What does the GRD button on the CNC do when pressed?

The GRD button on the CNC (Communication Navigation Control) is specifically designed to enhance safety and efficiency during flight operations. When this button is pressed, it immediately replaces the active frequency with the emergency frequency. This function is critical in situations where quick communication is necessary, such as emergencies, enabling pilots to establish immediate contact with air traffic control or distress services without having to manually dial the frequency.

The emergency frequency is universally recognized, allowing pilots to communicate effectively regardless of geographic location or local communication protocols. This rapid access ensures that if a pilot encounters a sudden emergency, they can react quickly to maintain safety and coordinate assistance.

Understanding the purpose of the GRD button helps pilots ensure they are prepared for any unforeseen circumstances that may arise during flight operations.