RAF Avro Lancaster Bombers used in WW2 Photographer - Richard R Schunemann It was the Second World War, and British Royal Air Force (RAF) , raided Germany and bombed their cities. German defences were strong. German fighter planes and anti-aircraft gunners shot down British bomber planes. The Royal Air Force wanted to save their planes and pilots. Adding armour plates to the planes can protect. But too much armour adds to the weight and affects the range, speed and air time of fighter planes. RAF analysed fighter planes that returned from their missions for bullet holes. They found that wings, nose and couple other areas took the most hit. But cockpit, engine and tails were less damaged. They decided to fix armour plates to protect damaged areas of the plane. But Abraham Wald, a Hungary Mathematician suggested the opposite. His suggestion shocked everyone. But Wald reasoned, RAF was analysing planes that survived the mission. Yes, these planes took hits. But they were still able to