On December 11, 1941, Germany and Italy, fulfilling obligations of the Axis treaty with Japan, declared war on the United States.
It turned out to be a fateful decision. The Americans quickly switched to war economy and became the primary supplier of war materiel for the British and Soviets already fighting the Nazi Germany and Italy and also soon joined the fight themselves. During the first half of the year, defeating Germany, although a priority on paper, had to be put on the back burner, as Japan had to be stopped in the Pacific. Only the victory at Midway allowed the Americans to sent their air force to Europe.
The preliminary scope of the American air force participation in the war with Germany was established on January 13, 1942 in Washington. The American air force along with the RAF was to take part in offensive operations against the German home territory. The mutual declaration regulating these matters was signed by President Roosevelt and Prime Minster Churchill. It served as the basis for the plan code named “Rainbow”, according to which four heavy bombardment groups and three fighter groups were to be stationed in Great Britain. Later, they were to be reinforced to a total of 21 bomber and 11 fighter groups.
The following plan, code named “Bolero”, regulated the entirety of issues related to preparation, redeployment and organization of the American military forces in Great Britain. On February 23, 1942, Headquarters VIII Bomber Command (VIII BC) of the USAAF 8th Air Force was established under Brig. Gen. Ira C. Eaker. Operational units were Heavy Bombardment Groups (BG) made of four Bombardment Squadrons (BS). In the initial period each squadron consisted of nine aircraft. For combat missions the bombardment group sent three squadrons on a rotation basis. First bomber units equipped with Boeing B-17 Flying Fortress aircraft reached England at the beginning of July 1942.
On May 5, 1942 Maj. Gen. Carl A. Spaatz assumed command of the newly formed USAAF 8th Air Force. The 8th Air Force Staff was relocated to Great Britain on June 18, 1942.
The fundamental objective of the American strategic bombardments was the destruction of the German air force, therefore, the main target were aircraft and aircraft engine factories. Shipyards and submarine naval bases were other priority targets, as their destruction would turn the scales in the battle of Atlantic in favour of the Allies. Following the annihilation of the Luftwaffe’s fighter force and Kriegsmarine’s submarines the bombing raids were to paralyze communications system and then power plants along with liquid fuel production facilities.
First American air force units became operational on August 15, 1942. These were 97. BG composed of 340., 342. and 414. bombardment squadrons, as well as, 31. FG equipped with British Spitfire VB fighters.
On August 17, 1942, twelve B-17 Flying Fortress of the 340. Bomber Squadron from the 97. Bomber Group, escorted by four RAF squadrons of the 11 Fighter Group, equipped with the most modern fighter of the time – the Spitfire IX, bombed the marshalling yard, engine house and repair workshop at Rouen-Sotteville. The American bomber formation was led by Col. Frank A. Armstrong Jr., Commander of the 97. BG. On board B-17E, 41-9023, leading the second section of six bombers, was the commander of VIII BC, Brig. Gen. Ira C. Eaker. After take off, the American machines formed up two flights made of six planes each. These were made of two V-formations made of three planes each, arranged in such a way, that the leading plane of the second formation was on a line coming through the leading plane and its right side wingman of the first formation. The Americans dropped 16,700 kg of bombs from 7,000 metres on the largest railway junction in the northern France. However, their aim was poor and only a single bomb scored a direct hit on the engine house destroying four train engines and while some were damaged. Despite the anti-aircraft fire American bombers managed to return to base safely. Fighter escort repulsed the attack of II./JG 26 aircraft loosing three Spitfires of the 401 and 402 Squadrons. Germans reported downing four enemy fighters, one for Lt. Caderbach, Ofw. Philipp, Lt. Sternberg and Uffz. Vogt. American gunners downed Fw 190 A-3, W.Nr. 5332, flown by Lt. Herbert Horn 3./JG 2. German pilot died in the wreckage of his aircraft. The first B-17 gunner of the USAAF 8th Air Force credited with downing Luftwaffe’s aircraft was Sgt. Ken Rest, ball turret gunner of the B-17E “Birmingham Blitzkrieg” of 414. BS.
Conclusions for the future operations were drawn from the results of the first bombardment. Too few planes were sent to destroy such a large target, insufficient training of the crews resulted in poor aim and formation was stretched, which reduced efficiency of defensive fire. Moreover, the escorting Spitfires were four minutes late for the randezvous with the bombers.