U.S. Navy Flight Deck Hearing Protection Use Trends: Survey Results

Abstract : Hearing loss claims have risen steadily in the U.S. Department of Veterans Affairs across all military services for decades. The U.S. Navy, with U.S. Air Force and industry partners, is working to improve hearing protection and speech intelligibility for aircraft carrier flight deck crews who work up to 16 hours per day in 130-150 dB tactical jet aircraft noise. Currently, flight deck crews are required to wear double hearing protection: earplugs and earmuffs (in cranial helmet). Previous studies indicated this double hearing protection provides approximately 30 dB of noise attenuation when earplugs are inserted correctly and the cranial/earmuffs are well-fit and in good condition. To assess hearing protection practices and estimate noise attenuation levels for active duty flight deck crews, Naval Air Systems Command surveyed 301 U.S. Navy Atlantic and Pacific Fleet flight deck personnel from four aircraft carriers and two amphibious assault ships. The survey included a detailed assessment of cranial helmet fit and maintenance condition (e.g., earmuff headband tension, earcup foam and cushion integrity); earplug use and insertion depth; anthropometric measures; and personal/historical data. Data analysis showed that 79% of surveyed flight deck personnel ears received an estimated 0-6 dB of noise attenuation from either shallow earplug insertion depths or never wearing earplugs (47% reported never wearing earplugs). For subjects who reported they sometimes or always wore earplugs (14% reported always wearing earplugs), only 7% inserted the earplugs deeply enough in both ears to achieve the maximum expected noise attenuation of 22 dB in both ears. Worn without earplugs, the cranial helmet with earmuffs has been reported to provide approximately 21 dB of noise attenuation when correctly fit, worn, and maintained.