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If You Can't Turn it Down, Block it Out! Preventing Hearing Loss

  • Published
  • By MSgt Julie Meintel
  • 445th Airlift Wing
TMF Fall 2014 --  

If you are reading this article, chances are very good that you are involved in some way in the mobility world, the flying world, or both. All of us who live and work in and around these environments need to make sure we are protecting ourselves from their varied risks. One of those risks is damage to our hearing and hearing loss.

In 2001, the National Institute for Occupational Safety and Health and the occupational safety and health community in general named hearing loss one of the top priority areas for research heading into the new century. According to a paper published by the Centers for Disease Control (CDC), noise-related hearing loss is 100 percent preventable, but once acquired, it is irreversible and permanent. Among the professions at risk for work-related hearing damage and hearing loss are carpenters, plumbers, construction workers, agriculture workers, and yes, you guessed right, military.

So, what exactly is noise, and how does it affect what you do? The term itself is pretty subjective, but for our purposes here, it just means any unwanted or annoying sounds. It can be of a very short duration, or it might last for your whole workday. Steady noise is just that; it might start out suddenly or gradually, and it tends to be at a lower intensity level, but it lasts for a long period. Impulse or blast noise tends to be much shorter and more intense. Think firing a gun, or a radio squelching feedback at high volume, or even breaking the sound barrier.

The flight line is often a noisy place to be, whether you are an aircrew member operating an aircraft, a mechanic or crew chief fixing an aircraft, or a passenger service representative delivering passengers to an aircraft. That is why every vehicle that goes out to the flight line should always have a box of earplugs on it, and every time you step off the van and onto the flight line, you should stick those little foam plugs in your ears. The constant whine of the engines, the external power carts, and other machinery will really take its toll on your hearing over the long term, and hearing is not something you can get back.

Ok, so now we know that we need to be careful with noise and our hearing, but how do we know what is a normal noise and what is potentially damaging? How is noise measured? Well, noise is measured in decibels. Measuring sound is a little bit tricky, since the human ear is so incredibly sensitive. The smallest audible sounds register at 0, so near total silence would be 0 decibels (dB), a normal conversation is about 60 dB, and a jet engine is around 130 dB. You can rupture an eardrum with blast noise at 140 decibels.

Decibel Levels of Common Sounds - Fig 1.

What do these numbers mean? Well, according to the same FAA pilot safety brochure, the number of decibels you are exposed to has a direct correlation to the damage you are inflicting upon your ears. Damage can range from simple ear discomfort for exposure of short duration, at around 120 decibels, all the way to permanent hearing impairment and even loss at sustained exposure for eight hours a day to loud noise above 90 decibels.

Think about your work environment and check the chart to see the approximate decibel range you work in most days. Here's another chart; this one reflects the maximum amount of exposure time to protect your hearing. Fig 2

Thankfully, hearing loss is 100 percent preventable, and it really doesn't take that much work or equipment to protect your ears. Keep those little foamy earplugs in your pockets or your toolkit; they muffle loud sounds significantly, and they are small and incredibly easy to use. Wear a headset on and around the airplane if you have one, and if you have the noise-canceling type of headset, that's even better. To maximize your hearing protection, wear the earplugs AND your headset all the time on the flight line and in flight.

What if you have already sustained some level of hearing loss? Is your flying career over? Not necessarily. Air Force flying physical standards for hearing include follow-up testing by an audiologist if your hearing falls outside of normal limits, or what is referred to as H-1 profile. H-2 profile does not automatically require a waiver, but it does require a more in-depth audiology workup. H-3 requires a waiver, and many times when a flyer is initially given H-3 profile, flying will be restricted until further testing and a waiver are accomplished. If you are diagnosed with hearing loss, talk to your flight surgeon about what further testing may be required and what you may need to do in order to keep flying.

The Air Force Waiver Guide (www.wpafb.af.mil/shared/media/document/AFD-130118-045.pdf), updated in May of 2013, outlines in detail what constitutes different levels of hearing loss and profile levels for safe flying. The Air Force uses these decibel levels to categorize hearing loss.
  • Normal hearing (0 to 25 dB HL)
  • Mild hearing loss (26 to 40 dB HL)
  • Moderate hearing loss (41 to 70 dB HL)
  • Severe hearing loss (71 to 90 dB HL)
  • Profound hearing loss (greater than 91 dB HL)
While hearing aids can be helpful, they can't replace a healthy and functional auditory system. Our hearing naturally degrades a bit as we age, and if we give the process a head start by not doing everything we can to protect our hearing, we can be setting ourselves up for bigger problems down the line.