Definition
A Computer Navigation Fix (CNF) is a defined geographic point in space identified by a five-letter name that begins with the letters 'CF' (e.g., CFWBA). CNFs are used by the Flight Management System (FMS) and Area Navigation (RNAV) systems to support the construction of published instrument procedures and routes, but they are not recognized as compulsory reporting points by Air Traffic Control. CNFs do not appear in normal pilot/controller phraseology and are not used in clearances. Their purpose is purely to give the navigation database a stable reference point where no named waypoint, fix, NAVAID, or intersection already exists.
Plain English
A CNF is a hidden navigation point used by the airplane's flight computer to help draw a route or approach correctly. It has a five-letter name starting with 'CF', but pilots and controllers don't talk about it on the radio — it's just there to keep the computer's map accurate.
Context Anchor
Seen in the Pilot/Controller Glossary and in discussions of instrument procedures, navigation databases, and computer-based route guidance.
Derivation
The 'CF' prefix in every CNF name is a deliberate marker that tells the navigation system — and any chart-reader who notices — that this point exists for the computer rather than for ATC communication.
Why Pilots Care
Pilots must recognize CNFs so they do not mistake them for charted waypoints during flight planning or in the cockpit.
Intuition Check
Do not read “fix” as a repair. In this context, a fix is a defined position, and a CNF is a defined position mainly for the navigation computer.
Example Sentence 1
While reviewing the RNAV approach plate, the pilot noticed several CNFs along the final segment and recognized they were database points, not fixes to report to ATC.
Example Sentence 2
Before departure the pilot verified that every CNF in the database matched the planned RNAV track.