291 B-17 Flying Fortresses The second Schweinfurt raid,[9] also called Black Thursday, was a World War II air battle that took place on 14 October 1943, over Nazi Germany between forces of the United States 8th Air Force and German Luftwaffe fighter arm (Jagdwaffe).

The American bombers conducted a strategic bombing raid on ball bearing factories to reduce production of these vital parts used in all manner of war machines.

American wartime intelligence claimed the first Schweinfurt–Regensburg mission in August had reduced bearing production by 34 percent but had cost many bombers.

Despite these changes, a series of minor mishaps combined with the ever-increasing efficiency of the German anti-aircraft effort proved to be devastating.

The bomber formations were left exposed to attacks by German fighters and the faulty preparations for the creation of reserves in the summer of 1943 meant that such costly operations could not be sustained.

[12] The Germans had built up enormous reserves of ball bearings and were receiving supplies from all over Europe, particularly Italy, Sweden and Switzerland.

[16] One fighter outfit was diverted to escort a squadron of 29 B-24s that switched to a spoof mission to Emden because of the bad weather forecast.

The Luftwaffe military intelligence officers had suspected a deep penetration air raid because of the substantial amount of bombers.

[23]: 191  Despite General Henry H. Arnold's claim that the Black Thursday "loss of 60 [downed/ditched] American bombers in the Schweinfurt raid was incidental", unescorted daylight bomber raids deep into Germany were suspended until the February 1944 Big Week missions with P-51B Mustang escorts that included additional Schweinfurt day/night USAAF/RAF bombing on 24 February.

[21]: 67 Another example of the strategy of using heavy bombers against a particular wartime resource, the Oil Campaign of World War II was essentially started by RAF Bomber Command in August 1941 – two months after Hitler's invasion of the Soviet Union, and six months before the United States entered the war.