Noise Pollution in Flying Airplanes - A Comparison
When we talk about Ear Pollution we must have an understanding of the intensity of common sounds for comparison. The list below gives you an idea where noise behind a Single Engine Small Plane stands with respect to other intensities of sound.
1. Threshold of Hearing........0 DecibelsWhen we talk about Ear Pollution we must have an understanding of the intensity of common sounds for comparison. The list below gives you an idea where noise behind a Single Engine Small Plane stands with respect to other intensities of sound.
2. Whisper.....................30 "
3. Quiet Office................40 "
4. Normal Speech...............60 "
5. Busy Street.................73 "
6. Cockpit Noise...............105 "
7. Hard Rock Music.............110 "
8. Threshold of Pain...........140 "
High intensity noise is one of the major causes of permanent hearing loss. It cannot be reversed. Sounds which exceed 85 decibels pose the greatest threat to the hearing mechanism. There are few sounds in nature that surpass this level and the ear is not prepared to cope with more than 85 decibels.
The exposure to high intensity of sound is important. The longer the exposure per week the earlier the hearing loss begins.The ear has three conduits for sound, outer ear (pinna), the middle ear, that houses the three little bones of the ear, that help transmit sound waves to the inner ear. High intensity sound affects the inner ear nerve found in the chochlea. (A sea shell shaped coiled structure) Hearing for high pitched sounds is affected first. With more exposure, more and more of the pitch range is destroyed until your hearing is really handicapped. Again, it is important to repeat that a noise induced hearing loss is permanent and cannot be reversed by medical treatment.
Frequently, hearing aids are not very beneficial since the nerve endings are destroyed. Hearing sensitivity is usually measured by finding the lowest intensity level a person can hear low, medium and high frequency musical tones. We interpret these sounds as different pitches. The impression of these sounds are recorded on an audiogram. If you ever went to an audiologist he or she would explain what the tracings represent.
If you remember your days as an audiophile the whole thing hinged on you receiving sound that was not distorted. If the ear is healthy the listener will have little difficulty in distinguishing between the various speech sounds.On the otherhand, if you have impaired hearing due to exposure to high intensity noise in the cockpit without protection, you may have great difficulty distinguishing such words as he and she, not and got and slow and low.For example, the phrase " You are too slow for a safe landing" and the phrase "You are too low for a safe landing" are similar but different enough to cost you your life.
Several things can be done to cut down on or prevent high intensity sound to protect against permanent hearing loss.Simplest solution is to buy a set of tight fitting earplugs. Sound reducing earmuffs are even better. Revolver and pistol shooting earplugs and muffs are acceptable if they fit. (A wad of cotton is useless!)
Scientists have found that understanding speech in noise is not impaired when wearing ear protection. Anyone who questions this can purchase a headset built into protective muffs. You can purchase these at any pilot supply store. High intensity noise does cause stress related error making decisions and general fatique that I have discussed in earlier articles. One point to remember is that engine noise, even with protectors on, is still loud enough to hear a decrease in RPM or a missing magneto.
A final note, if you feel that your hearing may be impaired please make an appointment with an audiologist at your earliest convenience. They can assist you in finding the best ear protectors for your needs.
