# The Air Navigation (Noise Certification) Order 1990, Paragraph 2


The noise levels required by paragraph 3 of this Part of this Schedule shall be measured at the following points—
(a) on take-off—
(i) at a flight path reference point located on the ground vertically below the flight path defined in the take-off reference procedure and 500 metres horizontally in the direction of flight from the point at which transition to climbing flight is initiated in the reference procedure;
(ii) at two other points on the ground symmetrically disposed about the flight path defined in the take-off reference procedure and lying on a horizontal line through the flight path reference point at right angles to the direction of flight at a distance of 150 metres.
(b) on overflight—
(i) at a flight path reference point located on the ground 150 metres vertically below the flight path defined in the overflight reference procedure;
(ii) at two other points on the ground symmetrically disposed about the flight path defined in the approach reference procedure and lying on a horizontal line through the flight path reference point at right angles to the direction of flight at a distance of 150 metres.
(c) on approach—
(i) at a flight path reference point located on the ground 120 metres vertically below the flight path defined in the approach reference procedure;
(ii) at two other points on the ground symmetrically disposed about the flight path defined in the approach reference procedure and lying on a horizontal line through the flight path reference point at right angles to the direction of flight at a distance of 150 metres.

---
Source: https://www.legislation.gov.uk/uksi/1990/1514/schedule/1/part/IX/paragraph/2 (the official version)
Page: https://openlegislation.uk/air-navigation-noise-certification-order-1990/schedule-1/part-IX/paragraph-2
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.