How is Class A airspace depicted on an en route low altitude chart?

Class A airspace is not depicted on en route low altitude charts because it is generally located above 18,000 feet mean sea level (MSL) and is regulated by specific air traffic control procedures that differ from those applicable at lower altitudes. This airspace is primarily used for high-altitude en route navigation and IFR operations, which are not the focus of low altitude charts.

Low altitude charts are designed for operational use by aircraft flying below 24,000 feet MSL, and therefore, they do not include information about airspace classifications that are above this range. Each type of airspace has its own representation on the charts, but Class A airspace is simply excluded from these lower altitude charts due to its altitude and control requirements. This is why Class A airspace does not appear in any form, such as lines or shaded areas, on en route low altitude charts.