Curiously, the only transmission she seems to have received on radio was the telegraphed A on 7,500 kilocycles, but she did not receive that signal long enough to get the aural-null, a minimum of sound for a bearing.
If neither the line of position nor the bearing could come from the loop antenna or the radio, there were still the aids of celestial navigation.
For navigator Fred Noonan, veteran of eighteen previous Pacific air crossings, it should have been relatively easy to determine position, if his navigation instruments were operating correctly and if the weather were clear enough to take fixes from the stars or the sun.
Before dawn on July 3 he could have taken a fix from the stars. But an error in his chronometer of a mere four seconds would lead to a mistake of one mile in the longitude of his determined position. If the sextant were in error, however, the mistakes could have canceled out by the taking of three observations. Yet it would seem that Noonan could not shoot the stars, for as early as 2:45 A.M. AE reported the weather as “cloudy and overcast,” and at 3:45 A.M. as still “overcast.” If that bad weather continued until dawn, Fred Noonan could not use celestial navigation regardless of instruments.
Notwithstanding these difficulties, if he saw the sun after dawn, he could have shot a sun line. But if 157-337 were a sun line, it was worthless without a geographical point of reference, because the line could be drawn anywhere on the globe. No point of reference was given by AE in her last report.
Thus the question persisted: Where was she?
7. The Disappearance and the Search
Amelia Earhart and Fred Noonan and their plane were lost somewhere over a possible area of 450,000 square miles in the South Pacific. The United States Navy was determined to find them.
In Washington Chief of Naval Operations Admiral William D. Leahy acted quickly and ordered ships and planes to take up the search for the missing fliers. In addition to the Itasca, an aircraft carrier and its full complement of planes, a battleship, four destroyers, a minesweeper, and a seaplane were pressed into service. Together these ships and planes would search for sixteen days an area of more than 250,000 square miles.
Commander Thompson of the Itasca made some quick decisions after Amelia failed to arrive at Howland. If she had flown to the south, she should have seen Baker Island, just 38 miles south of Howland. The area to start looking for her, he concluded, was in the northwest quadrant indicated by the 337° of her last position report of 157-337.