06 - Background to noise and regulation

Background to noise and regulation

Sources of airport noise

Noise at airports is caused by a variety of sources, not only from aircraft taking off and landing on our runway but also:

• engines running on the airfield prior to take off and after landing
• vehicles on the airfield servicing aircraft
• cargo vehicles servicing cargo operations
• ground running of engines.

Noise from aircraft is caused by air going over the aircraft’s fuselage (body) and wings – known as airframe – and its engines. When air passes over the aircraft’s airframe, it causes friction and turbulence, which results in noise.

The level of noise generated varies according to aircraft size and type, and can differ even for identical aircraft. Engine noise is created by the sound of the engine’s moving parts and by the sound of air being expelled at high speed. Aircraft have been getting progressively quieter as designs and engine technology have advanced, and it is expected that today’s airlines will be operating even quieter models in the future.

Different people react differently to noise. Perceptions vary not only on the level of noise but also depending on the character, on the time of day, the location and the level of background noise present. Reactions to noise can be influenced by an individual’s attitude to the noise level experienced. However, these attitudes are less well understood than the technical science of sound-generation and measurement.

The Scottish Government in Planning Advice Note 1/2011: Planning and Noise, details common sounds, and their decibel rating at source:

• unsilenced pneumatic drill (at 7m distance) – 95 dBA
• heavy diesel lorry (40km/h at 7m distance) – 83 dBA
• modern twin-engine jet (at take-off at 152m distance) – 81 dBA
• passenger car (60 km/h at 7m distance) – 70 dBA
• office environment – 60 dBA
• ordinary conversation – 50 dBA
• quiet bedroom – 35 dBA.

To put some of these noise levels into perspective 70 dBA is the average noise level at the Newbridge roundabout while standing on the pavement while 60 dBA is the average noise level generated by aircraft in the communities close to the airport at the eastern end of Ratho Station or in parts of Cramond. Actual average noise levels in Ratho Station may be higher due to the proximity of motorways and arterial routes into Edinburgh. On that basis, someone’s perception of noise at different points within Ratho Station or Cramond could vary.

PAN 1/2011 helpfully describes perception in relation to the decibel scale. It advises that decibels incorporating an ‘A’ frequency weighting (dBA), differentiate between sounds of different frequency (pitch) in a similar way to the human ear and broadly agree with people’s assessment of loudness.

It also explains that for noise of a similar character, a change of 3 dBA is the minimum perceptible under normal conditions, and a change of 10 dBA corresponds roughly to halving or doubling the loudness of a sound.

In practice, the perceived exposure of aircraft noise is influenced by weather conditions, character of the location and individual attitudes as well as the source level of noise.

For aviation purposes, as a flight increases in altitude the noise from the aircraft disperses and dissipates outwards, with noise levels decreasing as the height of the aircraft increases. In order to assess environmental noise exposure to those living near an airport, it is necessary to take into account the impact of many events over longer periods – days, months, years. These events will generally differ in magnitude; there will be different numbers in each hour or day; and they will occur at different times of day. Most measurements for these assessments use the LAeq time averaging parameter.

Noise contour maps are used to predict which geographical areas will likely be the most disturbed by noise. They are provided to us by our regulator the CAA based on the previous year’s actual data, and help Edinburgh Airport to predict areas where noise disturbance may occur and determine areas that may be entitled to extra insulation in their homes to help reduce the noise disturbance from aircraft.

Lden Contours
The Environmental Noise (Scotland) Regulations 2006 requires that strategic noise mapping should be conducted every five years. Unlike the conventional summer 16-hour dB LAeq contours, the regulations require a different range of noise parameters: Lday, Levening, Lnight, LAeq16hr, and Lden. A full definition of these terms is provided in the glossary.

LAeq Contours
Under UK legislation the most common method for representing noise at airports is the Equivalent Continuous Sound Level, LAeq which is an average of the noise levels for the busiest 16 hours of the day, between 07:00-23:00 from mid-June to mid-September. In line with UK Government policy, this assessment parameter is used in the production of airport masterplans.

It is difficult to compare the two noise metrics due to the different methods of calculating them, however, in general terms, the Lden contours tend to be larger than the dB LAeq. This is due to the Lden for evening and night periods penalties of 5 dB and 10 dB. Although the weightings do not directly mirror perceptions, it is clear from community engagement and surveys that flights at night time and evenings tend to cause greater annoyance and disturbance than flights during daytime.

