Showing papers on "Aircraft noise published in 2022"

Balanced Approach to Aircraft Noise Management

Abstract: Abstract ICAO Balanced Approach (BA) to aircraft noise management in airports is reviewed in accordance with historical and technological challenges. All four basic elements of the BA are subject to noise exposure control with dominant emphasis on reduction of noise at source and compatible land usage inside the noise zoning around the airports. Noise abatement procedures and flight restrictions are used at any airport due to its specific issues and should be implemented on a basis of cost–benefit analysis. Noise exposure reduction is an intermediate goal, a final goal—to reduce noise impact, which is mostly represented by population annoyance as a reaction to noise exposure, is discussed also.

Challenges and opportunities for low noise electric aircraft

Abstract: A new class of electric aircraft is being developed to transport people and goods as a part of the urban and regional transportation infrastructure. To gain public acceptance of these operations, these aircraft need to be much quieter than conventional airplanes and helicopters. This article seeks to review and summarize the aeroacoustic research relevant to this new category of aircraft. First, a brief review of the history of electric aircraft is provided, with an emphasis on how these aircraft differ from conventional aircraft. Next, the physics of rotor noise generation are reviewed, and the noise sources most likely to be of concern for electric aircraft are highlighted. These are divided into deterministic and nondeterministic sources of noise. Deterministic noise is expected to be dominated by the unsteady loading noise caused by the aerodynamic interactions between components. Nondeterministic noise will be generated by the interaction of the rotor or propeller blades with turbulence from ingested wakes, the atmosphere, and self-generated in the boundary layer. The literature for these noise sources is reviewed with a focus on applicability to electric aircraft. Challenges faced by the aeroacoustician in understanding the noise generation of electric aircraft are then identified, as well as the new opportunities for the prediction and reduction of electric aircraft noise that may be enabled by advances in computational aeroacoustics, flight simulation, and autonomy.

Long-term aircraft noise exposure and risk of hypertension in the Nurses' Health Studies

Abstract: Aircraft noise can affect populations living near airports. Chronic exposure to aircraft noise has been associated with cardiovascular disease, including hypertension. However, previous studies have been limited in their ability to characterize noise exposures over time and to adequately control for confounders.The aim of this study was to examine the association between aircraft noise and incident hypertension in two cohorts of female nurses, using aircraft noise exposure estimates with high spatial resolution over a 20-year period.We obtained contour maps of modeled aircraft noise levels over time for 90 U.S. airports and linked them with geocoded addresses of participants in the Nurses' Health Study (NHS) and Nurses' Health Study II (NHS II) to assign noise exposure for 1994-2014 and 1995-2013, respectively. We used time-varying Cox proportional hazards models to estimate hypertension risk associated with time-varying noise exposure (dichotomized at 45 and 55 dB(A)), adjusting for fixed and time-varying confounders. Results from both cohorts were pooled via random effects meta-analysis.In meta-analyses of parsimonious and fully-adjusted models with aircraft noise dichotomized at 45 dB(A), hazard ratios (HR) for hypertension incidence were 1.04 (95% CI: 1.00, 1.07) and 1.03 (95% CI: 0.99, 1.07), respectively. When dichotomized at 55 dB(A), HRs were 1.10 (95% CI: 1.01, 1.19) and 1.07 (95% CI: 0.98, 1.15), respectively. After conducting fully-adjusted sensitivity analyses limited to years in which particulate matter (PM) was obtained, we observed similar findings. In NHS, the PM-unadjusted HR was 1.01 (95% CI: 0.90, 1.14) and PM-adjusted HR was 1.01 (95% CI: 0.89, 1.14); in NHS II, the PM-unadjusted HR was 1.08 (95% CI: 0.96, 1.22) and the PM-adjusted HR was 1.08 (95% CI: 0.95, 1.21). Overall, in these cohorts, we found marginally suggestive evidence of a positive association between aircraft noise exposure and hypertension.

