Definition
An ATC service that allows an IFR aircraft to fly between two airports within approach control airspace without entering the en route (Center) structure. The flight is handled entirely by a sequence of approach control facilities, using published TEC routes filed by route name or code.
Plain English
A way to fly IFR from one nearby airport to another by being passed from one approach controller to the next, instead of being handed up to the higher-altitude Center controllers.
Context Anchor
Pilots encounter TEC when planning or receiving an IFR clearance for short flights in busy terminal regions, especially where published TEC routes are available.
Derivation
"En route" comes from the French for "on the way." "Tower en route" signals that the "on the way" portion of the flight stays inside terminal (approach control) airspace rather than climbing into Center's airspace.
Why Pilots Care
Reduces flight planning workload for routine short IFR trips while maintaining safety through ATC oversight.
Intuition Check
Do not assume “Tower” means one airport tower controls the whole trip. In TEC, the flight is handled through local terminal control facilities along the route.
Example Sentence 1
For the short IFR hop from Long Beach to San Diego, the pilot filed a published TEC route to stay within SoCal Approach's airspace.
Example Sentence 2
Under TEC, the tower provided vectors and altitude assignments without a full flight plan.