Plain English Meaning

A common rulebook that tells navigation database makers how to write each piece of a flight procedure into the FMS, so every flight management system reads it the same way and flies it the same way.

Full Definition

A set of industry specifications, published by Aeronautical Radio, Inc. (ARINC), that define how flight procedure data — including waypoints, courses, altitudes, and the path-and-terminator legs that make up departures, arrivals, and approaches — must be encoded into the navigation databases used by aircraft flight management systems. The most relevant document is ARINC Specification 424, which standardizes the format so that any compliant FMS can read and fly the same coded procedure consistently.