What is the highest priority in ATC Interphone priorities?

In air traffic control (ATC), the highest priority is given to distress messages, which include Emergency Security Control of Air Traffic (ESCAT). Distress messages are critical communications indicating an emergency situation where a pilot or aircraft is in grave danger. In these circumstances, the need for immediate assistance and response is paramount, overshadowing other types of messages.

When a distress message is communicated, controllers prioritize these communications to ensure that the affected aircraft receives timely assistance and that decisions can be made to safeguard lives. This priority is in place because the primary goal of ATC is the safety of aircraft operators, passengers, and crew, which supersedes all other communication priorities.

Other types of messages, such as urgency messages, IFR movement messages, and approval requests, have significant importance, but they do not match the critical nature of distress messages. Urgency messages, for example, indicate a situation that requires attention but is less severe than a distress situation. Similarly, IFR movement messages and approval requests are concerned with operational efficiency and management, which are essential but secondary to ensuring safety during life-threatening situations.