What procedures do pilots follow if they lose communication with ATC?

Answer: C — Follow lost communication procedures and squawk 7600

When pilots lose communication with Air Traffic Control (ATC), they are trained to follow specific lost communication procedures to ensure their safety and the safety of other aircraft. These procedures include squawking 7600 on their transponder, which indicates a radio communication failure. This alert not only informs ATC of the communication loss but also allows other aircraft in the vicinity to be aware of the situation. Following lost communication procedures typically requires the pilot to maintain the last assigned altitude and heading, or to proceed to a predetermined point — often a fix, airway, or route — as outlined in their flight plan or applicable procedures. These protocols aim to maintain a structured and safe operational environment despite the communication failure, helping to minimize confusion or potential hazards during the flight. The other choices presented do not align with the standard protocols when communication is lost. Returning to the departure airport may not be practical or possible depending on the flight's progress. Squawking 7700 designates an emergency, which is not specifically appropriate unless the communication loss is accompanied by another serious emergency requiring immediate attention. Emergency landing procedures would typically be relevant if there were a specific situation needing such actions rather than a general loss of communication.