Comparative assessment of measured and modelled aircraft noise around Amsterdam Airport Schiphol

Abstract: The impressive growth of the aviation industry and the number of flights entail several environmental repercussions, such as increased aircraft noise emissions. With the worrying number of complaints from the communities around airports comes also the distrust in numerical models used for aircraft noise prediction. In this study, we compare the ‘Dutch aircraft noise model’ predictions to measured values from the NOise MOnitoring System (NOMOS) around Amsterdam Airport Schiphol between 2012 and 2018. While the model underestimates aircraft noise in 2012, the model prediction improved throughout the years. We observe a decreasing trend of measured aircraft-related Lden values of 0.6 dB(A)/year (a total of 3.6 dB(A) over the investigation period), although the total number of flight movements increased during the observation time. We propose that a change in fleet mix, as well as the implementation of Noise Abatement Procedures at Schiphol Airport, fuelled this trend.

Annoyance due to residential road traffic and aircraft noise: Empirical evidence from two European cities

Abstract: Based on a study in two European cities, Mainz in Germany and Zurich in Switzerland, the article investigates both acoustical and non-acoustical factors affecting indoor annoyance due to residential road traffic and aircraft noise. We specifically focus on three factors: (1) the role of windows as a feature of the building where people live; (2) the role of individual environmental concern as a general attitude; and (3) the role of household income as an indicator of socioeconomic resources. Empirical results show that closed windows in general and closed high-quality windows in particular are an important barrier against outdoor road traffic and aircraft noise, as well as a helpful subjective coping tool against corresponding annoyances. Environmental concern, too, proves to be a significant predictor of noise annoyance. Environmentally highly concerned people articulate feelings of annoyance more often than environmentally less concerned ones. As expected income is negatively related to road traffic noise annoyance. However, we find a positive association of income with annoyance from aircraft noise. Although objective exposure to aircraft noise is lower for high-income households, they feel stronger annoyed by noise from airplanes. Income shows various indirect effects on noise annoyance. A comparative analysis of road traffic and aircraft noise annoyance yields similarities, but also remarkable differences in terms of their influence factors.

Computational Study on Noise of Urban Air Mobility Quadrotor Aircraft

Abstract: This paper investigates the acoustics of a one-passenger and a six-passenger quadrotor urban air mobility (UAM) aircraft in level flight based on a high-fidelity computational fluid dynamics (CFD) approach. The CFD simulations are carried out using the HPCMP CREATE TM -AV multidisciplinary rotorcraft analysis and simulation tool Helios. The acoustic simulations are performed using the acoustic prediction tool PSU-WOPWOP. A total of three CFD models are simulated: a onepassenger isolated rotor configuration, a one-passenger full configuration with a fuselage, and a six-passenger isolated rotor configuration. The noise comparison between the one-passenger isolated rotor case and the full configuration case shows that the vehicle fuselage increases the A-weighted sound pressure level (SPL) up to 5 dB. The acoustic comparison between the one-passenger and the six-passenger isolated rotor configuration shows that the maximum overall SPL difference is up to 14 dB. Furthermore, it is shown that the noise of the six-passenger configuration is approximately 11 dB lower than that of a similar-sized conventional helicopter in an overhead scenario. The community noise impact of UAM aircraft is also assessed and compared to various background noise levels. The results show that the one-passenger quadrotor noise can be fully masked by freeway noise at an altitude greater than or equal to 1000 ft, while the six-passenger quadrotor noise can only be partially masked by freeway noise even at an altitude of 1000 ft.

On the Fundamental Possibility of a Supersonic Civil Aircraft to Comply with ICAO Noise Requirements Using Existing Technologies

Abstract: Compliance with environmental protection regulations, in particular, community noise requirements, constitutes one of the major obstacles for designing future supersonic civil aircraft. Although there are several noise sources that contribute to the total noise level of supersonic aircraft, it is the turbulent jet that appears most problematic; jet noise is a dominant noise source for low-to moderate- bypass-ratio engines, and at present there are no effective methods of jet noise reduction other than decreasing jet speed by increasing bypass ratio, which, in turn, is constrained by aerodynamic requirements for supersonic flight. The present study considers a concept of supersonic civil aircraft under the assumption that its total noise is determined by turbulent jets; it is shown that compliance of the supersonic aircraft with the current regulations for subsonic aircraft noise (Chapter 14 Volume I Annex 16 ICAO) would require the decreased jet speed that corresponds to a prohibitively high bypass ratio of aircraft engines. To enable jet noise reduction without necessarily increasing bypass ratio, a novel configuration of supersonic aircraft is proposed that meets the requirements of Chapter 14, thereby demonstrating that the norms of Chapter 14 are achievable for future supersonic civil aircraft with the use of existing technologies.

