Transport CommitteeWritten evidence from The Authorities’ Aircraft Noise Council (LAANC) (AS 83)

LAANC is an umbrella local authority organisation which represents the interests of two dozen Local Councils comprising Boroughs, Unitary Boroughs, London Boroughs, County and Parish Councils serving a wide area around Heathrow Airport.

The Constitution of LAANC covers environmental issues as well as aircraft noise and represents a very large community many of whom have direct contacts with Heathrow.

The main points that LAANC wishes to make to the committee are summarised below. Detailed responses to the committee’s questions are attached as appendices.

Main Points

It should be acknowledged that the provision of capacity cannot (within the current UK aviation regulatory framework) be guaranteed to produce increased connectivity for UK plc. This is especially the case at Heathrow. In LAANC’s view the Government need to identify if further regulatory powers need to be taken (for example, reintroducing some form of Traffic Distribution Rules) to ensure that government can play a part in maintaining connectivity. The choice of where planes fly to currently is made by neither the airport owner nor the Government. It is made by the airlines who naturally prioritise the more profitable routes.

LAANC believes that the key issues for the Government in developing future policy are the requirements for runway capacity and the case for connectivity. In respect of Heathrow it has suited the Heathrow owner to conflate the two issues. It suits Heathrow’s business model to claim that additional capacity is best located at their airport—as opposed to those of rival owners—for example Gatwick or Birmingham. It also suits the operator to claim that the UK economy requires additional hub capacity and that that too can be located at Heathrow. Yet as the Mayor of London has shown there are other potential sites for a hub airport in the South East which would not be constrained in the same way as Heathrow which is set in the most densely populated part of the country.

The current DfT Aviation Framework consultation document confirms that London is already one of the best connected cities in the world and has adequate supply of airport and runway capacity for the short to medium term (up to 2030). The capital has five airports (Heathrow, Gatwick, Stansted, Luton and London City) which together serve more routes than any other European city. There are other “near London” airports, currently under used (e.g Ashford and Manston) which have adequate runway length to contribute to the London airport system. Overall the United Kingdom position is very strong the UK being directly connected to more than 360 international destinations. Using available airline seat kilometres as a connectivity metric, only the Chinese and US aviation networks are more extensive than the UK.

LAANC urges the government to take action to ensure that aviation forms part of an overall UK strategic national integrated transport infrastructure framework that encompasses airports, roads and rail, including any potential high speed rail. It is difficult to see how the decision already taken for a preferred high speed rail route with a spur to Heathrow can be taken forward at this stage when the decision on where any future aviation hub might be will not be taken before 2015 at the earliest.

Airports cannot be allowed to have increased capacity at any cost. There must be sufficient weight given to complying with relevant European environmental legislation on issues such as local air quality and ensuring the avoidance of significant adverse noise impacts in order to protect the health and well being of local communities. UK policy on aircraft noise is currently to “limit and, where possible, reduce the number of people in the UK significantly affected by aircraft noise”. Successive governments have used the 57LAeq decibel contour as a benchmark for identifying onset of significant community annoyance. This covers an area of 106 square kilometres and a population of 224,500 where people live. The Government now admits that community response to aircraft noise has changed over the last 30 years and that this 57LAeq contour is out of calibration. It also concedes that the failure to update social surveys and community response data since the 1985 ANIS and in particular the failure of the ANASE study has led to a breakdown of trust with communities affected by aircraft noise—particularly when the headline results of the ANASE study have been shown to be in line with other independent studies in Europe.

UK aircraft noise policy needs to acknowledge the impact of aircraft noise on people’s health and wellbeing. The noise climate around Heathrow is simply too noisy already for too many people, the Aviation Framework Consultation document admits that Heathrow has a significantly greater noise impact per flight than any other major European airport. However even this admission does not adequately describe the disruption to sleep from being awakened by the first arrival of the day at 4.30am for example or the constant passage of flights overhead during the day at 90 second intervals. The current noise metrics also are unable to recognise the value of predictable periods of respite during the day.

A more accurate measure of community exposure to aircraft noise must be adopted as soon as possible, including recognition that the frequency of flights is an important aspect rather than just the noise of an individual flight.

LAANC supports the government’s s proposals to extend fifth freedoms, review the current runway slots mechanism and access to other UK airports. LAANC believes all of theses measures will be helpful in incentivising the best use of regional airports, which in turn provide the opportunity for relieving the pressure at congested south east airports.

