What does code 7600 signify?

Code 7600 signifies a loss of communication with the aircraft. When an aircraft transmits this squawk code on their transponder, it alerts air traffic control that there is a communication failure. This situation may arise if the pilot is unable to maintain radio contact due to equipment malfunction, thus informing controllers that they must proceed with alternative methods for the aircraft's navigation and separation, such as visual cues or pre-established protocols for proceeding in an uncontrolled environment.

Understanding the significance of each transponder code is vital for maintaining safety in aviation operations, particularly in emergency situations. The other options relate to normal operations or specific protocols that are not indicated by the use of code 7600.