CONFIDENTIAL
The B-747 (S) is a special version of
a special version of the B-747 designed for long range flights and therefore will be heavier and noisier. It is assumed to represent 10 percent of all B-747 operations.
1.2
TIME OF DAY
Night operations, defined as occurring from 2200 to 0700 hours for community noise impact evaluation purposes, are projected represent 10 percent of total daily movements. This split is assumed to apply evenly to all aircraft types.
2.
DERIVATION OF NOISE CONTOURS
to
Due to the limited time constraints of this study, noise contours were derived in two stages. First, the Integrated Noise Model
(INM) was used to derive noise contours for selected simple straight-in and straight-out approach and departure scenarios. Six scenarios were run,
representing the following conditions.
1.
2•
3.
4.
5.
70 percent departures 30 percent approaches 30 percent departures 70 percent approaches
50 percent departures
6. 50 percent approaches
With the assumption that 70 percent of the time the airport operates to the northeast, and 30 percent to the southwest, Scenarios 1 and 2 represent activity to the northeast of the airport and Scenarios 3 and 4 represent activity to the southwest. Scenarios 5 and 6 represent activity in both directions if different meteorological conditions are assumed. Noise contours for various values of NEF were computer plotted for each of these scenarios. Runway length was assumed to be
3700m in all cases.
The second step of the derivation involved adjusting the plotted contours to reflect turns, nighttime restrictions, occurence of departures and approaches on the same runway, and interactive influence of adjacent runways. These adjustments are discussed separately below.
2.1
TURNS
were
Since all approaches were assumed to follow straight-in paths beginning at about 8nm from touchdown, and since at this distance they contribute negligible noise exposure, no approach turns considered. Departure turns were assumed to commence when aircraft reached an altitude of 500 feet, assuming a conservative 6 percent rate of climb. Initially, all departure paths were assumed to follow a 4000m radius, which is typical of DC-10 and B-747 aircraft. In further studies options No. 2 and 3 (Section 4), the early turn northeasterly departure path was adjusted to reflect behavior of other aircraft by plotting expected turning paths for the B-747, DC-10, L-1011, and 2 engine aircraft, weighting each path by the percent of airport operations represented by each type, and then finding the average between
9-3
CONFIDENTIAL
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