Jet route. A route designated to serve flight operations from 18,000 feet MSL up to and including FL 450.
Local area augmentation system (LAAS)
Localizer (LOC) ...
Jet routes start at 18,000 feet mean sea level (msl) and extend upward to an altitude of 45,000 feet msl (altitudes above 18,000 feet are called "flight levels" and are described as FL450 for 45,000 feet msl). Jet routes have names like J42 or J121.
En Route High Altitude Charts portray Jet routes, distances, time zones, special use airspace, radar jet advisory areas, and other data. IFR flight plans are necessary for all flights above 18,000 feet.
b. A published procedure (DP Transition) used to connect the basic DP to one of several en route airways/jet routes, or a published procedure (STAR Transition) used to connect one of several en route airways/jet routes to the basic STAR.
"J" routes are Jet routes, used for flight above Flight Level 180- 18,000 feet. Below FL180 the "Victor" routes are used.
all have names that start with the letter J, and are called Jet Routes. These run from 18,000 feet to 35,000 feet (5,486 meters to 10,668 meters). The altitude separating the low and high airway structures varies from country to country.
See also: Aircraft, Flight, Navigation, Route, Pilot