A special VHF/HF communications system for calling a single, specific air carrier aircraft is known as what?

The special VHF/HF communications system for calling a single, specific air carrier aircraft is known as SELCAL. This is an acronym for Selective Calling, which is a system that allows air traffic controllers and ground stations to contact individual aircraft selectively rather than broadcasting messages to all planes in the vicinity.

SELCAL works by assigning a unique code to each aircraft, which consists of four tones transmitted over radio frequencies. When this specific code is sent out, only the aircraft with the corresponding SELCAL code will receive the signal and alarm, indicating that there is a message waiting for it. This system significantly enhances the efficiency of communication, especially in busy air traffic environments, as it minimizes unnecessary radio chatter and allows flight crews to remain focused on other critical tasks.

Understanding SELCAL is crucial in regard to how communications are managed in aviation, as well as the benefits it brings in terms of operational efficiency and safety in communication protocols with air traffic control and other ground stations.