Which incident requires immediate notification to the NTSB?

Immediate notification to the National Transportation Safety Board (NTSB) is required for certain incidents that may indicate a significant safety concern or potential for an accident. In this case, a flight control system malfunction is a critical safety issue that directly affects the ability to control the aircraft. Since flight control systems are essential for safe operation, any malfunction that impacts their functionality poses an immediate threat to the aircraft's safe operation and requires prompt reporting to the NTSB.

This requirement is governed by NTSB regulations, ensuring that any serious threats to aviation safety are investigated thoroughly. Incidents such as fuel leaks, cabin fires, and engine failures are also serious but may not automatically invoke the same immediate notification requirement unless they compromise the aircraft's flight safety or lead to an incident that involves serious injury, substantial damage, or an investigation-worthy situation. In the case of a flight control system malfunction, the potential immediacy of the danger necessitates immediate action and reporting.