treatment and Active Control). ANC was applied to a fan model of 0.47m-diamete r in the SNECMA test facility in Villaroche, France. Loudspeakers mounted flush with the inner wall of the inlet duct were used as secondary acoustic sources. CNRS and EADS implemented various algorithms for active control using microphones as error sensors which are mounted (1) in the inlet duct and (2) in the free field upstream of the fan intake. DLR performed an acoustic mode analysis of the sound field in the inlet duct for the cases with and without ANC. For this purpose DLR designed and constructed a special duct section with 96 ports for wall-flush mounting of precision microphones and developed an appropriate analysis technique. Decomposition of the sound field into azimuthal and radial mode components provided detailed information on the effectiveness of the various active noise control techniques used. The sound power reductions achieved with ANC in the upstream far field were documented by microphoneantenna measurements conducted by SNECMA and served for further validation of the experimental findings.

Integral techniques for jet aeroacoustics calculations

Abstract: Reducing aircraft noise by a factor of four in the next twenty years is one of NASA's goals. Major reduction in acoustics emissions of aircraft jet engines is only possible with a reduction in jet noise. Hence, there is a need for improving the current state-of-the-art jet noise prediction methodology. We have developed in the past a Kirchhoff method code in order to evaluate the acoustic signals from an unsteady CFD code. In this paper, an integral acoustic code based on the porous Ffowcs Williams-Hawkings (FW-H) method is developed for the noise prediction of three-dimensional turbulent jets. The porous FW-H method can be more robust than the Kirchhoff method with regard to the choice of control surface, hence our efforts are focused in the development of the porous FW-H method. The resulting FWH code also includes refraction corrections to account for the zone of silence, as well as techniques to include acoustic sources outside the CFD domain. The code is validated for point sources. Once validation is complete, the code will be used to study the aeroacoustics of a three-dimensional turbulent jet at a Reynolds of number of 500 and possibly of another turbulent jet at a Reynolds number of 3600. The control surface needed for the FW-H method will be outside the jet flow, but inside the CFD boundaries in order to avoid boundary effects. The quantities on the control surface will be obtained using a Direct Numerical Simulation (DNS) code. The radiating sound will then be evaluated using the acoustics code developed herein.

Aircraft Noise Model Validation

Abstract: Aircraft noise models are now used widely by a large number of countries. Models vary in detail depending upon the needs of their users. Increasingly, models are becoming more sophisticated as additional needs develop. Traditionally noise models have been used to depict long-term historical noise exposure. However, they are often used to assess noise mitigation options and other ‘what if’ type scenarios. These applications have meant that a number of noise models have been subject to close scrutiny by interested parties, spurring further validation and model development studies. Throughout the paper, the various techniques and methods are illustrated using data from a recent UK study of approach noise at London Heathrow airport. The deficiencies with present noise modelling techniques such as lateral attenuation are discussed and possible options for future development are considered.

Aircraft noise valuation studies and meta-analysis

Abstract: Aircraft noise has a negative impact on consumer welfare in the regions affected. One of the consequences is that property values decrease. This paper gives a survey of studies from various countries on the relationship between the volume of aircraft noise and the values of dwellings. A meta-analysis is carried out to arrive at a synthesis of these studies and to find factors that explain the variance in the outcomes found in the studies.

Air traffic noise and hypertension in Stockholm County

Abstract: On any given day, according to The Economist , over 4 million people take to the skies. A quarter of a million people are airborne at any moment.1 Health impacts of noise can begin even before birth, and with high levels and an increasing distribution of exposure, any associations between aircraft noise and morbidity are clearly of relevance to public health.2 3 Rosenlund et al (page 769) assess associations between blood pressure and aircraft noise by comparing two study populations, around Arlanda airport and in another part of Stockholm County. Noise contours are constructed over the region for maximum noise level (MNL) and an energy averaged level (FBN). Health outcomes of people living in proximity tend on …

