How soon must notification be made to the NTSB after an aircraft experiences substantial damage?

When an aircraft experiences substantial damage, it is crucial to notify the National Transportation Safety Board (NTSB) immediately. This requirement is grounded in the NTSB's role in ensuring the safety and oversight of aviation operations. Immediate notification allows the NTSB to effectively respond to incidents, gather crucial data, and investigate potential safety issues that could affect future operations. By facilitating quick reporting, the system helps to identify and address hazards promptly, thus enhancing overall aviation safety. This requirement emphasizes the urgency and importance of timely communication in the realm of aviation incidents.