What does transponder code 7500 indicate?

• A. Emergency.
• B. Ground equipment malfunction.
• C. Hijacking or unlawful interference.
• D. Radar contact loss.

Answer: (C)

Transponder squawk codes are a quick, standardized way for pilots to signal a situation to air traffic control by selecting a four-digit octal code on the aircraft’s transponder. The code 7500 is the hijack/unlawful interference signal, so when a flight crew sets it, ATC treats it as a potential hijack and will initiate security procedures, prioritize that flight, and coordinate with ground authorities to manage the situation and guide a safe landing. This code is distinct from others that indicate different problems, such as 7600 for loss of radio communications and 7700 for a general emergency.