After a welded repair to a pressurized type turbine engine oil tank, what pressure should the tank be checked to?

The correct choice is that the tank should be checked to at least 5 PSI after a welded repair. This pressure level is generally deemed sufficient for ensuring that there are no leaks present in the tank following repairs. A pressure check at this level can help identify small leaks that might not be apparent under normal operating conditions.

Performing a pressure check at a standardized level such as at least 5 PSI is a common practice in maintenance protocols for fuel tanks and similar components. It's important to ensure the integrity of the tank to prevent any issues that could arise during operation due to leaks, which could lead to inefficient performance or safety hazards.

Checking at a higher pressure, such as 10, 15 PSI, or considering that no pressure check is needed, may either exceed what is necessary for leak detection or ignore vital safety protocols. Therefore, the minimum of 5 PSI strikes a balance between ensuring safety and avoiding unnecessary complications.