In what situation might a "mayday" call be made?

A "mayday" call is specifically used in situations where there is an immediate threat to life or the vessel itself. This distress signal alerts rescue services that someone is in a critical situation requiring urgent assistance. In the case of a capsized vessel, lives are often at risk, and prompt help is necessary to rescue those in peril.

A call for help regarding fuel needs or navigational aid changes does not convey the same level of emergency. These situations, while potentially problematic for the vessel's operation, do not pose an immediate danger to life and therefore would not warrant a "mayday" call. Similarly, drifting can be concerning, but unless it leads to an emergency situation, it does not require the urgency of a distress signal like a "mayday." In contrast, the capsizing of a vessel constitutes a clear emergency, which is why this option is the appropriate context for making such a call.