Information on measures to reduce the impact of aviation noise
In addition, there are ways to reduce the impact of noise through mitigation strategies.
Reduction of noise at source
This means identifying ways to reduce the noise that aircraft produce – and is the single most effective way to cut noise. Since the jet engine was invented, there have been all kinds of changes that have helped reduce noise levels. To demonstrate the impact of this, in 2012, the 57dBA Leq aircraft noise contour area around Heathrow covered just over a tenth of the area it did in 1974.
Progress on reducing aircraft noise has slowed down in recent years – partly because levels had already dropped a long way. However, the latest designs are far quieter than older planes. Despite being one of the largest passenger aircraft in the world, the Airbus A380 is also one of the quietest. There was a conscious effort during development to make it quieter – showing what is possible, even for very large aircraft.
In the future, one way to reduce noise further could be to set incentives for airlines and manufacturers to opt for less noisy aircraft. Read more about potential incentives in Chapter 7 of the CAA’s report Managing Aviation Noise.
Reduction of noise through operational measures
This involves taking measures to minimise noise exposure through optimised departure and arrival operating procedures, and using optimised flight paths that take flights away from the most populated areas, as far as possible. Clearly, this is difficult for airports that are situated in densely populated areas. However, there are practical steps that can be taken.
For example, the CAA manages the UK’s airspace and makes decisions on how this is structured and used. Using data gathered from Noise and Track Keeping systems, we can consider the noise impacts of moving flight paths away from particular areas. This is also a crucial aspect of planning any new airports, or airport extensions: additional flight paths may be required so that not all flights take place over the same areas.
With existing flight paths, there are also ways to reduce the noise created by take-off or landing. For some years, efforts to reduce noise were focussed on take-off, but now more and more options to reduce noise at landing exist. These range from simple steps, like not lowering landing gear too early, to more complex options like taking slightly steeper approaches to the airport. Different options have a noise impact at different distances from the airport – so benefit different groups of people.
Airports can take a lead role in this area of noise reduction. Some airports publish league tables that compare their airline customers' performance across a series of noise mitigation measures.
Reduction of noise through land-use planning
Land-use planning tends to be outside the control of the aviation industry and in the hands of local and national governments. However, there are two key ways that it can help with noise reduction:
• for new airports, it means planners selecting sites away from densely populated areas. This obviously has to be balanced with practical considerations – airports need to be accessible to the people who wish to fly from them.
• for existing airports, it means planners limiting development under flight paths, or even potential future flight paths, to try and minimise future noise problems.
Restrictions on operations
This includes things like limitations on operational times – such as not allowing flights to land or take-off at night – or on the total number of operations. The specific types of aircraft that could be operated could also be restricted to mitigate impacts on a site-by-site basis.
Currently, some form of restriction exists on night flights at nineteen UK airports:
|Belfast City||Cardiff||Glasgow||London Heathrow||Oxford|
|Birmingham||East Midlands||Leeds/Bradford||London Luton||Southampton|
|Bournemouth||Edinburgh||London City||London Stansted|