Guidelines for the LTO Noise Assessment of Future Civil Supersonic Aircraft in Conceptual Design

Abstract: One of the most critical regulatory issues related to supersonic flight arises from limitations imposed by community noise acceptability. The most efficient way to ensure that future supersonic aircraft will meet low-noise requirements is the verification of noise emissions from the early stages of the design process. Therefore, this paper suggests guidelines for the Landing and Take-Off (LTO) noise assessment of future civil supersonic aircraft in conceptual design. The supersonic aircraft noise model is based on the semi-empirical equations employed in the early versions of the Aircraft NOise Prediction Program (ANOPP) developed by NASA, whereas sound attenuation due to atmospheric absorption has been considered in accordance with SAE ARP 866 B. The simulation of the trajectory leads to the prediction of the aircraft noise level on ground in terms of several acoustic metrics (LAmax, SEL, PNLTM and EPNL). Therefore, a dedicated validation has been performed, selecting the only available supersonic aircraft of the Aircraft Noise and Performance database (ANP), that is, the Concorde, through the matching with Noise Power Distance (NPD) curves for LAmax and SEL, obtaining a maximum prediction error of ±2.19%. At least, an application to departure and approach procedures is reported to verify the first noise estimations with current noise requirements defined by ICAO at the three certification measurement points (sideline, flyover, approach) and to draw preliminary considerations for future low-noise supersonic aircraft design.

Incident hypertension in relation to aircraft noise exposure: results of the DEBATS longitudinal study in France

Abstract: Background Although several cross-sectional studies have shown that aircraft noise exposure was associated with an increased risk of hypertension, a limited number of longitudinal studies have addressed this issue. This study is part of the DEBATS (Discussion on the health effect of aircraft noise) research programme and aimed to investigate the association between aircraft noise exposure and the incidence of hypertension. Methods In 2013, 1244 adults living near three major French airports were included in this longitudinal study. Systolic and diastolic blood pressure, as well as demographic and lifestyle factors, were collected at baseline and after 2 and 4 years of follow-up during face-to-face interviews. Exposure to aircraft noise was estimated for each participant’s home address using noise maps. Statistical analyses were performed using mixed Poisson and linear regression models adjusted for potential confounding factors. Results A 10 dB(A) increase in aircraft noise levels in terms of Lden was associated with a higher incidence of hypertension (incidence rate ratio (IRR)=1.36, 95% CI 1.02 to 1.82). The association was also significant for Lday (IRR 1.41, 95% CI 1.07; to 1.85) and Lnight (IRR 1.31, 95% CI 1.01 to 1.71). Systolic and diastolic blood pressure increased with all noise indicators. Conclusion These results strengthen those obtained from the cross-sectional analysis of the data collected at the time of inclusion in DEBATS, as well as those from previous studies conducted in other countries. Hence, they support the hypothesis that aircraft noise exposure may be considered as a risk factor for hypertension.

Application of Mathematical Modeling to Study Near-Field Pressure Pulsations of a Near-Future Prototype Supersonic Business Aircraft

Abstract: The paper considers practical aspects of mathematical modeling in predictions of the level of near-field pressure pulsations of a near-future prototype supersonic business aircraft. A numer...

Auralization of aircraft flyovers with turbulence-induced coherence loss in ground effect.

Abstract: Residents around airports are impacted by noise produced by civil aircraft operations. With the aim of reducing the negative effects of noise, new low-noise aircraft concepts and flight procedures are being developed. The design processes and the assessments of design variants can be supported by auralization of virtual flyovers. The plausibility of auralized aircraft is increased by considering the effects of atmospheric turbulence on sound propagation. This paper presents a simple approach to include turbulence-induced coherence loss in ground effect. Compared to earlier approaches, the proposed model is closer to the physical mechanisms. It is based on the von Kármán turbulence spectrum and a time-variant partial decorrelation filter. The application of the model to jet aircraft flyovers revealed audible improvements by reducing unnatural flanging. The proposed model increases the accuracy and plausibility of aircraft flyover auralizations. It will thus be applied in the perception-based evaluation of future aircraft concepts.

