F-35 Lightning II News

New Active Noise Reduction Earplugs promise relief for JSF Maintainers

September 28, 2004 (by Amy Behrman) - The F-35 Joint Strike Fighter (JSF) program is sponsoring the development of advanced hearing protection technologies designed to prevent noise-induced hearing loss for Navy, Marine Corps and Air Force Joint Strike Fighter maintenance personnel.
Under the Lockheed Martin F-35 JSF contract, earplug designer Adaptive Technologies, Inc. (ATI) will produce about 40 test units, enough to qualify and demonstrate the system's utility as an F-35 platform solution for hearing protection. Officials are hopeful that a successful fleet demonstration will strengthen the case for broader application and funding.

According to ATI, the "QuietCommTM" Digital Active Noise Reduction (ANR) earplug provides breakthrough hearing protection for military personnel in extremely high noise environments. In some carrier deck locations, three seconds of unprotected exposure can cause permanent hearing damage

Designed for military jet support personnel, the custom earplug offers protection in high intensity ambient noise, and clear communication with improved speech intelligibility.

"This active noise reduction earplug, coupled with the ATI microphone, new ear cushions from David Clark Company, and a new ATI foam insert, offers a breakthrough advancement in hearing protection technology...the likes of which haven't been seen for deck crew and flight line personnel in close to 50 years," said Jim D'Andrade, Naval Air Systems Command (NAVAIR) senior systems engineer.

The unique earplugs contain a miniature microphone and speaker used to conduct the active cancellation portion of the attenuation, as well as provide communications capability. Sound inside the ear canal is actively canceled through a process known as active noise reduction (ANR).

While the concept of ANR is pervasive in headsets, this is the first practical application of the technology for deep-insert earplug devices. The real benefit is realized through extending the bandwidth of active control performance from the traditional 800 Hz to as high as 3,000 Hz. This range enables the technology to realize improvements in speech intelligibility that are not possible with current technologies.

ATI has also worked closely with David Clark Company Inc. to demonstrate passive noise reduction improvements using a new ear seal and interior foam in a retrofit package. When coupled with the new passive ear seal and interior foam, the ANR earplug technology will provide more effective hearing protection than ever before.

According to James Wilt, technical point of contact for NAVAIR's hearing protection project, integration of the new earplug with state-of-the-art passive protection technologies leads to a total hearing protection package that can provide attenuation nearing 46 dB. This enables effective communication and hearing protection for up to 60 launch and recovery sequences before exceeding the total safe daily exposure limit.

"This is significant when you consider that a single launch in a 24-hour period can exceed the safe noise dose," said Wilt.

Tactical jet engine noise is one of the loudest sounds in the world, and can reach 150 dB(A) for carrier aircrew standing along the foul line during a catapult launch.

In an effort to increase awareness of the consequences of unprotected noise exposure, NAVAIR Human Systems representatives continue to meet with Fleet Fail Safe Teams, Air Medical Safety Officers, Squadrons, Operational Advisory Groups, Integrated Management Panels, and similar aviation life support forums, while documenting earplug usage aboard carriers and LHA-class amphibious ships.

The goal is to increase awareness and strengthen the case for improved policy, training, and enforcement, as well as to secure funding for advanced hearing protection technologies for the fleet.

Courtesy of Naval Air Systems Command Technology and Intelligence Office