Which squawk code is used to indicate a hijack or unlawful interference?

The squawk code used to indicate a hijack or unlawful interference is 7500. This specific code is recognized internationally by air traffic control and pilots as an alert for situations involving hijacking. When an aircraft transmits this code, it serves as a silent alarm to air traffic controllers, signaling that the flight crew is facing a threat from someone on board. It helps to ensure that appropriate measures can be taken by authorities to respond to the incident without alerting the hijacker that the flight crew has communicated the distress.

In aviation, squawk codes serve different purposes, and understanding their meanings is crucial for maintaining safety in the skies. 7600 indicates a radio failure, alerting air traffic control that the aircraft cannot communicate, while 7700 signifies a general emergency but does not specify the nature of that emergency. 7400 is not a standard code and is generally not recognized in the context of aviation emergencies. Each code serves a distinct purpose within the framework of air traffic management, making it essential to know which code corresponds to which situation.