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.
There is a presentation by Anderson Acoustics for Heathrow.
“Respite from Aviation Noise – Introduction to and update on current research”
Extracts below from the Respite document from Heathrow
RESPITE WORKING GROUP
REPORT A REVIEW ON THE STATE OF THE ART ON RESPITE
PREPARED FOR HEATHROW AIRPORT LTD
THE NEED TO BETTER UNDERSTAND THE CONCEPT OF RESPITE
There are three main drivers in the push for a better understanding of what respite from aircraft noise means and how to deliver it:
- 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 recent 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.
- The Airspace Modernisation Programme: The implementation of Performance Based Navigation (PBN) as part of the Airspace Modernisation Programme will result in much greater consistency and accuracy of aircraft flight paths. This will result in a concentration of noise along flight paths. This improved accuracy generates an opportunity for the pattern of flightpaths to deliver shared concentration1 but raises a question as to whether respite can be provided through safe rotation of flightpaths.
- The UK policy context: TheUK Aviation Policy Framework cites 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’s 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
1 Shared concentration is a term that has been used to describe the use of multiple PBN Standard Instrument Departure routes (SIDs) within a Noise Preferential Route (NPR swathe) – or indeed beyond. This could result in the concentration of noise along several different PBN SIDS which can be alternated so that noise is shared. In theory this concept may also be applied to arrivals.
DEFINITIONS OF RESPITE
It was established that there are no universal definitions of respite. For the purposes of this project, the Group developed the following working definitions for internal use for this work; Box 1:
Working Definitions used by the RWG for the purposes of this work
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.
CONCLUSIONS OF THE RESPITE WORKING GROUP
Page 9 of respite review
Overall, the following key conclusions were drawn by the RWG based on the review evidence:
- There is currently no clear, consistent or universally accepted definition of respite.
The RWG agreed on the working definitions above for the purposes of this project. 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.
- 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 respite2 . 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.
- 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.
- There is currently no single acoustic metric that can adequately describe respite
Our 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.
- 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.
- 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.
- 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.
RESEARCH PRIORITIES RECOMMENDED BY THE RESPITE WORKING GROUP
In addition to the key lessons learned listed above, the Group identified three priority areas where greater understanding is required in order to implement effective respite from aircraft noise, these should be prioritised in the next phases of research:
- What does the community value as effective respite?
- How can respite be delivered by an airport that is both operationally feasible, cost effective as well as valued by the local community?
- What are the objective measures to describe respite in a way that reflects community perception?
The concept of providing respite from aircraft noise to affected communities has become increasingly important in recent years. As well as increasingly demanded from those individuals affected at the community level, respite is already referred to in government policy and within the context of the airspace modernisation programme.
There are three main drivers in the push for a better understanding of what respite from aircraft noise means and how to deliver it:
- Community Demand
- Airspace modernisation programme
- UK Policy Context
PBN and respite
If PBN is to be used to enable respite, a major question for policy makers is whether to concentrate flights over specific areas and/or use multiple routes to provide respite. A policy that will result in greater noise concentration may need to be presented hand-in-hand with a respite policy that provides breaks from noise and overflights to the affected community. However, this could be at odds with current UK policy of limiting and where possible reducing the number of people significantly affected by aircraft noise.
Within the context of airspace re-design, it is important to note that any changes to airspace design needs to take into account many complex issues, and any development of an effective respite strategy needs to give priority to these factors from the outset for any practical respite options to be implemented. The issues to consider include:
- Airspace design limits
- Efficiency and resilience requirements
- Aircraft capabilities and avionics
- Consideration of track miles, fuel burn and associated cost
- Aircraft traffic control and controllers workload
- Pilot’s workload
- Trade off with other environmental factors
The UK Policy Context
The UK Aviation Policy Framework cites 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.
2.3.1 Current government guidance
The UK Government’s overarching policy is “to limit and where possible reduce the number of people in the UK significantly affected by aircraft noise” (DfT, 2013).
This has meant, in practical terms, that aircraft are increasingly concentrated along the fewest possible number of specified routes, avoiding densely populated areas as far as possible. As a result, and owing in part to improvements in aircraft technology and using tailored operational procedures, annual Lden and summer average LAeq,16hr6 noise contour areas have reduced over time. (CAA, 2014)
Providing options for delivering any form of respite from aircraft noise has become a key issue in the noise policy agenda.
The member states of ICAO’s have adopted a “Balanced Approach” to noise management through the exploration of four principal elements, namely reduction at source (quieter aircraft), land-use planning and management, noise abatement operational procedures and operating restrictions, with the goal of addressing the noise problem in the most cost-effective manner. While not explicitly mentioned in the Balanced Approach, respite is one of the operational measures which should considered in that context. The EU has also adopted the Balanced Approach and has required the use7 of PBN to secure the emission efficient and safe use of airspace.
