The AIRM imports ISO 19115:2003 - Geographic information — Metadata. This forms the semantic reference used in the AIRM itself. Therefore, in effect, this requirement asks that the metadata fields contained in information definitions conform to the semantics of ISO 19115:2003.
Given that the AIRM imports the ISO standard, it is possible to view it, in UML format, by downloading the AIRM.
The figure below contains a snippet of the ISO 19115 standard. You can see some of the basic metadata fields covered by the standard such as contact details and citation information.
ISO 19115:2003 is used by many ATM business domains. It is mentioned explicitly in ICAO Annex 15 Aeronautical Information Services and in the ICAO Doc 10066 PANS AIM. Therefore, the Aeronautical Information Exchange Model (AIXM) makes use of ISO 19115. This is a clear example of when an information definition that defines metadata fields has based its metadata on the metadata semantics of the AIRM.
However, other information definitions may use other metadata standards such as Data Catalog Vocabulary (DCAT) - Version 2. The important thing is that the semantics of the metadata can be mapped to ISO 19115. This is crucial for semantic interoperability. A mapping between various metadata standards can be found here.
[ ] The definitions of the metadata fields in the information definition are consistent (not contradictory) with the AIRM's metadata standard (ISO 19115:2003 - Geographic information — Metadata).