What is the transponder code used to indicate a total communication failure in flight?

The transponder code used to indicate a total communication failure in flight is 7600. This code alerts air traffic control that the pilot is unable to communicate verbally, which is crucial for maintaining safety and situational awareness. When a pilot sets their transponder to 7600, it signals to air traffic controllers that they should expect no radio communications from the aircraft. This prompts controllers to take appropriate measures, such as providing visual separation and monitoring the aircraft closely, to ensure the safety of the flight and surrounding air traffic.

In the context of transponder codes, 7700 indicates an emergency situation that requires immediate assistance, while 7500 is specifically for a hijacking event. The code 0000 does not correspond to any specific situation and is generally not used in flight operations. Understanding these codes and their meanings is essential for pilots to effectively communicate their status during various in-flight emergencies.