 Under the provisions of the Civil Aviation Act aircraft in flight are specifically exempted from trespass and nuisance controls , which denies any form of redress to those living near airports who are disturbed by noise . Government sanctioned measurements of noise near airports take an average sound level , measured in decibels ( dB ) , over a 16 ‑ hour day , and are expressed as an LAeq figure . Officially , 57 dB LAeq is the threshold at which noise levels become disturbing , 63 dB LAeq represents moderate disturbance , whilst 69 dB LAeq represents high disturbance . Technological improvements in aircraft design means that aircraft are becoming quieter . Taking Heathrow as an example , between 1990 and 2004 the area around the airport affected by noise levels of 57 db LAeq and above fell by 60 per cent , whilst the number of people similarly affected fell by 51 per cent . Campaign groups dispute the methodology used to measure noise , asserting that it is flawed in a number of ways . Amongst other issues they point to the World Health Organisation view that annoyance begins at 50 db LAeq whilst serious annoyance begins at 55 dB LAeq , and they assert that the LAeq measurement does not give sufficient weight to the increasing incidence of noise events . Their conclusion is that noise levels , and the number of people affected , have increased rather than decreased . This is borne out by the latest survey of attitudes to noise published in November 2007 which reports that , compared with over 20 years ago , more people today are annoyed by the same level of noise as measured by LAeq . Whilst this may be attributable to changing attitudes , the report concludes that the contribution of aircraft numbers to annoyance has increased , and that an alternative method of estimating levels of annoyance that takes this into account would appear to be more relevant than the LAeq measurement . The report has attracted criticism in peer reviews , and one such review , characterising the survey as inconclusive , counsels " ... against using the detailed results and conclusions [ ... ] in the development of government policy . " 