LAANC supports the Mayor of London’s proposal that runway utilisation at any of the London airports should be at no more than 75% in order to avoid congestion on the ground, congestion in the air and to improve the passenger experience in terms of the airport’s ability to recover from disruption.

Currently it seems there is no overall agreement within the airlines about how much or where extra runway capacity is needed. Before any decisions are made on the provision of extra capacity or whether the hub model is the correct operating model for increasing capacity and maintaining connectivity, the impacts of various changes should be appropriately taken into account including new technologies such as video-conferencing; substitution of short haul for rail trips; increasing oil prices; constraints in terms of reducing climate change emissions; and the impact of new generation aircraft, such as the Boeing 787 which will have the ability to fly longer distances.

An international hub needs to be situated where there is sufficient land to facilitate its function as a hub. LAANC believes that on environmental grounds alone Heathrow should be excluded from the review of airport capacity which is to be undertaken by the Davies Commission. There are equally strong operational reasons why a new expanded hub airport could not be sited at Heathrow. The Mayor of London has estimated that based on forecast growth a third runway would be full by 2030. The hub airport model has an insatiable demand for additional runway and terminal capacity. The many connecting flights which feed the long haul routes all need to arrive within a narrow time frame if passengers are not to be left waiting for hours for their transfer flight. Successful hub airports make sure they have additional runway capacity to cope with these “waves” of arrivals. It is why three runways will never be enough at Heathrow.

Comparisons with key competitors are always made to support Heathrow’s case for expansion—but the nearest, Charles de Gaulle, has four runways (and is located away from the capital), Frankfurt has four runways and Schiphol has six. There are simply no circumstances in which a four-runway Heathrow would ever be acceptable. It would give rise to a host of new flight paths over residential areas on all sides of the airport and in so doing unreasonably impact upon new communities not currently affected by aircraft noise.

Key Recommendation

LAANC would ask the Committee to recognise that a third short runway at Heathrow is not likely to be sufficient in the long term and there will inevitably be pressure for a 4th runway. There is insufficient land for Heathrow Airport to expand to meet the long term requirements of a hub airport. To attempt to propose airport expansion in such an already congested location, with the devastating impacts arising from the demolition of homes and the loss of communities and the unacceptable levels of noise and air pollution that this would be bring to large areas of London, is not rational in any future aviation policy.

20 October 2012




This paper presents evidence that there is a useful correlation between the aircraft noise annoyance studies reported in a recent European Environment Agency (EEA) report and the UK Government’s ANASE study. Both sets of studies have found a significant shift in that aircraft noise now causes annoyance at lower levels than it did previously. The significance of this, in relation to the current framework scoping consultation, is that it provides some support for the use of the ANASE findings in the development of future aviation policy. This is important, as without this support, the ANASE findings have been set aside. However, until the ANASE issue can be resolved, the conclusion is that the EEA findings should be accepted for the development of future aviation policy, in relation to annoyance. There remains an important caveat to this, in that the EEA evidence itself needs to be improved by including the significance of flight numbers in any noise annoyance assessment. Only once this is resolved can the question of acceptable aviation capacity be addressed fully. So, in spite of the various study deficiencies, the message remains clear, that aircraft noise now causes annoyance at lower levels than it did previously, and this issue must be addressed in any future aviation policy.

EU and UK Models for Aircraft Annoyance

The recent European Environment Agency report[1] is a good practice guide intended to assist policy makers and competent authorities in understanding and fulfilling the requirements of Directive 2002/49/EC,[2] commonly referred to as the Environmental Noise Directive, relating to the assessment and management of environmental noise. It summarises the latest European view on issues such as exposure-response relationships and thresholds for health endpoints (annoyance, sleep disturbance, cardiovascular effects and cognitive impairment). Individual annoyance relationships with the noise metric Lden are given for road, rail and aircraft noise.

The EEA report gives a previously used European aircraft noise annoyance relationship based on studies carried out prior to 1990. This is the same relationship as given in the 2002 EU Position Paper.[3] The relationship gives an estimate of the percentage of persons highly annoyed at a given Lden noise exposure.

The EEA report mentions studies showing a trend change in annoyance around 1990, and gives an updated European annoyance relationship based on aircraft noise studies carried out after 1990. These were all European studies (Switzerland, Germany, Netherlands) regarded as more appropriate for the EU than the pre-1990 studies, which were mainly carried out in the USA and Australia.

Figure 1 gives the results for the pre-1990 and post-1990 studies in terms of percentage highly annoyed in relation to Lden. It can be seen that levels of annoyance at a given noise level are much higher for the post-1990 studies than for the pre-1990 studies. The analysis given in Figure 1 is confined to the range of noise levels in the ANASE study (40.9 to 64.2 dB LAeq,16h).