Aircraft noise monitoring: principles and practice

Abstract: The microphone is a key element, avoid under-range and overload probbeing the transducer that converts the lems. If an operator is present to sound pressure variations into an elecrespond to the prevailing noise clitrical signal. Measurement micromate, the instrument does not need a phones, particularly ones for accurate dynamic range that can accommodate wide-range measurements, are almost all the sound levels likely to be exclusively air condenser devices. A encountered. With unattended noise very thin metal foil diaphragm is monitoring, the instrument needs to spaced a small distance away from a be able to respond to any sound level fixed backplate to form a capacitor. within its overall capability. It is The diaphragm is charged in one of therefore quite common for instrutwo ways: either being coated with a mentation for unattended noise monipolymer to retain some charge, in the toring to have a very wide dynamic case of the perma-charged electret range, possibly incorporating some microphone; or it has a high polarisauto-ranging function though such ing voltage (~200 V) applied. In either systems must not be defeated by short Fundamentals of hearing

Structural Acoustic Prediction and Interior Noise Control Technology

Abstract: This report documents the results of Task 14, "Structural Acoustic Prediction and Interior Noise Control Technology". The task was to evaluate the performance of tuned foam elements (termed Smart Foam) both analytically and experimentally. Results taken from a three-dimensional finite element model of an active, tuned foam element are presented. Measurements of sound absorption and sound transmission loss were taken using the model. These results agree well with published data. Experimental performance data were taken in Boeing's Interior Noise Test Facility where 12 smart foam elements were applied to a 757 sidewall. Several configurations were tested. Noise reductions of 5-10 dB were achieved over the 200-800 Hz bandwidth of the controller. Accelerometers mounted on the panel provided a good reference for the controller. Configurations with far-field error microphones outperformed near-field cases.

A Differential Global Positioning System for Determining Time Space Position Information in Support of Aircraft Noise Certification

Abstract: Federal Aviation Regulation (FAR) Part 36, “Noise Standards: Aircraft Type and Airworthiness Certification,” requires that measured aircraft noise certification data be corrected to a nominal reference-day condition. This correction process which can be quite rigorous is typically done for sequential 1⁄2-second acoustic data records measured for a given aircraft noise certification event. Consequently, the process requires precise time-space-position-information (TSPI) for each acoustic data record within each event. Traditionally, noise certification applicants have used optical positioning systems such as still cameras and video 10 cameras, radar, or in rare instances, laser tracking systems. The accuracy of these systems is typically on the order of 10 to 20 ft., although the accuracy of laser tracking systems can be much better. In addition, many of these traditional systems only provide TSPI data over a relatively limited time interval in the vicinity of aircraft overhead, thus requiring extrapolation of TSPI data to sufficiently define aircraft position for each acoustic data record within each certification event. With the advent of differentially corrected global positioning systems (dGPS), the accuracy and limitations associated with traditional TSPI systems are easily overcome. This paper describes a dGPS TSPI system developed by the U.S. Department of Transportation (DOT) Volpe Center Acoustics Facility (Volpe). The paper includes descriptions of both the hardware and software components of the system. It also details the static and dynamic system performance.

Assessing the economic impact of aircraft noise on communities

Abstract: ASSESSING THE ECONOMIC IMPACT OF AIRCRAFT NOISE ON COMMUNITIES by Ithan B. Zimmer The impact of aircraft noise on communities is complex and multi-dimensional. This matter cannot be resolved without careful analysis of a complex array of related problems and issues including the environment, the economy, and quality-of-life concerns of people living in proximity to airports or aircraft routes. The effects of community noise are widespread and varied. Impacts can include sleep and speech interference, activity interference, general annoyance, and property value decrease. In order to improve public policy and provide a foundation for additional research, it is imperative to establish the extent of a problem. Dollars are often the least common denominator in distinguishing the magnitude of an impact. This research addresses this problem in terms of the cost of noise impact to an order-of-magnitude. It is extremely difficult to measure and price accurately most of these impacts. However, this dissertation evaluates, in dollars, the cost of aircraft noise to communities and provides possible strategies to mitigate negative consequences of that noise. The economic effect on the community is derived from the impact of aircraft noise on residential real estate values and the reduction of student proficiency rates on standard assessment tests. It is assumed that noise is an inconvenience to the community and a symptom of airport related issues that include not only the quality-of-life of citizens, but also the economic well-being of the community and region at-large. It must be recognized that airports provide and facilitate economic growth and prosperity for a region. Directly and indirectly, the aircraft industry provides jobs, wages, and airport-related regional sales. Presently, there are no universally accepted cost models and virtually all existing models assess real estate impact as the primary cost concern. The primary thesis goal is not to find a precise value for the cost of aircraft noise, but rather to establish a rationale for utilizing and quantifying criteria in order to assess the cost of noise to communities. This, in turn, may assist in developing public policy to address the expanded concerns related to aircraft noise. ASSESSING THE ECONOMIC IMPACT OF AIRCRAFT NOISE ON COMMUNITIES

