PBN is a very important subject in modern Air Navigation and is about to become a requirement to obtain or to revalidate the instrument rating previleges.
PBN is defining a global Standard for RNAV and RNP specifications and is one of the enablers of an Airspace Concept. The others are Communications, ATS Surveillance and ATM.
The PBN Concept has three components: The Navigation Specification, the Navaid Infrastructure and the Navigation Application.
PBN is detailed in the ICAO DOC 9613 which is divided in two Volumes.
The App allows you to test your knowledge about PBN. Have fun.