Art. 44 Radioreglement 1979, Order of priority of communications
44.1 § 1 The order of priority for communications in the aeronautical mobile service and the aeronautical mobile-satellite service shall be as follows, except where impracticable in a fully automated system in which, nevertheless, Category 1 shall receive priority:
1 Distress calls, distress messages and distress traffic.
2 Communications preceded by the urgency signal.
3 Communications relating to radio direction-finding.
4 Flight safety messages.
5 Meteorological messages.
6 Flight regularity messages.
7 Messages relating to the application of the United Nations Charter.
8 Government messages for which priority has been expressly requested.
9 Service communications relating to the working of the telecommunication service or to communications previously exchanged.
10 Other aeronautical communications.
44.2 § 2 Categories 1 and 2 shall receive priority over all other communications irrespective of any agreement under the provisions of No. 35.1.