According to scheduled service regulations, what rest is needed if a scheduled flight is between 8 and 9 hours?

For scheduled service regulations, the requirement for rest periods is established to ensure that flight crews are adequately rested to operate safely. When a scheduled flight lasts between 8 and 9 hours, the regulations specify that the flight crew must have a minimum of 10 hours of rest before their next duty period. This ensures that pilots and crew can maintain a high level of performance and alertness, which is essential for managing the complexities of flight operations.

This requirement is part of broader regulations set forth by aviation authorities that focus on fatigue management within flight operations. Adequate rest is critical in preserving safety, as fatigue can significantly impair a pilot's ability to perform essential tasks.

In contrast, other rest durations specified in the options either do not meet the minimum required for flights of that length or provide unnecessary flexibility that does not align with established safety standards. Therefore, understanding the framework of regulations around crew rest helps ensure compliance and safety in Part 135 operations.