Abstract: Outflow valve assemblies for an aircraft, aircraft including an outflow valve assembly, and methods for installing an outflow valve assembly on an aircraft, are provided. In one example, an outflow valve assembly includes a louver that is movably disposed to at least partially cover an opening formed through a fuselage on an aircraft. A motor is coupled to the louver and is configured to move the louver between a closed position to obstruct fluid communication through the opening and an open position to allow fluid communication through the opening between inside and outside of the aircraft. A sound absorptive panel is disposed adjacent to the opening to attenuate noise that is generated when the louver is in the open position.

Abstract: Arrangements for communication and/or noise attenuation within an aircraft, and aircraft and methods for making aircraft including such arrangements are provided. In one example, an arrangement includes an array of first microphones cooperatively configured to be directed towards a first aircraft operator when disposed in a first cockpit seat to receive a first communication input from the first aircraft operator. An array of first speakers is cooperatively configured to be directed towards the first aircraft operator when disposed in the first cockpit seat to provide a first communication output to the first aircraft operator.

Abstract: An aircraft includes a turbine engine, a vibration sensor, and a processor. The vibration sensor is attached to the turbine engine and is configured to output a vibration sensor signal. The processor is programmed to determine whether the vibration sensor signal indicates that fan case liner damage has occurred due to icing conditions. The processor is further programmed to indicate that a fan case inspection should be conducted in response to the vibration sensor signal indicating that fan case liner damage has occurred.

Abstract: An aircraft includes a fuselage, a cabin surface, and a first chamber. The cabin surface is disposed within the fuselage and defines a first aperture and at least part of a cabin air mass having a first acoustic mode. The first chamber is acoustically coupled with the aperture and has a length that is one quarter of a wavelength of sound at the first acoustic mode.

Abstract: An aircraft includes a fuselage, a cabin surface, and a first chamber. The cabin surface is disposed within the fuselage and defines a first aperture and at least part of a cabin air mass having a first acoustic mode. The first chamber is acoustically coupled with the aperture and has a length that is one quarter of a wavelength of sound at the first acoustic mode.

Abstract: Aircraft, wing-to-body fairing assemblies, and air exchange systems are provided. An aircraft includes a fuselage, a wing secured to the fuselage, an outer skin panel, and an air exchange system. The outer skin panel is secured to the wing and/or the fuselage and at least partially defines a cavity. The air exchange system is secured to the outer skin panel and exchanges air between the cavity and an external environment. The air exchange system includes an air inlet, a diffuser, and a silencer. The air inlet is disposed in the outer skin panel and accommodates an air flow between the cavity and the external environment. The diffuser is attached to the air inlet and has a varying cross sectional area to change the speed of the air flow. The silencer is attached to the diffuser and communicates the air flow between the diffuser and the cavity and reduces noise.

Abstract: Aircraft, wing-to-body fairing assemblies, and air exchange systems are provided. An aircraft includes a fuselage, a wing secured to the fuselage, an outer skin panel, and an air exchange system. The outer skin panel is secured to the wing and/or the fuselage and at least partially defines a cavity. The air exchange system is secured to the outer skin panel and exchanges air between the cavity and an external environment. The air exchange system includes an air inlet, a diffuser, and a silencer. The air inlet is disposed in the outer skin panel and accommodates an air flow between the cavity and the external environment. The diffuser is attached to the air inlet and has a varying cross sectional area to change the speed of the air flow. The silencer is attached to the diffuser and communicates the air flow between the diffuser and the cavity and reduces noise.

Abstract: Embodiments of thermal-acoustic sections for an aircraft for reducing noise along an acoustic path produced from an acoustic source are provided herein. The thermal-acoustic section comprises a first porous layer having a first characteristic acoustic impedance. A second porous layer is disposed adjacent to the first porous layer and has a second characteristic acoustic impedance that is greater than the first characteristic acoustic impedance. The thermal-acoustic section is configured to be positioned along the acoustic path such that at least a portion of the noise from the acoustic source is directed through the first porous layer to the second porous layer to promote absorption of the noise.

Abstract: Embodiments of thermal-acoustic sections for an aircraft for reducing noise along an acoustic path produced from an acoustic source are provided herein. The thermal-acoustic section comprises a first porous layer having a first characteristic acoustic impedance. A second porous layer is disposed adjacent to the first porous layer and has a second characteristic acoustic impedance that is greater than the first characteristic acoustic impedance. The thermal-acoustic section is configured to be positioned along the acoustic path such that at least a portion of the noise from the acoustic source is directed through the first porous layer to the second porous layer to promote absorption of the noise.

Abstract: A vibration isolation system for attenuating vibration energy between two aircraft structures, such as between the aircraft's fuselage and interior cabin. The vibration isolation system includes a first isolator attached to the first structure, a second isolator attached to the second structure, and an intermediate mass attached between the first and second isolators. The intermediate mass may be electrical cables, wiring bundles, a cable holder, or other component disposed between the two structures. Cable holder intermediate masses can be fabricated from an electrically conductive material to provide electromagnetic interference shielding for cables disposed therein. Multiple vibration isolation systems can be disposed between the fuselage and interior cabin to provide a less noisy cabin. Additional noise and vibration suppressors, such as skin damping material and acoustic blankets, also can be disposed between the fuselage and interior cabin to further reduce noise in the interior cabin.

Abstract: Embodiments of thermal-acoustic sections for an aircraft for reducing noise along an acoustic path produced from an acoustic source are provided herein. The thermal-acoustic section comprises a first porous layer having a first characteristic acoustic impedance. A second porous layer is disposed adjacent to the first porous layer and has a second characteristic acoustic impedance that is greater than the first characteristic acoustic impedance. The thermal-acoustic section is configured to be positioned along the acoustic path such that at least a portion of the noise from the acoustic source is directed through the first porous layer to the second porous layer to promote absorption of the noise.

Abstract: A vibration isolation system for attenuating vibration energy between two aircraft structures, such as between the aircraft's fuselage and interior cabin. The vibration isolation system includes a first isolator attached to the first structure, a second isolator attached to the second structure, and an intermediate mass attached between the first and second isolators. The intermediate mass may be electrical cables, wiring bundles, a cable holder, or other component disposed between the two structures. Cable holder intermediate masses can be fabricated from an electrically conductive material to provide electromagnetic interference shielding for cables disposed therein. Multiple vibration isolation systems can be disposed between the fuselage and interior cabin to provide a less noisy cabin. Additional noise and vibration suppressors, such as skin damping material and acoustic blankets, also can be disposed between the fuselage and interior cabin to further reduce noise in the interior cabin.

Abstract: Aircraft panels are formed of a honeycomb core material and the skin. The honeycomb core material and the skin are selected to provide subsonic wave speed across the panel, thereby reducing sound transmission.