Avstandsmark

An avstandsmark, commonly known in English as a "distance marker," is a navigational aid used primarily in aviation to indicate the remaining distance to a specific point, such as an airport or waypoint. These markers are often employed in instrument flight rules (IFR) operations to assist pilots in maintaining precise flight paths, especially during approaches to landing.

Avstandsmark systems typically operate using very low-frequency (VLF) or ultra-low-frequency (ULF) radio signals, which can travel long distances and are less affected by atmospheric conditions. The markers transmit coded signals that are received by onboard avionics in the aircraft. These signals are then processed to provide the pilot with an audio or visual indication of the distance remaining to the designated point. For example, a typical avstandsmark might emit a series of Morse code-like tones or beeps, where the pattern changes to indicate decreasing distance.

In Norway, avstandsmark is a term specifically associated with the country’s aviation infrastructure. Norway utilizes these systems extensively due to its vast and often remote terrain, where visual navigation can be challenging. The markers are strategically placed along approach paths to major airports, such as Oslo Gardermoen Airport (ENGM) or Bergen Airport, Flesland (ENBR), to enhance safety and precision during landings.

Avstandsmark systems are distinct from other navigational aids like VOR (VHF Omnidirectional Range) or ILS (Instrument Landing System), which provide directional or glideslope information rather than distance. While modern aviation increasingly relies on GPS and other satellite-based technologies, avstandsmark remains a reliable backup system, particularly in regions where satellite signals may be less reliable or unavailable. The use of avstandsmark reflects Norway’s commitment to maintaining robust and redundant navigational infrastructure for both commercial and general aviation.