The Avro Lancaster was one of the most important weapons of WW II. This legendary bomber first saw action in 1942. Powered by 4 Merlin engines, it could deliver a huge payload and was the only aircraft to carry the Tallboy and Grand Slam earthquake bombs as well as the Upkeep 'bouncing' bomb on Operation Chastise-the famous Dam Busters raid. At the height of production, over 1.1 million men and women were employed making 'Lancs'; more service personnel were involved flying and maintaining them than any other British aircraft, ever. Mainly operational as a Night Bomber over Nazi Germany, the Lancaster was supremely adaptable and they were used on anti-submarine patrols, photo-reconnaissance missions, as aerial refuelling tankers and post-war, transatlantic passenger airliners. Lancaster's completed an average of 21 bombing missions before being lost and the average age of their 7 man crews was 22 years.