Definition
Low-altitude RNAV (area navigation) airways established by the FAA for use by aircraft equipped with IFR-approved GPS. T-routes provide a published low-altitude route structure between waypoints, typically from 1,200 feet AGL up to but not including 18,000 feet MSL, and offer an alternative to the conventional Victor airway system that depends on VOR ground stations.
Plain English
T-routes are low-altitude flight paths defined by GPS waypoints rather than by ground-based radio beacons. A pilot with an approved GPS can fly them just like a regular airway, but without needing to track a VOR signal.
Context Anchor
Seen on low-altitude IFR en route charts and in instrument flight planning when choosing or filing an IFR route.
Derivation
The 'T' designator simply identifies these as RNAV (GPS) low-altitude routes, distinguishing them from the older 'V' (Victor) airways built around VOR stations. The letter is a chart-coding convention rather than an abbreviation of a word.
Why Pilots Care
They offer more direct paths, reduce reliance on older ground stations, and can shorten flight times in the low-altitude structure.
Intuition Check
Do not assume the T means a temporary route or a training route. In this context, T is the FAA label for a published low-altitude area navigation route.
Example Sentence 1
We filed T-295 from the departure fix to our destination because the GPS routing was more direct than any Victor airway available.
Example Sentence 2
T-routes appear in blue on the enroute chart and require RNAV equipment to use.