Shifting paradigms: From noise abatement to acoustics-oriented (aircraft) design

Sabine C. Langer – s.langer@tu-braunschweig.de

TU Braunschweig, Institute for Acoustics and Dynamics, Braunschweig, Lower Saxony, 38108, Germany

LinkedIn: http://www.linkedin.com/in/sabine-langer-6450a033a

Popular version of 4aEA2 – Toward acoustics-oriented aircraft design for highly integrated transport aircraft
Presented at the 190th ASA Meeting
Read the abstract at https://eppro01.ativ.me/web/index.php?page=Session&project=ASASPRING2026&id=4071512

–The research described in this Acoustics Lay Language Paper may not have yet been peer reviewed–

“Noise must one day be fought as bitterly as cholera and the plague,” Robert Koch the German bacteriologist famously said at the turn of the 20th century. He was right—today we know that too much noise can harm our well-being and lead to real health problems.

Traditionally, we’ve tried to “combat” noise with after-the-fact abatement measures. But wouldn’t it make more sense to prevent noise before it ever starts? That’s why, decades ago, ISO standards laid out rules for low-noise design across the entire sound-generation chain—from the source, through all the transmission paths, to the listener. Yet in our modern, highly technical, urban world, these low-noise principles alone aren’t enough: noise challenges are still growing.

Take traffic, for example. In cities around the world, countless people are constantly disturbed by the noise of cars, trains and aircraft. We need to step up our efforts with a full paradigm shift toward acoustics-oriented design—a strategy that defines desired sound characteristics right at the start of product development and then uses methods and tools to predict, create, implement, and assess those acoustic properties throughout the entire process.

Diagram showing shift from noise abatement to acoustics-oriented design in product development over time.Figure 1: From noise abatement to acoustics-oriented design in all phases of product development (Image adapted from Rothe[1]) and Langer [2])

That sounds great in theory—but how do you predict what a complex system like an aircraft will sound like before you even build a prototype? The answer is advanced computer modelling, efficient simulation and perceptual-driven assessment. These tools let us forecast how a future aircraft will sound like and let us even listen to it.

Diagram showing an aircraft design process from modeling to simulation to assessment with a detailed plane and blade passing frequency chart.Figure 2: Enabler for acoustics-oriented design: Modeling, Simulation, Assessment (Image adapted from Langer [3] )

Implementing acoustics-oriented design, we make sure that tomorrow’s aircraft not only burn less fuel and emit fewer pollutants but also sound pleasant—both inside the cabin and out on the ground.

[1] Rothe, S.: Design and placement of passive acoustic measures in early design phases. Schriften des Instituts für Akustik. 2022
[2] Langer, S.: Paving the path for acoustics-oriented design. ISCV31, 2025
[3] Thoma, J.; Delfs, J.: Proskurov, S.; Langer, S. C.: Cabin acoustics in preliminary aircraft design with propulsion pressure field excitation. DAS-DAGA2025/629, 2025.

The FAA allows Americans to be exposed to unsafe levels of aircraft noise

Daniel Fink – djfink01@aol.com
Twitter: @QuietCoalition

Board Chair, The Quiet Coalition, 60 Thoreau Street, Concord, MA, 01742, United States

The Quiet Coalition is a program of Quiet Communities, Inc., Lincoln, MA, USA

Popular version of 4aNS8-The Federal Aviation Administration (FAA) allows Americans to be exposed to unsafe levels of aviation noise

Presented at the 183rd ASA Meeting

Photo credit: Pixabay 

The American Public Health Association states, “Noise is unwanted and/or harmful sound.” Noise not loud enough to damage hearing causes high blood pressure, heart attacks, and strokes. The Federal Aviation Administration (FAA) considers noise an annoyance but does not acknowledge the adverse health effects of aircraft noise. Based on the Schultz curve, the FAA adopted 65 dBA Day-Night Level (DNL) as “the threshold for significant aviation noise, below which residential land use is compatible.”  The FAA’s recent Neighborhood Environmental Survey found that many more Americans are annoyed by noise than previously known.

Schultz Curve and Neighborhood Environmental Survey results, showing that many more Americans are annoyed by noise than the Schultz Curve showed. Source: FAA

Schultz Curve and Neighborhood Environmental Survey results, showing that many more Americans are annoyed by noise than the Schultz Curve showed. Source: FAA

[I have to tell you a little about the science of sound or noise measurement. The words sound and noise are used interchangeably. Sound is measured in decibels (dB). The decibel scale is logarithmic. This means that a 10 dB increase from 50 to 60 dB indicates 10 times more sound energy, not merely 20% more. Because noise disrupts sleep, DNL measures noise for 24 hours but adds a 10 dB penalty for noise between 10 p.m. and 7 a.m.  A-weighting (dBA) adjusts sound measurements for the frequencies heard in human speech. A-weighting is not the right measure for aircraft noise because aircraft noise has lower frequencies than speech. A-weighting also reduces unweighted sound measurements by about 20-30 dB.]

According to the Environmental Protection Agency (EPA), though, safe noise levels are only 45 dB DNL for indoor noise and 55 dB DNL for outdoor noise. The World Health Organization (WHO) recommends lower aircraft noise levels: 45 dB Day-Evening-Night Level (adding a 5 dB penalty for noise between 7-10 p.m.) and 40 dB at night.  Both EPA safe noise levels and WHO recommended aircraft noise levels are obviously much lower than the FAA’s 65 dBA DNL, especially because they use unweighted dB.

Being annoyed or disturbed by aircraft noise is stressful.  Stress increases heart rate and blood pressure. Stress increases blood levels of stress hormones.  Stress causes inflammation of the blood vessel lining. in turn causing cardiovascular disease, including hypertension and heart attacks, and other adverse health effects. Scientific experts think that the evidence is strong enough to establish causality, not merely a statistical association. Epidemiological studies demonstrating these effects have been confirmed by human and animal research. The biological mechanisms are now understood at the cellular, subcellular, molecular, and genetic levels.  Aircraft noise also affects poor and minority communities more than others. Children are also more sensitive to damage from noise, which also interferes with learning.

The FAA insists that more research is needed, but no more research is needed to know that aviation noise is hazardous to health.  The FAA must establish lower noise standards to protect Americans exposed to aircraft noise.