What does the term "ADF" stand for in aviation?

The term "ADF" in aviation stands for Automatic Direction Finder. This is a navigational radio system used to determine the direction of a distant radio beacon, usually associated with NDBs (Non-Directional Beacons). The ADF system receives signals from these beacons, allowing pilots to determine their bearing relative to the station. This information is crucial for accurate navigation, particularly in conditions where visual references are limited, such as in poor weather or at night.

The ADF operates by indicating the direction to the radio beacon on a cockpit instrument, which helps pilots in course corrections and maintaining their desired flight path. Understanding the function and operation of the ADF is essential for pilots using older navigation systems or operating in areas where GPS is not available.