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The Flight Path of Aircraft Noise Measurement

The measurement of aircraft noise has never been an easy task. Measurement ofan individual aircraft with the human observer using a hand-held sound level meter and deciding the beginning and end ofthe noise event has, for decades, been one way of achieving measurement data. For measurement of aircraft noise 24 hours a day, an automatic system has naturally always been needed. Until the 1970s such a system was not truly practicable and when the first one did arrive, it was less than perfect. The main problem was and is to separate the noise of the aircraft from all other noises in order to allocate responsibility for the noise to the correct source. Once the noise event has been properly identified, the actual measurement although a far from trivial task is relatively simple. To see the difficulties that had to be overcome and the progress made, a short history of automatic measurement around airports is a sensible starting point.