High-Fidelity Computational Analysis on the Noise of a Side-by-Side Hybrid VTOL Aircraft

Abstract: This paper investigates the acoustics of a side-by-side urban air mobility (UAM) aircraft with 0%, 5%, 15%, and 25% rotor overlaps in forward flight based on high-fidelity computational fluid dynamics (CFD) simulations. The CFD and acoustics simulations are carried out using the HPCMP CREATE TM -AV rotorcraft simulation and analysis tool Helios and the acoustic prediction tool PSU-WOPWOP. First, the influence of the finest wake-grid spacing (Δ finest ) on the side-by-side rotor acoustics is studied. No significant difference in overall sound pressure level (OASPL) is found between the two wakegrid spacing cases: Δ finest = 5% C tip and 10% C tip . Physical noise sources, such as impulsive self blade–vortex interactions, rotor-to-rotor blade–vortex interactions, and separated flow and blade interactions, are investigated in details based on high-fidelity CFD simulation results and noise-integrand analyses. The effect of rotor overlap on rotor acoustics is also assessed. It is found that the maximum OASPL difference among the overlap cases is about 1 dB, but the radiation patterns are different for each overlap case. Furthermore, the noise of the side-by-side rotor with 0% and 25% overlaps is compared against the noise of a conventional helicopter and various background noises. The side-by-side rotor noise is comparable with the helicopter noise around 1000 Hz. The results also show that the side-by-side rotor noise could not be fully masked by the freeway background noise even at an altitude of 1500 ftand exceed Uber's noise guideline of 62 dBA at 500 ft. Thus, noise reduction technology should be pursued to lower UAM aircraft noise, which is one of major technical barriers for UAM public acceptance.

System Noise Assessment and Uncertainty Analysis of a Conceptual Supersonic Aircraft

Abstract: : This paper describes a system noise assessment of a conceptual supersonic aircraft called the NASA 55t Supersonic Technology Concept Aeroplane (STCA), its prediction uncertainty, and related validation tests. A landing and takeoff noise (LTO) standard for supersonic aircraft is needed to realize future supersonic aircraft, and the noise impact due to the introduction of future supersonic aircraft should be analyzed to develop the standard. System noise assessments and uncertainty analyses using Monte Carlo simulation (MCS) were performed. The predicted noise levels showed good agreement with the prior study for both the benchmark case and statistics of the predictions. The predicted cumulative noise level satisfied the ICAO Chapter 4 noise standard, and its standard deviation was approximately 2 EPNdB. Moreover, sensitivity analysis using the obtained datasets revealed strong correlations with the takeoff noise for jet noise, fan exhaust noise at the flyover measurement point, and airframe trailing edge noise. Further understanding of these extracted factors, which were estimated to have a significant impact on the LTO noise, will be beneficial for the development of LTO noise standards and the design of supersonic aircraft.