HA = “Highly annoyed”

At 59 dB Lden, for example, the relationship adopted for the pre-1990 studies in Figure 1 gives 16% highly annoyed. In the case of the post-1990 studies, the relationship adopted gives the same percentage highly annoyed at around 49 dB Lden.

Thus, the EEA report suggests that levels of annoyance (expressed as percentage highly annoyed) that occurred at 59 dB Lden in the pre-1990 studies occurred at around 49 dB Lden in the post-1990 studies, a reduction of around 10 dB Lden.

The Government’s aviation policy uses 57 dB LAeq,16h as the level of daytime noise marking the approximate onset of significant community annoyance. This level is based on the Aircraft Noise Index Study (ANIS)[4] carried out in the UK in the 1980s.

The CAP725 document[5] produced by the Civil Aviation Authority in 2007 outlines methodologies for environmental assessment of an airspace change proposal. It gives an aircraft noise annoyance response relationship for calculating percentage of people highly annoyed using LAeq,16h noise levels. The relationship is based on the Schultz curve produced in 1978.[6] The document states that the ANIS results exhibit the same general trend as the aircraft studies in the Schultz analysis. The EU annoyance relationships use the Lden noise metric rather than the LAeq,16h noise metric used in the UK.

Analysis of data[7,8] relating to Heathrow airport in 2006 shows that Lden is typically around 1.7 dB higher than LAeq,16h. This 1.7 dB adjustment has been used to convert LAeq,16h to Lden to give the CAP725 annoyance relationship shown in Figure 1.

The Attitudes to Noise from Aviation Sources in England (ANASE) study[9] reported in 2007 that annoyance with a given level of aircraft noise is much higher than when the ANIS study was carried out. The ANASE study made a direct comparison with the ANIS study in terms of “mean annoyance” with aircraft noise. This showed that the level of mean annoyance found at 57 dB LAeq,16h in the ANIS study was found in the ANASE study at a level of just over 50 dB LAeq,16h, a reduction of just less than 7 dB LAeq,16h.

The Government accepted that the ANASE study demonstrated that annoyance with a given level of aircraft noise is higher than found in the ANIS study. However, on advice contained in an independent peer review report,[10] the Government decided that the detailed findings of the ANASE study should not be relied on.

Most of the analysis in the ANASE report related to “mean annoyance”, and trend lines were fitted to graphs of mean annoyance versus LAeq,16h. Figure 7.2 of the ANASE report gave a graph of percentage “at least very annoyed” versus LAeq,16h, but no trend line was fitted to the plotted data points. In the ANASE study, responses from respondents were recorded using an annoyance scale of (i) “Extremely annoyed”, (ii) “Very annoyed”, (iii) “Moderately annoyed”, (iv) “Slightly annoyed” and (iv) “Not at all annoyed”. The annoyance scale did not include a response of “Highly annoyed” as used in the EEA and CAP725 reports so comparison of the results of the different studies is not straightforward.

However, section 6 of the ANASE peer review report[10] assumes that the ANASE term “at least very annoyed” is equivalent to the term “highly annoyed” used in other studies. This assumption allowed the peer reviewers to deduce (apparently by eye) two trend points for the plotted ANASE data points. The two ANASE trend points given in the peer review report are 8.5% highly annoyed at 47/48 dB LAeq,16h, and around 40% highly annoyed at 57 dB LAeq,16h. These trend points relate to the corrected version of ANASE report Figure 7.2 given in the Erratum dated 1 November 2007 contained in the ANASE final report dated October 2007. This paper therefore tentatively plots the ANASE data, but makes plain that the ANASE values for “highly annoyed” have been derived.

The two ANASE derived trend points are plotted in Figure 1, after converting LAeq,16h to Lden by adding 1.7 dB, derived from Heathrow data for 2006. Using the same assumptions that (i) the ANASE term “at least very annoyed” is equivalent to “highly annoyed” in other studies, and (ii) Lden can be estimated from LAeq,16h by adding 1.7 dB, the results derived for all ANASE sites have been plotted in Figure 1. That figure also shows a third order polynomial trend line fitted to the ANASE derived results. The relatively poor agreement between the plotted data points and the fitted trend line (R2 = 0.667) reflects the spread of the data points, but this is not unusual in social surveys of this kind.

