How does ATC primarily communicate with aircraft?

Air Traffic Control (ATC) primarily communicates with aircraft using radio telephony, which utilizes voice communication over specific radio frequencies. This method allows for direct, real-time communication between pilots and air traffic controllers, facilitating clear instructions regarding altitude changes, flight paths, and other critical operational information.

Radio telephony is well-established and preferred due to its immediacy, ability to convey tone and urgency, and the ability for both parties to engage in a dialogue. Pilots and controllers rely on this instant exchange, particularly in busy airspace or during time-sensitive situations, where clarity is paramount.

Other communication methods mentioned, such as visual signals, might be used under specific circumstances but are not the primary means of communication, especially at high altitudes or in low-visibility conditions. Text messaging or data link communication may complement radio calls in certain advanced systems, but they do not replace the necessity for direct voice communication in the majority of situations. Satellite communication can enhance global communications, particularly in remote areas, but it generally supplements rather than substitutes for the immediate and robust communication achieved through radio telephony.