On July 2, 1937 at 0000 GMT, Earhart and Noonan took off from Lae. Their intended destination was Howland Island, a tiny piece of land a few miles long, 20 feet high, and 2, 556 miles away. Their last positive position report and sighting were over the Nukumanu Islands, about 800 miles into the flight. The U.S. Coast Guard cutter USCGC Itasca was on station near Howland, assigned on short notice to communicate with Earhart's plane and guide her to the island once she arrived in the vicinity.
But it soon became evident that Earhart and Noonan had little practical knowledge of the use of radio navigation. The frequencies Earhart was using were not well suited to direction finding (in fact, she had left behind the lower-frequency reception and transmission equipment which might have enabled Itasca to locate her), and the reception quality of her transmissions was poor. After six hours of frustrating attempts at two-way communications, contact was lost.
A coordinated search by the Navy and Coast Guard was organized and no physical evidence of the flyers or their plane was ever found. Earhart and Noonan's fate has been the subject of many rumors and allegations which were never substantiated. Modern analysis indicates that after passing the Nukumanu Islands, Earhart began to vector off course, unwittingly heading for a point about 100 miles NNW of Howland. A few hours before their estimated arrival time Noonan calculated a "sun line," but without a successful, radio-frequency range calculation, a precise "fix" on the plane's location could not be established. Researchers generally believe that the plane ran out of fuel and that Earhart and Noonan perished at sea.