Simultaneous Use of Ground Reflection and Lateral Attenuation Noise Models

Abstract: No AccessEngineering NotesSimultaneous Use of Ground Reflection and Lateral Attenuation Noise ModelsJeffrey J. BertonJeffrey J. Berton https://orcid.org/0000-0002-8258-0883NASA John H. Glenn Research Center at Lewis Field, Cleveland, Ohio 44135*Aerospace Engineer, Propulsion Systems Analysis Branch. Senior Member AIAA.Search for more papers by this authorPublished Online:22 Dec 2021https://doi.org/10.2514/1.C036488SectionsRead Now ToolsAdd to favoritesDownload citationTrack citations ShareShare onFacebookTwitterLinked InRedditEmail About References [1] Chien C. F. and Soroka W. W., “Sound Propagation Along an Impedance Plane,” Journal of Sound and Vibration, Vol. 43, No. 1, Nov. 1975, pp. 9–20. https://doi.org/10.1016/0022-460X(75)90200-X CrossrefGoogle Scholar[2] Chien C. F. and Soroka W. 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Berton13 June 2022On the Design of Variable Noise Reduction Systems for Supersonic Transport Take-off Certification Noise ReductionLaurens Voet, Raymond L. Speth, Jayant S. Sabnis, Choon S. Tan and Steven R. Barrett13 June 2022 What's Popular Volume 59, Number 2March 2022 CrossmarkInformationThis material is declared a work of the U.S. Government and is not subject to copyright protection in the United States. All requests for copying and permission to reprint should be submitted to CCC at www.copyright.com; employ the eISSN 1533-3868 to initiate your request. See also AIAA Rights and Permissions www.aiaa.org/randp. TopicsAeronauticsAerospace Information ReportAircraft Components and StructureAircraft ControlAircraft DesignAircraft Flight ManualAircraft Operation ManualAircraft Operations and TechnologyAircraft Stability and ControlAircraftsAviationAviation NoiseCivil AircraftEnvironmental Impact of AviationHelicoptersRotorcrafts KeywordsSupersonic AirplanePerceived Noise LevelAIREffective Perceived Noise LevelInternational Civil Aviation OrganizationAircraft ConfigurationsAviation Environmental Design ToolSupersonic TransportsComputingProbability Density FunctionsAcknowledgmentThe author thanks the NASA Commercial Supersonic Technology Project for supporting this study.PDF Received1 April 2021Accepted28 November 2021Published online22 December 2021

Delayed Deceleration Approach Noise Impact and Modeling Validation

Abstract: A validation methodology and evaluation of delayed deceleration approach performance and noise-impact modeling using noise measurements and radar data are presented. Advanced procedures such as delayed deceleration approaches, where aircraft maintain higher speeds and therefore remain cleanly configured and at lower thrust levels for longer flight periods, can be used for airport noise abatement. Delayed deceleration approaches have been shown in modeling to offer noise reductions before the stabilization point compared to procedures that decelerate early. The delayed deceleration approach validation methodology is demonstrated through monitoring of operational radar data with varying velocity profiles from Boeing 737, Airbus A320, and Embraer E190 flights and comparing modeled sound exposure levels of these procedures with available ground-noise-monitor data at two major airports. Thrust from radar flights was modeled based on weight predicted from final approach speed and assumed configuration. When corrected for atmospheric conditions, modeled noise is shown to be consistent with noise-monitor readings under reasonable flap-deployment schedule assumptions during observed early, intermediate, and delayed deceleration approaches. In addition, delayed deceleration approaches correlated with monitor readings with lower noise levels of an average of 3–6 dB compared to early deceleration approaches across different aircraft types.

Uncertainty Quantification for Aircraft Noise Emission Simulation: Methods and Limitations

Abstract: Implementing measures for the reduction of aircraft noise impact, such as optimization of flight paths and aircraft, requires sophisticated simulation capabilities. These tools have to incorporate simulation of aircraft noise generation at the source (i.e., emission) and account for prevailing sound propagation effects to ultimately predict noise levels as received on the ground. Obviously, understanding the associated uncertainties is crucial when aiming at a reliable and meaningful assessment. It also becomes essential when comparing different technologies, mixing experimental and numerical data, or using simulation methods of different fidelity (e.g., semi-empirical and first-order methods). This research focuses on quantifying uncertainties in the first step in aircraft noise simulation (i.e., the prediction of the emission situation). The quantified uncertainties reflect imperfections of models for different aircraft noise sources and variability of model input parameters at different operating conditions. A general framework is presented, which also accounts for limited knowledge of the underlying data distributions, and quantitative comparisons of different uncertainty methods are provided. In particular, the first-order second-moment analysis is compared to higher-order polynomial chaos methods, and the advantages and disadvantages of the different methods are discussed.

