Their view was reported to Berlin. Sperrle was assisted by the Oberkommando der Luftwaffe (OKL—High Command of the Air Force). Staff officers were trained to solve operational level problems and the OKL's reluctance to micromanage gave Sperrle and Richthofen a free hand to devise solutions to tactical and operational problems. An important step was the development of ground-air communication, via the use of frontline signals posts which were in contact with army and airbases simultaneously. Information telephoned to airbases was relayed rapidly by radio to aircraft in flight. This innovation was put into practice during the conflict. Sperrle left Germany by air on 31 October 1936 and arrived in Seville, via Rome on 5 November. Sperrle was sent a Kampfgruppe (bomber group—K/88), Jagdgruppe 88 (fighter group 88—J/88) and Aufklärungsstaffel (reconnaissance squadron—AS/88). They were supported by a Flak Abteilung (F/88) with three heavy and two light batteries with communications, transport and maintenance units. The Germans could not afford to fully equip the Legion, and so the air group made use of Spanish equipment. Of the 1,500 vehicles used, there were 100 types creating a maintenance nightmare. The first mission for the Legion was to airlift 20,000 men of the African Army. These veterans, once landed, provided a core of battle–hardened veterans. Spanish Civil War Sperrle began the war with 120 aircraft, and for the first four months the German aviators failed to make an impact. Sperrle lost 20 percent of his strength in the failed attempt to seize Madrid in 1936. The material support provided was inadequate and left him with just 26 Ju 52s and two Heinkel He 70 aircraft by the end of January 1937. Sperrle's personal leadership and the dedication of senior officers prevented a collapse in morale. The cause of this defeat was the appearance of Soviet-designed and built Polikarpov I-15 and Polikarpov I-16 fighter aircraft in the Spanish Republican Air Force which won air superiority. Bombing raids against Cartagena and Alicante, and the Soviet air base at Alcalá de Henares, failed. Sperrle personally led an attack against the Republican Navy at Cartagena, sinking two ships. The Republican fleet was forewarned, however, and the majority put to sea and escaped the bombing. Attacks against Madrid, in which 40 tons of bombs were dropped from 19 November 1936, also failed. The bombing and shelling inflicted 1,119 casualties between 14 and 23 November, including 244 dead—303 buildings were hit.