Definition
A published waypoint or fix used to connect the end of a Standard Instrument Departure (SID) with the en route structure or with a random RNAV route segment. It marks the point where the departure procedure ends and the transition to the en route phase of flight begins.
Plain English
It is the point where your departure path from the airport hands you off to your en route course. After you cross it, you are no longer flying the departure procedure — you are flying the route to your destination.
Context Anchor
Seen when planning or filing an instrument flight plan that uses a published departure and then continues on a random RNAV route.
Derivation
Transition comes from the Latin transire, meaning 'to go across.' A departure transition fix is the crossing point — the place where you go across from the departure phase to the en route phase.
Why Pilots Care
Ensures continuous navigation coverage and legal route compliance when leaving a departure procedure for direct routing.
Intuition Check
Do not read “fix” as repair, and do not read “transition” as a vague change. Here, the term means a specific named navigation point where one planned part of the route changes to the next.
Example Sentence 1
After takeoff, the crew flew the SID and crossed the departure transition fix before turning on course toward their first en route waypoint.
Example Sentence 2
Flight planning software inserted the departure transition fix automatically to link the SID with the enroute segment.