What should be communicated in a pan-pan message?

A pan-pan message is used to communicate a situation that is urgent but does not pose an immediate threat to life. It serves as a formal communication indicating that assistance may be required, but there's no immediate danger, thus allowing other vessels and authorities to prepare for the situation without the need for immediate action.

In maritime communications, the pan-pan signal is a standardized distress signal that conveys urgency, distinguishing it from mayday messages which are reserved for life-threatening emergencies. By using pan-pan, operators can effectively alert others about their situation, ensuring that responders prioritize resources appropriately.

The other options include scenarios that typically require more immediate action or are categorized under different communication signals. For instance, a notification of a fire on board or an emergency medical situation generally falls under the mayday category, signaling an immediate threat to life or safety. A planned route change does not indicate any urgency or danger and would usually be communicated through standard navigational channels rather than a distress message.