Instrument flight procedures (IFP) are used by aircraft flying in accordance with instrument flight rules and are designed to facilitate safe and efficient aircraft operations. These procedures are an essential component of the aviation system. Every day, thousands of aircraft around the world are flying instrument departure, arrival or approach procedures to airports in every country.
IFP Guidance Material
RNP AR Manual (Doc 9905)
Manual on the Development of a Regulatory Framework for Instrument Flight Procedure Design Service (Doc 10068)
PBN Manual (Doc 9613)