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making it an expensive option), nor do we believe they will be in widespread production by 2010, especially without any global or regional regulatory or economic drivers, an issue enlarged on below.

The vision for 2020 is less clear still. The interim target is based on making marginal improvements to existing technologies, but achieving the full 10 EPNdB reduction will clearly require a new generation of airframes and engines. Such designs might include over-fuselage wings and engines as well as ‘blended-wing’ aircraft, a concept not yet far advanced beyond the drawing board.

Few would disagree that ACARE’s goals will be tough to meet. In fact they will require a faster rate of technological introduction than over the past 20 years, even though it is generally acknowledged that the current generation of technology is now at a stage  of offering diminishing returns.

But the crucial point is that ACARE focuses on what the best new technology can achieve, rather than on what the market is likely to demand.  Without regulation or stringent standards, uptake is likely to be slow. This is acknowledged in the CAA report, which notes that “full capacity (702,000 ATMs) may not be realised in 2020 without significant incentives to encourage airlines to replace the current large numbers of four-engined aircraft with a greater proportion of large twin-engined aircraft” (p. iv).  Most airlines currently using Heathrow have young fleets and significant early fleet replacement is unlikely without substantial incentives or penalties. The Department for Transport has not proposed any such measures, however.

In the short-term, the CAA’s noise report assumes a 25dB decrease in some cases: “The next generation 220-300 seat wide-body airliners are much more mature in design...  cumulative certificated noise levels are expected to be around 25dB below Chapter 3 levels” (2.3.11); “the new technology 450 seat aircraft is envisaged to have a cumulative margin relative to Chapter 3 of around 25dB, compared with 16dB for the Boeing 777-300ER.” (2.3.12). Many of these aircraft are already in service. Chapter 3 came into effect in 1977, and by 2006 (the date when Chapter 4 came into force) most in-production aircraft were already capable of delivering significant cumulative reductions.  

Is the correct metric being used?

The inadequacy of relying on any single metric was recognised by Government in the first stage of its consultation for the White Paper in 2000, when it acknowledged that ‘no single metric can capture all the characteristics of noise, nor of the annoyance it causes’.6 Nonetheless, the Government continues to use 57Leq dBA as the indicator for the onset of significant noise annoyance.

The ‘ANASE’ study7 concluded that there is no noise level at which there is an onset of significant annoyance: every flight triggers some annoyance.  ANASE was a complex and ground-breaking study, and it raises uncomfortable conclusions for the Government’s approach to aircraft noise and the adequacy of its policies. We are disappointed that the findings of ANASE were not used in the noise assessment underpinning this consultation despite having access to the results for almost a year prior to publication.  

6 Future of Aviation (DETR, 2000) para 142

7 MVA Consultancy and others (2007) Attitudes to Noise from Aviation Sources in England.

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