# The Air Navigation (Noise Certification) Order 1990, Paragraph 4


The noise levels specified in paragraph 3 of this Part of this Schedule may be exceeded at one or two of the measuring points specified in paragraph 2 if—
(a) the sum of the excesses does not exceed 4 EPNdB;
(b) at no measuring point is the excess greater than 3 EPNdB; and
(c) any excesses are completely offset by reductions at the other measuring point or points.

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Source: https://www.legislation.gov.uk/uksi/1990/1514/schedule/1/part/IX/paragraph/4 (the official version)
Page: https://openlegislation.uk/air-navigation-noise-certification-order-1990/schedule-1/part-IX/paragraph-4
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.