Measurements Techniques for Transportation Noise

Abstract: The noise from transport systems (roads, railways and aircraft) are increasing more and more both in space and in time and, therefore, they are still the major factor responsible for environmental noise pollution. The population exposed to transport noise is also increasing, and the corresponding health effects on people (i.e. annoyance and sleep disturbance) become more severe. Due to this current situation international and national legislation has been issued and implemented to reduce the harmful effects of such noise. This paper describes the techniques prescribed by recent Italian legislation to measure road, railway and aircraft noise.

Perceptions of Aircraft Noise, Sleep and Health: Report to Civil Aviation Authority

Abstract: The report is intended to explore public perceptions of aircraft noise at night around UK airports, and also to identify the nature of the impacts. Also covered is an examination of relationships between perceptions of night-time aircraft noise, noise sensitivity and noise-disturbed sleep. The work was also concerned with alternative data collection strategies concerned with perceptions of aircraft noise. The research comprised discussions with residents around Heathrow and Manchester airports as well as an analysis of a previous survey in Bristol concerning aircraft noise at night. An interview survey was carried out of respondents around Heathrow, Manchester, Gatwick, East Midlands and Stanstead airports, as well as a postal survey in similar aras. Results analyse and classify aircraft night-time noise and its varying effect on sleep distrubance and health within the areas detailed.

The Influence of Nocturnal Aircraft Noise on Humans - A New Comprehensive Approach

Abstract: The DLR Institute of Aerospace Medicine in Cologne investigates the influence of nocturnal aircraft noise on human sleep and performance. 128 healthy volunteers aged 18-65 are being examined in four studies during 13 consecutive nights (2300-0700) in our sleep laboratory. The results will be validated in 2 field studies investigating 64 volunteers, thus 2496 nights in total will be observed. Various physiological signals are sampled: polysomnographic measurements (EEG, EOG, EMG), the electrocardiogram, finger pulse amplitude, respiration and actigraphy. The stress parameters cortisol, epinephrine and nor-epinephrine are extracted from nocturnal urine samples. The AGARD-Stres battery is used to examine the possible interference of aircraft noise induced sleep disturbances with mental performance. In order to measure subjective reactions, psychometric questionnaires are filled out twice a day. In 9 of the 13 nights of the laboratory studies, aircraft noise with varying frequencies of occurrence (4 to 128 events) and noise levels ranging from 50 to 80 dB LAS,max (LAS,eq(3) 31.2-52.6 dB) is presented by loudspeakers. Correct playback is assured by re-measurements of terz levels in each bedroom. The noise has been recorded in bedrooms with closed or tilted windows of residents living near an airport using a class 1 noise level meter. Since all parameters are stored simultaneously on hard disk, single noise events can be analysed and correlated with physiological parameters.

Recognition and quantification of aircraft noise events inside dwellings

Abstract: To examine the relation between aircraft noise and a certain parameter inside dwellings (e.g. sleep disturbance) it is necessary to determine whether an aircraft passage occurs and to value such an event. Monitoring the sound level is necessary for that purpose. As partner in a large survey our company is responsible for the acoustical aspect for which we monitor the sound level inside a number of dwellings on different locations in the vicinity of Amsterdam Airport Schiphol. In a pilot study, done by another research institute, the recognition and the quantification of the aircraft noise events was done on a real-time basis by which a threshold level had to be exceeded, with minimal duration and a certain exceedance hysteresis. The disadvantage of this method was that in situations with a high background level or noise disturbance (passing cars, snoring, overlapping aircraft events) events were missed or were taken into account incorrectly. Therefore a method has been developed by which the sound level is registered continuously, so afterwards a correct analysis is possible. By linking the noise data to radar observation data from the airport Flight track And Noise Monitoring System (FANOMOS) a good estimate can be made on what moment an aircraft passes. The method is automated in such a way that for every aircraft event maximum and SEL-values are determined. Based on different criteria the event is evaluated whether it has to be taken into account or not. In comparison with the pilot setup the percentage of correctly determined aircraft events is highly increased.

