Definition
Course or bearing values published on en route charts that are referenced to magnetic north rather than true north. On IFR en route low altitude charts, airway courses, radials, and bearings are depicted as magnetic reference bearings, meaning the numerical value already incorporates the local magnetic variation and matches what a pilot reads directly from a magnetic compass or heading indicator.
Plain English
The course numbers printed on the chart are based on magnetic north, so they line up with what your compass shows. You don't have to add or subtract anything to use them.
Context Anchor
Seen on IFR en route charts where published directions, routes, and navigation aid information are shown for instrument flying.
Derivation
"Magnetic" refers to magnetic north (the direction a compass needle points), not true north (the geographic pole). "Reference" means the baseline the bearing is measured from. So a magnetic reference bearing is a direction measured from magnetic north as its zero point.
Why Pilots Care
Aircraft magnetic compasses and heading indicators show magnetic north, so chart bearings that match this reference allow direct use without conversion and reduce heading errors.
Intuition Check
Do not read bearing here as a mechanical part that supports a wheel or shaft. In navigation, a bearing is a direction, and magnetic means that direction is measured from magnetic north, not true north.
Example Sentence 1
The airway is labeled 090, and because en route charts use magnetic reference bearings, the pilot simply flies a magnetic course of 090 to stay on the airway.
Example Sentence 2
When selecting a VOR radial on the chart, the pilot uses the magnetic reference bearing shown rather than calculating a true heading.