Which section of aviation regulations outlines the requirements for a static system leakage check?

The section of aviation regulations that outlines the requirements for a static system leakage check is Part 91. This part governs the general operating and flight rules for aircraft, including the maintenance of equipment necessary for the safe operation of the aircraft. Specifically, Part 91.411 requires that the static pressure system, which is crucial for the operation of altimeters and other flight instruments, be tested for leaks according to established standards. This is essential for ensuring that all components function accurately and reliably during flight, thereby maintaining flight safety. Other sections, such as Part 43, do cover maintenance regulations, but they do not specifically address the static system leakage check as defined in Part 91.