Noise Contour
The noise contours generated for Dublin Airport represent an average summer
day. This is achieved by taking all the flights over the 92 day period of
16th June to 19th September and dividing the total by 92 - thus an average that
encompasses all the aircraft types that go in and out of the airport in that
summer period. This makes sure none of the noisier aircraft types are
missed out. The summer period is used as this is when commercial airports
are at their busiest with holiday travel etc. [This 92 day period is used
by Heathrow, Gatwick and Stansted amongst others to generate the noise contours
that they publish every year.]
The contours do not equate to any one day's flying at Dublin -
they are an average. One would never measure precisely the same day after day, hence
why an average is used to make things fair. The way noise
is calculated, the results will tend towards the noisier events, so it is a very fair way
of doing the calculations.
The contours are generated by using a
computer programme that looks at every aircraft type, how often it flies, whether
it is a departure or arrival and if a departure, where the plane is going so the
programme can assess how heavy the aircraft will be, thus how it will take
off. The noise level and flight profile information used is all standard
information that is within the computer model. This model is published by
the United States Government's Federal Aviation Authority and it is used
worldwide - it is known to be an accurate method and is widely
accepted.