Claim: The Augsburg raid, also known as Operation Margin, was the Lancaster's first major test.
Evidence: The Augsburg Raid, also referred to as Operation Margin, was a bombing raid made by the RAF on the MAN U-boat engine plant in Augsburg undertaken during the daylight hours of 17 April 1942. 44 Squadron had been working with the Lancaster prototype since its arrival there in September, and had laid sea mines with the aircraft in March to gain some operational experience, but the Lancaster was still unknown to the Germans. This would be the aircraft's first major test.