Which squawk code is used for reporting unlawful interference (hijacking)?

The squawk code used for reporting unlawful interference, such as a hijacking, is 7500. This specific code is designated for situations involving unlawful control of an aircraft, enabling air traffic control (ATC) to prioritize and respond appropriately when a flight may be in distress due to such interference.

When a pilot sets the transponder to squawk 7500, it alerts ATC without raising alarm among any potential hijackers who may be on board. This is vital for maintaining the pilot's safety while also signaling to ATC that immediate and specific measures may need to be taken, such as alerting law enforcement or rerouting responding aircraft.

In contrast, the other squawk codes serve different purposes: 7600 indicates a radio communication failure, which is important for notifying ATC that the aircraft cannot communicate; 7700 is the emergency code, used for any general in-flight emergency or distress situation; and 1234 is simply a random code that does not signify any specific issue. Understanding these distinctions is crucial for both pilots and air traffic controllers to ensure effective communication and safety in the airspace.