24 August 1921--During its fourth trial flight, the R-38 (ZR-2) rigid airship built for the Navy by the Royal Air Force, broke into two parts and fell into the Humber River at Hull, England. It carried to their deaths 28 British nationals and 16 Americans, including Air Commodore E. M. Maitland and Commander L. H. Maxfield, the latter the prospective American commanding officer.