The role of urbis' noise and noise effects maps in local policy

Abstract: An important aspect of the EU noise policy is mapping of noise and noise effects and the formulation of noise action plans. In the Netherlands, due to the new policy on noise (MIG), the municipalities will be responsible for the formulation of a local noise policy. An instrument for the assessment of the noise and noise effects in a municipality or a region can form the basis of setting realistic goals. TNO has developed a GIS based instrument, Urbis, which makes it possible to assess the noise and noise effects in a city or region as a whole, with a high level of detail at relatively low cost. The noise and noise effects maps are based on existing information, wherever possible. Information on activities (e.g. road traffic data), emissions (e.g. rail noise emissions) or immissions (e.g. aircraft noise contours) is used, combined with information on the area (e.g. building configurations). Recently, Urbis has been applied in several (parts of) municipalities. Results of these surveys in the form of detailed noise maps and diagrams will be presented. Also, the implementation of this information in the municipal policy is discussed

The acoustical geometry of aircraft overflights

Abstract: Noise perceived in the surroundings of an airport is an important cause of annoyance because aircraft are very high sound power noise sources and, as a result of the lack of obstacles, propagation conditions are fairly good. Several publications, such as ICAO's Annex 16 on aircraft noise as well as Circular No 205 of the same entity, suggest methods to predict noise levels in the surroundings of an airport, including how to compute several descriptors which have proved useful in airport environmental noise assessment. However, they require intensive use of data regarding noise emission from different aircrafts, which in practice may be difficult or expensive to obtain. In this paper we show how these data may be easily derived from field measurements performed during aircraft overflights. From an aircraft overflight noise signal, acquired with a digital audio tape (DAT) recorder, the audio signal is computer-processed to plot its spectrogram. This is used to estimate the aircraft's speed and to derive the aircraft's altitude and elevation angle. Once the geometry of the overflight has been secured, the last step involves matching the propagation-corrected measured noise at several instants with the corresponding aircraft position. This allows to draft the polar pattern of the aircraft viewed as a noise source. (A) For the covering abstract see ITRD E113232.

Speech interference levels at airport noise impacted schools

Abstract: Schools that are not within the current 65-dBA DNL contour used by Federal Aviation Administration (FAA) to determine eligibility for school sound proofing, may still be impacted by aircraft noise associated with airport operations. Interior noise levels at several schools near the Newark International Airport (EWR) were monitored to determine the Speech Interference Level (SIL) at classrooms and other instructional areas of these schools. The high levels of interior PSIL were measured during the events of aircraft fly-overs. The measured PSIL can reach as high as 73 dB. The differences in PSILs between the ambient and aircraft fly-overs are 20 dB or more.

The person-events index - a simple but invaluable aircraft noise assessment tool

Abstract: In the mid 1990s there was a public outcry following the opening of a new runway at Sydney Airport. There were strident community claims that the Environmental Impact Statement (EIS) for the project had been misleading because it 'hid' the fact that the purported noise benefits of the project were only achieved through concentrating the noise on a small number of suburbs. The noise assessment in the EIS had used conventional thinking - a reduction in the number of persons within an airport's noise contours is a positive outcome. However, minimisation of the number of persons within the contours can be achieved in several ways. 'Real' noise reductions can be made, for example, by re-routing flights over non-residential areas. On the other hand this outcome can also be achieved simply by focussing the noise on a smaller number of people - the same macro noise exposure result but a very different outcome for the community. The Person-Events Index (PEI) is a simple tool, based on the N70, which, amongst other things, allows the decision maker and the community to very clearly see whether claimed environmental benefits of a project will simply be achieved by concentrating, rather than by reducing aircraft noise. The PEI is not designed to determine whether Option A is better than Option B. It is a tool to build public confidence in decision making processes through improving the transparency of conventional assessment approaches. (A) For the covering abstract see ITRD E113232.

Aircraft noise propagation in coastal areas

Abstract: Department of Defense (DoD) environmental noise management efforts employ computer models to project noise exposure around military installations, ranges, and operating areas. Both the DoD airfield noise model (noisemap) and the heavy weapons noise model (bnoise) assume propagation over land. In order to ensure the accuracy of these models for Navy and Marine Corps installations in coastal areas, the U.S. Navy has been funding studies of propagation over water. These studies have included: (1) joint work with the Swedish Air Force, (2) helicopter noise measurements along the southern California shore, (3) aircraft noise propagation studies in Florida and California, and (4) studies of gun fire propagation at the land–water boundary. Lessons learned from these efforts have been incorporated into the design of a new study of aircraft noise to be conducted this year.