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IFR low altitude en route charts — Aviation Definition | Keynomen Aviation

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IFR low altitude en route charts

IFR is the abbreviation for instrument flight rules.

Plain English Meaning

These are the maps instrument-rated pilots use to plan and fly routes in the lower part of the airspace system, below 18,000 feet. They show the airways, radio navigation aids, and required altitudes, and they also mark out the military training routes a pilot needs to be aware of.

Full Definition

Aeronautical charts published by the FAA for navigation under Instrument Flight Rules at altitudes below 18,000 feet MSL. They depict airways, navigation aids, intersections, minimum altitudes, boundaries, airports with , and other information needed to fly the - system. They also depict Military Training Routes that operate at and below 1,500 feet (IR and VR routes identified by four-digit numbers).

IFR low altitude en route charts

controlled airspace

instrument approaches

Context Anchor

Seen during IFR flight planning and when checking a planned route for Military Training Routes.

Derivation

"En route" comes from French, meaning "on the way" or "during the journey." These are the charts you use while underway between departure and destination, as distinct from charts used for approach or departure procedures at an airport.

Why Pilots Care

They allow pilots to plan safe IFR flights while remaining aware of military training activity that could affect their route.

Intuition Check

“Low altitude” does not mean just above the ground here; it means the lower range of IFR charting, generally below 18,000 feet above mean sea level. “IFR” also does not mean “only in clouds”; it means flight conducted under instrument flight rules.

Example Sentence 1

Before the cross-country flight, she pulled up the IFR low altitude en route chart to check for any Military Training Routes crossing her planned course.

Example Sentence 2

Military training routes are marked on IFR low altitude en route charts so civilian pilots can avoid them when possible.