Non-Directional Beacon (NDB)

An Non-Directional Beacon is a radiotransmitter located at a known place, used as an aid for aerial or maritime navigation in the manner of a radio beacon.

NDBs consist of two parts: the Automatic Direction Finder (ADF) equipment that is in the aircraft which detects the signal from an NDB, and the transmitting NDB.

They have continued to provide a fundamental and reliable means for aircraft navigation despite the arrival of GNSS and modern ground-based systems. Nevertheless, there are still operational equipment that require inspection.