vluchtniveau

Vluchtniveau is the Dutch term for flight level, a standardized altitude reference used in aviation for describing the height at which an aircraft flies. A vluchtniveau is expressed as FL followed by a number, for example FL350, which denotes about 35,000 feet in standard atmosphere.

Flight levels are based on a reference pressure of 1013.25 hPa and correspond to pressure altitude rather than true geometric height. The actual height above mean sea level varies with atmospheric conditions, especially temperature and pressure. Because flight levels are tied to standard pressure, they are most useful for maintaining consistent vertical separation in controlled airspace.

In many airspaces, a designated transition altitude marks where pilots and controllers switch from altitude (which uses local pressure settings, known as QNH) to flight levels (which use standard pressure). Below the transition altitude, aircraft commonly fly altitudes referenced to local pressure; above it, they fly fixed flight levels. The exact transition altitude varies by country and airspace.

Terminology and usage: vluchtniveau is used primarily in IFR operations and in controlled European airspace to ensure uniform vertical separation. When an aircraft is cleared to a specific vluchtniveau, the crew sets the altimeter to the standard pressure setting (1013.25 hPa) and maintains the corresponding FL value, regardless of actual surface weather. For example, FL100 corresponds to approximately 10,000 feet pressure altitude.

See also: flight level, altitude, transition altitude, altimeter setting, air traffic control.