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GEA and the Environment
(1) Aircraft Noise
Aircraft noise has historically
been a major environmental issue for aviation. It remains high on the agenda
of public concern, with the focus mainly on flight operations close to airports.
Noise is a difficult issue to evaluate as it is particularly open to subjective
reactions.
How is noise measured?
The most widely used unit for
measuring noise levels is dB(A) (The A-weighted scale in decibels). This unit
attempts to reflect human reaction to "loudness". The human ear's
response to sound relates to sound pressure in a way that is approximately logarithmic.
This means that a significant reduction in noise activity results in a comparatively
small reduction in the noise perceived by the human ear.
However, there is another measure
of noise uniquely related to aircraft: the perceived noise (PNdB) and effective
perceived noise (EPNdB). These scales incorporate the different frequencies
and duration of noise patterns, resulting from various speeds and modes of operation
of aircraft. There is no agreement, even among the experts, on which measurement
is the most representative, or the most relevant in a particular situation.
However, the International Civil Aviation Organization (ICAO) uses EPNdB for
expressing its noise certification standards.
A single aircraft operation can
be measured by recording noise levels on the ground within the surrounding area.
By joining points together which register the same noise level, a contour can
be obtained which represents the "noise footprint" of that that particular
aircraft movement. All of the movements of different types of aircraft can be
integrated into a contour map of impact, thereby giving a picture of the overall
noise impact at a particular airport.
Industry Efforts to Reduce Aircraft Noise
Over the last 10 years aircraft
have been required to become less noisy. Consequently, the number of people
living in areas exposed to unacceptably high aircraft noise has dropped significantly.
In 1978, 6 to 7 million people lived within areas exposed to average cumulative
noise levels of 65 decibels (dB) or higher. By 2000 that number has fallen to
approximately 500,000.
This change was accomplished with
the design of quieter engines and, as an interim measure, "hush kits"
were installed on some older aircraft. The change came in three stages where
the aircraft noise level in decibels was reduced to less objectionable and less
dangerous levels. As of the first of January 2000 Stage 3, the final stage,
was implemented. The noise level of Stage 3 aircraft is comparable to a busy
urban street and is much quieter than the Stage 2 aircraft noise level which
is similar to an amplified rock music concert.
The issue of aircraft noise is the responsibility of the International
Civil Aviation Organization (ICAO) and its Committee on Aviation Environmental
Protection (CAEP). Much of ICAO's effort to address aircraft noise over the
past 30 years has been aimed at reducing noise at source (engine noise), although
land use planning and management around airports, and noise abatement procedures
for take-off, approach and landing are also addressed.
Since the first aircraft noise standards were adopted in 1977,
engine noise reduction technology has been continuously developed and new generation
aircraft have achieved a significant margin on this standard. The growing concern
over increased aircraft traffic and the associated noise impact has impelled
ICAO to concentrate its efforts on the development of a new noise standard and
on removal of the marginal aircraft. In June 2001, on the basis of recommendations
made by the CAEP, ICAO adopted a new, more stringent noise standard that imposes
a cumulative increased stringency of -10 dB relative to current limits. Commencing
1 January 2006, the new standard will apply to newly certificated airplanes
and to airplanes for which re-certification is requested.
GEA and its members welcome the new standard. They are engaged
in retiring and replacing older jets and engines that do not meet noise standards.
The express industry is committed to using the most environmentally friendly
modes of transport available in order to be able to guarantee just-in-time next
day delivery. However, public understanding is essential to an effective program
to reduce aircraft noise so that we do not raise the expectations of airport
neighbors for noise reductions beyond the levels that technology and reasonable
cost-effectiveness can achieve.
Moreover, engine noise reduction will not be an effective
solution on its own. While the express industry continues to make an enormous
effort by renewing its fleet, authorities must also implement much-needed land-use
planning and insulation programs around airports. This will strike the fair
balance between protecting residents from noise and ensuring the well-being
of the European economy.
Noise Reduction Efforts in Europe
Members of the European Express Association rely on over 223
aircraft on a daily basis to ensure that express deliveries reach their destinations
overnight to meet customers' demands. Environmental considerations are key to
selecting these aircraft and operators are currently investing over €3.3
billion in even quieter and cleaner aircraft for use in the EU.
The express industry does not rely entirely on air transport
to deliver packages, indeed it has long been recognized for being a truly intermodal
sector. As well as road and air, ferry services are regularly used for the short
sea passages of shipments, particularly across the English Channel and between
the islands of Denmark. Rail services, on the other hand, are not greatly used.
Although the point-to-point speeds of rail can be high, especially for distances
of between 100 and 500 kilometers, they are rarely so for freight. In Europe,
the average freight train travels at around 15 kilometers per hour.
Nevertheless, express delivery continue to study the use of
trains with other transporters of similar time-sensitive material, such as mail
and newspapers, and will use rail services as and when the price and flexibility
of the services match the needs of the express industry and its customers.
Why do we fly at night?
Express delivery companies work through the night to meet
customers’ requirements for next day deliveries: realistic alternatives
do not exist. These deliveries include emergency spare parts, key components
for manufacturing, time sensitive pharmaceuticals, and business orders for new
economy companies. Over 95% of traffic is business-to-business.
The operational patterns of express delivery make daytime
operations at airports impractical. The hub and spoke concept of delivery pioneered
by express companies requires a large number of aircraft to arrive at and depart
from a single airport in a window of approximately four hours. Such concentrated
air traffic cannot occur during the daylight traffic peak for passenger carriers.
(2) Aircraft Engine Emissions
Like most forms of transportation, aircraft produce chemical
emissions as a result of the fuel combustion process within the engine. The
principal effluents are water (H2O), carbon dioxide (CO2) and oxides of nitrogen
(NOx).
Technologies to increase fuel efficiency and to control the
combustion process are the principal means to reduce aircraft emissions. In
the past 30 years, the introduction of new technology has doubled aircraft fuel
efficiency, significantly reducing aircraft emissions. More efficient flight
operations also result in reduced delays and direct routing and also reduce
the fuel required for a flight.
Further Reducing Aircraft Emissions
Aircraft are required to meet the engine certification standards
adopted by the Council of the ICAO. These standards establish limits for emissions
of oxides of nitrogen (NOx), carbon monoxide, unburned hydrocarbons, for a reference
landing and take-off (LTO) cycle below 915 metres of altitude (3 000 ft). Although
these standards are based on an aircraft's LTO cycle, they also help to limit
emissions at altitude. There are also provisions regarding smoke and vented
fuel.
The ICAO has adopted several approaches for meeting the standards.
It promotes the use of operational measures as a means of limiting or reducing
the impact of aircraft engine emissions. These operational measures address
aircraft ground level and in-flight operations, as well as ground service equipment
and auxiliary power units.
Additionally, the ICAO is developing a policy for the use
of market-based measures to limit or reduce emissions.
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