Plain English Meaning

A radio beacon that is physically on the airport grounds. Pilots fly toward it using their ADF needle, and passing over it means they are at the airport.

Full Definition

A non-directional beacon (NDB) located on the airport itself, used as the final approach fix for an NDB instrument approach procedure. Because the beacon sits on the airport, station passage over the NDB indicates arrival at or very near the missed approach point.

Context Anchor

Seen on NDB instrument approach procedures when the beacon is located at the destination airport rather than away from it.

Derivation

NDB stands for non-directional beacon. 'Non-directional' means the beacon sends its signal equally in all directions, so the aircraft equipment (the ) is what determines the to it. 'On-airport' simply describes where this particular beacon is sited.