Two states can agree, through a bilateral letter of agreement, to delegate the responsibility for providing air traffic services (ATS) within a certain airspace from one state to the other. There can be numerous reasons for this. For example, a part of Scottish airspace is delegated to the Danish air navigation service provider (ANSP), because Denmark has better radar coverage within the specific area. In this area, which is within Scottish airspace, ATS is provided by the Danish ANSP.
My question is regarding the need to publish details about such airspace delegations in the national aeronautical information publications (AIP).
The previously mentioned delegated airspace is described in AIP Denmark section ENR 2.2 (Other regulated airspace). However, a part of German airspace within Hannover upper flight information region (UIR) is also delegated to Denmark, but this airspace is not shown anywhere in the AIP. To me, this seems very inconsistent, which brings me to my question: under which circumstances are states required to publish information about delegation of ATS? I am interested in references to ICAO SARPs or PANS, or, alternatively, EU regulations.
The below chart (AIP Denmark ENR 6.2 – 1) clearly indicates some delegated areas in Scottish airspace and around the border to Sweden (which I have marked with blue), but, the delegated area in Germany (which I have marked with red) is not shown.
The area is, however, shown on this "Sector Boundary Structure Chart" chart published by Eurocontrol:
I have looked in ICAO Annex 4 and Annex 15 without any luck. Appendix 1 of Annex 15 states that:
ENR 2.1 shall contain, among other things:
Detailed description of flight information regions (FIR), upper flight information regions (UIR), and terminal control areas (TMA), including:
2) identification of unit providing the service;
I usually see delegated airspaces listed in ENR 2.2, though, so they do not seem to need to be covered in ENR 2.1.
ENR 2.2 shall contain:
Where established, a detailed description of other types of regulated airspace and airspace classification.
It is not specified exactly what this includes.