09/20/2011

Sion Air Show: Magnificent and noise

Sion air show: very exciting and interestion, but SO NOISY sometimes. Most people, but not everyone, blocked their ears when the military jets strutted their stuff.


The 3-day air show, the first at Sion for many years, seems to have been a big success, despite the poor weather on the Saturday and execrable weather on Sunday. Fortunately, I had booked to go on the Friday and Saturday: the blue sky of Friday, plus relative lack of crowds, made it a really good day (and I saw our Swiss jetman flying).

As one interested in the noise that aircraft make, I noted the difference between the noise of civil aviation aircraft using Geneva airport and that of all sorts of aircraft, ancient and modern. The demonstrations of the jet fighters competing for a contract with the Swiss Air Force was incredible, and warranted the many warning announcements over the loudspeakers. Incredibly, many people did not seem to bother with the ear plugs provided, nor even cover their ears, at the loudest moments. Worse, some parents let their children hear this noise!

So what was the noise level. On my iPhone I have two apps for measuring noise, in the standard Mode A deciBels (dBA) used for aircraft measurements. One of these refused to measure above 100 dBA, but the other one showed peaks of just over 112 dBA: pretty well identical for the three noisiest jets. As a comparison, the noisiest civil aircraft in Geneva occasionally get into the mid nineties, whilst one or two miitary planes coming here very occasionally have hit around 100 dBA.

For the non-experts, the noise is measured on an exponential scale such that an increase of 3 dBA represents a doubling of the noise. Thus, these peaks at Sion were about 16 times a miltary plane in Geneva and around 50 times louder than the worst civil aviation aircraft.

There are many Web sites that deal with the possible harmful effects of noise. One of these indicates for how long one can hear a noise without risking damage: the maximum exposure time is halved for each three dBA increase. For 112 dBA it is stated that the maximum exposure time is about one minute.

I hope that no-one did any damage to their hearing.

 

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