Definition
The four-digit transponder code (7700) used to indicate a general in-flight emergency. When set on the aircraft transponder, it causes the aircraft's radar return to be highlighted on air traffic control displays, alerting controllers immediately that the flight is in distress.
Plain English
A special number you put into your transponder to tell air traffic control you have an emergency. As soon as you select it, your aircraft stands out on their radar screens and they know something is seriously wrong.
Context Anchor
Seen in transponder use, emergency procedures, and cockpit discussions of how an aircraft identifies itself to air traffic control during an emergency.
Why Pilots Care
It triggers priority routing, airspace clearance, and rapid assistance from controllers and emergency services.
Intuition Check
Code 7700 does not tell controllers what kind of emergency you have. It tells them that there is an emergency and that the flight needs urgent attention.
Example Sentence 1
After losing engine power, the pilot squawked Code 7700 and began looking for a place to land.
Example Sentence 2
ATC spotted Code 7700 on the scope and began vectoring the aircraft toward the nearest suitable airport.