Which type of emergency should be declared by facility personnel?

Declaring an emergency is crucial in aviation to ensure the safety of all involved, particularly when immediate action is required. The scenario involving an unexpected loss of radar and radio contact with an aircraft is critical because it indicates a severe communication failure that can jeopardize the safety of the aircraft and its occupants. In such situations, controllers must act quickly to attempt to regain contact, provide assistance, or guide the aircraft to safety, making it imperative to declare an emergency.

In contrast, while bad weather can certainly impact operations and calls for caution, it may not always necessitate an emergency declaration unless it poses an imminent threat. Similarly, an aircraft running low on fuel is indeed a serious concern, but it may not warrant an emergency status unless the situation escalates or if the flight crew expressly indicates that they require immediate assistance. Mechanical issues can also pose safety risks, yet the level of urgency can vary depending on the nature of the issue and the pilot's assessment. Thus, the loss of contact stands out as an immediate signal for emergency response protocols, requiring personnel to react decisively to ensure the aircraft's safety.