Davies noise

I’m not a Yorkshireman but, for once, I need to be as blunt as a Yorkshireman.  The Airports Commission has got it wrong on noise.  And, unless it changes tack, its final recommendation will be fatally flawed and forever contested.

The Airports Commission has accepted the industry’s chosen method of measuring aircraft noise.  That enabled it to write this dreadful paragraph (6.102) in its Interim Report:

“The number of people affected by noise around Heathrow is higher than at any other European airport, with a population of roughly 240,000 currently living within the 57LAeq.  By 2030, this is forecast to fall by roughly 150,000 due to improvements in technology and operations.  The impact of the construction and operation of the proposed third runway is estimated to be roughly neutral possibly even offering a further reduction over the expected baseline.”

Yes, by 2030 the planes will be a bit quieter and they will possibly be descending more steeply so flying higher for longer periods, but, with a third runway, there will be another 280,000 of them.  Only by using a distorted metric can the Airports Commission write the paragraph it did. 

There is one thing above all the metric fails to take on board properly.  It does not recognise that it is the sheer number of planes now using Heathrow that causes so much disturbance and brings so many complaints.  The fact that the planes have become quieter is welcome but not significant when set aside the fact that aircraft numbers have doubled since the 1980s.

The Commission has underestimated the current levels of noise annoyance because the metric it uses to measure it (called LAeq) gives too little weight to the number of aircraft overhead and too much to the noise of each individual plane when assessing noise disturbance.  As a result, it does not reflect the extent of the problem.

One example illustrates just how far off-course the Commission is.  Using the current way of measuring noise, four hours worth of non-stop noise from Boeing 757s at a rate of one every two minutes is said to cause the same annoyance as one extremely loud Concorde followed by 3 hours 58 minutes of relief: http://www.hacan.org.uk/resources/reports/hacan.the_quiet_con.pdf  Clearly not a reflection of reality! 

The Commission’s chairman, Sir Howard Davies, recognized in his speech introducing the Interim Report on 17th December that there are other ways of measuring noise annoyance to the one he is currently using.  Let’s hope it is top of his New Year’s wish list to explore these other metrics or his final report will lack validity.

The irrelevance of the current metric, allowing the claim that fewer people are affected by noise from Heathrow than for decades, is contradicted by the reality on the ground.  When HACAN started 45 years ago, it had a different name KACAN – Kew Association for the Control of Aircraft Noise.  (I know we specialize in dreadful acronyms!).  It represented just the West London suburbs of Kew and Richmond.  Even when fighting the Terminal 5 Inquiry, HACAN just covered West London and parts of Berkshire.  It was only in the mid-1990s that HACAN started to become the regional body it is today.  And that was entirely because the number planes using Heathrow had reached a tipping point for so many people across London and the Home Counties.  This summer the greatest number of complaints HACAN received was from SE London: http://www.hacan.org.uk/resources/reports/living.under.the.heathrow.flight.path.today.pdf

In my view, the aviation industry is clinging on to its noise metric, LAeq, because, without it, its claims that a 3rd runway could be built with no increase in the noise footprint would unravel.

However, there is another prop the industry in the UK also needs to sustain that claim.  It maintains that people only start to get annoyed when aircraft noise, averaged out over a 16 hour day, reaches 57 decibel – what is known as the 57 db LAeq contour.  Outside that contour are places like Fulham and Putney.  Go tell Justine Greening, the feisty MP for Putney, that aircraft noise is not a problem in her constituency!

In fact, in her submission to the Airports Commission, Greening was scathing about the current contour: ““I believe this strongly shows that taking a traditional 57dB approach to assessing the level of noise annoyance from any new aviation strategy will exclude a large number of people who will be annoyed and affected but live outside of the 57dB noise contours.”

The European Commission also believes that the 57 db LAeq contour is misleading.  It requires member states to use a different metric – called 55Len – when drawing up their noise maps.  Under this method, noise is averaged out over a 12 hour day; then, separately, over a 4 hour evening and an 8 hour night, with 5 and 10 decibels added to the evening and night periods respectively to reflect the lower background noise levels at these times.  This comes up with more realistic results.  It extends the noise boundaries to places like Vauxhall and Clapham.  But even this method does not cover all the places where people are annoyed as the averaging out includes the quieter periods of the day and the quiet days of the year.  If averages were taken only at times the planes were flying, then the contour would stretch into South East London.  Now, that’s reality!

It is little wonder the UK aviation industry is so reluctant to use the metric recommended by the European Commission.  It would force it to admit that over 700,000 people are impacted by noise from Heathrow; as against ‘only’ 240,000 using its favoured method.

People of my generation will remember the day when that blunt Yorkshireman, Harvey Smith, gave a V-sign to the judges following a near perfect round which won him the British Show Jumping Derby in 1971.  Howard Davies, although a Mancunian, needs to take a leaf out of Harvey Smith’s book and do the same to the aviation industry’s chosen method of measuring noise annoyance.  Or all his final recommendations will be fatally flawed. 

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