When should a message be transmitted immediately after a call up?

Transmitting a short message immediately after a call-up is essential for maintaining efficient communication and ensuring clarity in air traffic management. When the message is concise, it allows for quick transmission and comprehension by both the air traffic controller and the pilot. This minimizes the time that the aircraft spends on frequency, which is crucial in busy airspace to reduce congestion and enhance safety.

A long message requiring writing would not be ideal for immediate transmission, as it would take up more time and require careful note-taking, potentially delaying other communications. Complex messages that need clarification would necessitate further discussion, making immediate transmission impractical. Furthermore, if the communication pertains to a different aircraft, it should not follow the initial call-up, as it would confuse the intended recipient and disrupt the communication flow. Hence, the nature of the message being short justifies immediate transmission after a call-up for efficient and clear communication.