CONFIDENTIAL
NEF
NEF contour
In view of this latter point it is important to be clear about the range of possibilities that have been taken into account in this appraisal. In the first instance (figure 5.1) a drawing has been prepared which attempts to cover the range of operating possibilities and the re- sultant noise conditions.
In essence this drawing distinguishes between the 25 contour that represents the "best case" situa- tion (ie. the best contour from a noise point of view) and a second 25 which encompasses a whole range of alternative operating conditions. Being a purely theore- tical amalgam of the effects of many possibili- ties, this second outer contour should not be construed as а "worst case" but it is indicative of the potential extent of land area that might be affected by noise in excess of 25 It has been accepted that encroachment into this area could therefore feasible (depending upon the airport operating system chosen) but it is acknowledged in turn that any such encroachment may be worsening the noise environment elsewhere. The usefulness of this first drawing has been primarily to guide the search for alternative sites for displaced major growth (see figures 5.6 and 5. 7). In order to test the "impact" of the airport on the preferred strategy as it stands however a specific set of operating conditions has had to be assumed (see figures 5.2 and 5.3 for the existing situation, and 5.4 and 5.5 for the major growth strategy). These operating conditions relate to the year 1995 and assume:
NEF.
i)
24 hour operations.
ii) 448 aircraft movements per day.
iii) 70% of aircraft movements to the North East.
It should be noted that the third operation
assumption
is not necessarily RMP-Encon's "preferred" mode of operation, and is far from optimal from a noise point of view, as a comparison with figure 5.1 shows.
5-7
CONFIDENTIAL