fast operational restriction (the phase-out of chapter 2 aircraft by 2002), once this was complete the contour began to expand again in line with ATMs – in other words the on-going replacement of aircraft at the margins of the fleet is not enough to offset the effects of growth. What is more, no further phase-out is in prospect: ICAO failed in 2001 to agree on a phase-out of the noisiest Chapter 3 aircraft, and the issue has not been raised since. So once the anomalous effect of Concorde has been set aside, it can be seen that the noise climate, even as measured by the Government’s preferred metric of averaged noise contours, is deteriorating, and the Government has failed to honour its guarantee on noise.
And here we come to the crux: even if the specific target relating to the 57 dBALeq contour were to be achieved, the noise guarantee it is supposed to deliver would not have been honoured, namely to take all practicable steps to prevent any deterioration in the noise climate around the airport after the phase out of Chapter 2 aircraft is completed (as it was from 1 April 2002), and to continue efforts to do everything practicable to improve the noise climate over time.9 If aircraft technology continued to improve but no additional flights were permitted at Heathrow, then by 2030 almost half of those residents currently exposed to 57dBA or more would no longer be: the technological improvements could be used to improve quality of life for local residents. Instead, increased capacity at Heathrow would mean that almost all of the slack will be used to allow more aircraft to fly. If public annoyance increases, as it undoubtedly would if residents were subjected to a third runway and/or mixed mode, then by definition the noise climate has deteriorated, and the Government has failed to honour its guarantee on noise, regardless of the 57 Leq dBA contour.
9 The Future Development of Air Transport in the UK: South East (DfT 2003) 16.32