What should you do if an assigned beacon code disappears?

In the scenario where an assigned beacon code disappears, notifying your supervisor is essential due to the potential implications on the safety and coordination of air traffic. The disappearance of a beacon code could indicate that the aircraft is experiencing technical difficulties, experiencing communication issues, or possibly has entered a situation that requires immediate attention. By informing your supervisor, you are ensuring that the appropriate steps are taken to assess the situation and provide any necessary assistance or direction.

Taking action like attempting to re-establish contact may be appropriate, but it's vital to first inform your supervisor so that they can guide the response according to the operational protocols in place. Changing the code or continuing operations as normal could lead to further complications, especially in maintaining situational awareness and ensuring the safety of all aircraft in the vicinity. Therefore, notifying your supervisor is the most prudent action to take in this circumstance.