# Commission Regulation (EC) No 1032/2006 of 6 July 2006 laying down requirements for automatic systems for the exchange of flight data for the purpose of notification, coordination and transfer of flights between air traffic control units (Text with EEA relevance), Division 5.3.1: A crossing clearance request process shall be replied to by:

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

an acceptance of the proposed route/airspace crossing details, or,
a counter-proposal including different route/airspace crossing details as specified in section 6 below, or
a rejection of the proposed route/airspace crossing details.

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Source: https://www.legislation.gov.uk/eur/2006/1032/annex/I/part/C/division/5/division/5.3/division/5.3.1 (the official version)
Page: https://openlegislation.uk/eu-regulation-2006-1032/annex-I/part-C/division-5/division-5.3/division-5.3.1
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.