Sociodemographic Patterns of Exposure to Civil Aircraft Noise in the United States

Abstract: Background: Communities with lower socioeconomic status and higher prevalence of racial/ethnic minority populations are often more exposed to environmental pollutants. Although studies have shown associations between aircraft noise and property values and various health outcomes, little is known about how aircraft noise exposures are sociodemographically patterned. Objective: Our aim was to describe characteristics of populations exposed to aviation noise by race/ethnicity, education, and income in the United States. Methods: Aircraft noise contours characterized as day–night average sound level (DNL) were developed for 90 U.S. airports in 2010 for DNL ≥45 dB(A) in 1-dB(A) increments. We compared characteristics of exposed U.S. Census block groups at three thresholds (≥45, ≥55, and ≥65 dB(A)), assigned on the basis of the block group land area being ≥50% within the threshold, vs. unexposed block groups near study airports. Comparisons were made across block group race/ethnicity, education, and income categories within the study areas (n=4,031–74,253). We performed both multinomial and other various multivariable regression approaches, including models controlling for airport and models with random intercepts specifying within-airport effects and adjusting for airport-level means. Results: Aggregated across multiple airports, block groups with a higher Hispanic population had higher odds of being exposed to aircraft noise. For example, the multinomial analysis showed that a 10-percentage point increase in a block group’s Hispanic population was associated with an increased odds ratio of 39% (95% CI: 25%, 54%) of being exposed to ≥65 dB(A) compared with block groups exposed to <45 dB(A). Block groups with higher proportions of residents with only a high school education had higher odds of being exposed to aircraft noise. Results were robust across multiple regression approaches; however, there was substantial heterogeneity across airports. Discussion: These results suggest that across U.S. airports, there is indication of sociodemographic disparities in noise exposures. https://doi.org/10.1289/EHP9307

Effect of Slat Tracks and Inboard Slat Tip Geometry on Airframe Noise

Abstract: This paper summarizes results from simulations of the JAXA OTOMO2 high-lift wing noise research model using lattice-Boltzmann method very large eddy simulations (LBM-VLES). Sensitivity studies are conducted by varying aspects of the slat geometry, focusing on slat tracks and the inboard slat tip, to evaluate changes in airframe noise. Simulations are validated with experimental data, when available, with very good agreement. Results indicate the slat track and inboard tip are dominant noise sources and their noise is highly sensitive to the different geometries tested, suggesting that slat aeroacoustics being part of the wing design process can lead to substantial benefits in noise reduction. The effectiveness of a slat cove filler in the presence of slat tracks is significantly reduced, indicating that 2D approaches to slat noise reduction might not be effective in reality. The slat root is also shown to influence noise due to wing sweep noticeably.

Understanding the Basics of Aviation Noise

Abstract: Abstract This chapter deals with the description of the physical mechanisms of noise, the noise perception and the annoyance induced by air traffic in the aeronautics domain. The authors introduce the basics of aviation noise, describe the main characteristics of the noise emitted by an aircraft in flight, recall the fundamental laws of the audition and noise perception and present the specific context for the annoyance due to aviation noise. This chapter presents and details, as simply as possible, the complex relationships between physical phenomena and noise perception in order to highlight the key notions in aviation noise issues. The readers will find answers to many usual and legitimate questions, for example what is the relationship between the perceived noise and the level of the physical noise related to the European ACARE goals which are expressed sometimes as EPNL reduction in dB or sometimes as perceived noise reduction in percent.

Comparison of Semi-Empirical Noise Models with Flyover Measurements of Operating Aircraft

Abstract: The contribution of the engine and the airframe to the total noise generated by an aircraft varies with the operating conditions. Semi-empirical models are able to account for such variations but require detailed engine and airframe data as input that is not readily available for most aircraft types and operations. This hinders the validation of these models through comparison between predictions and experimental data. This work investigates the sensitivity of semi-empirical models of engine and airframe noise to slight variations of the input data, representative of uncertainties in geometrical parameters and variability of the aircraft operating conditions during flyovers. In addition, the predictions are compared to measurements of A320, A330, and B777 landings and departures. This, together with the sensitivity analysis, indicates frequency regions where a mismatch between measurements and predictions exists. The deviation between predictions and measurements for landings can be partially explained by the underestimation of the sound pressure level of the higher harmonics of the fan. For takeoff, the models predict lower levels than measured. This is hypothesized to be associated with jet-installation noise, which is not accounted for in the semi-empirical models. The predicted spectra of the Airbus A320 and A330 were adjusted to account for jet installation noise, using levels available in the literature. This resulted in a better agreement between modeled and measured spectra at low frequencies.

