Flak as a last defensive layer

Second World War air defence aimed to destroy aircraft before they released their weapons. Modern defenders may instead have to hit the missile itself, which brings gun systems such as Phalanx back into the engagement. Air-bursting 40 mm or 57 mm rounds can fill a larger volume with fragments than 20 mm fire, so a near miss may damage a missile's sensors, control surfaces, or engine. The Type 31 is proposed as a task-group point-defence escort whose guns could shield a carrier or another high-value unit. Dense fire cannot guarantee a kill, but it creates more chances to damage an incoming weapon.