4,000 were killed, 10,000 injured and 450,000 made homeless. The 16 raids on Berlin cost Bomber Command more than 500 aircraft, with their crews killed or captured. This was a loss rate of 5.8%, which was above the 5% threshold that was considered the maximum sustainable operational loss rate by the RAF. In December 1943, for example, 11 crews from No. 460 Squadron RAAF alone were lost in operations against Berlin; and in January and February, another 14 crews were killed. Having 25 aircraft destroyed meant that the fighting force of the squadron had to be replaced in three months. At these rates Bomber Command would have been wiped out before Berlin." It has been largely acknowledged that the Battle of Berlin was a failure; for the RAF, British official historians have stated that "in an operational sense the Battle of Berlin was more than a failure, it was a defeat". March 1944 to April 1945 In 1943, the U.S. Army and the Standard Oil company built a set of replicas in western Utah, of typical German working class housing estates, "German Village", which would be of key importance in acquiring the know-how and experience necessary to carry out the firebombings on Berlin. It was done with the assistance of Erich Mendelsohn, a Jewish architect of structures in Berlin who fled the Nazis in 1933. The Big Week (Sunday, 20–Friday, 25 February 1944) heavy bomber offensive began shortly after the Eighth Air Force commander, Maj. Gen. Jimmy Doolittle, had implemented a major change in fighter defense of USAAF strategic bomber formations that had bolstered the confidence of U.S. strategic bombing crews. Until that time, Allied bombers avoided contact with the Luftwaffe; now, the Americans used any method that would force the Luftwaffe into combat. Implementing this policy, the United States looked toward Berlin. Raiding the German capital, the USAAF reasoned, would force the Luftwaffe into battle. Consequently, on 4 March, the USSTAF launched the first of several attacks against Berlin. Fierce battles raged and resulted in heavy losses for both sides; 69 B-17s were lost on 6 March but the Luftwaffe lost 160 aircraft. The Allies replaced their losses; the Luftwaffe could not. At the tail end of the Battle of Berlin the RAF made one last large raid on the city on the night of 24–25 March, losing 8.9% of the attacking force, but due to the failure of