Plain English Meaning

The controller is telling you to set 7700 on your transponder so that everyone on radar instantly sees you have an emergency.

Full Definition

An ATC instruction directing the pilot to set the transponder to code 7700, the universal emergency code, which alerts every air traffic control facility receiving the signal that the aircraft is in distress.

Context Anchor

Seen in transponder and ATC phraseology, especially during emergency communications or radar services.

Derivation

‘Squawk’ comes from World War II IFF (Identification Friend or Foe) systems nicknamed ‘Parrot,’ so transmitting a code became ‘squawking.’ ‘Mayday’ comes from the French ‘m’aidez’ meaning ‘help me,’ adopted internationally as the spoken distress call. Combined, the phrase means ‘send the distress signal.’