What action is necessary when an operator cannot hear incoming messages properly?

When an operator cannot hear incoming messages properly, the necessary action is to request clarification and repeat back what was heard. This action is essential in ensuring clear communication and understanding. By asking for clarification, the operator acknowledges the potential difficulties in reception and seeks to confirm the intended message, which can help avoid misunderstandings or miscommunications that could affect operations.

Repeating back what was heard also serves as a useful practice in radio communication known as "read-back" or "repeat-back." This technique helps to establish a clear channel of communication and allows the sender to verify that their message was understood correctly, even if there was an issue with clarity. It is an important safety measure, especially in environments where accurate information is crucial.

This approach promotes effective communication without disrupting operations unnecessarily, unlike some of the other options that could lead to different complications or delays.