Which squawk code indicates a radio failure?

The squawk code that indicates a radio failure is 7600. When a pilot encounters a situation where they lose radio communication capabilities, they are required to set their transponder to this code. This alerts air traffic control and other aircraft that the pilot is experiencing difficulties with radio communications, allowing them to take appropriate action.

Using 7600 helps maintain situational awareness among all aircraft in the area, as air traffic controllers will understand the pilot's inability to communicate via radio and will provide necessary instructions or visual aids to guide the pilot safely.

The other squawk codes have specific meanings: 7700 indicates an emergency situation, 1200 is used for VFR (Visual Flight Rules) operations, and 7500 is associated with unlawful interference, like hijacking. Understanding these codes is crucial for effective communication and safety in aviation.