Say Again?

by The Raviator
Presented by AKG Headsets

All of us lose some hearing as we age, but for every non-pilot reporting hearing loss at age 50, there are five pilots who report hearing loss. Moreover, as an aviator and musician, I encounter more hearing impaired pilots than rock n’ roll guitar players. This caught me by surprise because while deaf musicians may not make the prettiest music (Beethoven being a notable exception), depriving pilots of any one primary sense is a safety hazard to themselves, their passengers, and those on the ground. Therefore, I felt compelled to investigate further.

While music fluctuates across the frequency spectrum, airplanes relentlessly push the same ones. That makes aviation punishing to the ears because the duration of noise is as relevant as its volume – the louder the sound, the quicker the damage.

For example, passing truck traffic will put you at risk after eight hours, while rumbling subway trains will get you in four hours. Most general aviation airplanes emit sufficient noise to cause damage after just one hour. The magic number is 85 decibels (dB) – anything less poses little-to-no risk. The rule of thumb is that any noise is potentially dangerous if you must shout over it in order to be heard. In other words, everyone traveling in small planes must wear hearing protection.

Hearing damage may not be immediate or apparent. However, once it happens, it cannot be reversed. Human hairs deep in the ear canal carry sound to the auditory nerve. These hair cells are vulnerable to noise, and excessive exposure leads to cell death and Noise Induced Hearing Loss (NIHL). Unlike amphibian hair cells, ours do not grow back.

The most obvious preventative measure pilots can take is to wear appropriate headsets. Given the many options available, it can be difficult to identify the line between need and want.

Ultimately, any mid-priced basic passive headset should adequately protect against NIHL due to flying. That usually means a larger ear cup that seals well around your ear and is made from quality materials by a reputable manufacturer. Some models implement special foam to improve the seal around sunglasses, while others provide adjustable clamping force around the ears. Depending on how well a particular headset fits a unique head, these features can enhance overall noise attenuation. Ear plug style headsets also provide adequate protection as long as the seal in the ear remains tight.

While passive headsets protect against NIHL, there are other safety issues that Active Noise Reduction (ANR) headsets help resolve. The most notable is fatigue due to noise. When one is subjected to constant sound pressure, awareness and response time diminish. The consequences can be catastrophic. Other than ear plugs, which can be tiring if uncomfortable, ANR is the only technology that adequately reduces engine noise. With it engaged, you lower the overall noise floor, which keeps your hearing threshold low. Because one needs communications to be 10-15 dB above background noise in order to be intelligible, ANR also enables one to lower the radio and thus maintain a quieter volume across the entire frequency spectrum.

Within ANR, there is analog and digital, feedback and feedforward. ANR recognizes noise within predictions set by manufacturers, and consequently produce an inverse wave to cancel that noise. However, digital enables the headset to survey and analyze present and changing conditions irrespective of manufacturer predictions, essentially adapting to the pilot’s head and current cockpit conditions. Feedback addresses undesirable noise inside the ear cup, while feedforward catches noise before it gets in. When combined (“hybrid circuit”), the result is greater noise reduction across a wider frequency range because feedforward does not have to avoid frequencies being used for communications inside the cup.

ANR is complex technology and costs more. However, the value is huge when compared to the overall expense of being a pilot. If one flies two hours a week on average, a premium headset adds about $1 per flight hour; this assumes 10 years of headset life, which is perfectly reasonable. For this reason, a headset that offers both passive and active noise protection is about the cheapest insurance money can buy. Plus, one normally gets a host of other benefits that enhance comfort and convenience, as well as improve the overall flying experience.

NIHL is completely preventable according to the National Institute of Health. It isn’t rocket science, and one doesn’t need to labor over graphs and comparative analysis. Implementing common sense and an “investment versus expense” attitude will go a long way to preserving safety and quality of life.

EDITOR’S NOTE: The Raviator, a musician and pilot, is a thought-provoking speaker on two primary issues: marketing to the next generation and preventing pilot hearing loss. Learn more at http://Raviator.com.

AKG is a new addition to the premium pilot headset market, offering hybrid active noise canceling, Bluetooth connectivity, and integrated LED map lights. Learn more at http://akg.com/akg+aviation-1704.html

This entry was posted in Dec 2014/Jan 2015, Products & Services, Sections and tagged , . Bookmark the permalink.

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