Final answer:
The PIC must report any change in PIC status promptly, usually immediately, according to specific regulatory or carrier requirements, to maintain safety and compliance with aviation regulations.
Step-by-step explanation:
The term PIC stands for Pilot in Command, which is widely used in aviation. The timeframe within which a PIC must report that he or she will no longer act as PIC can vary by regulation and the operating authority. However, for most civil aviation authorities, like the Federal Aviation Administration (FAA), there is an expectation that such a change in flight status should be reported as promptly as possible, often immediately or according to specific regulatory or operational requirements set forth by the operating carrier or authority. The timeliness of this reporting is crucial for maintaining safety, accountability, and compliance with aviation regulations.