Development and Validation of Generic Maneuvering Flight Noise Abatement Guidance for Helicopters

Abstract: An extensive flight-test campaign has been conducted to look into developing actionable advice for pilots of today's vehicles to reduce their acoustic footprints. Ten distinct vehicles were tested at three different test ranges, with nine of the vehicles' data being documented here. Twelve pairs of turning conditions were tested to determine their effect on blade–vortex interaction noise. Each turning flight condition was evaluated using the peak A-weighted, band-limited (50–2500 Hz), sound pressure level measured throughout the maneuver. This metric was a surrogate for blade–vortex interaction (BVI) noise, and the difference between the peak values of each turning pair was investigated. That peak value difference was subsequently corrected by the offset from the intended vehicle altitude at turn initiation from the actual altitude at initiation. The corrected amplitudes were investigated and grouped into six validated actionable guidance principles that can be given to pilots to immediately reduce their acoustic footprint during operations. This generic guidance works by keeping the rotor well away from the wake throughout the maneuver, thus increasing miss distance and reducing the occurrence of objectionable BVI noise.

Prediction-Based Approaches for Generation of Noise-Power-Distance Data with Application to Urban Air Mobility Vehicles

Abstract: In contrast to most commercial air traffic today, vehicles serving the urban air mobility (UAM) market are anticipated to operate within communities and be close to the public at large. The approved model for assessing environmental impact of air traffic actions in the United States, the Federal Aviation Administration (FAA) Aviation Environmental Design Tool (AEDT), does not directly support analysis of such operations due to a combined lack of UAM aircraft flight performance model data and aircraft noise data. This paper addresses the latter by offering two prediction-based approaches for generation of noise-power-distance (NPD) data for use within AEDT. One utilizes AEDT’s fixed-wing aircraft modeling approach and the other utilizes the rotary-wing aircraft modeling approach.

Long-term aircraft noise exposure and risk of hypertension in postmenopausal women.

Abstract: Studies of the association between aircraft noise and hypertension are complicated by inadequate control for potential confounders and a lack of longitudinal assessments, and existing evidence is inconclusive.We evaluated the association between long-term aircraft noise exposure and risk of hypertension among post-menopausal women in the Women's Health Initiative Clinical Trials, an ongoing prospective U.S.Day-night average (DNL) and night equivalent sound levels (Lnight) were modeled for 90 U.S. airports from 1995 to 2010 in 5-year intervals using the Aviation Environmental Design Tool and linked to participant geocoded addresses from 1993 to 2010. Participants with modeled exposures ≥45 A-weighted decibels (dB [A]) were considered exposed, and those outside of 45 dB(A) who also did not live in close proximity to unmodeled airports were considered unexposed. Hypertension was defined as systolic/diastolic blood pressure ≥140/90 mmHg or inventoried/self-reported antihypertensive medication use. Using time-varying Cox proportional hazards models, we estimated hazard ratios (HRs) for incident hypertension when exposed to DNL or Lnight ≥45 versus <45 dB(A), controlling for sociodemographic, behavioral, and environmental/contextual factors.There were 18,783 participants with non-missing DNL exposure and 14,443 with non-missing Lnight exposure at risk of hypertension. In adjusted models, DNL and Lnight ≥45 db(A) were associated with HRs of 1.00 (95% confidence interval [CI]: 0.93, 1.08) and 1.06 (95%CI: 0.91, 1.24), respectively. There was no evidence supporting a positive exposure-response relationship, and findings were robust in sensitivity analyses. Indications of elevated risk were seen among certain subgroups, such as those living in areas with lower population density (HRinteraction: 0.84; 95%CI: 0.72, 0.98) or nitrogen dioxide concentrations (HRinteraction: 0.82; 95%CI: 0.71, 0.95), which may indicate lower ambient/road traffic noise. Our findings do not suggest a relationship between aircraft noise and incident hypertension among older women in the U.S., though associations in lower ambient noise settings merit further investigation.