What transponder code indicates a general emergency?

The transponder code that indicates a general emergency is 7700. This code is recognized internationally and serves as a signal to air traffic control and other aircraft that the aircraft is experiencing an urgent situation requiring immediate assistance.

Using 7700 allows pilots to communicate their status quickly and without needing verbal communication, which could be crucial if the aircraft is unable to maintain normal radio procedures. When this code is activated, it draws attention from both air traffic controllers and nearby aircraft, indicating that the pilot may need priority handling or assistance due to emergencies such as mechanical failure, medical emergencies on board, or any situation that compromises safety.

In contrast, the other codes serve different purposes: 7500 indicates a hijacking or unlawful interference, while 7600 signals a radio communications failure. The 7800 code is not typically in use and does not correspond to any standard emergency situation.