Steve Mitchell, technical fellow at ERM, considers how the Airports Commission's work on noise mitigation for a new London runway may impact other UK airports.
There is a long history in the UK of airport noise policy developed for London airports leading to equivalent noise management standards consequently being expected at other smaller airports.
In July 2015 the Airports Commission (AC) submitted its final report to government recommending a new runway should be built at Heathrow if certain conditions can be met. The government is considering the commission’s recommendations.
While Heathrow and Gatwick airports will be directly affected by the outcome, it is worth looking at how this will change the way noise impacts will be assessed and managed at other airports.
Changing the way we look at airport noise impacts
Since the Airport Commission’s appraisal framework was developed in 2014, it has been studying the local and national noise impacts of two runway options at Heathrow and one at Gatwick in great detail.
The framework itself has set new standards for the assessment of noise and includes new methods to quantify its health effects, for example, number above contours - which count the number of aircraft that exceed a given noise peak threshold as they fly overhead, for example, 60 or 70 dB (N60 and N70) - may now be required in the assessment of noise from airport expansion plans.
It is likely to become standard practice to quantify health impacts, to monetise predicted community annoyance, effects on sleep, effects of learning rates in schools and increased rates of hypertension and strokes in affected communities.
Mitigation and compensation – a new approach
In 2013 the commission shortlisted three options for London Airports. The options are a second runway at Gatwick, a third North West runway at Heathrow and an extended northern runway at Heathrow. Once shortlisted, the promoters of these schemes refined their proposals, each competing for the commission’s preference.
For example, for the first time ever, compensation (as opposed to mitigation to reduce noise) was offered by the Heathrow and Gatwick promoters. Heathrow tested increased approach slopes and shifting approach thresholds to raise the heights of arriving aircraft flying over affected communities.
Additional departure and curved arrival routes are to be designed into radically revised airspace proposals using precision navigation technologies to fly aircraft more accurately over less populated areas. Perhaps the most controversial is Heathrow’s proposal to alternate these new and old routes to provide periods of relative quiet, or ‘respite’, on a regular basis, with the new routes overflying thousands of previously undisturbed people for the first time.
A wider effect
The commission’s final report weighs up the pros and cons of the preferred options acknowledging that the noise impact of a third runway at Heathrow would be considerably greater than that of a second runway at Gatwick. To address this, the report lists several conditions of its recommendation, which require Heathrow to reduce its noise impacts. These are:
- a ban on night flights;
- more reliable respite for overflown communities;
- a legally-enforced ‘noise envelope’;
- a statutory independent aviation noise authority;
- minimum compensation funds;
- a noise levy to fund a far stronger and more generous set of compensation and mitigation schemes; and
- a pledge to never develop a fourth runway.
The commission believes that a ban on flights from 2330 to 0600 hours is feasible. This raises the likelihood of tighter night restrictions or bans at other airports.
There has been much discussion on the value of respite at Heathrow, and the commission believes it should be pursued. There are at least three types of respite, including runway alternation, flight route alternation and dispersion within routes. Respite is not excluded from single runway airports, and pressure may begin to build for it to be introduced at other regional airports. The airspace consequences would need careful planning.
Perhaps the greatest implication from the competition to limit noise impacts at Heathrow and Gatwick could be the compensation that may be offered to those affected. The commission’s final report states:
‘Heathrow Airport Limited should be held to its commitment to spend more than £1 billion on community compensation, including £700 million on noise insulation, and should be prepared to go further. Support for schools should be a priority.’
Developing equitable compensation schemes for communities affected by aircraft noise is not straightforward, particularly when flight routes are changed. Stakeholders affected by noise from other airports will be keeping a close eye the outcome in case they feel it is applicable to their situation.
