Definition
A radio frequency designated for two-way voice communication between an aircraft in flight and a ground station, such as an air traffic control facility or a Flight Service Station.
Plain English
A radio channel used so a pilot in the air can talk to someone on the ground.
Context Anchor
Seen when cancelling an instrument flight plan by radio, especially after landing at an airport without a control tower.
Derivation
Frequency comes from a Latin word meaning repeated or occurring often. In radio use, it came to mean the rate of a radio wave, which is what separates one radio channel from another.
Why Pilots Care
Enables pilots to cancel IFR clearances without landing or diverting to a phone, keeping the flight legal and efficient.
Intuition Check
Frequency here does not mean how often something happens. It means the specific radio channel used for communication between the aircraft and a ground station.
Example Sentence 1
After landing at the uncontrolled field, the pilot used the published air-to-ground frequency to cancel the IFR flight plan with Flight Service.
Example Sentence 2
ATC assigned a specific air-to-ground frequency for the pilot to report cancellation once clear of clouds.