What Is Squawk? Definition & Meaning in Aviation
A squawk is a four-digit code that an aircraft’s transponder sends so air traffic control can identify it on radar.
In plain language
Controllers assign a code to each flight. Three codes are reserved for emergencies: 7500 (hijacking), 7600 (radio failure) and 7700 (general emergency).
Example
If a flight on the map suddenly shows squawk 7700, the crew is declaring an emergency.
Why it matters
Squawk codes let controllers identify aircraft on radar and signal emergencies. Public trackers display them, but a code alone should never be taken as proof of what is happening on board.