This is really OT ...
Last week pilots of Grob Tutor aircraft were told that were to limit their
flying to 8 hours a week because of the damaging exposure to noise levels above
87dB. The alternatives tried, using foam ear plugs, were ineffective (as well
as dangerous) because the noise is at predominantly at 80 and 100Hz. Our
helmets, commonly considered decent noise attenuation devices, are also useless
for defence against such low frequencies; I suspect that it's less a problem of
sound entering the ear canal, more one of overall vibration. But, as usual, I
have to admit to being no expert in this area.
The problem arose because the EU forbids extended exposure to such levels; it
has done so since 2003 or 2005 (not sure about when) but the trials in our
aircraft have only just been noted (or carried out) and there is a sudden panic
to limit exposure, and presumably liability by my employer.
I pooh-poohed the idea that it was a problem initially, but I am now a convert.
I have had my ears tested annually for the last 35 years and all I have lost
is a bit of high-tone hearing. However, it appears that we aren't tested for
hearing at these low levels and I now don't know what damage has been caused to
my hearing.
Are there any experts reading this who might comment?
Chris
On 16 May 2010, at 12:00, Wayne Harridge wrote:
>> Add to that the problem we now
>> have with low-frequency noise (80 or 100Hz) and my flying hours will be
>> right down this year.
>>
>
> What's that all about Chris ?
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