# Commission Implementing Regulation (EU) 2019/123 of 24 January 2019 laying down detailed rules for the implementation of air traffic management (ATM) network functions and repealing Commission Regulation (EU) No 677/2011 (Text with EEA relevance), Division 4: Airspace design projects shall be compatible and consistent with the European Route Network Improvement Plan. At least the following changes to airspace design projects require compatibility checking and need to be notified to the Network Manager:

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

(a)changes in route alignment;
(b)changes in route direction;
(c)changes in route purpose;
(d)free route airspace description, including associated utilisation rules;
(e)route utilisation rules and availability;
(f)changes in vertical or horizontal sector boundary;
(g)addition or removal of significant points;
(h)changes in cross-border airspace utilisation;
(i)changes to the coordinates of significant points;
(j)changes affecting data transfer;
(k)changes affecting data published in aeronautical information publications;
(l)changes affecting letters of agreement with regard to airspace design and utilisation.

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Source: https://www.legislation.gov.uk/eur/2019/123/annex/I/part/B/division/4 (the official version)
Page: https://openlegislation.uk/eu-regulation-2019-123/annex-I/part-B/division-4
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.