Gatwick sets up a “Noiselab” website, so people can see more about its plane noise
Gatwick airport realises the increased impact of the noise from its planes is causing considerable upset, anger and opposition. As part of its PR offensive, to try to persuade people that it is going everything possible to minimise noise and take people’s complaints (“concerns” in Gatwick language) seriously, it has launched a website called “Noiselab” as a noise monitoring tool. The aim is to allow people to look at the noise close to various monitors and see how much is from aircraft, how many flights etc. It does not appear that many of these noise monitors are new. The noise level readings at the various monitoring points are only given as averaged LAeq values over a 16-hour day and a 8-hour night. This averaging process destroys the usefulness of this tool as a measure of noise annoyance, especially under flight paths. What people hear is the noise level (LAmax) of each aircraft. The “fly-over” average also reduces the actual noise nuisance, and there is no measure of background noise levels (LA90) against which each aircraft noise event is clearly heard. However the network of monitors should be welcomed because they could be put to proper use, for example if LAmax measurements were taken and the N70 metric [this means the number of noise events noisier than 70dB] was used and the “fly-over” value was given as a Sound Exposure Level (SEL).
Gatwick Airport launches noise monitoring tool
Image copyrightWilliam Boyack
People living and working under Gatwick Airport flight paths are being given the chance to monitor noise from planes with the launch of an online tool.
The Noise Lab provides up-to-date information using live data from a network of on-the-ground sound monitors to produce community noise reports.
Gatwick Airport said it had been modelled on a similar tool introduced by Schiphol Airport in Amsterdam.
Spokesman Tom Denton said it would help to “better understand” noise concerns.
“This noise lab provides up-to-date flight tracking information which will help us to more accurately monitor concerns and, in time, consider options for further noise mitigation measures. [Lovely the way airports always call complaints or genuine upset from noise “concerns.” Typical greenwash word. AW comment]
“We recognise aircraft noise is a real problem for some people and we are determined to do what we can to minimise the amount we generate and mitigate against its effects,” he said. [Everything short of actually reducing it, or preventing its growth as numbers of flights grow. Everything that costs Gatwick and airlines nothing, or inconveniences them in any way. AW comment]
Sally Pavey, chairman of Communities Against Gatwick Noise Emissions (CAGNE), welcomed any steps that would help residents but said their lives were still being affected by aircraft noise.
“Gatwick Airport is not addressing the real cause of the issue, which is the concentrated flight paths introduced in May last year,” she said.
There are an average of 350 daily take-offs from Gatwick’s single runway. [There were 254,542 Gatwick Air Transport Movements in 2014. That comes to an average of 697 per day. And the number was higher in 2015. Link AW comment]
Earlier this year, Ms Pavey joined other groups from across the South East to deliver a protest letter to the government about increased noise from Gatwick should a second runway be approved, saying tens of thousands of people had already had their lives blighted.
The monitoring tool is not very easy to use !
Map below shows the locations of the noise monitors http://noiselab.casper.aero/lgw/#page=databrowser
http://noiselab.casper.aero/lgw/#menu=n_meetposten/page=nmt_70/target=subcontent has more data on each of the noise monitors. (Some is historic, some live)
You can put in the dates you want to look at and the corresponding noise and number of flights. For example for all of August:
Looking at the CAA data
, there were 27,089 flights for August in total using Gatwick.
That comes to 873 flights per day on average at Gatwick in August 2015 – that means about 436 take offs per day, on average.
But the Gatwick figures for the numbers of planes on its flight paths – on the image above – come to 230 take offs. For 24 hours. Not a total of 436.
So where are other 206 flights going? Why are they not included?
Comment from an AirportWatch member, who is a noise expert:
Looking at this Gatwick Noise Lab monitoring tool, the noise level readings at the various monitoring points are only given as averaged LAeq values. The first value is given for the average level of a “fly-over” which is generally in the order of about 30 seconds (some less, some more).
The second value is given as an average level over a 16-hour day and a 8-hour night.
In my view, this averaging process completely destroys the usefulness of this tool as a measure of noise annoyance, especially under flight paths.
The 16-hour and 8-hour average LAeq values as a metric to assess noise annoyance and sleep disturbance are wholly inadequate – as we know.
