The 2D approach draws from the steps of 4D per Figurewith the steps being D2 (Define Problem) and D6 (Solve Problem) AS Problem Solving Requirements for SuppliersSAE International. AS Supplier Self Release. See more AS Problem Solving Requirements for Suppliers. In cases where high process capability is present, best practice is to check measurement capability against the “% of process variation” rather than the “% of total tolerance” seen in AS MSA Acceptance Limits Description. This course is