What percentage of the takeoff fuel consumption of the engine must the fuel flow rate for gravity systems be according to Federal Aviation Regulations?

The correct answer is that the fuel flow rate for gravity systems must be 150 percent of the takeoff fuel consumption of the engine according to Federal Aviation Regulations. This requirement ensures that the aircraft has an adequate fuel supply to maintain engine operation during critical phases of flight, such as takeoff.

The regulation stipulates this percentage to provide a safety margin, taking into account potential variations in fuel flow due to factors like temperature changes, fuel density, and system reliability. By demanding a fuel flow that exceeds the standard consumption rate during takeoff, it helps to ensure that the engine can operate efficiently and safely without risk of fuel starvation.

This regulatory framework supports operational safety and pump performance, particularly in gravity-fed systems that may not provide the same pressure or flow characteristics as fuel injectors or pumps. The higher flow requirement serves as a precautionary measure that enhances the overall reliability of the aircraft's fuel system during critical operations.