This specification covers the procedure for ultrasonic inspection of flat, contoured, and cylindrical products having a cross sectional-thickness of 0.02 to 0.5 inches (0.5 to 12.7 mm). This specification does not apply to inspection of composite materials.This process has been used typically for locating and defining internal defects such as cracks, voids, laminations, and other structural discontinuities which may or may not be exposed to the surface, but usage is not limited to such applications.