Definition
An ATC instruction directing a pilot to switch off a specified transponder mode or to stop transmitting a specified transponder code. The pilot turns off the named function (for example, Mode C altitude reporting) or discontinues use of the named code, while leaving the rest of the transponder operating normally.
Plain English
Controller is telling you to turn off a particular transponder feature or stop using a particular code. You don't switch the whole transponder off — just the part they named.
Context Anchor
Heard on the radio when a controller wants a selected transponder code or transponder function turned off.
Derivation
Squawk' comes from the World War II IFF system codename 'Parrot,' so transmitting a transponder signal became 'squawking.' 'Stop squawk' simply means stop that particular squawk.
Why Pilots Care
Prevents radar clutter, code conflicts, and unnecessary altitude reporting in terminal areas or after landing.
Intuition Check
“Stop squawk” does not mean stop talking on the radio. It means stop transmitting the specified transponder mode or code.
Example Sentence 1
Tower advised, 'Stop squawk Mode C,' so the pilot switched the transponder from ALT to ON, leaving the code transmitting without altitude.
Example Sentence 2
The tower instructed the arriving aircraft, 'Stop squawk 1200 used, squawk standby.'