Final answer:
Mode 3 code 7600 indicates a loss of radio communications in aviation.
Step-by-step explanation:
In aviation, Mode 3 code 7600 indicates a loss of radio communications. This code is used when a pilot is unable to communicate with air traffic control due to radio equipment failure or any other reason. It alerts the air traffic control to the situation, and they can take appropriate measures to ensure the safety of the aircraft.