Growing up, I remember being told to me to protect your ears because “you could lose your hearing and it’ll never come back.” Like most of us, I imagine, advice such as this was not fully appreciable until our adult lives. In aviation-based emergency services there are two things that are guaranteed:
1. You WILL get that call that is going to put you over shift on the morning that you have made plans.
2. We operate in a noisy environment.
Research performed over the past several decades collectively indicates that, as can be assumed, the more flight time an individual has to their name the more likely they are to experience hearing loss. While some research indicated an increased likelihood of hearing loss with those that participate in rotary-wing aviation over fixed-wing aviation, there is also research that claims quite the contrary. Despite the opposing claims, the common denominator of hearing loss in aviators remains the same.
Recently an informal survey of industry members was performed in an attempt to gauge various thoughts regarding the use of hearing protection in their professional lives. In total 126 individuals of varying job titles completed the survey. While respondents indicated utilizing primarily flight helmets and headsets, some indicated supplementing standard hearing protection with active noise reduction (ANR) system, communication ear plugs (CEP), standard foam earplugs or various combinations thereof. It also became evident that the type of hearing protection utilized, and even the overall stance on the issue, in this industry is far from standardized. While some organizations perform annual hearing tests, others do not. Over thirty-percent of respondents went so far as to indicate that they feel currently utilized hearing protection is inadequate with over twenty-five percent indicating they suffer from hearing loss as a result of their flight position. Even more surprising, however, was that nearly five percent of respondents indicated that they are required to provide their own hearing protection.
Moving past the data portion and on to the practical application of hearing protection, let’s briefly talk about the types of hearing protection technology currently available on the market. Since it becomes quite prohibitive to provide acoustical countermeasures on many aircraft on the basis that it would increase its weight thus reducing its capacity, sound protection must be utilized by an individual person. Personal sound protection basically boils down to two types: active noise reduction (ANR) and passive noise reduction. ANR is electronic technology that samples the noise in a given environment and emits sound waves to cancel out unwanted noise thus making it sound as if noise has been “blocked” while passive noise reduction simply insulates your ears from the noise through use of various materials such as foam. While each has its advantages and disadvantages, research suggests ANR may not be the magic bullet in combating noise that one may be led to believe. In fact, data in one study indicated that conventional earmuffs, when utilized in conjunction with earplugs, outperformed ANR. ANR also has the disadvantage of requiring a power source to function, be it a battery pack or integration into the aircraft’s electrical system. Should your ANR system lose power you lose the afforded noise attenuation, a failure point that does not exist with passive noise reduction technology. ANR also comes at a cost; aviation helmet ANR kits start at several hundred dollars with some purpose-built headsets costing well over one thousand dollars.
After sifting through all the data and the chatter, what is the best way to protect your ears in aviation medicine? I guess the answer would depend largely on what type of aviation environment you work in. Research indicates that ANR is more effective in environments with lower frequency noises, i.e. airplanes (I love my Bose headset on commercial flights by the way!), where passive noise reduction is more effective in higher frequency noise environments such as helicopters.
So what products are out there and what do you need to actually buy? Again, that depends. Although this factor is more budget dependent. First and foremost, it is important to have a solid foundation from which to build. Specifically, everyone should have a helmet, or headset, that is properly fit (i.e. snug to your head). While individually issued and fitted helmets can be cost prohibitive for some organizations, loose fitting helmets can allow unwanted sound to reach your ears. In that regard, even simply wearing glasses in combination with a helmet or headset can create a gap between your head and the ear seal enough to allow more sound to reach your ear. While there are a number of options when it comes to helmets, there is at least one manufacturer that produces a helmet marketed specifically at the search and rescue community claiming, among other things, an additional 2db of noise attenuation when compared to their standard helmet.
When it comes to ANR, there are a number of kits available that can be installed into existing equipment and you’re in business. With passive noise resistance, there are a few more options. The simplest option, i.e. requiring no additional actions by the end user when it comes to its utilization, is to install noise-dampening inserts and ear seals in/on-to your helmet earcups. One particular manufacturer specifies a 5db reduction in sound by using their inserts alone.
While additional noise reduction can be accomplished by utilizing disposable foam earplugs in conjunction with your helmet, research suggests this method ultimately defeats the whole purpose of the earplugs as operators frequently turn up radios to hear through them. Enter CEP, or communication ear plugs. CEPs are essentially earphones, either custom molded or generally sized, wired and plugged into your existing comms that one wears under their helmet. This combination of both earphones and earplugs allows sound to be blocked by the inserts but offers a more intelligible audio signal.
With passive noise resistance, you can purchase components together or individually while with ANR it is all or nothing. At the end of the day overall costs to fully equipping a helmet with passive noise resistance can be comparable to ANR depending on the extent to which you employ passive noise components. One last pointer to reduce noise that I’ve personally noticed over the years, and comes at no cost, is to simply lower one of your helmet visors. While it offers eye protection, your visor offers the secondary benefit of blocking some ambient noise.
At the end of the day implementing effective hearing protection should be just as important as any other piece of PPE we use in this industry and, like all PPE, it’s only effective if it’s utilized. Even though I’m sure most of us have done it at least once, wearing your helmet in the aircraft only to take it off to do a hot load/unload is a prime example. If a piece of equipment is uncomfortable it quickly becomes the piece that becomes hated and left on the shelf at the hangar. Fortunately, in the aviation hearing protection world, there are plenty of options to make sure your helmet is functional, comfortable and offers the hearing protection we need.
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