2.3.2 Noise policy in the UK
The Aviation Policy Framework (APF) includes respite as a measure to reduce and mitigate noise in communities already exposed. It recommends exploring “options for respite which share noise between communities on an equitable basis, provided this does not lead to significant numbers of people newly affected by noise”.
It does not define new or significantly. It also highlights the importance of ensuring predictability to local communities in airspace planning (DfT, 2013, p. 62).
The Civil Aviation Authority (CAA) includes respite as one of four key areas for improving aircraft operations in order to better manage aviation noise, in particular in the context of expanding capacity (CAA, 2014).
The Air Navigation Guidance, produced by the Department for Transport and CAA, suggests exploring options for respite with local communities by designing different routes that can be used alternately. However, it includes a caveat that this should be achieved without significantly increasing the number of people newly exposed to noise (DfT, 2014, pp. 28,29).
The Airports Commission in the UK also considers respite as a key strategy to mitigate noise impacts on the population. Its Appraisal Framework evaluates the noise implications of applying different respite strategies to each of the three shortlisted options for increasing long-term capacity in the UK (Airports Commission, 2014 and 2015).
None of the above references offer specific guidance on what respite means, nor how it should be implemented or delivered. This is in line with Government and International policy guidance which promotes local solutions for local problems,
From the UK Government and UK regulatory perspective, respite is generally understood as a key measure to mitigate the impact of aircraft noise over communities significantly exposed to aircraft noise. However, there is no specific definition to help measure, quantify or implement respite.
From the community and residents’ perspective, respite is highlighted as a crucial factor to consider when planning flightpaths. According to John Stewart, Chair of HACAN, respite is related to the provision of predictable periods of relief from the noise of the planes landing and taking off at Heathrow. In his own words, these are periods where there should be no planes overhead. Some of the people complaining about aircraft noise at Heathrow Airport highlight the importance of sharing and fairness10 in the distribution of the noise and the need for respite periods (Stewart, 2015).
The main operational challenges identified are related to the provision of respite within the context of PBN implementation. The use of PBN has led to the greater concentration of flight tracks over narrower paths and an increased negative community reaction. PBN will be implemented worldwide and this work has confirmed the need to consider supplementary strategies to provide a break from these more concentrated overflights (and hence increased noise exposure), and to consider fairness as a concept.
This work has also raised the issue of how to disperse routes while flight tracks are more concentrated on individual paths and has identified a risk of overlapping “respite areas” as one of the main obstacles for delivering effective respite. UK Government Policy now needs to consider its implied position on shared concentration for arrivals and departures, as this could impact how respite is implemented, through either rotating a small number of routes or spreading aircraft out over a larger number of routes.
Based on the research priorities identified above, the RWG has developed a list of actions in order to address the priorities and move forward with research:
1. Understand what the community values as effective respite as a priority, before any other work is undertaken.
2. Clarify the definitions for: ‘a period of time’, ‘break’, ‘reduction’ in terms of community perception.
3. 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.
4. Understand more clearly which parameters are useful to describe respite in a way that is valued by the community.
5. Test the list of candidate measures after further research is completed.
6. Identify the relative importance of acoustic metrics and non-acoustic metrics.
7. With a clearer understanding of how the community values respite, conduct further research, focussing on: • Selecting the most suitable engagement process with all stakeholders (community, industry, regulator, etc.) • Identifying the key information to share • Describing and presenting that information in the most suitable way for all parties • Identifying the most effective combinations of media to use • Selecting the optimum temporal separations or patterns required
The Group agreed that priority must be given to gaining a better understanding of how the community values respite, before considering operational feasibility, cost-effectiveness and the development of metrics. The following key objective for research was identified:
KEY RESEARCH OBJECTIVE
To better understand the key characteristics of an effective respite strategy for Heathrow Airport and its local communities, consistent with efficient operations.
Two phases of research were identified in relation to this key objective:
Phase 1: To develop a set of principles for providing effective respite from aviation noise. Phase 2: To test out practical implications for airspace design of emerging principles from (1).
In the APF Aviation Policy Framework
Respite Pages 61 & 62
However, in certain circumstances, such as where there is intensive use of certain routes, and following engagement with local communities, it may be appropriate to explore options for respite which share noise between communities on an equitable basis, provided this does not lead to significant numbers of people newly affected by noise. Whether concentration or respite is the preferred option, those responsible for planning how airspace is used should ensure that predictability is afforded to local communities, to the extent that this is within their control. Further guidance on these airspace matters will be provided when the Department for Transport updates its guidance to the CAA on environmental objectives relating to the exercise of its air navigation functions (see Chapter 5)
In recognising these higher costs upon local communities, we expect the aviation industry to make extra efforts to reduce and mitigate noise from night flights through use of best-in-class aircraft, best practice operating procedures, seeking ways to provide respite wherever possible and minimising the demand for night flights where alternatives are available. We commend voluntary approaches such as the curfew at Heathrow which ensures that early morning arrivals do not land before 4.30am.