in England. They flew in a formation of 36, four-engined, B-17G Flying Fortress heavy bombers, belonging to the 349th, 350th, 351st and 418th Bomber Squadrons. The bomber group approached from the west and flew at great height over Germany and initially without fighter escort. However, the plan was that they would rendezvous with US P-51D Mustang fighters of the 55th and 339th Fighter Groups over the crest of the Ore Mountains. The US Mustangs had taken off from RAF Horham.