On November 30th Heathrow published is review of 2016. It comes in the form of two reports:
Key points of interest from the first report include the fact that during the year there was a 70/30% west/east split in wind direction (generally, aircraft land take-off into the wind); and that planes adhered to runway alternation 90% of the time.
But it was the second report which Heathrow highlighted. It said, ” Although 2016 had the highest passenger traffic, the Lden 55 dBA contour had its smallest area and the fewest number of people living within it over the 11-year study period (2006-2016)”. In other words, the noise contours are shrinking because of the introduction of less noisy planes.
But, as HACAN pointed out in its response, “This doesn’t tell the whole story. The way Heathrow measures the noise gives too much weight to the noise of individual aircraft which has fallen but not enough to the number of planes going overhead. It is the sheer volume of planes that drives people to distraction these days.”
But HACAN added, “We do welcome the inclusion for the first time in the report a range of new metrics which actually paint a more accurate picture of the noise experienced by residents than its over-dramatic headline suggests. Heathrow becomes one of the first airports in the world to use such a wide range of metrics.”
Heathrow has not just averaged out the noise over the day – the traditional way of measuring the noise – but has, additionally indicated the number of planes going over each community and how noisy they are which many believe is a more meaningful measurement. Because planes have become quieter, this metric also shows a reduction in the numbers impacted. Heathrow has also for the first time produced noise contours just for the days of the year when planes are flying over communities rather than just the annual average which can be misleading because it includes the days when there are no planes.
Heathrow does acknowledge that the noise climate between 2006 and 2016 has become a little worse in some areas, particularly those ‘south of Windsor’ due to the increase in planes, often large, heavy planes, serving long-haul destinations.
It is not clear that the report has fully factored in the increased concentration that some communities have experienced, both on landings and departures.