| Topic: | Re:Re:Re:Re:Re:Re:Re:Re:Re:Re:Re:Re:Re:3rd runway noise in Chiswick | |
| Posted by: | Tom Pike | |
| Date/Time: | 08/02/08 08:06:00 |
| Jeff, there are several issues here: "I believe that the noise level experienced in Stavely Gardens (an otherwise quiet residential road) while a stream of twin engine medium sized aircraft bound for the northern runway pass over is a good representation of the noise levels my bit of Chiswick would experience with a third runway." Yes, this would be very close to that expected under the R3 flightpath in Chiswick, although the planes will be 170s apart rather the 100s at present. My only issue is the chance of actually experiencing such a stream. That's why I think Battersea gives a better location to make a real-world judgement - the 747s will sound much more like A320s. But given the wide disparity between individual perceptions of noise, it would be worth experiencing both locations before coming to any strong conclusion about relocating. For the record, CAA work out that this noise corresponds to 55 to 56 dBA 16h Leq right under the flightpath down the High Road from Stamford Brook to Chiswick Roundabout. I absolutely agree that we can't trust BAA. That is why we must get an ironclad guarantee on the 57 dB Leq contour area. Before you retort that you have no faith in this particular measurement, it is important to understand the implications of such a guarantee. First, future improvements in aircraft noise performance become irrelevant - if the planes don't get quieter, then capacity at Heathrow can't grow. The unfortunate corollary - we don't get any benefit from quieter planes - just more of them! Secondly, noisy planes will not land on R3. Because of the way the dB Leq contours work, a noisy plane landing on R3 will cost more than twice the contribution to the noise cap as landing on the existing runways. BAA will have to keep R3 quiet to land more planes. Adopt an alternative measure such as the HACAN-preferred number of planes above a certain peak noise, and you no longer have this critical restriction that the Leq measure provides. You might despise the measurement, but the choice of Leq is in our favour! Because of these implications there will be no incentive to BAA increasing the runway length until the heavies are as quiet as the A320's of today. And why should they? Two thirds of the predicted aircraft in 2030 are light and medium two-engined jets - more than enough to have R3 running at capacity with its current length. We should fight hard to stop any further expansion of Heathrow - killing R3 is the best possible outcome, and it will not be objections to noise that land the fatal blow. I certainly think that R3 is not a foregone conclusion. Getting BAA on pain of multi-billion pound damages to commit to keeping to the 57 dBA Leq 16h contour area might be a bit of a mouthful as a rallying cry. But it forms a critical backstop that will very much limit the noise from R3. |