If you lose contact with Air Traffic Control, what is the appropriate squawk code to use?

When a drone or aircraft loses communication with Air Traffic Control, the appropriate squawk code to use is 7600. This specific code is designated for communication failure, allowing other aircraft and Air Traffic Control to recognize that you are unable to make contact. Using this squawk code alerts regional traffic management systems and nearby aircraft to be aware that you may not be receiving instructions, which is crucial for maintaining safety in the airspace.

Understanding the functions of other squawk codes further clarifies why 7600 is the correct choice. A code of 7700 indicates an emergency situation requiring immediate assistance, while 7500 signifies that an aircraft is being hijacked or experiencing unlawful interference. Lastly, 1200 is used for VFR (Visual Flight Rules) operations, signifying that the aircraft is not under instrument navigation and communicating normally. Hence, upon losing communication with ATC, squawking 7600 is the appropriate action to take.