Controlling the noise levels within the interior of an aircraft is a complex problem that requires a complete understanding of the noise sources and paths. Since the sound field is dynamic, and the sources and paths are distributed throughout the aircraft, engineers must take a systems approach to reduce interior noise levels in the most efficient way.

For nearly 20 years, E-A-R Specialty Composites has employed systems engineering techniques to address the complex requirements of aircraft interior noise control. Our Applications Engineers understand aircraft weight metrics, aircraft environments, FAA regulations, airborne and structureborne acoustics, and material behavior, and they use that breadth of knowledge to solve the unique requirements of each customer. An E-A-R treatment package typically includes (A) skin damping, (B) fiberglass bags, (C) overframe blanket and (D) sidewall damping.

Why Treat Your Aircraft Like a Truck?
Controlling the interior noise in a heavy-duty truck is different from controlling it in a Cessna Citation. We understand that, because we1ve develop treatment packages for both. Of the hundreds of methods and materials that could be employed, however, very few can optimize the noise reduction for the added weight‹usually a key design goal necessitated by an aircraft's limited weight budget. So E-A-R developed proprietary materials and advanced techniques that can achieve both sound and weight goals.

Noise Control Methods
Traditional aircraft noise control, based on Class 8 truck experience, employs large mass layers along with thermal/acoustical fiberglass bags. Although this method can be effective, it is extremely heavy. Moreover, it addresses only the airborne component of the acoustic energy.

E-A-R employs the company's high performance materials and optimal installation methods‹along with the standard bagged fiberglass‹to address both the structureborne and airborne components of the sound field. This systems approach addresses all sources and paths within the aircraft. Where a common aircraft treatment comprises fiberglass bags, a mass layer such as Ensolite® foam and an overframe blanket, a typical E-A-R solution includes:

Fiberglass bags
Skin damping
Sidewall damping
Floorboard damping
Overframe blanket

Addressing each critical noise source and path provides maximum noise reduction for minimum added weight.