Definition
An FAA aeronautical chart series designed for instrument flight rules (IFR) navigation at or above 18,000 feet MSL. These charts depict the high-altitude jet route structure, navigation aids, intersections, controlling agencies, and related airspace information used in the upper airspace.
Plain English
A type of aviation chart used for IFR flying in the upper part of the sky, generally above 18,000 feet. It shows the routes, fixes, and navigation information pilots need at those altitudes.
Context Anchor
Seen when checking FAA NOTAMs for route-related information before a flight, especially when planning to use upper-level instrument routes.
Derivation
‘Enroute’ simply means ‘along the route of flight,’ from the French ‘en route’ (on the way). ‘High Altitude’ here is a defined airspace band, not a casual description — it refers specifically to the airspace at and above 18,000 feet MSL, where the jet route structure exists.
Why Pilots Care
Pilots need the correct chart series so they receive accurate NOTAMs and navigation data for their actual flight altitude.
Intuition Check
Do not read “High Altitude” as simply “a flight that feels high.” Here it means the FAA’s upper en route system. Do not read “Enroute” as including every airport detail along the trip; this category is about the between-airports route structure.
Example Sentence 1
Before the flight, the captain pulled out the Enroute High Altitude chart to review the jet routes between Denver and Chicago.
Example Sentence 2
A temporary flight restriction appeared on the Enroute High Altitude chart near the destination.