FAA AMT (Aviation Maintenance Technician) Airframe Practice Exam

Which of the following would be most useful to locate and troubleshoot an internal fuel leak in an aircraft fuel system?

1. A fuel system schematic

2. An external fuel leak detector

3. A pressure gauge

4. A fuel quality tester

The correct answer is: A fuel system schematic

A fuel system schematic would be the most useful in locating and troubleshooting an internal fuel leak in an aircraft fuel system. By referring to a fuel system schematic, maintenance technicians can trace the path of the fuel from the tank through the system, helping them identify potential areas where a leak may be occurring. This schematic provides a detailed diagram of the fuel system layout, including all components and connections, which is essential for pinpointing the source of the leak. Option B, an external fuel leak detector, would not be as useful for locating an internal fuel leak since it is designed to detect leaks on the outside of the aircraft. Option C, a pressure gauge, could be helpful in diagnosing certain fuel system issues, but it might not necessarily pinpoint the location of an internal fuel leak. Option D, a fuel quality tester, is used to assess the quality of the fuel rather than locating a leak within the system.