If you encounter unlawful interference and are unable to communicate, what should you do?

In situations of unlawful interference where communication with air traffic control is compromised, it is crucial to adopt measures that can help ensure safety and maintain situational awareness. Changing altitude is a recognized procedure that can assist in avoiding potential conflicts and signaling for assistance without direct communication.

By choosing to change your altitude by 500 feet below FL290, you are moving lower than the standard flight levels others may be using, which could facilitate more effective navigation and reduce the risk of encountering other aircraft. This maneuver not only provides a buffer in height but also can alert any nearby aircraft or air traffic services that might be observing your flight path.

Opting for different altitudes such as ascending to higher levels or making larger altitude changes may not be as effective in certain situations, especially if those actions lead to potential congestion at higher altitudes or if there are no advantages to a higher altitude in this specific scenario. Changing your flight path could also create complications or confusion without adequate communication, making it less favorable when immediate evasive action is needed.

Thus, the recommended action to change altitude by 500 feet below FL290 is a method grounded in safety protocols, designed to provide an appropriate response while considering the operational environment.