Definition
A radio phraseology used by air traffic control to instruct a pilot what action to take if no further transmission is received from ATC within a specified time period. It is most commonly used during radar vectors, approaches, or holding instructions, where loss of communication could otherwise leave the pilot without clear guidance on what to do next.
Plain English
ATC is telling you: 'If you don't hear from me again within this many minutes, do this.' It's a backup instruction in case the radio link breaks down.
Context Anchor
Heard in controller instructions, especially when the pilot is receiving close radio guidance, such as during an approach guided by controller instructions.
Derivation
Transmission comes from a Latin word meaning to send across. In aviation radio use, it means a spoken message sent across the radio from one station to another.
Why Pilots Care
It tells a pilot exactly when to stop waiting and begin the published lost-comm route, altitude, and transponder actions that keep the flight safe and predictable for controllers.
Grounding Statement
If the stated time passes and no controller voice is heard, the silence itself becomes the signal to act.
Intuition Check
Do not treat this as a casual estimate of when the controller might call again. In this phrase, the time is an action trigger tied to radio silence.
Example Sentence 1
ATC: 'Cessna Three-Four-Tango, fly heading two-seven-zero, vectors for the ILS; if no transmission received for one minute in the turn, contact approach on one-two-four-point-seven.'
Example Sentence 2
The controller noted the TIME — IF No Transmission Received for had passed and began issuing traffic advisories to other aircraft in the area.