ICCAN produces review and 6 recommendations about aviation noise metrics and their measurement
The issue of plane noise has been of great concern to hundreds of thousands of people, for ages. ICCAN was set up in 2019 to look into the problem, seeing if there might be ways to manage it better, and for people to be considered more – and their noise concerns taken seriously. One key problem is how noise is measured, and therefore how overflown communities can get factual data on the noise they are experiencing. This is complicated. Acoustics is not a simple science, and especially difficult to explain in plain English to laypeople. The noise an area suffers depends on the number of planes overhead, their height, their type, what they are doing at the time, the frequency of the flights overhead, the time of day (or night) and the background level of noise an area already experiences. Traditionally aircraft noise is averaged over a period of time. That provides numbers that can be compared to other places and other times. But it makes no sense to those being affected. But nobody hears an average of plane noise. They hear a number of separate noisy events. Now ICCAN has produced a review of aircraft noise metric and their measurement, and their six recommendations, for how improvements should be made.
.
Tweet
The six recommendations:
Recommendation 1:
ICCAN supports the continued use of the LAeq-based metrics currently used for noise monitoring and statutory reporting where appropriate. However, we also recommend that supplementary Single Event metrics are routinely published by airports to better reflect the way in which noise is experienced on the ground.
Recommendation 2:
The approach to noise monitoring around the UK is neither consistent nor clear to stakeholders; we will develop best practice guidance for UK airports on the approach, standards and quantity of aviation noise monitoring.
Recommendation 3:
To help rebuild trust and ensure airports and communities work in partnership, we will provide best practice guidance on the provision of temporary noise monitors by airports to communities.
Recommendation 4:
Noise data transparency needs to improve. Our best practice guidance will develop standards to enable comparable noise monitoring data to be published annually, so communities can track changes and trends around their airports.
Recommendation 5:
The threshold for noise monitoring data from airports of 50,000 Air Traffic Movements (ATMs) should be replaced with a lower threshold for publication of noise monitoring data, but applied proportionately and, potentially, with tiered requirements.
Recommendation 6:
Improving noise monitoring consistency and application requires UK-wide leadership. We see ICCAN’s future role as providing that national leadership and standard setting.
A review of aviation noise metrics and measurement
July 2020
by ICCAN (the Independent Commission on Civil Aviation Noise)
Below is just
Chapter 6 : Key findings and recommendations
ICCAN says:
Our review of aviation noise metrics, noise monitoring and data publishing has identified some key areas where transparency and process can undoubtedly be improved. These include the lack of a consistent and unified approach to monitoring and processing noise data, a lack of data transparency, and opaque and inconsistent publishing practices surrounding noise metrics.
In an era when open and transparent data is rightly becoming the norm, it will become increasingly important that the aviation industry and its regulators publish and use consistent data to manage the adverse effects of aviation noise. This needs to be supported by the publication of noise metrics that are reflective of a community’s actual experience of aviation noise exposure and should be published in an accessible way.
Only by de-mystifying the complex subject that is the measurement of noise can trust start to be re-built between the industry, regulators and the local communities around airports.
We believe our findings and recommendations, along with the next steps we propose, will be a positive move in the right direction to rebuild that trust.
Recommendation 1:
ICCAN supports the continued use of the LAeq-based metrics currently used for noise monitoring and statutory reporting where appropriate. However, we also recommend that supplementary Single Event metrics are routinely published by airports to better reflect the way in which noise is experienced on the ground.
We acknowledge that there is no one metric that can reflect annoyance, or associated health issues. Having considered the metrics available, and the concerns frequently raised by stakeholders, we conclude that the best approach at present is to use different metrics for different purposes, in order to cater for the different needs of stakeholders. The metrics need to strike the balance between being relevant, accurate and meaningful while also easily communicated to non-experts.
We conclude that continued use of the LAeq-based metrics that are currently required in UK legislation and policy are appropriate. Although the LAeq-based metrics have their disadvantages, they are useful due to the large data sets that have already been amassed. Furthermore, research has shown that they do correlate with some aspects of annoyance and health (as reviewed in Aircraft Noise and Health Effects: A yearly update (CAA, 2019) and Aircraft Noise and Annoyance: Recent findings (CAA, 2018)).
However, we acknowledge and agree that people do not experience noise as an average, and therefore reliance entirely on LAeq does nothing to aid public understanding, let alone trust, in the data being published. It is our view that the LAeq type metrics can be strengthened by coupling them with a complementary metric that represents different aspects of aviation noise.
Our initial opinion is that the Number Above (Nx) is the most appropriate complementary metric. This will enable communities to see official data relating to the frequency of significant noise events over their communities. We will do further work to analyse and determine/define at what noise level such a metric should be set, along with the time period covered for predictive flight information, and this will form part of future best practice guidance. We believe this would be an important step to help increase the transparency of noise measurements to stakeholders.
Recommendation 2:
The approach to noise monitoring around the UK is neither consistent nor clear to stakeholders; we will develop best practice guidance for UK airports on the approach, standards and quantity of aviation noise monitoring.
Noise data is at the heart of the discussion around aviation noise. However, the methodologies for recording noise data are set out in various publications drawing on a variety of sources dating back to 1971 (ICAO, 2019). This means that not only are some of the requirements in need of updating, but the best practice isn’t a coherent narrative. It is also highly likely that there is some discrepancy in the practices for noise monitoring between UK airports due to factors such as different contractors, type and age of recording equipment, budgets etc.
