Yellow circle on seat kept crew breathing easy

Some have joked that the yellow circle on the pilot’s seat of the Avro Lancaster gave German pilots something to aim for — seemingly very sporting of the English, but not true. The paint had a practical purpose. The odd-colored orb contained pigment sensitive to poison gas. When a crewman saw a shade other than bright yellow, there was big trouble. And this warning was not only for gas that might potentially be used by the Germans. The UK was fully prepared to employ its own stockpiles of poison should Hitler have chosen to go down that dark path. Planes like the Lancaster would be the delivery system to enemy cities or military strongpoints. During a botched drop, it was quite possible for unlucky flyers to expose themselves to their own toxicant.