On 16 July 1945, at Kirtland Field, two B-29 Superfortress observation planes had set out early in the morning with instructions from Oppenheimer to steer a course at least 15 miles west of the atomic detonation point, Trinity Site. Because of thunderstorms, the planes dropped from 23,000 to 18,000 feet before circling the Trinity Site during the first atomic bomb detonation. While "The Gadget" underwent field-testing at Trinity, the nuclear components for the bombs and the active materials were being sent piecemeal to Tinian. Shortly before the bomb testing at the Trinity site, components of Little Boy were driven from Los Alamos to Kirtland Field and then flown to San Francisco. This included some of the U-235. From San Francisco, they were transported to Hunters Point to board the cruiser , bound for Tinian. Following that, the Fat Man plutonium core and its initiator were driven down to Albuquerque. They left Kirtland Field on 26 July and were flown in a C-54 Skymaster to Tinian, where they arrived 28 July. Such was Kirtland Field's last important role in the U.S. defeat of Japan, thereby ending World War II.