The first aerial circumnavigation of the world was completed in 1924 by four aviators from an eight-man team of the United States Army Air Service, the precursor of the United States Air Force. The 175-day journey covered over . The team generally traveled east to west, around the northern-Pacific Rim, through to South Asia and Europe and back to the United States. Airmen Lowell H. Smith and Leslie P. Arnold, and Erik H. Nelson and John Harding Jr. made the trip in two single-engined open-cockpit Douglas World Cruisers (DWC) configured as floatplanes for most of the journey. Four more flyers in two additional DWC began the journey but their aircraft crashed or were forced down. All airmen survived. In 1930, Australian Charles Kingsford Smith with a team of three others completed the first circumnavigation of the world by flight traversing both hemispheres, including the first trans-Pacific flight, from the US to Australia, in 1928. Kingsford Smith flew a Fokker F.VIIb/3m trimotor monoplane. U.S. preparation for circumnavigation attempt In the early 1920s several countries were vying to be the first to fly around the world. The British had made one unsuccessful around-the-world air flight attempt in 1922. The following year, a French team had tried; the Italians, Portuguese, and British also announced plans for a world-circling flight. In the spring of 1923, the U.S. Army Air Service became interested in having a squadron of military aircraft undertake a round-the-world flight. It assigned a group of officers in the War Department planning group, formed as the World Flight Committee, the job of finding a suitable aircraft and planning the mission. This high-level Army enterprise, under the ultimate command of General Patrick, would ultimately have the additional support of the Navy, Diplomatic Corps, Bureau of Fisheries and Coast Guard Services. The War Department instructed the Air Service to look at both the Fokker T-2 transport and the Davis-Douglas Cloudster to see if either would be suitable and to acquire examples for testing. Although deemed satisfactory, the planning group considered other U.S. Air Service military aircraft both in service and production, with a view that a dedicated design that could be fitted with interchangeable landing gear, wheeled and pontoons for water landings, would be preferable. When the head of Davis-Douglas, Donald Douglas, was asked for information on the Davis-Douglas Cloudster, he instead submitted data on a modified DT-2, a torpedo bomber that Douglas had