 Complete the following phrase:  On June 11, 1934 he assumed command at NAS Lakehurst, and was promoted to commander on 1 February 1935. Rosendahl served as an official observer on the German airship , on transatlantic flights between Frankfurt and Rio de Janeiro in AugustSeptember 1936. He was in command at Lakehurst on the night of May 6, 1937 and witnessed the 