What is the primary purpose of squawk code 7500?

Squawk code 7500 is specifically designated to signal a hijacking incident. When an aircraft's crew enters this code into the transponder, it serves as an alert to air traffic control and other aircraft in the vicinity that the aircraft is experiencing a serious threat from unlawful interference. This allows air traffic controllers to take immediate action, such as diverting other aircraft away and coordinating a response with security and law enforcement agencies.

While other squawk codes serve different purposes—such as indicating lost communications or emergencies—7500's distinct function is solely to indicate a hijacking situation, thereby granting it a status of utmost urgency and concern in aviation safety protocols.