Definition
An instrument approach procedure that uses a Non-Directional Beacon (NDB) as the primary navigation aid for guiding the aircraft to the runway environment. The pilot tracks bearings to or from the NDB station using an Automatic Direction Finder (ADF) receiver in the aircraft, following published courses, altitudes, and minimums on the approach chart until reaching the missed approach point or visual contact with the runway.
Plain English
A way of flying down to a runway in cloud or low visibility by using a simple ground radio beacon. The aircraft has an instrument that always points toward the beacon, and the pilot uses that pointer to fly the published path down to the airport.
Context Anchor
Seen on instrument approach charts and used during instrument flying when an airport has an NDB-based approach procedure.
Derivation
NDB stands for Non-Directional Beacon — "non-directional" because the beacon transmits its signal equally in all directions, leaving it to the aircraft's receiver to determine the direction back to the station. "Approach" refers to the published instrument procedure flown to reach the runway.
Why Pilots Care
Gives pilots a reliable backup navigation method for landing safely in poor weather when more modern systems are unavailable.
Grounding Statement
Picture the beacon as a radio point on the ground: the airplane can tell where that point is, but the pilot still has to fly the correct path and descent.
Intuition Check
An NDB approach is not an automatic path to the runway. It gives direction information from a beacon, not a built-in glidepath or hands-off guidance.
Example Sentence 1
With the ILS out of service, the crew briefed and flew the NDB approach to runway 27.
Example Sentence 2
During training the instructor had the student track the NDB signals to complete the full approach to the runway.