What people hear is the noise level (LAmax) of each aircraft.
The “fly-over” average also reduces the actual noise nuisance – by the averaging process – and there is no measure of background noise levels (LA90) against which each aircraft noise event is clearly heard.
[When assessing environmental noise it is generally useful to establish what is the general or “background” noise level in the area; this is best represented by the LA90 (also written dBA L90 or L90 dB(A) ), which is the level exceeded for the 90% of the time under consideration. Such measurements are designated say 36.7 dBA LA90 or 36.7 LA90. Typical daytime background noise levels range from 18 LA90 in a remote rural areas, through 30 to 40 LA90 in “typical” or “quiet” suburban areas, to 50 to 60 LA90 for busy urban areas. AW comment]
However the network of monitors should be welcomed because they could be put to proper use.
It would be much more useful if LAmax measurements were taken and the N70 metric [this means the number of noise events noisier than 70dB] was used and the “fly-over” value was given as a Sound Exposure Level (SEL). [SEL is the logarithmic measure of the A-weighted , Sound Pressure Level squared and integrated over a stated period of time or event, relative to a reference sound pressure value. The units are the decibel (dBA).]
The SEL measure accounts for both the duration and intensity of the noise and the SEL metric has the added advantage of complementing the N70 type metric.
And finally the LA90 background noise levels must be used. All these metrics are standard in even the simplest of acoustic monitors. And these monitors also measure using C-weighting which would more closely match aircraft noise characteristics with large low frequency content.
And it’s worth observing that the peak noise level comparison chart in the Gatwick Noise Lab shows the loudest level at 130dB (for a pneumatic drill). What it omitted to say is that 130dB is the threshold of pain and 120dB is the threshold of discomfort and that an aircraft at 50 metres away emits 140dB – twice as loud as the threshold of pain.
Gatwick launches UK’s first community noise lab
• Innovative noise lab provides up to date information on aircraft noise
• Clearer picture of emerging trends to help with longer-term noise mitigation
• Developed with community in mind
Gatwick Airport has launched the UK’s first community noise lab – an innovative and interactive online tool designed to help local people more accurately monitor aircraft noise.
The new noise lab is modelled on a similar tool introduced by Schiphol Airport – the first of its kind in the world – and provides members of the public with better overflight information. It is hoped this will provide a clearer picture of emerging trends and help with the development of longer-term noise mitigation measures.
The new tool was developed with input from local council environmental health officers and GATCOM – Gatwick’s Consultative Committee. It uses live data from a network of on-the-ground noise monitors to produce community noise reports.
The innovative tool was developed by Casper, an IT company specialising in the development of real-time location-based monitoring and analysis tools and can be viewed here: http://noiselab.casper.aero/lgw/.
Tom Denton, Gatwick’s Head of Corporate Responsibility, said:
“This noise lab provides up-to-date flight tracking information which will help us to more accurately monitor concerns and, in time, consider options for further noise mitigation measures.
“We recognise aircraft noise is a real problem for some people and we are determined to do what we can to minimise the amount we generate and mitigate against its effects. This lab is just one of a number of measures we’re introducing, to better understand people’s concerns.”
Gatwick is also pursuing many measures to reduce aircraft noise, including:
- incentivising airlines by charging them less to use quieter aircraft – almost all (99%) of the aircraft currently using Gatwick are among the quietest types in operation, and
- employing a continuous descent approach, so aircraft use less thrust by gliding and descending at a continuous rate – generating significantly less noise.
Noise generated by the airport has been steadily reducing, as demonstrated by the land area (noise contour) covered by the loudest noise levels reducing from 94.5km² to 85.6km² in the past six years. Additionally, Gatwick spent £2.35 million on its industry leading noise insulation scheme last year – a 95% take up of the allocated budget – with 730 households signing up to receive £3,600 of acoustic insulation.
Notes to Editors
While other UK airports have introduced flight trackers these have a 24 hour delay and do not provide as detailed information on aircraft movements. [This is untrue. Heathrow’s webtrak at http://webtrak5.bksv.com/lhr4 now has just a 20 minute delay. Seems Gatwick has not bothered to check. AW comment].