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HMEC300US.book Se ite 27 Mittwoch, 7. April 2004 3:24 15
Valuable information on NoiseGard™
The NoiseGard™ principle
One of the greatest stress factors today is noise. Research has shown that noise affects
the nervous system, and can cause tiredness, poor concentration, irritability and tension.
Of even greater concern is the permanent damage to hearing that can result from noise
at high levels.
This problem concerns pilots in particular. Cockpit noise amounts to about 80 dB(A) in
jets and to 90 up to 97 dB(A) in turboprops. During takeoff and landing, the noise level
is even higher. To be able to understand radio traffic in spite of the noisy environment,
the ATC signal level must be set to at least 95 dB(A). Permanent hearing loss caused by
the continuous noise in aircrafts is the reason why many pilots became prematurely
disabled or lost their pilot´s license.
Circumaural communication headsets provide noise attenuating properties and are
commonly used to address this problem. However, the noise attenuation of these
headsets is uneven. High frequencies are reduced considerably, but low frequency wind
and engine noise, the most prominent noise in many of today's aircrafts, is attenuated
very little.
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