Definition
A class designation for a VOR, VORTAC, or VOR-DME navigation facility designed to provide reliable signal coverage at high altitudes and over long distances. A High Altitude (H) class facility is generally usable from 1,000 feet AGL up to 60,000 feet, with service volumes that vary by altitude band and extend out to 130 nautical miles at the higher altitudes.
Plain English
An H facility is a long-range ground-based navigation station built to be received from far away and from very high up. It is the most powerful of the three standard VOR classes (Terminal, Low, High), and is the type airliners and high-flying aircraft typically rely on.
Context Anchor
Seen in FAA abbreviations, notices, charts, and route or procedure information where a short letter code is used.
Derivation
High comes from older English words meaning tall or elevated. Altitude comes from Latin words meaning height. Together, high altitude simply points to height above the surface or above a reference level; in FAA shorthand, H is the short label for that high-altitude category.
Why Pilots Care
Determines the switch to standard altimeter setting, triggers oxygen requirements, and changes how vertical navigation and separation are handled.
Intuition Check
High Altitude does not just mean “pretty high up” in casual speech. In this FAA shorthand, H is a category label that separates high-altitude aviation information from low-altitude information.
Example Sentence 1
Our route relies on a High Altitude VOR, so we'll have solid signal coverage all the way up at FL350.
Example Sentence 2
Once above high altitude the crew set the altimeter to 29.92 and began using flight levels.