Definition
The phase of instrument flight conducted under Instrument Flight Rules (IFR) that covers the cruise portion along published or assigned routes between airports (en route) and the transition into and out of the airport environment (terminal). It involves flying on filed clearances, communicating with Air Traffic Control (ATC), navigating using charts and instruments, and following published procedures from departure through arrival.
Plain English
Flying by instruments along a planned route under ATC's direction, then handling the busier airspace near the airport at each end of the trip.
Context Anchor
Seen in instrument training when studying how a flight moves from departure, to the route between airports, to the arrival area near the destination.
Derivation
En route' comes from French, meaning 'on the way.' 'Terminal' comes from Latin terminus, meaning 'end' or 'boundary' -- the area at each end of the journey, near the airport. Together they describe the two distinct phases of an IFR flight between departure and approach.
Why Pilots Care
These two phases use different charts, different ATC services, and different rules. Knowing which phase you are in tells you which chart to have out, which frequency to expect, and what level of ATC workload to plan for.
Intuition Check
“Terminal” does not mean the passenger building here. It means the operating area and procedures near an airport, especially during departure and arrival.
Example Sentence 1
The chapter on IFR en route and terminal operations covers everything from joining your assigned airway after departure to receiving vectors for the approach.
Example Sentence 2
Clearing each term in IFR En Route and Terminal Operations allowed the student to follow the chapter without confusion.