The essential target was RAF Fighter Command. The service's destruction would deny the British their air superiority asset. Throughout July and early August, the Germans made preparations for "Adlertag". The date of the assault was postponed several times because of bad weather. Eventually, it was carried out on 13 August 1940. The German attacks on 13 August inflicted significant damage and casualties on the ground, but, marred by poor intelligence and communication, they did not make a significant impression on Fighter Command's ability to defend British air space.