What action should a pilot take if they feel they are not fit for duty?

When a pilot feels they are not fit for duty, the correct course of action is to notify their supervisor and follow the established fitness for duty processes. This response is vital for maintaining safety, not just for the pilot, but for the entire crew and passengers. Reporting unfitness ensures that the situation is managed correctly, adhering to company policies and regulations. It indicates that the pilot is prioritizing safety and accountability over personal or professional concerns, which is a critical aspect of aviation operations.

Taking this action helps ensure that there is a proper assessment of the pilot's condition, and if necessary, an appropriate replacement can be arranged. Additionally, following the prescribed processes provides a structured approach to handling such situations, ultimately working towards a safer operational environment.

The other options do not embody the safety culture that is imperative in aviation. Ignoring feelings of unfitness can lead to serious safety hazards, and simply seeking help from a co-pilot or delegating duties without formal notice does not address the root issue of fitness for duty.