Quantitative Fractography (QF) is a technique used to analyse fatigue failures by measuring specific features on the crack surface of structures or components. These features correlate directly with the load history experienced during flight or fatigue testing. Changes in the fatigue loading, such as variations in stress ratio, leave visible markings on the fracture surface. Measuring the spacing of these marks produces a crack growth (CG) curve. By applying marker loads after each cycle block, distinct marker bands appear, aiding analysis. QF helps determine crack growth rate, crack initiation (CI) life, and supports failure analysis. It also provides data to predict aircraft structure life, set non-destructive testing (NDT) intervals, and compare analytical predictions with experimental CG curves.