Definition
An electronic circuit in a radio receiver or transmitter that automatically detects small drifts away from the selected operating frequency and corrects them, holding the equipment locked on the intended frequency.
Plain English
A built-in feature that keeps a radio tuned to the right frequency on its own, instead of the pilot having to retune it as the equipment warms up or drifts.
Context Anchor
Seen in aircraft radio, navigation receiver, and avionics equipment descriptions.
Derivation
Automatic means it works without the user doing anything. Frequency refers to the radio channel the equipment is set to. Control means the circuit actively adjusts to keep that frequency steady. Together: the circuit automatically controls the frequency.
Why Pilots Care
Maintains clear reception on comm and nav radios without constant retuning, reducing workload and preventing signal loss.
Analogy
It is like a person gently turning a radio knob to keep a station clear, except the equipment makes those tiny corrections by itself.
Intuition Check
Automatic Frequency Control does not choose the correct frequency for the pilot. It only helps hold the receiver on the signal after the equipment is already tuned close enough.
Example Sentence 1
The receiver's automatic frequency control kept the navigation signal locked in clearly even after the avionics had been running for an hour.
Example Sentence 2
Early ADF units used automatic frequency control to keep the needle locked on the beacon despite minor oscillator drift.