Environmental Engineering Reference
In-Depth Information
legally binding, but it nevertheless raises the expectations of airport neighbours in
those countries who are signatories.
ICAO responses
In this context, are existing measures sufficient to meet these expectations? To date,
the response of regulators, in addition to the measures discussed above, has been to
pursue the reduction of noise at source, working through the International Civil Avi-
ation Organization (ICAO).
5
Although there has been no improvement (until last
year) to the current Chapter 3 noise standard since its introduction in 1977, a deci-
sion by some countries (namely, European states, the US, Canada, Japan, New Zealand
and Australia) to phase out the operation of Chapter 2 aircraft by April 2002 has
resulted in a reduction in noise exposure levels at some airports despite a growth in
traffic. However, as the benefits of this phase-out programme have now been fully
realized, it is highly questionable whether airports can continue to maintain this
trend. In fact, as ICAO's own analysis highlights, without any further action, the num-
ber of people affected by aircraft noise in the countries implementing the Chapter 2
phase-out will increase by 21 per cent 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 per cent and 169 per cent respectively during
this period, while the increase in the US and Canada will only be 3.5 per cent.
Presented with this evidence, there were few amongst the industry who doubted
the need to look at further improvements in the stringency of the existing noise cer-
tification standards. This led ICAO's Committee on Aviation and Environmental
Protection (CAEP) to recommend that a new certification standard should be intro-
duced for all new subsonic jet aircraft entering service from 1 January 2006 (to be
known as Chapter 4). The recommended standard, later adopted by ICAO's coun-
cil, improves on the existing Chapter 3 standards by a cumulative margin of 10 dB(A).
At face value, this may appear a significant step forward, and one that local com-
munities 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 stan-
dard 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 dB(A). 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 dB(A), while over 95 per cent of the current in-production
aircraft are already capable of meeting the new standard, and around 75 per cent are
capable of meeting an improvement of at least 14 dB(A).
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
