Aircraft noise impacts on surrounding communities cannot be fully described by the Australian Noise Exposure Forecast (ANEF) alone. ANEF maps and the related guidance contained in Australian Standards are primarily concerned with land use planning and building treatments for new development sites in the vicinity of an aerodrome. The ANEF describes noise exposure over an average day and therefore does not describe the noise in the way in which an individual might experience it. Community reaction to noise is complex and relate to acoustic and non-acoustic factors, and an individual's impression will usually be based on observations and effects over shorter periods
As part of the updated to the ANEF for RAAF Base East Sale, additional noise information will be generated to assist stakeholder's understanding of aircraft noise, and communicate how aircraft noise levels are likely to be experienced in practice.
One such type of information is the Number Above (N) concept, consistent with guidance contained in Australian Standards, Department of Infrastructure publications and routinely presented in aircraft noise assessments.
N-values refer to a number of aircraft events exceeding maximum noise levels (eg 60, 65 and 70 dB) at a given location, during a 24 hour period. For example, "N70 20 events" refers to a situation where 20 events exceed a maximum noise level of 70 dB LAmax. This threshold is commonly used for documenting aircraft noise operations which are at a level that could give rise to speech interference inside a dwelling with partially open windows.
To compare aircraft operations around RAAF Base East Sale, the N70 is presented for both the 2015 year (current) and 2035 year (forecast).