Definition
NAV/ is a flight plan or route data field prefix used in ICAO flight plans and RNAV procedure coding to identify navigation-related information, most commonly the navigation specification or required navigation performance (RNP) capability associated with a route or procedure. On RNAV departure charts and in flight management system (FMS) route coding, NAV/ introduces the navigation database identifier or navigation specification that applies to the segment.
Plain English
NAV/ is a label that flags what comes next as navigation information — usually which navigation standard or database entry applies to a route.
Context Anchor
Seen when filing an instrument flight plan for routes or departures that depend on the aircraft’s navigation capability, including area navigation departures.
Derivation
NAV is the standard aviation shorthand for navigation. The trailing slash is ICAO and FMS convention for a data field prefix — the slash separates the label from the value that follows (for example, NAV/RNP1).
Why Pilots Care
When filing or loading an RNAV departure, the NAV/ entry tells the system and ATC which navigation specification the aircraft is using. Getting this wrong can mean the FMS loads the wrong procedure or ATC expects performance the aircraft cannot deliver.
Intuition Check
Do not read NAV/ as a cockpit button, a route instruction, or a command to navigate. In this context, it is a flight plan label for navigation-capability information.
Example Sentence 1
The crew confirmed the NAV/ field in the flight plan matched the RNAV departure procedure loaded in the FMS.
Example Sentence 2
The departure transitions from vectors to NAV/ once the aircraft is established on the RNAV route.