Which of the following incidents with a turbine aircraft requires immediate NTSB notification?

The requirement for immediate notification to the National Transportation Safety Board (NTSB) in the context of turbine aircraft incidents primarily focuses on occurrences that potentially affect the safety of flight and may require investigation.

In the case of a compressor blade failure that penetrates the cowling, this is significant because it indicates a potential failure of a critical engine component. Such an incident can lead to more serious consequences, including a loss of engine power or control. Therefore, the NTSB needs to be notified immediately to assess the implications for airworthiness and to prevent similar incidents from occurring in other aircraft.

While the other scenarios, like fuel leakage, engine failure, and minor damage to the fuselage, may also raise safety concerns, they generally do not trigger the same immediate NTSB reporting requirements unless they result in major accidents or injuries. Thus, the compressor blade failure represents a distinct and serious hazard that warrants prompt reporting for further investigation and regulatory action.