plane noise

I've always thought that the 57 dBA noise limit on overhead planes referred to the plane not giving a 57dBA noise on the ground, and where it exceeded that, then compensation was required to the residents below.
Think I was little simplistic in my assumption there, especially as I've often heard planes at far, far above that level , certainly in Fulham and thereabouts [and just assumed they were flouting the regulations].

The noise level is averaged over a year to ascertain the plane noise level [ I have no idea how they subtract from 'natural sounds' [car noise, fireworks, birdsong etc]

Noise measurements are NOT linear- and the pressure [noise level] doubles every 3 dB.
A noise of 57dBA is about the same as in an office, ie pretty damn quiet and you certainly wouldnt object at that level. I realise that this is now out of date, but Concorde is equivalent to 120 747's in noise terms [ no wonder some countries banned it from overflying ! ].

IMO, this is an absolute disgrace and should be changed say to overhead noise being no more than 70 dB at any time or something like taking into account the frequency of overflys.

Maybe this would be too labour intensive to do, in which case something like 66dB averaged over a peak hour may be easier?