Heathrow study on “respite” shows there is no clear definition, and no clarity on what it means, or whether it helps

Heathrow, and the supporters of its plans for a 3rd runway (increasing the number of planes using the airport by up to 50%) have been enthusiastic about the concept of “respite” from plane noise. This is the idea that people will be less unhappy about the amount of plane noise, if they get some predictable times when they are spared the noise.  During those times, the noise is over other people (and vice versa). Heathrow has a Respite Working Group (RWG), set up in October 2014,  and it commissioned research to show if respite would be effective. The long awaited report has been published (though it was finished in May 2017 …) and it merely confirms the vagueness of the concept, and therefore how little confidence anyone has in it reducing the upset, distress and annoyance caused by unwanted plane noise.  The study might have been expected to a). define what respite actually is (in terms of amount of noise, duration, time of day).  b). what amount of respite is actually valued by overflown communities. Instead we have no certainty of when someone is getting “respite.” Does it mean no plane noise at all?  Or a bit less plane noise than usual, if the plane is a mile or two away rather than overhead? Does it mean half an hour without planes, or 8 hours without planes? And so on.  The RWG just wants more research ….

There are 128 pages of the study.




Some extracts from the report:

The development of satellite navigation technology means that aircraft can now be flown much more consistently on specified paths giving the airport greater control over the noise impacts of aircraft. In particular, it gives added impetus to assessing the value to residents of sharing aircraft noise between communities so that, at any given time, some communities experience respite (i.e. airport-managed perceptible relief from aircraft noise).

The concept of providing respite from aircraft noise has taken on increasing importance in recent years, as a useful and effective strategy for providing a break from aviation noise. However, there are no specific guidelines to explain what respite from aircraft noise means and how it should be implemented.

Heathrow Airport Ltd identified a need to improve its understanding of respite from aviation noise and in October 2014 set up a Respite Working Group (RWG) to investigate and advise. The RWG identified some knowledge gaps and recommended a laboratory and field based research project. That research commenced in February 2016 to address the key objectives identified by the RWG.

This aim (sic) of this report is to consolidate and provide an overview of the learning gathered through this journey to improve understanding of the concept of “respite”. It presents the story so far from the formation of the Respite Working Group to the recent research work. A separate report was provided by the RWG on the “State of the Art of respite” and a detailed Technical Report on the recent lab and fieldwork research has been developed. These can be found at 1 , 2 and both should be read in conjunction with this overview report for full details.

Community demand for respite: There is a consistent call from residents living under flightpaths for a break from aircraft noise. This has intensified due to the negative reaction towards trials of revised airspace design. It is important to understand what the communities themselves (both those currently overflown and those not) consider effective respite to be and how that could be achieved in reality.  [Have people asked for respite, or for less noise? The two things are not the same. AW comment] 

Future Airspace Strategy: The implementation of Performance Based Navigation (PBN) as part of the Future Airspace Strategy will may result in the concentration of noise over fewer specific locations. This improved accuracy also generates an opportunity for the pattern of flightpaths to deliver shared concentration3 but raises a question as to whether respite can be provided through rotation of flightpaths within the complexity/interaction with other airfields and procedures.

The UK policy context: The UK Aviation Policy Framework 4cites the principle of respite as a measure for reducing the impact of aircraft noise. However, there is currently no guidance on its definition, implementation or delivery. The member states of ICAO have adopted a “Balanced Approach” to noise management and while not explicitly mentioned in the Balanced Approach, respite is one of the operational measures which should considered in that context.

Key conclusion:

There is currently no clear, consistent or universally accepted definition of respite.

The RWG agreed on working definitions for the purposes of their project – see Box 1. There are many factors affecting the perception of respite and additional work is required to further define ‘a period of time’, ‘break’ and ‘reduction’ in terms of community perception.

Relief can be defined as a break from or a reduction in aircraft noise.

Respite can be defined as a scheduled relief from aircraft noise for a period of time.

