Definition
The network of Federal airways in the United States that extends from 1,200 feet above the surface up to, but not including, 18,000 feet MSL. These airways are designated Victor airways (V-airways) when based on VOR navigation, and are depicted on en route low-altitude charts.
Plain English
It is the system of published flight highways used at lower altitudes -- below 18,000 feet -- that connects navigation aids and gives pilots defined routes to fly between them.
Context Anchor
Seen on FAA low-altitude en route charts and used when planning or receiving an instrument flight rules clearance below 18,000 feet mean sea level.
Why Pilots Care
It defines the protected routes and minimum altitudes available for IFR operations below the high-altitude jet route structure.
Grounding Statement
On a low-altitude en route chart, this is the connected network of charted paths a pilot can use to build an instrument route below 18,000 feet.
Intuition Check
“Low-altitude” does not mean flying close to the ground. In this FAA context, it means the airway system used below 18,000 feet mean sea level, as opposed to the high-altitude route system.
Example Sentence 1
The instructor filed the IFR route along Victor airways within the low-altitude airway structure.
Example Sentence 2
A temporary deviation took the flight off the low-altitude airway structure before rejoining the airway.