Aircraft noise

How we monitor and measure noise in the borough

How is the borough affected by aircraft noise?

Large aeroplanes using Gatwick and Heathrow fly over the Borough, and although audible do not give rise to many complaints.  Aircraft starting their final descent into Heathrow pass over the north of the Borough, particularly Chislehurst and Sundridge Park.  In general, descending aircraft will pass over this area much lower than those taking off and so they will be louder.

The airport at Biggin Hill affects a few people living alongside it as well as those living under the flight path.

What monitoring is being done?

A permanent noise monitor has been established at Oaklands School, in the valley almost under the flight path.  A second monitor has been established alongside the runway and this records noise levels for the summer months.

What can be done about aircraft noise?

Aircraft in flight are exempt from all environmental protection legislation, which is used to control noise nuisance.  However, control is exercised by the operating agreement in relation to the number of flight movements, the type of aircraft and the operating hours at Biggin Hill Airport.  Biggin Hill Airport is owned by the Borough of Bromley and the lease agreement with the Operators imposes restrictions.

How is aircraft noise measured?

The traditional method of expressing aircraft noise, the NNI (Noise and Number Index) is more appropriate for larger airports and involves complicated formulas combining the degree, time and duration of aircraft noise.  For Biggin Hill, we measure the noise level on two sites over the 15 hour working day and this gives a more realistic level, which is also easier to verify.  It is important that the monitoring locations are in areas where there are no other significant noise sources. Both sites are linked by modem to a computer, which interrogates them.