Key conclusion:

What the community values as respite is not fully understood.

Despite a number of related studies and implementation examples, there is at present no clear understanding of what the community values as effective respite (6) . Effective provision of respite depends not only on operational features but also specifically on how the community perceives and values respite. Community-level understanding is therefore a priority in developing an effective respite strategy for Heathrow Airport.

(6).  Although the term community refers to the population of overflown residents, it is worth noting that the opinions may not be entirely unanimous and that residents may have differing opinions on effective respite. 

Key conclusion:

There is no universal formula for the successful implementation of an effective respite strategy.  Operational design for respite needs to consider operating conditions at an airport.

The effective provision of respite depends on the relative position of the local community to the different flight paths that might be used, and how often each flight path is actually used. The operational conditions at an airport will determine which options may be feasible in terms of delivering respite. These could include factors such as safety, efficiency, aircraft and avionic capabilities and controllers’ workload, amongst others.

Key conclusion:

There is currently no single acoustic metric that can adequately describe respite. Review work has shown that only a few metrics have been used to objectively describe respite.

Since it is not clear what the community deems as effective respite, and therefore which parameters are useful in describing its key elements, it is not possible to choose a suitable metric that is fit for purpose at this time. Instead, the Group has suggested a list of guiding principles and a candidate list of metrics to describe the noise environment in terms of offering respite.

Key conclusion:

Further work is needed to develop a clearer understanding of which parameters are useful in describing respite, in a way that is valued by the community.

Using this information we can then test the suitability of our candidate measures. We also need to understand the relative importance of acoustic and non-acoustic metrics in evaluating respite, so that we can put the usefulness and limitations of any acoustic metric in context.

Key conclusion:

A strong and effective communication strategy and good community engagement is essential for the successful implementation of respite.

From the cases analysed, two conclusions were drawn: multi-stakeholder engagement is fundamental and more efforts in communication are needed. It is key to engage all stakeholders during all phases of respite design and implementation. Communication should ensure that those involved understand the likely implications and associated trade-offs of respite implementation. Once we have a clearer understanding of how the community values respite, research can then focus on the selection of the most suitable engagement method for cross-sector involvement, how best to describe and present that information and the most effective combinations of media to use to disseminate the information.

Key conclusion:

There is currently insufficient information on the benefits of respite to health and on the economic value of the effects of respite.

There is clearly no one-size-fits-all solution, every end solution will vary – there is a need for further research.

The RWG (Respite Working Group) identified the following next steps to improve understanding and priorities for research:

  • Understand what the community values as effective respite.
  • Clarify the definitions for: ‘a period of time’, ‘break’, ‘reduction’ in terms of community perception.
  • Determine how far routes need to be changed to make a perceived difference and be of potential benefit in terms of height and position, for arrivals and departures.

and there are more ….



Implications for respite policy

› Residents may be unlikely to notice or appreciate small dB reductions in average sound level, particularly against the context of typical day-to-day variation, and if any such changes take place over long time scales. Within this limitation, residents are more likely to notice increases in noise than equivalent decreases.

› However, this research also highlights that there could be considerable benefit to the airport, even if periods of respite achieved only modest reductions in noise (i.e. 2-3 dB) – as a majority of respondents said they would feel more positive about the airport (even if it would not be particularly noticeable); nevertheless, a small minority would see it as a waste of resources. This is an example of the many non-acoustic factors that may have greater influence on community attitudes and acceptability of changes in air-space management and expansion at the airport..

› For many residents, non-acoustic factors (NAF), such as the effectiveness of public engagement, trust and understanding could be at least as important as actual sound level differences in terms of their appreciation of noise respite policy.

› The finding that there was strong consensus of preferring the quieter periods to be at either end of the day; and these apply for weekends as well as weekdays, implies that it will be difficult to allocate quieter periods at the preferred times, to everybody. This, not surprising, result confirms the need to understand how best to allocate managed respite – e.g. maximise the number of people who get more modest levels of respite OR maximise the level of respite albeit to a smaller number of beneficiaries. The sharing principle implicit in alternation is worthy of further investigation.

