Definition
The point in flight at which the aircraft's primary means of navigation changes from conventional ground-based navigation aids (such as VOR, DME, or NDB) to Area Navigation (RNAV), in which position is computed from satellite signals (GPS) and/or other multi-sensor inputs rather than from tracking signals to or from a specific ground station. The transition involves a procedural and avionics change: the flight crew selects the RNAV source on the navigation system, verifies the navigation database, and follows a course defined by computed waypoints rather than by radials or bearings to a station.
Plain English
The moment the aircraft stops navigating by tuning ground stations and starts navigating by GPS-defined points stored in the flight computer.
Context Anchor
Seen when reviewing or loading an instrument procedure in a GPS or flight management system, especially where the charted route changes into an RNAV portion.
Derivation
RNAV stands for Area Navigation. The name reflects the shift from navigating along fixed lines between ground stations to navigating freely within an area, using any point that can be defined by coordinates.
Why Pilots Care
Database errors or missing waypoints at this point can cause navigation inaccuracies or procedure deviations.
Intuition Check
Do not read “transition” here as any casual or gradual change the pilot chooses. In this context, it means a specific published changeover to RNAV guidance in the procedure.
Example Sentence 1
After departure, the crew confirmed the transition to RNAV by checking that the FMS was tracking the published waypoints rather than the departure VOR.
Example Sentence 2
Database coding issues prevented a smooth transition to RNAV during the enroute phase.