21.—(1) No later than 6 months after commencement of the authorised development a written scheme detailing operational noise management and attenuation measures, and their ongoing maintenance, must be submitted to the relevant planning authority for its approval.
(2) The authorised development must not be brought into use until, following consultation with the relevant district authorities, the scheme submitted under sub-paragraph (1) has been approved in writing by the relevant planning authority.
(3) The noise attenuation measures detailed in the scheme approved under sub-paragraph (2) must be installed during the course of the construction of the authorised development and the authorised development must be operated afterwards in accordance with the scheme approved under sub-paragraph (2).