Definition
Ground-based radio facilities equipped to determine the bearing of an aircraft's radio transmission relative to the station. By having the pilot transmit on a specified frequency, the station measures the direction the signal is coming from and can provide that bearing to the pilot or to air traffic control, who can then guide the aircraft toward the station or toward an airport.
Plain English
Stations on the ground that can tell which direction your radio call is coming from. When you talk on the radio, they figure out where you are in relation to them, and they can use that information to help guide you home.
Context Anchor
Seen in emergency procedures when a pilot is lost, disoriented, or asking for help over the radio.
Why Pilots Care
Gives a pilot a usable heading to a safe facility when other navigation is unavailable.
Intuition Check
Do not read this as any station that gives directions. In this context, it means a ground radio facility that finds the direction of an aircraft's transmitted signal.
Example Sentence 1
When the pilot became disoriented in deteriorating weather, the controller used direction finding stations to determine her position and vector her toward the nearest airport.
Example Sentence 2
ATC used direction finding stations to locate the aircraft transmitting on the emergency frequency.