› The sample sizes obtained in this study are relatively modest and the confidence intervals around many of the findings are quite wide. If there is a need to obtain more precise estimates of thresholds and/or values, then it would be reasonably easy to roll-out the research design to new sample sites, to test responses elsewhere around Heathrow, and to increase the overall sample base of responses. On the other hand, since these results, albeit based on modest sample sizes, nevertheless appear to be generally consistent with both established theory and with recent qualitative (open ended in-depth interview) research carried out in areas around Heathrow.


The work to date is part of a programme of work with the overall aim to “To better understand the key characteristics of an effective respite strategy for Heathrow Airport and its local communities, consistent with efficient operations.”

At the current time the following stages have been undertaken.

  1. Need for better understanding of respite and establishment of RWG

2. State of the Art on respite and recommendations for research

3. Lab work and fieldwork on community attitudes – perceived differences and                                temporal preferences

The first stage was recognising the need to look at respite and the setting up of the Respite Working Group (RWG).

This followed with the RWG report on the state of the art on respite and recommendations for research priorities.

The latest research has focussed on the identified priority of gaining a better understanding of how the community values respite. It has been aimed at determining information on community attitudes with respect to perceived differences and temporal preferences. It is clear that effective respite is both a function of noise level difference and of the non-acoustic factors. In fact, non-acoustic factors, such as the effectiveness of public awareness, trust and understanding could be at least as important as actual sound level differences in terms of their appreciation of an effective noise respite policy. This recent work has given some basic information on noise level differences; using judgments of quasi artificial scenarios in the laboratory. However, the valuation of effective respite is also strongly dependent on the non-acoustic factors which can only be investigated in the field, based on real life experience of respite provision.

So what next?

1. Dissemination: The recent findings need to be shared with the aviation industry and community.

2. Understanding implications: There is a need to apply the learnings from this new research to understand the degree to which perceivable differences would exist (in terms of scale and populations) between comparable scenarios. It is therefore recommended that there should be an immediate assessment to explore the dB differences on maps for different flight operations. This will give insights into the inferred spatial differences between 2 routes to achieve different levels of noise benefits – the missing link to Research Question 1. It should aim to highlight the use of the basic difference principles and associated limitations.

3. Reconvene the RWG: Moving forward, the RWG should meet to consider priorities and make recommendations based on the recent research and the implications of that research as outlined above (2).

4. Consideration of the role of Non Acoustic Factors: If consideration is being given to extending the research, it might be considered opportune to widen the research objectives to include the possible contributions to attitudes and perceptions made by non-acoustic factors, based on real life experience of respite provision in the field.

See the full study at



See earlier:


Study for Heathrow on “respite” from plane noise cannot define it or agree on its effective use

The concept of “respite” (meaning giving areas that are over-flown some time periods when they are not over-flown, is being considered as a way to make otherwise unacceptable levels of plane noise – eg. from a new runway – acceptable. The concept works well for the two Heathrow approach paths over London now, with the landing runway switched at 3pm, allowing people almost half a day without the noise. But with 3 runways, one would need to always be in mixed mode, and so people could no longer get such long “respite” periods. Nobody knows what actually constitutes respite, how quiet the quiet periods should be, how long they should last, how often they should be, how predictable and so on.  Heathrow set up The Respite Working Group (RWG) in October 2014 to provide advice to the Heathrow Noise Forum on the management and assessment of respite. Heathrow employed Anderson Acoustics to look into respite, to define it and to understand how it might be useful. However, their review concluded that: There is currently no clear, consistent or universally accepted definition of respite.  What the community values as respite is not fully understood. There is currently no single acoustic metric that can adequately describe respite. There is no universal formula for the successful implementation of an effective respite strategy and operational design for respite needs to consider operational conditions at an airport. And there is currently insufficient information on the benefits of respite to health and on the economic value of the effects of respite.