All these factors mean that it is likely that noise monitoring quality is variable across the UK. In part this is unavoidable, but the situation could be improved to increase consistency. It is our opinion that there should be more explicit industry-wide codes of best practice, which will include tiered minimum standards, to ensure the quality of data gathering is adequate.
Our next step is will be to take the lead on providing that best practice guidance, and we will do this by working in partnership with credible partners and stakeholders. This approach would ensure that a robust and practical guidance is achieved which meets stakeholders’ needs.
As UK airports vary significantly in their size and density of the affected population around an airport, and the number of flightpaths used, frequency of flights etc., we will ensure our guidance is tiered so it can be applied proportionately, based on their characteristics. This would help ensure that expectations and resources required are reasonable. If changes were implemented, it would necessitate a transition time to allow the airport to finance and install any required monitoring equipment.
Recommendation 3:
To help rebuild trust and ensure airports and communities work in partnership, we will provide best practice guidance on the provision of temporary noise monitors by airports to communities.
Many airports already provide a limited number of temporary mobile noise monitors. We believe that doing so helps airports understand better the impact on their surrounding communities, and specific impacts on certain individual communities which helps communities further trust that the airports are acting in their best interests.
To ensure that resources and effort by airports is best used, we intend to produce a code of best practice which will guide airports in the provision of such monitors. This will
accompany the best practice guidance for noise recording and include minimum standards for the meters, along with extra information around the minimum duration that a noise monitor should be installed to make sure that a representative sample of data is collected.
Recommendation 4:
Noise data transparency needs to improve. Our best practice guidance will develop standards to enable comparable noise monitoring data to be published annually, so communities can track changes and trends around their airports.
Openness between airports and affected communities is an important aspect of noise monitoring. While we accept – and this report shows – that noise measurements and data are complex areas, we nevertheless advocate full transparency and sharing of data. This would bring about increased confidence of community stakeholders.
However, we recognise this would help but not fully restore confidence of community stakeholders unless the published data was independently verified. We suggest that airports should not be asking themselves ‘Why should we publish this data?’, rather the question should be ‘Why shouldn’t we?’. While we recognise it could take some time to develop processes that ensure accuracy and fairness we acknowledge it should be our ambition to have accessible data which enables airport noise management to be accurately and fairly compared. By being more open and transparent, airports can continue to build trust with their communities.
The presumption should be that data collected from airport noise monitors is made publicly available. It may be appropriate to have separate data publications aimed at different stakeholders, who will have different requirements. For example, data published in its raw format is large in volume and complex and therefore may be unusable to local communities. Raw data, however, may be of greater interest to bodies such as government, regulators or the academic community.
To facilitate this ambition, we will develop as part of our best practice guidance, clear guidelines with credible associates and stakeholders to ensure that it is ambitiously achievable and clear to all. By adopting this approach, we hope to ensure the guidance meets stakeholders’ needs and is suitably robust.
The guidance will include careful consideration of factors such as:
- Where should the data be published?
- What format(s) should be used?
- What is an appropriate processing level?
- Is the data understandable, useful, transparent and contain the relevant metrics?
- Is the data accessible in terms of volume and complexity?
- Has the data been quality assured and processed to an agreed standard?
- Is it comparable with other UK airports, or airports of comparable size internationally?
Recommendation 5:
The threshold for noise monitoring data from airports of 50,000 Air Traffic Movements (ATMs) should be replaced with a lower threshold for publication of noise monitoring data, but applied proportionately and, potentially, with tiered requirements.
The impact of the COVID-19 pandemic on the aviation industry has been pronounced, and has led to significantly fewer numbers of ATMs across UK airports, as it has across the world. In light of this, we do not consider the threshold for noise monitoring data from airports of 50,000 ATMs (see Endnote 39) to be appropriate for the short to medium term.
We also do not believe it is helpful to have a hard threshold; we believe that there should be a lower threshold for publication of noise monitoring data, but applied proportionately and, potentially, in a tiered fashion that reflects the resources available to the different sizes of airports and the impact of their activity. It is logical to suggest that this data is should be published annually, on the same basis as the designated airports.
We believe that increased transparency will contribute to building a more detailed picture of the impacts of noise on affected populations. his is especially important as the UK’s airspace will be undergoing modernisation and will continue to evolve (DfT & CAA, 2019). Greater transparency will also give stakeholders the opportunity to have a much more realistic grasp on how aviation noise is changing year-on-year.
It would also be important for planning authorities to have access to current and accurate information. Furthermore, by providing frequent forward-looking information (aircraft noise disclosure) about local aviation activity, this can play an important part in mitigating community annoyance (Australian Government, 2003) (Australian Government, 2019). Having more noise data available to examine, could also help feed into future studies around health and social impacts of aviation noise, which will be important for policy and legislation development in the future.
Recommendation 6:
Improving noise monitoring consistency and application requires UK-wide leadership. We see ICCAN’s future role as providing that national leadership and standard setting.
As can be seen from our findings and recommendations, we see the potential for much improvement in the way in which aviation noise is measured, collected and communicated to the public. The piecemeal approach – some airports under statutory obligations and some not; some publishing certain data and others not – leads to the impression that the industry is not being honest with the levels of noise (whether or not that is the case).
Correcting this needs co-ordinated and expert leadership and we see ICCAN’s role, as it evolves, as being to provide that leadership. This will be even more important as the industry recovers from the COVID-19 pandemic.
As with other aspects around how aviation noise is managed, we see opportunity in the resetting and restarting of aviation: the opportunity to improve processes, practices and behaviours of all involved in aviation, and in this case of those that capture, use and disseminate noise measurements.
.
.
See full report at
.
.
.