CAA data show nearly 6,000 more people in Heathrow’s 57 Leq loud noise contour in 2014 than in 2013

The Evening Standard reports that recent CAA data show that over 270,000 people – a 13-year high – suffered from the sound of Heathrow planes overhead last year, which was a rise of nearly 6,000 on 2013.  This was also the highest number affected by noise since 2001.  In theory, planes are supposed to be getting marginally less noisy, as new models slowly replace older ones.  But as planes get ever larger, they are noisier than smaller planes they replace – and these planes are perceived to fly lower. The figures may indicate that Heathrow’s claims it can add a runway and even reduce total noise are not credible. The Airports Commission is likely to have been over-optimistic in presuming that would be possible. London’s population is growing and the CAA analysis shows the number of people suffering noise, using the Government’s preferred measurement, the 57 Leq noise contour, from Heathrow planes rose from around 264,250 to over 270,000 people, though the size of the contour fell from 107.3 km sq to 104.9 km sq. The numbers within the 57 Leq contour fell from 1988 to 2001, but this trend failed to continue over the following years.


The DfT data show for Heathrow:  link

2011 108.8 km squ 243,350 people in the 57 Leq contour

2012 110.1 km squ and 239,600 people

2013 107.3 km squ and 264,250 people

2014 104.9 km squ and 270,000 people in the 57 Leq contour


Thousands more people suffer blight of Heathrow noise, aviation bosses reveal

Number of affected neighbours rises to 13-year high

By Nicholas Cecil (Evening Standard)

Thousands more people around Heathrow are being blighted by aircraft noise, according to official figures.

Just over 270,000 individuals – a 13-year high – suffered from the sound of planes overhead last year, which was a rise of nearly 6,000 on 2013. 

The figures compiled by the Civil Aviation Authority also showed the highest number of people affected by noise since 2001.

Anti-expansion campaigners immediately seized on the revelations to cast doubt on the Airports Commission’s conclusion that the west London airport could expand while cutting the number of people disturbed by noise.

John Stewart, chairman of the HACAN campaign group, said: “These figures suggest that the Commission has been too optimistic in predicting that the noise climate will improve over the next few decades even with a third or fourth runway in place.”

London’s population is growing and the CAA analysis shows the number of people suffering noise, using the Government’s preferred measurement, [the 57 Leq noise contour] from Heathrow planes rose by two per cent from 2013 to 2014.

But the area affected actually also shrunk by 2% from 107.3 kilometres squared to 104.9 kilometres squared. [See DfT data ]

The aviation experts put these two changes partly down to variations in the noise contour shape which expanded in the region between Feltham and Twickenham, and also to the west of Windsor, while contracting near Barnes and in the area west of Slough.

Tory mayoral hopeful Zac Goldsmith, MP for Richmond Park and a leading anti-third runway campaigner, said: “Despite some marginally quieter planes, London’s growing population has more than cancelled out any gains and an additional 300,000 flights will clearly make things dramatically worse.”

The CAA report for the Government showed a marked decline in the number of people and the size of the area blighted by Heathrow plane noise between 1988 and 2001, but this trend failed to continue over the following years.

However, Heathrow stressed it had commissioned a separate analysis from the CAA which showed more than 46,000 fewer people were disturbed by plane noise last year, compared to 2013.

This was using a different measurement which is preferred by City Hall and the European Commission, and put the airport’s noise footprint at its “smallest level in our history”, added a spokeswoman.

The different findings in the two CAA studies are not necessarily contradictory as the measurement preferred by City Hall and the European Commission includes and heavily weights night flights which have got quieter, according to the experts, and the way it measures noise also means it found a wider area affected, 210.7 kilometres squared in 2014 compared to 220.4 kilometres squared 12 months earlier, and a bigger population of more than 700,000.

A Heathrow spokeswoman said: “The area around Heathrow is a popular place to live and research shows aircraft noise has little impact on the willingness of people to move into the area, nor on the ability of residents to find buyers when they choose to sell their house.”

The rise is the number of people disturbed by noise under the Government’s preferred measurement level, which measures flights during summer days, could be partly down to people moving into new homes and properties becoming households of multiple occupancy.

Heathrow emphasised CAA figures show that there are 16 per cent more homes now than in 1991 within the Government’s preferred measurement level noise contour around the airport.



John Stewart commented in a blog: 

[The CAA and Heathrow are measuring the noise using different metrics].

The CAA use the 57 LAeq noise contour.

Heathrow use the 55 Lden contour.

“The CAA is using the Government’s preferred noise measurement known as the 57 LAeq contour. This looks at the number of planes, and the noise of each plane, flying over an area over a 16 hour day. The noise is then averaged out over the day. If the average is 57 decibels or more, that area is considered to be affected by the noise.

This 57 decibel cut off point has for years been widely criticized. Places like Fulham and Putney, clearly impacted by aircraft noise, lie outside the contour. Most European countries use a different measurement and the recent Airports Commission Report downplayed it.

But the CAA is correct that the numbers within the 57LAeq contour have risen. This is thought to be down to people moving into new homes and properties becoming households of multiple occupancy. [ie. higher population density.  AW note].  This increased population has off-set any benefits from less noisy aircraft and improved operational practices.

So where did Heathrow get its figures? It used the measurement known as Lden recommended by the European Commission. This averages out noise over a 12 hour day, then separately over a four hour evening and an eight hour night. It adds 5 decibels to the evening measurement and 10 decibels to the night one to allow for lower background noise levels at these times.

It is regarded as more accurate than the 57LAeq contour. It certainly tallies more closely with the actual areas where noise is problematic. In London is includes area such as Clapham. The total numbers affected has been considerably over 700,000.

Heathrow, however, has brought the total number down to 702,000. It’s is good PR for the company. Whilst their new figure is technically accurate, the sleight of hand they have used to get it would have wide-boys of the world purring with pleasure.

The reason why the overall numbers is down is simply because of a reduction in night noise. Because 10 decibels are added to night flight noise to account for the lower background levels, Heathrow has only to introduce a relatively small number of less noisy planes at night to make a disproportional impact to overall noise levels. That is what has happened.

[So the reduction in noise is more a statistical artefact than a real improvement for residents. AW note]