5.376 in the Radio Frequency Table Allocation of Ireland.

Content Type: ITU FOOTNOTE
Title: 5.376
Description: Transmissions in the band 1 646.5-1 656.5 MHz from aircraft stations in the aeronautical mobile (R) service directly to terrestrial aeronautical stations, or between aircraft stations, are also authorized when such transmissions are used to extend or supplement the aircraft-to-satellite links.
Source: https://search.itu.int/history/HistoryDigitalCollectionDocLibrary/1.43.48.en.101.pdf