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Tinted bands and figures giving a volume's ceiling and floor.
Also known as: Airspace class boundary, Control zone marking
Airspace on a chart is bounded by a tinted band with two figures giving its upper and lower limits. The floor figure matters most: below it the airspace is uncontrolled, and an aircraft a hundred feet lower is in a different regulatory world.
Bounds a volume of controlled airspace on a chart, with figures giving its upper and lower limits.
Contexts: Navigation, Maps
Places the regulatory boundary at the stated floor, so a small difference in altitude changes whether clearance is required.
Contexts: Navigation, Maps
Uses distinct tints and line styles for each airspace class, which govern what services and requirements apply within.
Contexts: Navigation, Maps
A band of soft tint following a boundary line on a chart, with two numerals stacked one above the other beside it.