It is important to note that Figure 1 shows that the annoyance levels at a given noise level are much higher for the EEA post-1990 studies than for the EEA pre-1990 studies. For example, percentage highly annoyed at 57 LAeq,16h (approximately equivalent to 58.7 dB Lden) is more than doubled from around 15% for the pre-1990 studies to around 37% for the post-1990 studies.

It can be seen from Figure 1 that the annoyance levels for the UK’s CAP725 relationship are generally lower than given by the EEA pre-1990 studies relationship, and much lower than given by the EEA post-1990 studies. This implies that continued use in the UK of the CAP725 annoyance relationship will seriously underestimate levels of aircraft annoyance. The ANASE trend line is generally similar to the EEA post-1990 studies relationship, and certainly in much better agreement with the EEA post-1990 studies relationship than is the CAP725 relationship.

The Government rejected the detailed findings of the ANASE study and continues to rely on the ANIS, Schultz and CAP725 aircraft noise annoyance relationships, even though these relationships are based on social surveys carried out more than 25 years ago. It seems doubtful that these relationships remain in calibration for current public attitudes, flight numbers, aircraft fleet mixes and aircraft noise characteristics. The EEA report supports this doubt on the continued validity of these relationships. This is because the EEA report suggests that levels of annoyance at a given noise level are much higher than suggested by previous European guidance. Furthermore, these EEA findings of much higher levels of annoyance seem to be replicated by the results of the recent ANASE study.

Objectives and Findings of the ANASE Study

The ANASE study was commissioned by the Government in 2001 in order to update the ANIS study of 1982 which led to LAeq,16h noise index being adopted by the Government for measuring aircraft noise.

The ANASE report recognises that the amount of air traffic has increased significantly since 1982 whilst the sound levels generated by individual aircraft events have been significantly reduced as older, noisier aircraft have been replaced by more modern aircraft types with quieter engines and much improved climb performance. It is also recognised that attitudes to aircraft noise may have been changed due for example to the general growth in personal income, higher expectations of a peaceful living environment and less tolerance of environmental intrusion.

The main findings of the ANASE study are reviewed below against the study objectives.

Objective 1

Re-assess attitudes to aircraft noise in England

The study found that the annoyance level of respondents increased as the noise indicator LAeq,16h increased, and that a large proportion of measured variation in annoyance can be accounted for by LAeq,16h.

However, for a given LAeq,16h, there is a range of reported annoyance indicating that annoyance is not determined solely by the amount of aircraft noise as measured by LAeq,16h. The main additional influences on the level of annoyance were found to be respondent’s household income and socio-economic group.

The study found that for the same amount of aircraft noise, measured by LAeq,16h, people were more annoyed in 2005 than they were in 1982.

The study showed that people are much more sensitive to aircraft noise at night (particularly around midnight and the early hours thereafter). In contrast, people are least sensitive to aircraft noise in the morning and early afternoon. Ideally, therefore, a noise indicator for aircraft noise should reflect these times of day sensitivities. In contrast, LAeq,16h does not reflect weighting for sensitivities by time of day.

Objective 2

Re-assess their correlation with the LAeq,16h noise index

The study considered whether LAeq,16h is the appropriate measure of aircraft noise for predicting annoyance.

The study found that while LAeq,16h continues to be a good proxy for measuring community annoyance at a given point in time, the relationship between LAeq,16h and annoyance is not stable over time.

Because of this, use of LAeq,16h to predict future levels of annoyance may be misleading. In particular, where numbers of aircraft are increasing significantly, the ANASE results suggested that under-prediction of annoyance is likely.

The study recognised that the LAeq,16h noise index incorporates a mathematical trade-off of 10 between event noise level and number of noise events,1 which means that each doubling or halving of the numbers of aircraft noise events counts as equivalent to a 3 dB increase or decrease in average noise levels.2 The results from the study suggested that the LAeq,16h noise indicator gives insufficient weight to aircraft numbers, and a relative weight of 20 appears more supportable from the evidence than the relative weight of 10 inherent in LAeq,16h.

Objective 3

Examine willingness to pay to remove aircraft noise

The study was required to examine (hypothetical) willingness to pay in respect of nuisance from aircraft noise, and whether attitudes might be affected if cash transfers or, for example, noise insulation grants were made available. The study found that aircraft event noise level, aircraft type, time of day and personal characteristics (in particular household income) influence annoyance and willingness to pay.

Aircraft noise action plans

The EEA report[1] provides the dose-effect relationships intended to be used to assess the effects of noise on populations as required by the Directive.[2] Section 6 of the EEA report suggests that the lower noise thresholds for mapping are intended to delimit the area where noise is “considered to be a problem”. These thresholds are noise levels above which health effects start to occur.

