What is the squawk code used for loss of communication?

The squawk code used for loss of communication is 7600. This code is specifically designated to indicate that the aircraft is experiencing radio communication failure or has lost the ability to communicate with air traffic control. When a pilot sets this squawk code into the transponder, it alerts air traffic control that the aircraft’s communication systems are not functioning properly. This allows air traffic controllers to take appropriate measures, including monitoring the aircraft's actions as it may not be able to receive instructions, thereby ensuring safety in the airspace.

The other squawk codes serve different purposes: 7500 signifies a hijacking situation, 7700 indicates an emergency that may be related to flight safety but is not limited to communication issues, and 7501 is not a standard squawk code recognized in air traffic communication procedures. Understanding these codes is crucial for aviation safety and effective communication during flight operations.