Journal of Aeronautics & Aerospace Engineering
Open Access

Aircraft Acoustics and Aerophones Maintaining Sound Dynamics in Aviation for Passenger Comfort and Aviation Performance

Daisuke Inoue^{* *}Correspondence: Daisuke Inoue, Department of Aerospace Engineerin, Nagoya University, Nagoya, Japan, Email:

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About the Study

Aircraft acoustics is an integral field of study in aviation engineering that deals with the control and management of sound within the aircraft environment. Sound dynamics, which includes the noise generated by various components of the aircraft, plays an important role in both passenger comfort and overall aviation performance. Understanding and mitigating the effects of sound, particularly unwanted noise, are vital for improving passenger experience, optimizing aircraft design and ensuring safe operations.

Understanding aircraft acoustics

Aircraft acoustics involves the study of noise generated during an aircraft’s operation. This noise can be generated by several sources, including engines, airframes and aerodynamic interactions. The term "aerophones" refers to the specific sounds produced by the aircraft as it interacts with air while in motion, contributing to what is typically considered the "noise profile" of an aircraft.

Aircraft noise can be categorized into two main types: Internal and external. Internal noise refers to the sound that reaches the cabin environment, impacting the passengers and crew. External noise primarily affects the environment around the aircraft, including the area near airports and is an important consideration for regulatory bodies aiming to reduce aviation's impact on local communities.

Sources of aircraft noise

Engine noise: One of the most significant contributors to overall aircraft noise is the engine. Jet engines, especially turbojet and turbofan engines, produce high levels of noise during takeoff, cruising and landing. The sound generated by engines is often associated with the thrust produced and factors like engine design, thrust settings and altitude all influence the sound dynamics of the aircraft.

Aerodynamic noise: The movement of air around the aircraft during flight creates aerodynamic noise. This includes the sounds produced by the friction between the air and the aircraft’s surfaces, such as the fuselage, wings and control surfaces. This type of noise becomes more pronounced at higher speeds and altitudes.

Propeller noise: Aircraft powered by propellers, such as small commuter aircraft, experience a distinct type of noise due to the rotating blades. These sounds are typically lower in frequency compared to jet engine noise, but they can still contribute significantly to the overall acoustic environment inside and around the aircraft.

Implications for passenger comfort

The primary concern for passengers in modern aviation is comfort and noise plays a substantial role in this aspect. Studies have shown that prolonged exposure to high noise levels can lead to discomfort, fatigue and even long-term hearing impairment.

Sound pressure levels: The intensity of the sound, measured in decibels, dictates its impact on the passenger experience. The sound dynamics inside the cabin must be carefully managed to maintain levels that are comfortable without being intrusive. Ideally, sound pressure levels should be maintained below 60 dB during cruising, with levels slightly higher during takeoff and landing.

Low-frequency noise: One of the most disruptive types of noise is low-frequency noise, which is produced by engines and aerodynamic forces. Low-frequency noise is particularly problematic because it can travel long distances, penetrate cabin insulation and cause discomfort, especially during long-haul flights.

Passenger health: Apart from discomfort, exposure to high levels of noise can have physiological effects. These include sleep disturbance, increased heart rate and elevated stress levels.

Ensuring a quieter cabin environment is thus necessary not only for passenger comfort but also for their well-being during flights.

Discussing aircraft acoustics requires innovative approaches in both aircraft design and operational strategies. Below are key measures taken to reduce noise levels:

Engine design improvements: Modern turbofan engines are designed with advanced noise-reducing technologies, including acoustic liners and quieter fan blades. These innovations help reduce the noise produced by the engine, particularly during takeoff and landing.

Aircraft shape and aerodynamics: The design of the aircraft plays an important role in controlling aerodynamic noise. Streamlined shapes and the use of winglets help reduce drag and turbulence, leading to lower noise levels. The shape and size of the aircraft's components are continually optimized to minimize aerodynamic sound production.

Active Noise Cancellation (ANC): Some airlines are employing ANC technologies within the cabin. These systems use microphones to pick up sound and generate sound waves that cancel out the unwanted noise. ANC systems have shown potential in reducing noise from the engines and air conditioning systems, significantly enhancing passenger comfort.