If you hear another airplane declare an emergency, what should you do?

When you hear another airplane declare an emergency, silencing your communication is the correct action to take in this situation. This allows the flight crew experiencing the emergency to communicate with air traffic control (ATC) without any interruptions or interference, which is crucial for their safety and the effective management of the situation.

The priority in an emergency is to ensure that the impacted aircraft can provide and receive information needed for their situation. By remaining silent, you demonstrate good airmanship and support the systemic approach to handling emergencies in aviation. Air traffic control typically will direct other aircraft to maintain silence if they are aware of an emergency unfolding.

In this case, continuing with your flight plan or switching frequencies would not be appropriate since that could further complicate communications or impede the emergency aircraft's process. Reporting the emergency to ATC might seem beneficial, but it could lead to additional radio traffic at an already critical moment. Maintaining silence is the most effective action you can take to aid in the emergency response process.