What is the correct transponder code to use for a communication failure?

The correct transponder code to use for a communication failure is 7600. When a pilot experiences a loss of communication, they should set their transponder to this code, which alerts air traffic control and other aircraft in the vicinity that the pilot is unable to communicate effectively.

Setting the transponder to 7600 helps in maintaining the safety and situational awareness of all parties involved, allowing ATC to recognize the issue and take appropriate actions, such as providing visual separation from other aircraft or attempting to reestablish contact through other means.

Understanding the significance of transponder codes is crucial for pilots as it directly relates to communication protocols and emergency responses in aviation. In contrast, the other codes refer to different emergencies: 7700 is for general emergencies, while 7500 indicates a hijacking situation. As for 7400, it is not an official code used for communication failures or emergencies, hence it does not apply in this context.