FAA AMT (Aviation Maintenance Technician) Airframe Practice Exam

How should the lines and fittings be tested if an aircraft's oxygen system has developed a leak?

1. Pressure tested with compressed air

2. Bubble tested with a special soap solution manufactured specifically for this purpose

3. Inspected visually for discoloration

4. Checked with a UV light for signs of leakage

The correct answer is: Bubble tested with a special soap solution manufactured specifically for this purpose

When an aircraft's oxygen system has developed a leak, the lines and fittings should be bubble tested with a special soap solution manufactured specifically for this purpose. Bubble testing involves applying the soapy solution to the areas where a leak is suspected while the system is pressurized. If there is a leak, the escaping gas will cause bubbles to form at the leaking spot, making it easy to identify and locate the leakage. This method is preferred as it is a safe and effective way to visually detect leaks in the oxygen system, ensuring the aircraft's safety and proper functioning. The other options are not as suitable for testing an aircraft's oxygen system for leaks. Pressure testing with compressed air can be dangerous for oxygen systems as it can introduce contaminants or cause damage if not done correctly. Inspecting visually for discoloration or using a UV light may not be effective in detecting small leaks that could compromise the integrity of the system. Therefore, bubble testing with a special soap solution is the most appropriate method in this scenario.