Guide to legislative controls

Currently, the UK Government only has direct responsibility for aircraft noise management at Heathrow, Gatwick and Stansted Airports. There are five main tiers of regulation governing aircraft noise in Scotland:

• International regulation
• European Union
• UK Government; CAA
• Scottish Government
• Local Authorities.

International regulation
At an international level, the International Civil Aviation Organisation (ICAO) sets progressively tighter certification standards known as Chapters for noise emissions from civil aircraft which member countries’ fleets must meet.

Further details of these standards can be found at www.caa.co.uk or www.icao.int

The ICAO is an inter-governmental organisation that sets operating standards for aviation operations over the world. These standards are adopted by ICAO member states. ICAO has set a number of standards for aircraft noise certification, which are contained in ICAO Appendix 16 Volume 1 – Environmental Protection, Aircraft Noise. This document sets maximum acceptable noise levels for different aircraft during take-off and landing, categorised as Chapter 2, 3 and 4 (see Appendix I for further details).

• Chapter 2 aircraft have been prevented from operating within the EU since 2002, unless they are granted specific exemption, and therefore the vast majority of aircraft fall within Chapter 3 and 4 parameters. These aircraft are quieter than Chapter 2 aircraft.


• Chapter 4 standards have applied to all new aircraft manufactured since April 2006. These aircraft must meet a standard of being 10 dB quieter than Chapter 3 aircraft based on three standard measuring locations close to the airport.


• A new standard, known as Chapter 14, is now under consideration by ICAO. As currently proposed this would represent an increase in stringency of 7 dB compared with Chapter 4 and would apply to new large civil aircraft submitted for certification after 31 December 2017 and smaller aircraft from 2020.

In addition to these specific requirements, the ICAO requires member states to adopt a ‘balanced approach’ to noise management which looks beyond individual aircraft to reduce noise impact through:

• reducing aircraft noise at source
• land-use planning
• changes to operational procedures
• restrictions on the use of the noisiest aircraft. For example EC Directive 92/14/EEC, which restricts the landing of Chapter 2 aircraft at European airports.

With the exception of military aircraft, aircraft which do not meet the standards specified in Part ll, Chapter 3 of Volume 1 ICAO Appendix 16 will not be permitted to operate to/from Edinburgh Airport.

European regulation
The European Union (EU) is increasingly assuming responsibility for the regulation of aircraft noise standards. The Directives of most relevance are:

• EC Directive 92/14/EEC, Chapter 2 which prevented aircraft from landing in the EU from 1st April 2002


• EC Directive 2002/30, which introduced discretionary powers to restrict the operation of marginally compliant Chapter 3 aircraft, where circumstances support this measure. The Directive also required the publication of an environmental noise objective for the airport and the adoption of a balanced approach to noise management including the four dimensions agreed by ICAO; and


• EC Directive 2002/49 (known as the Environmental Noise Directive or ENDs), which requires member states to create noise maps and five-year ENDs from all transport sources in urban areas. This is the Directive under which we have produced this draft noise action plan. Maps from each transport source are published on the noise mapping site https://noise.environment.gov.scot/

UK regulation
The UK Government is responsible for the policy framework for aircraft noise control at UK airports and has prescribed a range of controls on aircraft noise impacts.

• In December 2003, The Future of Air Transport White Paper outlined several new policies for airports which control, mitigate and compensate for aircraft noise.


• Full details of the range of aircraft operations related-noise controls are set out in statutory notices and published in the UK Aeronautical Information Package (UKAIP) and elsewhere as appropriate. These controls include techniques such as Continuous Descent Approaches (CDAs), other noise abatement procedures and operating restrictions (limits on night flights for example).


• The 1982 and 2006 Civil Aviation Acts grant the UK Government and airports powers to introduce noise control measures, including mitigation.

Scottish regulation and Local Authority regulations
The regulation of aviation and air transport (including the Civil Aviation Act) has not been devolved to the Scottish Government. However, certain functions, such as aircraft noise, are exercised by Scottish Ministers.

• Scottish Planning Policy (SPP). Planning Advice Notes (PANs) provide advice on good practice and other relevant information. PAN1/2011 demonstrates the role of the planning system in preventing and limiting the adverse effects of noise without prejudicing investment in enterprise, development and transport. PAN 1/2011 does not aim to provide a definitive source of prescriptive guidance on noise issues. Rather, it sets out the range of noise issues that planning authorities need to be aware of in formulating development plans, making decisions on planning applications and in taking enforcement action to preserve and enhance environmental quality.


• The Environmental Noise (Scotland) Regulations 2006 set out the information and general requirements of five-year Noise Action Plans from all transport sources in urban areas on which this NAP is based.