According to NTSB Part 830, which of the following incidents requires immediate notification?

Immediate notification is crucial in aviation safety, particularly when a flight crewmember is unable to perform their duties due to illness. When a crew member experiences an incapacitating condition, it poses an immediate risk not only to the safety of the flight but also potentially affects the ability of the remaining crew to manage aircraft operations effectively. This situation demands prompt attention to ensure that the safety of all on board is maintained and that alternative arrangements, such as a replacement crewmember or an emergency landing, can be coordinated if necessary.

The requirement for immediate notification underscores the seriousness of maintaining a fully functional and health-compliant team in operations. This dictates swift action to mitigate the potential risks associated with impaired flight crew capabilities. In contrast, other incidents, while potentially serious, may not necessitate as urgent a response or may fall under different reporting criteria as set forth by the NTSB.