The EEA report accepts that use of the current threshold levels for noise mapping of 55 dB Lden and 50 dB Lnight is understandable as a first step because of the large scale noise mapping required. However, the report points out that Member States are free to choose their own noise thresholds from where to start action planning, and the Lden threshold for noise mapping of 55 dB Lden does not take into account differences that exist between different noise sources. These differences are illustrated in Table 6.1 of the EEA report giving respective percentages highly annoyed at 45, 50 and 55 dB Lden for road, rail and aircraft noise. Table 6.1 of the EEA report is reproduced here (in part) as Table 1.

Table 1



Percentages of highly annoyed





55 dB




50 dB




45 dB




The EEA report states that while 55 dB Lden is a “fair” threshold for rail noise, use of 55 dB Lden for other noise sources leads to an underestimate of the actual burden.

Table 1 gives the percentage highly annoyed at 55 dB Lden for rail noise as 4%, while the percentage highly annoyed at 45 dB Lden for aircraft noise is given as 12%. This means that to achieve annoyance levels approaching that regarded as “fair” for rail noise, the threshold for aircraft noise may have to be lower than 45 dB Lden. In fact, Section 2 of the EEA report gives 42 dB Lden as a general noise threshold above which annoyance effects start to occur or rise above background.

It would therefore appear that the EEA report implies that the threshold for noise mapping where aircraft noise is considered to be a problem should be significantly lower than 55 dB Lden as currently used.


The EEA report recognises that levels of annoyance with aircraft noise are much higher for post-1990 studies than for pre-1990 studies.

This paper compares the results for different annoyance models over the range of noise levels in the ANASE study (40.9 to 64.2 dB LAeq,16h). Analysis in this paper shows that annoyance levels redicted by the UK’s CAP725 relationship are generally lower than given by the EEA pre-1990 relationship, and much lower than given by the EEA post-1990 relationship.

In contrast, the analysis shows that the much higher annoyance levels in the EEA post-1990 studies seem to be replicated by the ANASE study. Despite this, the Government continues to rely on the ANIS, Schultz and CAP725 aircraft noise relationships derived from social surveys carried out more than 25 years ago.

Until the issues of the ANASE study are addressed, it is suggested that Government policy should be based on guidance in the EEA report, including the specified relationship between annoyance and aircraft noise level.

Although the EEA report gives increased levels of aircraft noise annoyance, it does not address all the objectives of the ANASE study. These objectives include the suitability of LAeq,16h as an indicator of community annoyance, the importance of numbers of aircraft flights, the relative importance of different times of day, and determining willingness to pay to reduce annoyance from aircraft noise. Further work is necessary to address these objectives.

It is concluded that there is an urgent need for updated guidance from the Government on the annoyance relationship for aircraft noise, and the threshold level at which aircraft noise is considered to be a problem.


[1] Good practice guide on noise exposure and potential health effects. EEA Technical Report No. 11/2010. European Environment Agency, 2010.

[2] Directive 2002/49/EC. Directive of the European Parliament relating to the assessment and management of environmental noise, 2002. Official Journal of the European Communities, L 189, 12–25.

[3] Position paper on dose response relationships between transportation noise and annoyance. European Commission Working Group, 2002.

[4] United Kingdom Aircraft Noise Index Study. DR report 8402, Civil Aviation Authority, 1985.

[5] CAP725, CAA Guidance on the application of the airspace change process. Civil Aviation Authority, 2007.

[6] Synthesis of social surveys on noise annoyance. Schultz, Theodore J. Journal of the Acoustical Society of America, 64(2), 1978.

[7] London Heathrow Airport Strategic Noise Maps 2006. ERCD Report 0706. Civil Aviation Authority, 2007.

[8] Noise exposure contours for Heathrow Airport 2006. ERCD Report 0701. Civil Aviation Authority, 2007.

[9] ANASE: Attitudes to Noise from Aviation Sources in England. Final Report prepared for Department for Transport by MVA Consultancy, October 2007.

[10] Attitudes to Noise from Aviation Sources in England. Non SP Peer Review. Civil Aviation Authority and Bureau Veritas, draft July 2007, final October 2007.

File: Aircraft noise annoyance_3

1 LAeq,T = SEL + 10LogN – 10LogT, where SEL is event noise level (dB) for N events in T seconds.

2 10Log(2/1) = +3dB and 10Log(1/2) = -3dB.

Prepared 24th May 2013