What percentage of flight time is reserve fuel according to regulations, up to 45 minutes?

The correct percentage of flight time for reserve fuel, according to regulations, is 10% when considering the maximum limit of 45 minutes. This regulation is designed to ensure that aircraft have sufficient fuel reserves to account for unforeseen circumstances such as weather changes, diversions, or delays. When calculating flight fuel requirements, airlines and pilots must include this reserve, which serves as a safety measure.

To break this down further, the 10% reserve fuel is calculated based on the total flight time, which allows for a safe buffer in case the aircraft experiences unexpected issues while in flight. This regulation is crucial for ensuring the safety of passengers, crew, and the aircraft itself.

In this context, while the other percentages may seem plausible at first, they do not align with the established safety standards as set forth by aviation regulations. Therefore, the correct answer being 10% highlights the emphasis on flight safety through adequate preparation and contingency planning.