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An NGO Perspective on Chapter 4 Noise Standards

In 2001, ICAO agreed a new certification standard to be introduced for all new subsonic jet aircraft entering service from 1 January 2006 (to be known as Chapter 4). The new standard improves on the existing Chapter 3 standards by a cumulative margin of 10 dBA.


Background

In 2001, ICAO agreed a new certification standard to be introduced for all new subsonic jet aircraft entering service from 1 January 2006 (to be known as Chapter 4). The new standard improves on the existing Chapter 3 standards by a cumulative margin of 10 dBA.An NGO Perspective on Chapter 4At face value, this may appear a significant step forward, and one that local communities should embrace. Yet closer examination reveals a different picture. Noise certification of aircraft requires three measurements: one measured on approach, one on take-off, and a third at a sideline measurement point. The new Chapter 4 standard is based on the sum of the improvements at these three measurement points. In other words, the average reduction at each of the three measurement points is a little over 3 dBA. Against average background noise levels, changes of this magnitude can be very difficult to perceive for the average person. By the time the new standard comes into force, it will have been nearly 30 years since the introduction of the current Chapter 3 standard. Is this really the best we can expect from an industry that prides itself on its rate of technological innovation?Quite simply, the answer is no. Many aircraft in service today already improve upon Chapter 3 standards by cumulative margins in excess of 20 dBA, while over 95% of the current in-production aircraft are already capable of meeting the new standard, and around 75% are capable of meeting an improvement of at least 14 dBA.Nevertheless, this recommendation may still have met with some acceptance from airport neighbours if it had been accompanied by a decision to phase-out the worst performing Chapter 3 aircraft. Recent experience, as noted above, has shown the benefits of phasing-out Chapter 2 aircraft, and a decision to extend this policy further to some, or all, Chapter 3 aircraft would have been extremely popular amongst local communities. A few disproportionately noisy movements are frequently responsible for the majority of noise complaints at airports. Hence, it is commonsense that removing some of the worst performing aircraft from the fleet would have brought a clear environmental benefit.Instead, CAEP’s analysis failed to show any overall cost-effective benefit from a phase-out, and no agreement was forthcoming on implementing a phase-out strategy.As a result, Chapter 4 will do little to offset a growing aircraft noise problem in many regions: ICAO’s own analysis highlighted, that without any action, the number of people affected by aircraft noise in the countries implementing the Chapter 2 phase-out will increase by 21% between 2002 and 2020. Yet not all regions will be impacted in the same way: this significant increase hides the fact that the number of people affected by noise in Europe and, in the Australia, New Zealand and Japan region, will increase by 42% and 169% respectively during this period, while the increase in the US and Canada will only be 3.5%.From the perspective of airport neighbours, this outcome was disappointing and totally unacceptable, and is likely to lead to increasing pressure for local airport restrictions, opposition to new developments, and a deterioration in the often fragile relationship between airports and their communities.