The Canadian Forces Base at Goose Bay, Newfoundland, is currently used by Canada as a training centre for low level military flying. Approximately 6,000 training flights per year were being conducted within a 100,000 km2 designated area and 90 percent of these flights were between 30 and 150 metres above ground level. In 1987, the Canadian Department of National Defence proposed that the annual number of training flights be gradually increased to a maximum of 18,000 with an increased percentage of night flights. Originally, there was also a proposal to establish a NATO Tactical Fighter Centre which would support large scale military exercises an training in Air Combat Maneuvering. Both of these activities would result in the occurrence of sonic booms. However, in the early 1990′s NATO decided that the Tactical Fighter Centre would not be required and that component of the project was dropped.
BKL was responsible for the prediction and assessment of noise impact from increased low level training. Prediction of noise from low level flying was particularly challenging since flight paths and altitudes are virtually unrestricted within the large low level flying areas. Historic records of flight tracks were available on a Geographic Information System and this information, together with known or estimated probability distributions for aircraft altitudes and speeds plus known noise emissions from the various aircraft types, permitted us to model and predict the probabilities of aircraft noise events of various noise levels occurring within any particular area.
For low level military overflights, the onset rate of the noise can be high enough to cause a “startle reaction” in humans and animals. Although the designated flying areas contained no permanent human settlements, the areas were used frequently by the Innu Nation for various purposes and wildlife was abundant. Hence, startle was a major concern. Therefore, a correction factor was applied to the predicted noise levels of those overflights with high onset rates in an attempt to account for the increased disturbance.
A detailed literature review was performed. The potential noise effects within the low level flying areas were quite different from the potential noise effects on the residents of Goose Bay so they were assessed independently. In order to adequately assess the potential effects of noise on residences, schools and hospitals adjacent to the air base, Noise Exposure Forecast (NEF) contours were produced. Aircraft noise was also assessed in terms of single events; for example, a single aircraft departure or the ground run-ups typically performed by fighter aircraft immediately prior to take-off.
Public hearings were held by the Federal Government after completion of the Environmental Impact Statement and the many associated Technical Reports. BKL represented the Department of National Defence throughout these hearings on matters pertaining to aircraft noise and its potential effects. Ultimately, the project was approved subject to implementation of measures that had been proposed to mitigate noise and other adverse impacts.