 The 493d BG used B-24's until they were replaced with B-17's in September 1944.The group operated chiefly against industrial and military installations in Germany, attacking an ordnance depot at Magdeburg, marshalling yards at Cologne, synthetic oil plants at Merseburg, a railroad tunnel at Ahrweiler, bridges at Irlich, factories at Frankfurt, and other strategic objectives.On 25 September, a bombardment of Strasbourg left a number of buildings destroyed in the historical city centre.