Definition
An ATC instruction directing the pilot to switch the aircraft radio from the current controller's frequency to a different one, typically when transitioning between controllers, sectors, or facilities. The pilot is expected to tune the new frequency promptly and establish radio contact with the next controller.
Plain English
ATC is telling you to stop talking to them on this radio channel and start talking to the next controller on a different channel.
Context Anchor
You will hear this during radio work, especially when air traffic control passes you from one controller to another during departure, en route flight, or approach.
Derivation
Frequency comes from an older word meaning how often something happens. In radio, it means how often a radio signal repeats each second; in pilot use, that specific frequency acts like a communication channel.
Why Pilots Care
Keeps the pilot in continuous contact with the correct controller for clearances and traffic information.
Intuition Check
Do not read this as changing all radio settings or leaving communication entirely. In aviation radio use, it means tuning the communication radio to the next assigned channel and continuing to listen and talk there.
Example Sentence 1
After the handoff, Center instructed us to change frequencies to Approach on 124.35.
Example Sentence 2
The crew changed frequencies as instructed before contacting the next sector.