# Commission Directive (EU) 2015/996 of 19 May 2015 establishing common noise assessment methods according to Directive 2002/49/EC of the European Parliament and of the Council (Text with EEA relevance), Division 2.7.19: Segment Event level correction terms

Extent: E+W+S+N.I.

The NPD data define noise event levels as a function of distance perpendicularly beneath an idealised straight level path of infinite length along which the aircraft flies with steady power at a fixed reference speed. The event level interpolated from the NPD table for a specific power setting and slant distance is thus described as a baseline level. It applies to an infinite flight path and has to be corrected to account for the effects of (1) non-reference speed, (2) engine installation effects (lateral directivity), (3) lateral attenuation, (4) finite segment length and (5) longitudinal directivity behind start of roll on takeoff — see equations (2.7.25) and (2.7.26).

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Source: https://www.legislation.gov.uk/eudr/2015/996/annex/division/ASSESSMENT/division/2/division/2.7/division/2.7.19 (the official version)
Page: https://openlegislation.uk/eu-directive-2015-996/annex/division-ASSESSMENT/division-2/division-2.7/division-2.7.19
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.