Question
I was wondering if you could point me in the direction of any articles or research that outline the risks associated with hearing or ear health when flying, especially on small aircraft. The organisation I work for provides allied health services to rural and remote communities, and travel is by small 4-seater aircraft, which are quite noisy. In an effort to gain funding for appropriate noise cancelling headphones for staff to wear during flights I must show some definitive research but have not been able to find any relevant articles as yet. Thank you for any assistance you can offer.
Answer
There has not been a great deal of research done on the noise exposures associated with flying in small aircraft. The few studies that have been done have indicated that equivalent continuous average levels aboard light aircraft typically range from 88-94 dBA. These levels are high enough that hearing protection is warranted for passengers who travel regularly aboard light aircraft on trips that are more than a few hours in length. The occupational exposure limit for noise exposure in the US set by the Occupational Safety and Health Administration (OSHA) is an 8-hour average of 90 dBA;workers exposed above this level must use hearing protection devices. Note that allowable exposure levels are higher for shorter exposures;for example, for flights that are 4 hours in length, the allowable exposure level would be 95 dBA, and for flights of 2 hours duration, the allowable exposure would be 100 dBA. According to OSHA, and depending on the frequency and duration of flights, your workers may or may not be required to use hearing protection devices.
The US National Institute for Occupational Safety and Health recommends a more protective exposure limit of 85 dBA, and suggests that workers wear hearing protection when 8-hour daily average exposure levels exceed 85 dBA, 4-hour exposures exceed 88 dBA, and 2 hour exposures exceed 91 dBA. According to NIOSH, your workers likely should be required to wear hearing protection devices.
As an aside, it is not necessary to wear noise cancelling headphones onboard small aircraft;other types of passive hearing protectors, including foam and premolded earplugs, as well as passive earmuffs, will provide roughly as much (and possibly greater) reduction of noise at a considerably lower expense. However, communication between passengers will likely be easier with noise cancelling headphones, especially if the headphones have communication capability built in.
For more information from Dr. Neitzel, please check out his recorded course, Construction Noise: How Bad Is It and What Can Be Done About It? that can be found in the AudiologyOnline eLearning library.
Rick Neitzel is a Research Scientist in the University of Washington (UW) Department of Environmental and Occupational Health Sciences and a Certified Industrial Hygienist. He is also a Candidate in the Environmental and Occupational Hygiene PhD program at UW. He is President-Elect of the National Hearing Conservation Association, having previously served as Director of Communications and Treasurer, and sits on the Noise Committee of the American Industrial Hygiene Association. His research interests include quantitative and subjective exposure assessment in industrial and non-occupational settings, as well as development and evaluation of effective occupational health interventions.
