Definition
Aeronautical charts published by the FAA for IFR navigation at or above 18,000 feet MSL within the contiguous United States, Alaska, and Hawaii. They depict the jet route structure, including jet routes, VHF navigational aids (VORs and VORTACs) with frequencies and identifiers, reporting points, special use airspace, and military training routes that affect high-altitude operations.
Plain English
These are the navigation charts pilots use when flying on instruments at high altitudes (18,000 feet and above). They show the airways, navigation stations, and other information needed to fly safely in that airspace.
Context Anchor
Seen during IFR flight planning and in flight when a pilot is using FAA en route charts for operations at 18,000 feet MSL or higher.
Derivation
"En route" comes from French, meaning "on the way" or "during the journey." These charts cover the cruise portion of a flight, between departure and arrival, rather than the takeoff or landing phases.
Why Pilots Care
Above 18,000 feet, all flight is conducted under IFR, and the structure of the airspace is different from lower altitudes. Using the correct chart ensures the pilot has the right airways, frequencies, and altitudes for that environment.
Intuition Check
Do not read “high-altitude” as simply “pretty high.” Here it means the FAA en route chart series used for IFR flight at 18,000 feet MSL and above.
Example Sentence 1
Before departing on the cross-country IFR flight at FL310, the pilot reviewed the en route high-altitude charts to confirm the jet route and navaid frequencies.
Example Sentence 2
Before departure the crew reviewed the en route high-altitude charts to confirm available navigation aids and minimum altitudes for the planned IFR route.